Operations

Figure 3-1 shows how traditional DTE-to-DCE relationships map to a Cisco network access server (NAS). Data terminal equipment (DTE) uses data communication equipment (DCE) to send data over the PSTN.

In the context of EIA/TIA-232 and Cisco IOS software:

The DTE is the client PC and the Cisco IOS TTY lines.
The DCE is the client modem and the modem inside the NAS.
The dashed line between the DCEs is the modem carrier running on top of the voiceband circuit through the PSTN. EIA/TIA-232 (whether physical or logical) is used on the DTE lines, not on the DCE link.
The PSTN circuit runs through the circuit-switched half of the NAS.

Figure 3-1: A Standard Dial-Up Connection

Logical Packet and Circuit Components of a NAS

The NAS functions as a gateway between two different networks:

A circuit-switched network (for example, the PSTN)
A packet-switched network (for example, the Internet)

The NAS is half a circuit switch and half a packet switch (router). EIA/TIA-232 signaling on the line is displayed by the show line command and debug modem command. Figure 3-2 shows the modem access connectivity path.

Figure 3-2: Modem Access Connectivity Path

To understand the general call-processing sequence, match the following numbered list with the numbers shown in Figure 3-2:

1. 64K DS0 circuits extend from the NAS modems, through the internal TDM CSM bus, and through the circuit network (PSTN).

2. The NAS modems demodulate digital streams into analog-voiceband modulation. The virtual EIA/TIA-232 interface connects the modems (DCE) to the TTY lines.

3. The TTY lines are mapped into asynchronous interfaces. Interfaces are Cisco IOS software objects that move packets. TTY lines function at Layer 1. Interfaces function at Layer 2 and Layer 3.

4. The packets are delivered into the IP network.

EIA/TIA-232 in Cisco IOS

The Cisco IOS software variation of asynchronous EIA/TIA-232 is shown in Figure 3-3. The variation exists between the Cisco IOS line (DTE) and the NAS modem (DCE).

Six EIA/TIA-232 pins exist between each NAS modem and Cisco IOS line. One or more grounding wires also exist on physical EIA/TIA-232 lines; however, these wires do not convey signaling.
Each pin controls a different EIA/TIA-232 signal.
The arrows in Figure 3-3 indicate the signal transmission direction.

Figure 3-3: Cisco IOS EIA/TIA-232

Tips In Figure 3-3, notice that the DSR signal is the DCD signal for the modem. In the scheme of Cisco IOS software, the DCD pin on the DCE is strapped to the DSR pin on the Cisco IOS DTE side. What the Cisco IOS software calls DSR is not DSR; it is DCD. The DCE's actual DSR pin and ring ignore (RI) pin are ignored by the Cisco IOS software.

Table 3-1 describes how Cisco uses it's EIA/TIA-232 pins. The signal direction in the table is from the perspective of the DTE (IOS line):

Data signals (TxD, RxD)
Hardware flow control signals (RTS, CTS)
Modem signals (DTR, DSR, DCD, RI)

Table 3-1: EIA/TIA-232 Signal State Behavior

Signal Signal Direction Purpose

Transmit Data (TxD)

——>
(Output)

DTE transmits data to DCE.

Receive Data (RxD)

<——
(Input)

DCE transmits received data to DTE.

Request To Send (RTS)

——>
(Output)

DTE uses the RTS output signal to indicate if it can receive characters into the Rx input buffer¹.

The DCE should not send data to the DTE when DTR input is low (no RTS).

Clear To Send (CTS)

<——
(Input)

DCE signals to DTE that it can continue to accept data into its buffers.

DCE asserts CTS only if the DCE is able to accept data.

Data Terminal Ready (DTR)

——>
(Output)

DTE signals to DCE that it can continue to accept data into its buffers.

DTE asserts RTS only if the DTE is able to accept data.

Data Carrier Detect (DCD)

<——
(Input)

DCE indicates to DTE that a call is established with a remote modem. Dropping DCD terminates the session.

DCD will be up on the DCE only if the DCE has achieved data mode with its peer DCE (client modem).

¹The name RTS is illogical with the function (able to receive) due to historical reasons.

Signal	Signal Direction	Purpose
Transmit Data (TxD)	——> (Output)	DTE transmits data to DCE.
Receive Data (RxD)	<—— (Input)	DCE transmits received data to DTE.
Request To Send (RTS)	——> (Output)	DTE uses the RTS output signal to indicate if it can receive characters into the Rx input buffer¹. The DCE should not send data to the DTE when DTR input is low (no RTS).
Clear To Send (CTS)	<—— (Input)	DCE signals to DTE that it can continue to accept data into its buffers. DCE asserts CTS only if the DCE is able to accept data.
Data Terminal Ready (DTR)	——> (Output)	DTE signals to DCE that it can continue to accept data into its buffers. DTE asserts RTS only if the DTE is able to accept data.
Data Carrier Detect (DCD)	<—— (Input)	DCE indicates to DTE that a call is established with a remote modem. Dropping DCD terminates the session. DCD will be up on the DCE only if the DCE has achieved data mode with its peer DCE (client modem).

Cisco IOS Line-Side Inspection

To display the current modem-hardware states applied to a specific Cisco IOS line, enter the show line tty number command. The states of each logical EIA/TIA-232 pin change according to line conditions and modem events.

The following shows a line-side inspection of the idle state for TTY line 1:

5800-NAS#show line tty 1

   Tty Typ     Tx/Rx    A Modem  Roty AccO AccI   Uses   Noise  Overruns   Int
I    1 TTY              - inout     -    -    -      2       0     0/0       -
 
Line 1, Location:"", Type:""
Length:24 lines, Width:80 columns
Status:No Exit Banner
Capabilities:Hardware Flowcontrol In, Hardware Flowcontrol Out

  Modem Callout, Modem RI is CD, Line usable as async interface
  Integrated Modem
Modem state:Idle

  modem(slot/port)=1/0, state=IDLE
  dsx1(slot/unit/channel)=NONE, status=VDEV_STATUS_UNLOCKED
Modem hardware state:CTS noDSR  DTR RTS

Special Chars:Escape  Hold  Stop  Start  Disconnect  Activation
                ^^x    none   -     -       none         
Timeouts:     Idle EXEC    Idle Session   Modem Answer  Session   Dispatch
               00:10:00        never                        none     not set
                            Idle Session Disconnect Warning
                              never 
                            Login-sequence User Response
                             00:00:30
                            Autoselect Initial Wait
                              not set 
Modem type is unknown.
Session limit is not set.
Time since activation:never
Editing is enabled.
History is enabled, history size is 10.
DNS resolution in show commands is enabled
Full user help is disabled
Allowed transports are pad telnet rlogin v120 lapb-ta.  Preferred is telnet.
No output characters are padded
No special data dispatching characters

Table 3-2 describes some of the significant fields shown in the previous example:

Table 3-2: Show TTY Line Field Descriptions

Field Description

Capabilities
Describes different aspects of the line:

The flowcontrol hardware command displays as "Hardware Flowcontrol In, Hardware Flowcontrol Out."

The modem inout command displays as "modem callout."

The text "Line usable as async interface" means there is an "interface async N" that corresponds to "line N."

The text "Modem RI is CD" displays for historical reasons.

Modem state
Displays the current status of the modem.

Possible values include:

Idle—Modem is ready for incoming and outgoing calls.

Conn—Modem is connected to a remote host.

Busy—Modem is out of service and not available for calls.

D/L—Modem is downloading firmware.

Bad—Modem is in an inoperable state, which is manually configured by the modem bad command.

Bad*—During initial power-up testing, the modem startup-test command automatically put the modem in an inoperable state.

Reset—Modem is in reset mode.

Bad FW—The downloaded modem firmware is not usable.

Modem Hardware state
Displays the EIA/TIA-232 signal state status.

CTS and no DSR are incoming signals. DTR and RTS are outgoing signals. NoDSR means that no call is currently connected.

Field	Description
`Capabilities`	Describes different aspects of the line: The flowcontrol hardware command displays as "Hardware Flowcontrol In, Hardware Flowcontrol Out." The modem inout command displays as "modem callout." The text "Line usable as async interface" means there is an "interface async N" that corresponds to "line N." The text "Modem RI is CD" displays for historical reasons.
`Modem state`	Displays the current status of the modem. Possible values include: `Idle`—Modem is ready for incoming and outgoing calls. `Conn`—Modem is connected to a remote host. `Busy`—Modem is out of service and not available for calls. `D/L`—Modem is downloading firmware. `Bad`—Modem is in an inoperable state, which is manually configured by the modem bad command. `Bad`—During initial power-up testing, the modem startup-test* command automatically put the modem in an inoperable state. `Reset`—Modem is in reset mode. `Bad FW`—The downloaded modem firmware is not usable.
`Modem Hardware state`	Displays the EIA/TIA-232 signal state status. CTS and no DSR are incoming signals. DTR and RTS are outgoing signals. NoDSR means that no call is currently connected.

Understanding Modem Modulation Standards

To optimize modem connect speeds, you must understand the basic modem modulation standards. This section provides the basic rules for achieving maximum V.34 and V.90 modulation speeds:

V.34 Basic Rules

V.34 modulation should work on any land-line voiceband circuit. V.34 supports speeds ranging from 2400 to 33600 bps.

Speed is a function of:

The amount of usable spectrum across the channel (for example, 2400 to 3429 Hz)
The signal to noise ratio (SNR)

To achieve 33600 bps, the channel must deliver:

A response from 244 to 3674 Hz
A SNR of 38 dB or better

In practice, toll-quality voiceband circuits support V.34 at speeds of 21600 to 33600 bps.

The following six items reduce the achieved V.34 speed:

1. Robbed-bit signaling links in the circuit, which reduce SNR.

2. Extra analog-to-digital conversions. For example, non-integrated or universal Subscriber Line Concentrators (SLCs) reduce bandwidth and SNR.

3. Load coils on the local loop, which reduce bandwidth.

4. Long local loops, which reduce bandwidth and SNR.

5. The following electrical disturbances in the house wiring, which reduce SNR:

Cross talk from two lines in the same quad cable
Corroded connectors
Bridge-tapped lines running parallel to fluorescent lights
Flat silver-satin cables running parallel to power cables
Extra electrical equipment sharing the same power jack as the modem

6. Voiceband circuits that pass through sub-64k coding, such as a cellular or 32K ADPCM link. With 32k ADMCM, the speed is typically 9600 to 16800 bps.

V.90 Basic Rules

Many circuit components work together to deliver V.90 modulation. See Figure 3-4.

Figure 3-4: V.90 Network Components

Here are the V.90 basic rules:

Select recommended modem code. The following are reliable V.90 releases at the time of this publication:
- MICA Portware Version 2.6.2.0
- Microcom Firmware Version 5.2.1.0

: The latest modem code is posted on CCO at the following URL:
: http://www.cisco.com/kobayashi/sw-center/sw-access.shtml

Run a Cisco IOS release that is compatible with V.90. Table 3-3 shows the V.90 supported Cisco IOS releases at the time of this publication.

Table 3-3: V.90 Supported Cisco IOS Releases

Chassis Modem Type Cisco IOS Release

Cisco AS5800

MICA

11.3(6+)AA

12.0(1+)T

Chassis	Modem Type	Cisco IOS Release
Cisco AS5800	MICA	11.3(6+)AA 12.0(1+)T

Exactly one digital to analog conversion must exist in the circuit. The digital line must connect into a digital switch, not a channel bank. V.90 requires PRI (64k clear-channel DS0s). Channel banks destroy V.90 by adding additional analog-to-digital conversions. Telcos occasionally refer to channel banks as line-side services. Digital switches are sometimes referred to as trunk-side services. Figure 3-5 shows this.

Figure 3-5: No Channel Banks for V.90

In the local loop, less than three miles of twisted-pair copper line with no load coils is ideal. Load coils limit frequencies (passband). V.90 requires a 3000 Hz passband. A circuit that does not deliver a 3200 Hz passband will most likely not deliver V.90. Load coils are common in long loops in North America (at the 3.5 mile mark).

Sometimes the PSTN switch fabric is extended by a digital carrier. It is then converted to analog by a SLC. This setup complies with V.90. The digital-to-analog conversion is moved closer to the subscriber. However, non-integrated or universal SLCs do not comply to V.90.

Use a recommended V.90 client modem.

Electrical house wiring sometimes causes V.90 trainup to fail. For details, see the section "V.34 Basic Rules" section.

Task 1. Initiating a Modem Loopback Test Call

Test the access server's ability to initiate and terminate a modem call. Similar to sending a ping to the next-hop router, this test verifies basic connectivity for modem operations. Successfully performing this test gives you a strong indication that remote clients should be able to dial into the NAS. Figure 3-6 shows this test.

After completing this test, dial into the EXEC from a client PC and a client modem (no PPP).

Figure 3-6: Initiating and Terminating a Modem Call on the Same NAS

Note When calling between two digital modems, you will not achieve V.90. V.90 requires one digital and one analog modem.

Step 1 From a workstation, open two Telnet sessions into the NAS. One Telnet session is used to simulate the client. The other session is used to administer and run the debugs. In this way, the debug messages will not be scrambled into the loopback screen display.

Step 2 Configure the lines to support dial in, dial out, and outbound Telnet connections:

!
line 1/2/00 1/3/143

 modem inout

 transport input telnet

!

Step 3 From the administrative Telnet session, turn on the appropriate debug commands. Older software might require the debug modem csm command.

5800-NAS#debug isdn q931

ISDN Q931 packets debugging is on
5800-NAS#debug csm modem

Modem Management Call Switching Module debugging is on
5800-NAS#debug modem

Modem control/process activation debugging is on
5800-NAS#show debug

General OS:
  Modem control/process activation debugging is on
CSM Modem:
  Modem Management Call Switching Module debugging is on
ISDN:
  ISDN Q931 packets debugging is on
  ISDN Q931 packets debug DSLs. (On/Off/No DSL:1/0/-)
  DSL  0 --> 31
  1 - - - - - - -  - - - - - - - -  - - - - - - - -  - - - - - - - -
  DSL 32 --> 55
  - - - - - - - -  - - - - - - - -  - - - - - - - -
Modem Management:
  Modem Management Call Switching Module debugging is on
 
5800-NAS#

Tips For channel associated signaling (CAS), robbed bit signaling (RBS), and R2, use the debug cas command. If this command is not included in your software, use the modem-mgmt csm debug-rbs command; however, the service internal command is required.

5800-NAS(config)#service internal

5800-NAS(config)#end

5800-NAS#modem-mgmt csm debug-rbs

At the time of this publication, the Cisco AS5800 does not support the debug cas command or modem-mgmt csm debug-rbs command. As a workaround, complete the following steps:

a. Determine the slot positions of each card. Enter the show dial-shelf command.

b. Access the trunk card's console port. Enter the dsip console slave X command where X is the slot of the card that you want to perform debugging on.

c. Enter the command debug trunk cas port port-number timeslots range.

Step 4 Ensure that your EXEC session receives logging and debug output from the NAS:

5800-NAS#logging console

Step 5 From the client Telnet session, Telnet into one of the idle modems (not in use). To do this, Telnet to an IP address on the NAS (Ethernet or Loopback) followed by 2000 plus a TTY line number. This example Telnets to TTY line 1 (2001).

5800-NAS#telnet 172.22.66.23 2001

Trying 172.22.66.23, 2001 ... Open

Note This step is also known as a reverse Telnet.

For a Cisco AS5800, create an arbitrary IP host followed by a reverse Telnet. Use the show modem shelf/slot/port command to determine which modem is associated with which TTY line. The following example Telnets to TTY 500, which maps to modem 1/2/68.

5800-NAS#show modem 1/2/68

     Mdm  Typ     Status     Tx/Rx     G  Duration  RTS   CTS   DCD   DTR
     ---  ---     ------     -----     -  --------  ---   ---   ---   ---
   1/2/68 V.90    Idle    37333/31200  1  00:01:05  RTS   CTS   noDCD DTR
 
Modem 1/2/68, Cisco MICA modem (Managed), Async1/2/68, TTY500

Firmware Rev: 2.6.2.0
 
5800-NAS(config)#ip host mod500 2500 172.22.66.23

5800-NAS(config)#^Z

5800-NAS#telnet mod500

Trying mod500 (172.22.66.23, 2500)... Open

Step 6 Log in from the client Telnet session. The Cisco IOS software sends out a username-password prompt.

This is a secured device. 

Unauthorized use is prohibited by law.

 
 
User Access Verification
 
Username:admin

Password:
 
Sep 23 05:04:58.047: TTY0: pause timer type 1 (OK)
Sep 23 05:04:58.051: TTY1: asserting DTR
Sep 23 05:04:58.051: TTY1: set timer type 10, 30 seconds
Sep 23 05:05:03.583: TTY1: set timer type 10, 30 seconds

Step 7 Enter the at command to test connectivity to the NAS modem. The modem reports an "OK" return message.

at

OK

Step 8 Dial the PRI phone number assigned to the NAS (in this example, 5551234). A connect string appears when the modem connects.

atdt5551234

CONNECT 33600 /V.42/V.42bis

In this example:

Modulation connect speed = 33600 bps. Expect to get a maximum of 33600 bps if you use a PRI line. If you use RBS, expect to get a maximum of 31200 bps.
Error correction = V.42
Data compression = V.42bis

Step 9 From the administrative Telnet session, inspect the debug output:

000434: *May  2 23:01:39.507 UTC: ISDN Se1/0/0:23: RX <-  SETUP pd = 8  callrefB
000435: *May  2 23:01:39.507 UTC:         Bearer Capability i = 0x9090A2
000436: *May  2 23:01:39.507 UTC:         Channel ID i = 0xA98381
000437: *May  2 23:01:39.507 UTC:         Progress Ind i = 0x8083 - Origination 
000438: *May  2 23:01:39.507 UTC:         Calling Party Number i = 0x2183, '408'
000439: *May  2 23:01:39.507 UTC:         Called Party Number i = 0xC1, '324193'
000440: *May  2 23:01:39.511 UTC: allocate slot 2 and port 12 is allocated
 
000441: *May  2 23:01:39.511 UTC: ISDN Se1/0/0:23: TX ->  CALL_PROC pd = 8  calB
000442: *May  2 23:01:39.511 UTC:         Channel ID i = 0xA98381
000443: *May  2 23:01:39.511 UTC: CSM v(2/12) c(T1 1/0/0:0): CSM_EVENT_FROM_ISD.
000444: *May  2 23:01:39.511 UTC: CSM v(2/12) c(T1 1/0/0:0): CSM_PROC_IDLE:  ev.
000445: *May  2 23:01:39.511 UTC: ISDN Se1/0/0:23: TX ->  ALERTING pd = 8  callB
000446: *May  2 23:01:39.539 UTC: CSM v(2/12) c(T1 1/0/0:0): CSM_PROC_IC2_RING:.
000447: *May  2 23:01:39.539 UTC: ISDN Se1/0/0:23: TX ->  CONNECT pd = 8  callrB
000448: *May  2 23:01:39.563 UTC: ISDN Se1/0/0:23: RX <-  CONNECT_ACK pd = 8  cB
000449: *May  2 23:01:39.563 UTC: ISDN Se1/0/0:23: CALL_PROGRESS: CALL_CONNECTE0
000450: *May  2 23:01:39.563 UTC: CSM v(2/12) c(T1 1/0/0:0): CSM_EVENT_FROM_ISD.
000451: *May  2 23:01:39.563 UTC: CSM v(2/12) c(T1 1/0/0:0): CSM_PROC_IC6_WAIT_.
000452: *May  2 23:01:57.778 UTC: TTY1/2/12: DSR came up
000453: *May  2 23:01:57.778 UTC: tty1/2/12: Modem: IDLE->(unknown)
000454: *May  2 23:01:57.778 UTC: TTY1/2/12: EXEC creation
000455: *May  2 23:01:57.778 UTC: TTY1/2/12: create timer type 1, 600 seconds
000456: *May  2 23:02:05.462 UTC: TTY1/2/12: set timer type 10, 30 seconds

Note You must have the logging console feature turned on to view this output on the screen.

The bearer capability 0x8090A2 indicates an analog voice call. Alternative bearer services include 64K data calls, which are indicated by 0x8890. The calling party number is 408 (also known as ANI). The called party number is 5551234 (also known as DNIS). The debug q931 command shows the call coming into the NAS over ISDN.

*Jan  1 00:34:47.867:VDEV_ALLOCATE:1/2 is allocated from pool System-def-Mpool
*Jan  1 00:34:47.867:csm_get_vdev_for_isdn_call:fax_call=0
*Jan  1 00:34:47.867:EVENT_FROM_ISDN:(001A):DEV_INCALL at slot 1 and port 2
*Jan  1 00:34:47.867:CSM_PROC_IDLE:CSM_EVENT_ISDN_CALL at slot 1, port 2
*Jan  1 00:34:47.867:Mica Modem(1/2):Configure(0x1 = 0x0) 

*Jan  1 00:34:47.867:Mica Modem(1/2):Configure(0x23 = 0x0) 
*Jan  1 00:34:47.867:Mica Modem(1/2):Call Setup
*Jan  1 00:34:47.867: Enter csm_connect_pri_vdev function
*Jan  1 00:34:47.867:csm_connect_pri_vdev:tdm_allocate_bp_ts() call.

BP TS allocated at bp_stream0, bp_Ch5,vdev_common 0x610378B0
*Jan  1 00:34:47.883:ISDN Se0:23:RX <-  ALERTING pd = 8  callref = 0x8004
*Jan  1 00:34:47.883:        Progress Ind i = 0x8288 - In-band info or appropriate now 
available 
*Jan  1 00:34:48.019:Mica Modem(1/2):State Transition to Call Setup
*Jan  1 00:34:48.019:Mica Modem(1/2):Went offhook

*Jan  1 00:34:48.019:CSM_PROC_IC2_RING:CSM_EVENT_MODEM_OFFHOOK at slot 1, port 2
*Jan  1 00:34:48.019:ISDN Se0:23:TX ->  CONNECT pd = 8  callref = 0x8053
*Jan  1 00:34:48.047:ISDN Se0:23:RX <-  CONNECT_ACK pd = 8  callref = 0x0053
*Jan  1 00:34:48.047:EVENT_FROM_ISDN::dchan_idb=0x6149A144, call_id=0x1A,

ces=0x1 bchan=0x0, event=0x4, cause=0x0
*Jan  1 00:34:48.047:EVENT_FROM_ISDN:(001A):DEV_CONNECTED at slot 1 and port 2
*Jan  1 00:34:48.047:CSM_PROC_IC4_WAIT_FOR_CARRIER:CSM_EVENT_ISDN_CONNECTED at slot 1, 
port 2
*Jan  1 00:34:48.047:Mica Modem(1/2):Link Initiate
*Jan  1 00:34:48.047:ISDN Se0:23:RX <-  CONNECT pd = 8  callref = 0x8004
*Jan  1 00:34:48.047:EVENT_FROM_ISDN::dchan_idb=0x6149A144, call_id=0x8005, ces=0x1 
bchan=0x16, event=0x4, cause=0x0
*Jan  1 00:34:48.047:EVENT_FROM_ISDN:(8005):DEV_CONNECTED at slot 1 and port 0
*Jan  1 00:34:48.047:CSM_PROC_OC5_WAIT_FOR_CARRIER:CSM_EVENT_ISDN_CONNECTED at slot 1, 
port 0
*Jan  1 00:34:48.051:ISDN Se0:23:TX ->  CONNECT_ACK pd = 8  callref = 0x0004

MICA modem 1/2 goes offhook and receives the call. The debug modem csm command shows the call getting switched over to a modem.

*Jan  1 00:34:49.159:Mica Modem(1/2):State Transition to Connect

*Jan  1 00:34:53.903:Mica Modem(1/2):State Transition to Link

*Jan  1 00:35:02.851:Mica Modem(1/2):State Transition to Trainup

*Jan  1 00:35:04.531:Mica Modem(1/2):State Transition to EC Negotiating

*Jan  1 00:35:04.711:Mica Modem(1/2):State Transition to Steady State

*Jan  1 00:35:04.755:TTY3:DSR came up

*Jan  1 00:35:04.755:tty3:Modem:IDLE->(unknown)

Inspect the different modem trainup phases. The modem goes from Connect to Steady State in 15 seconds. The debug modem csm command displays the trainup phases. The debug modem command displays the logical EIA/TIA-232 transition message "DSR came up."

*Jan  1 00:35:04.759:TTY3:EXEC creation
*Jan  1 00:35:04.759:TTY3:set timer type 10, 30 seconds

*Jan  1 00:35:08.915:TTY3:Autoselect(2) sample 61 <------------------- a

*Jan  1 00:35:09.187:TTY3:Autoselect(2) sample 6164 <----------------- d

*Jan  1 00:35:09.459:TTY3:Autoselect(2) sample 61646D <--------------- m

*Jan  1 00:35:09.459:TTY3:Autoselect(2) sample 61646D69 <------------- i

*Jan  1 00:35:09.715:TTY3:Autoselect(2) sample 646D696E <------------- n

*Jan  1 00:35:09.715:TTY3:Autoselect(2) sample 6D696E0D <------------- <cr>

Decode the incoming character-byte stream for an EXEC shell login (no PPP). In this example, match the username "admin" to the character stream: 616D696E0D = admin carriage return.

The Cisco IOS samples four packets at a time. It searches for a header that matches one of your autoselect styles. The debug modem command generates the autoselect debug output.

*Jan  1 00:35:09.715:TTY3:set timer type 10, 30 seconds

*Jan  1 00:35:11.331:TTY3:Autoselect(2) sample [suppressed--line is not echoing]
*Jan  1 00:35:11.667:TTY3:Autoselect(2) sample [suppressed--line is not echoing]
*Jan  1 00:35:11.987:TTY3:Autoselect(2) sample [suppressed--line is not echoing]
*Jan  1 00:35:11.987:TTY3:Autoselect(2) sample [suppressed--line is not echoing]
*Jan  1 00:35:11.987:TTY3:Autoselect(2) sample [suppressed--line is not echoing]
*Jan  1 00:35:12.339:TTY3:Autoselect(2) sample [suppressed--line is not echoing]
*Jan  1 00:35:12.391:TTY3:create timer type 1, 600 seconds
5800-NAS>

Type 10 is the login timer. The timeout is 30 seconds. The user's EXEC-shell login password is suppressed.

Step 10 Identify who is logged in. TTY line 3 corresponds to modem 1/2. Use the show terminal command to see which modem is assigned to the TTY line.

5800-NAS>show user

    Line     User      Host(s)                  Idle Location
   3 tty 3   admin     idle                     0 
* 98 vty 0   joe       172.22.66.1              0 leftfield.corporate.com
 
  Interface  User      Mode                     Idle Peer Address

d. Program the terminal window not to pause in the middle of a screen display. To adjust the display output on a Cisco AS5800, enter the terminal length 0 command instead.

5800-NAS>terminal length 0

Step 11 Generate traffic across the modem link. Force the answering modem (in the NAS) to send a data stream to the client modem. The data stream generated by the show modem log command is about 1 MB. The data should scroll freely for one or two minutes.

5800-NAS>show modem log

doc-rtr58-01#sh modem log
Modem 1/2/00 Events Log:
  3w2d    :Startup event:MICA Hex modem (Managed)
           Modem firmware = 0.7.3.7
  2w2d    :Modem State event:
           State:Terminate
  2w2d    :Modem State event:
           State:Idle
Modem 1/2/01 Events Log:
  3w2d    :Startup event:MICA Hex modem (Managed)
           Modem firmware = 0.7.3.7
  2w2d    :Modem State event:
           State:Terminate
  2w2d    :Modem State event:
           State:Idle
Modem 1/2/02 Events Log:
  3w2d    :Startup event:MICA Hex modem (Managed)
           Modem firmware = 0.7.3.7
  2w2d    :Modem State event:
           State:Terminate
  2w2d    :Modem State event:
           State:Idle

Step 12 Look at the modem's operational statistics and verify that you have acceptable speed, line shape, and throughput. In this example, modem 1/2 accepts the call.

If you do not have a scroll bar in your Telnet application, limit terminal length to 24 lines to see all the command output.

If you are using Microcom modems, enter the modem at-mode slot/port command followed by the at@e1 command.

5800-NAS>show modem operational-status 1/2/00

Modem(1/2/00) Operational-Status:
 
 Parameter #0  Disconnect Reason Info: (0x0)
       Type (=0 ): <unknown>
      Class (=0 ): Other
     Reason (=0 ): no disconnect has yet occurred 
 Parameter #1  Connect Protocol: LAP-M 

 Parameter #2  Compression: V.42bis both 
 Parameter #3  EC Retransmission Count: 0 
 Parameter #4  Self Test Error Count: 0 
 Parameter #5  Call Timer: 597 secs 
 Parameter #6  Total Retrains: 0 

 Parameter #7  Sq Value: 4 
 Parameter #8  Connected Standard: V.34+ 

 Parameter #9  TX,RX Bit Rate: 33600, 33600 

 Parameter #11 TX,RX Symbol Rate: 3429, 3429 

 Parameter #13 TX,RX Carrier Frequency: 1959, 1959 
 Parameter #15 TX,RX Trellis Coding: 16, 16 
 Parameter #16 TX,RX Preemphasis Index: 0, 0 
 Parameter #17 TX,RX Constellation Shaping: Off, Off 
 Parameter #18 TX,RX Nonlinear Encoding: Off, Off 
 Parameter #19 TX,RX Precoding: Off, Off 
 Parameter #20 TX,RX Xmit Level Reduction: 0, 0 dBm 
 Parameter #21 Signal Noise Ratio: 41 dB 

 Parameter #22 Receive Level: -12 dBm 
 Parameter #23 Frequency Offset: 0 Hz 
 Parameter #24 Phase Jitter Frequency: 0 Hz 
 Parameter #25 Phase Jitter Level: 0 degrees 
 Parameter #26 Far End Echo Level: -52 dBm 

 Parameter #27 Phase Roll: 31 degrees 
 Parameter #28 Round Trip Delay: 1 msecs 
 Parameter #30 Characters transmitted, received: 70966, 80 

 Parameter #32 Characters received BAD: 2 
 Parameter #33 PPP/SLIP packets transmitted, received: 0, 0 
 Parameter #35 PPP/SLIP packets received (BAD/ABORTED): 0 
 Parameter #36 EC packets transmitted, received OK: 269, 61 
 Parameter #38 EC packets (Received BAD/ABORTED): 0 
 Parameter #39 Robbed Bit Signalling (RBS) pattern: 0 
 Parameter #40 Digital Pad: None,  Digital Pad Compensation:None
Line Shape:

..............................*
................................*
.................................*
................................*
................................*
.................................*
.................................*
.................................*
................................*
.................................*
.................................*
................................*
................................*
................................*
................................*
................................*
................................*
................................*
.................................*

Table 3-4 describes the significant parameters in the previous example. For a complete command reference description, refer to the following URL:

http://www.cisco.com/univercd/cc/td/doc/product/software/ios120/12cgcr/dial_r/drprt1/drmodmgt.htm

Parameter	Description
`Parameter #1 Connect Protocol: LAP-M`	LAP-M is the connection protocol.
`Parameter #6 Total Retrains: 0`	The modem has no retrain counts.
`Parameter #8 Connected Standard: V.34+`	The modem connects at V.34.
`Parameter #9 TX,RX Bit Rate: 33600, 33600`	The receive and transmit bit rate is 33600 bps, which is the fastest possible V.34 speed. You will never attain V.90 with this test. MICA-to-MICA calls default to V.34 modulation. V.90 requires one analog modem.
`Parameter #11 TX,RX Symbol Rate: 3429, 3429`	The transmit and receive symbol rate is 3429. To achieve 33600 bps, you must have a 3429 Hz passband.
`Parameter #21 Signal Noise Ratio: 41 dB`	The signal to noise ratio is 41 dB.
`Parameter #26 Far End Echo Level: -52 dBm`	Use this field to detect a near-end digital-to-analog conversion. For this test, an acceptable value is less than -55 dB. If you see a high level of far end echo (-55 or higher), a digital-to-analog conversion probably exists between the NAS and the switch. This conversion severely impairs modem performance.
`Parameter #30 Characters transmitted, received: 70966, 80`	The number of characters transmitted and received by the modem.
`Line shape:` `..............................` `................................` `.................................` `................................` `................................` `.................................` `.................................` `.................................` `................................` `.................................`	A line shape is the frequency-response graph of the channel. For this modem loopback test call, there should be no rolloff (even at the highest frequency). High-end rolloff is characteristic of an analog-to-digital conversion (not good). A flat vertical line shape is an ideal V.90 line shape. ISDN uses a 64KB clear channel. No statistical roll off should exist at the low end or the high end of the spectrum. The spectrum has a Y and X axis. The Y axis (vertical) represents frequencies from 150 Hz (top of chart) to 3750 Hz (bottom of chart) in 150 Hz steps. A flat spectrum plot is best, it is available for V.34, V.90, and K56Flex. The X axis (horizontal) represents a normal amplitude. The graph identifies nulls, bandwidth, and distortion (irregular shape).

Step 13 Turn off all debug commands:

5800-NAS# undebug all

All possible debugging has been turned off

Task 2. Initiating and Inspecting a V.90 Test Call

Before you let users dial in to the NAS, initiate and inspect a V.90 test call. V.90 call performance is heavily dependent upon the telco's network topology. There are many variables.

Most modem manufactures have unique AT command sets. The AT commands used in the following procedure may not be supported by your modem. For more information, see the following URLs:

Step 1 Locate a client PC, client modem, and an analog line.

Step 2 Test your EIA/TIA-232 connection to the client modem:

at

OK

Step 3 Verify that the modem is running the recommended firmware version. The following example shows a U.S. Robotics 56K fax external modem running V.4.11.2. Compare the firmware version with the version that is posted on the modem vendor's web site.

The ati3 and ati7 modem firmware commands are commonly used and are shown below:

ati3

U.S. Robotics 56K FAX EXT V4.11.2
 
OK
 
ati7

Configuration Profile...
 
Product type           US/Canada External
Product ID:            00568602
Options                V32bis,V.34+,x2,V.90
Fax Options            Class 1/Class 2.0
Line Options           Caller ID, Distinctive Ring
Clock Freq             92.0Mhz
EPROM                  256k
RAM                    32k
 
FLASH date             6/3/98
FLASH rev              4.11.2

 
DSP date               6/3/98
DSP rev                4.11.2

 
OK

Step 4 Verify that the modem is configured correctly. Enter the ati4 (USR) or at&v (Conexant) command. To reset the modem to the factory defaults, enter the at&f, at&f1, or at&f2 command.

ati4

U.S. Robotics 56K FAX EXT Settings...
 
   B0  E1  F1  M1  Q0  V1  X1  Y0
   BAUD=38400  PARITY=N  WORDLEN=8
   DIAL=TONE    ON HOOK   CID=0
 
   &A1  &B1  &C1  &D2  &G0  &H0  &I0  &K0
   &M4  &N0  &P0  &R1  &S0  &T5  &U0  &Y1  
 
   S00=000  S01=000  S02=043  S03=013  S04=010  S05=008  S06=002
   S07=060  S08=002  S09=006  S10=014  S11=070  S12=050  S13=000
   S15=000  S16=000  S18=000  S19=000  S21=010  S22=017  S23=019
   S25=005  S27=000  S28=008  S29=020  S30=000  S31=128  S32=002
   S33=000  S34=000  S35=000  S36=014S38=000  S39=000  S40=001
   S41=000  S42=000
 
   LAST DIALED #: T14085551234
 
OK

Step 5 Dial the access server's telephone number, log in, and access the EXEC shell. The client modem is connected at 48000 bps in this example.

atdt14085551234

CONNECT 48000/ARQ
 
This is a secured device. 

Unauthorized use is prohibited by law.

 
User Access Verification
 
Username:user

Password: 
 
5800-NAS>

Step 6 Inspect your call on the access server. In the example, the call landed on TTY line 1. The call has been up for 36 seconds.

5800-NAS>show caller	

                                                Active    Idle
  Line         User               Service       Time      Time
  vty 0        -                  VTY           00:07:46  00:00:00 
 
5800-NAS>show caller

Note The show caller command is supported in Cisco IOS Release 11.3 AA and 12.0 T. Use the show user command if your software does not support the show caller command.

Step 7 Inspect the physical terminal line that received the call. In the example, the call landed on modem 1/0.

5800-NAS>show terminal

Line 1/2/10, Location: "", Type: ""
Length: 24 lines, Width: 80 columns
Status: PSI Enabled, Ready, Active, No Exit Banner
Capabilities: Hardware Flowcontrol In, Hardware Flowcontrol Out
  Modem Callout, Modem RI is CD
Modem state: Ready
Modem hardware state: CTS DSR  DTR RTS
modem=1/2/10, vdev_state(0x00000000)=CSM_OC_STATE, bchan_num=(T1 1/0/0:0)
vdev_status(0x00000001): VDEV_STATUS_ACTIVE_CALL.
 
Group codes:    0
Special Chars: Escape  Hold  Stop  Start  Disconnect  Activation
                ^^x    none   -     -       none
Timeouts:      Idle EXEC    Idle Session   Modem Answer  Session   Dispatch
               00:10:00        never                        none     not set
                            Idle Session Disconnect Warning
                              never
                            Login-sequence User Response
                             00:00:30
                            Autoselect Initial Wait
                              not set
Modem type is unknown.
Session limit is not set.
Time since activation: 00:12:24
Editing is enabled.
History is enabled, history size is 10.
DNS resolution in show commands is enabled
Full user help is disabled
Allowed transports are lat pad v120 telnet rlogin dsipcon.  Preferred is lat.
No output characters are padded
No special data dispatching characters

Step 8 Program the display window so it does not pause in the middle of a screen display:

5800-NAS>terminal length 0

Step 9 Generate traffic across the modem link. Perform a lightweight stress test between the modems to generate meaningful modem-performance statistics.

5800-NAS>show modem log

Modem 1/2/00 Events Log:
  3w4d    :Startup event:MICA Hex modem (Managed)
           Modem firmware = 2.7.1.0
  3w4d    :RS232 event:  noRTS, noDTR, CTS, noDCD
  3w4d    :RS232 event:  noRTS, DTR, CTS, noDCD

The output generated by the show modem log command sends a large data stream across the modem link - about 1 MB of data. The data should scroll freely for one or two minutes.

Step 10 Inspect the NAS modem that answered the call, and verify that it has acceptable connect speed, throughput, and line shape. This example examines MICA modem 1/0. If you have Microcom modems, enter the modem at-mode slot/port command followed by the at@e1 command.

5800-NAS>show modem operational-status 1/2/00

Modem(1/2/00) Operational-Status:
 
 Parameter #0  Disconnect Reason Info: (0x0)
       Type (=0 ): <unknown>
      Class (=0 ): Other
     Reason (=0 ): no disconnect has yet occurred 
 Parameter #1  Connect Protocol: LAP-M 
 Parameter #2  Compression: None 
 Parameter #3  EC Retransmission Count: 2 
 Parameter #4  Self Test Error Count: 0 
 Parameter #5  Call Timer: 118 secs 
 Parameter #6  Total Retrains: 0 

 Parameter #7  Sq Value: 3 
 Parameter #8  Connected Standard: V.90 

 Parameter #9  TX,RX Bit Rate: 48000, 28800 

 Parameter #11 TX,RX Symbol Rate: 8000, 3200 
 Parameter #13 TX,RX Carrier Frequency: 0, 1920 
 Parameter #15 TX,RX Trellis Coding: 0, 16 
 Parameter #16 TX,RX Preemphasis Index: 0, 6 
 Parameter #17 TX,RX Constellation Shaping: Off, Off 
 Parameter #18 TX,RX Nonlinear Encoding: Off, Off 
 Parameter #19 TX,RX Precoding: Off, Off 
 Parameter #20 TX,RX Xmit Level Reduction: 0, 0 dBm 
 Parameter #21 Signal Noise Ratio: 36 dB 
 Parameter #22 Receive Level: -19 dBm 
 Parameter #23 Frequency Offset: 0 Hz 
 Parameter #24 Phase Jitter Frequency: 0 Hz 
 Parameter #25 Phase Jitter Level: 0 degrees 
 Parameter #26 Far End Echo Level: -37 dBm 
 Parameter #27 Phase Roll: 0 degrees 
 Parameter #28 Round Trip Delay: 23 msecs 
 Parameter #30 Characters transmitted, received: 67109, 43 

 Parameter #32 Characters received BAD: 0 
 Parameter #33 PPP/SLIP packets transmitted, received: 0, 0 
 Parameter #35 PPP/SLIP packets received (BAD/ABORTED): 0 
 Parameter #36 EC packets transmitted, received OK: 565, 43 
 Parameter #38 EC packets (Received BAD/ABORTED): 2 
 Parameter #39 Robbed Bit Signalling (RBS) pattern: 0 
 Parameter #40 Digital Pad: 6.0   dB,  Digital Pad Compensation:None
Line Shape:

.........................*

................................*

.................................*

.................................*

................................*

.................................*

.................................*

.................................*

................................*

................................*

................................*

................................*

................................*

................................*

................................*

................................*

................................*

Table 3-5 describes the significant output fields (bold font) in the previous example:

Parameter	Description
`Parameter #6 Total Retrains: 0`	Total retrains and speed shifts for the current connection. There are no retrains.
`Parameter #8 Connected Standard: V.90`	V.90 modulation is negotiated. Standard connect protocol which can be V.21, Bell03, V.22, V.22bis, Bell212, V.23, V.32, V.32bis, V.32terbo, V.34, V.34+, K56Flex, or V.90.
`Parameter #9 TX, RX Bit Rate: 48000, 28800`	The transmit speed (TX) is 48000 bps. The receive speed (RX) is 28800 bps. TX is the bit rate from the local DCE (NAS modem) to the remote DCE (client modem). RX is the bit rate from the remote DCE to the local DCE. V.90 uplink speed tends to be lower than V.34 uplink speed.
`Parameter #21 Signal Noise Ratio: 36 dB`	The signal to noise ratio (SNR) is 36 dB. (40 dB is a perfect SNR. MICA measures the SNR in the signal band. The SNR value ranges from 0 to 70 dB, and it changes in 1 dB steps. A 28.8 kbps connection requires a SNR of about 37 dB. SNRs lower than 37 dB reduce the quality of the connection. A 33.6 kbps connection requires a SNR of about 38 to 39 dB.
`Parameter 30 Characters transmitted, received: 67109, 43`	67109 characters are transmitted by the NAS modem to the client modem over the synchronous/asynchronous connection.
`Line shape:` `.........................` `................................` `.................................` `.................................` `................................` `.................................` `.................................` `.................................` `................................` `................................` `................................` `................................` `................................` `................................` `................................*`	A line shape is the frequency-response graph of the channel. A flat vertical line shape is an ideal V.90 line shape. ISDN uses a 64-kb clear channel. No statistical roll off should exist at the low end or the high end of the spectrum. The spectrum has a Y and X axis. The Y axis (vertical) represents frequencies from 150 Hz (top of chart) to 3750 Hz (bottom of chart) in 150 Hz steps. A flat spectrum plot is best, it is available for V.34, V.90, and K56Flex. The X axis (horizontal) represents a normal amplitude. The graph identifies nulls, bandwidth, and distortion (irregular shape).

Step 11 Enter the +++ command to jump back to the client modem and examine client-side performance statistics. The modem connection to the NAS is not dropped.

5800-NAS>+++

OK
at

OK

In the example, the client modem reports both "OK" messages. The +++ modem-escape sequence is similar to a router's Telnet-escape mode (Shift + Ctrl + 6 + x). See Figure 3-7.

Figure 3-7: Using Modem-Escape Mode to View Client-Side Modem Statistics

Step 12 Enter the ati6 command to display, among other things, the receive and transmit-carrier speeds. Compare the displayed information with the output from the show modem operational-status command.

If ati6 is not supported by your modem, try at&v1. For additional client report statistics, enable Windows modemlog.txt or ppplog.txt files.

ati6

U.S. Robotics 56K FAX EXT Link Diagnostics...
 
Chars sent                   98      Chars Received           104701

Chars lost                    0
Octets sent                 354      Octets Received          104701
Blocks sent                  95      Blocks Received             914
Blocks resent                 4
 
Retrains Requested            0      Retrains Granted              0

Line Reversals                0      Blers                         0
Link Timeouts                 0      Link Naks                     1
 
Data Compression       NONE
Equalization           Long
Fallback               Enabled
Protocol               LAPM

Speed                  48000/28800 

V.90 Peak Speed        48000

Current Call           00:04:46

 
Online

 
OK

Tips For a detailed explanation of this command, refer to the following URL:
http://808hi.com/56k/diag3com.htm

Step 13 Inspect frequency levels (dB) and other diagnostic functions. The following AT commands display the client modem's view of the frequency response. The display is a companion to the output of the show modem operational-status command (see Step 9).

aty11

 
Freq         Level (dB)
 
150           24
300           23
450           22
600           22
750           22
900           22
1050          22
1200          22
1350          22
1500          22
1650          22
1800          23
1950          23
2100          23
2250          23
2400          23
2550          23
2700          23
2850          23
3000          23
3150          23
3300          24
3450          25
3600          27
3750          31
 
ati11

U.S. Robotics 56K FAX EXT Link Diagnostics...
 
 
Modulation                  V.90

Carrier Freq     (Hz)       None/1920

Symbol Rate                 8000/3200

Trellis Code                None/64S-4D
Nonlinear Encoding          None/ON
Precoding                   None/ON
Shaping                     ON/ON
Preemphasis      (-dB)      6/2
Recv/Xmit Level  (-dBm)     19/10
Near Echo Loss   (dB)       7
Far Echo Loss    (dB)       0
Carrier Offset   (Hz)       NONE
Round Trip Delay (msec)     24
Timing Offset    (ppm)      1638
SNR              (dB)       48.1

Speed Shifts Up/Down        0/0

Status :                    uu,5,13Y,19.4,-15,1N,0,51.1,7.3
OK

Step 14 (Optional) To return to online mode and the router prompt, enter the ato command. After your enter this command, however, the +++ escape sequence is still in the EXEC session's input buffer. If you press the carriage return (<CR>), you will receive an error about +++ being an unknown command. To clear the input buffer, type Ctrl U after the ato command.

ato

% Unknown command or computer name, or unable to find computer address
5800-NAS>

Configuring PPP and Authentication

This section describes how to configure the AS5800 for PPP and local authentication.

The following sections are provided:

After local authentication is verified, use TACACS+ and a remote authentication server or RADIUS.

Task 1. Configuring PPP Authentication for Local AAA

Configure AAA to perform log in authentication by using the local username database. The login keyword authenticates EXEC terminal shell users. Additionally, configure PPP authentication to use the local database if the session was not already authenticated by login.

Step 1 Create a local log in username database in global configuration mode. In this example, admin is used for the administrator and the remote client's login password is user.

!

username admin password adminpasshere

username dude password dudepasshere

!

Warning This step also prevents you from getting locked out of the NAS. If you get locked out, you must reboot the device and perform password recovery.

Step 2 Configure local AAA security in global configuration mode. You must enter the aaa new-model command before the other two authentication commands.

!

aaa new-model

aaa authentication login default local

aaa authentication ppp default if-needed local

!

Step 3 Log in with your username and password:

5800-NAS#login

 
This is a secured device. 

Unauthorized use is prohibited by law.

 
 
User Access Verification
Username:dude

Password: 
 
5800-NAS#

Caution A successful login means that your local username will work on any TTY or VTY line. Do not disconnect your session until you can log in. (If you get locked out, you will need to perform password recovery by rebooting the device.)

Task 2. Configuring IPCP Options

Create a pool of IP addresses to assign to the PC clients dialing in. As the clients connect, they request IP addresses from the NAS.

Tips Remote ISDN LANs and remote nodes are primarily differentiated by an IP addressing scheme. Remote LANs can appear as remote nodes by using port address translation (PAT).

Step 1 Define the local IP address pool and DNS servers:

!

ip local pool addr-pool 172.22.90.2 172.22.90.254

!

async-bootp dns-server 172.30.10.1 172.30.10.2

!

For clients using server-assigned addressing (if there are any) you must specify primary and secondary DNS servers. The clients send config-requests to the NAS if the clients are configured to receive NAS assigned WINS and DNS servers.

Note RFC 1877 describes DNS and NBNS servers. The domain name must also be configured on the client.

Step 2 Verify that the IP address pool was created:

5800-NAS#show ip local pool

 Pool                     Begin           End             Free  In use

 addr-pool                172.22.90.2     172.22.90.254    253       0

5800-NAS#

Task 3. Configuring LCP Options

The group-async interface is a template that controls the configuration of all the asynchronous interfaces in the NAS.

Asynchronous interfaces:

Are lines that can run in PPP mode
Use the same number as its corresponding line
Save you time and configuration file size by configuring the asynchronous interfaces as a group-async

The client PPP framing must match the Cisco IOS interface. Figure 3-8 shows this concept.

Figure 3-8: Modem Dialup PPP Framing

The following group-async configuration applies to asynchronous interfaces 1/2/00 through 1/10/143:

!

interface Group-Async0

 ip unnumbered FastEthernet0/1/0

 encapsulation ppp

 async mode interactive

 ppp authentication chap pap

 peer default ip address pool addr-pool

 no cdp enable

 no ip directed-broadcast

 group-range 1/2/00 1/10/143

!

Table 3-6 describes the previous configuration snippet in more detail:

Table 3-6: Interface Group Async Command Descriptions

Command Purpose

ip unnumbered FastEthernet0/1/0
Conserves IP address space by configuring the asynchronous interfaces as unnumbered.

encapsulation ppp
Enables PPP.

async mode interactive
Configures interactive mode on the asynchronous interfaces. Interactive means that users can dial in and get to a shell or PPP session on that line.

ppp authentication chap pap
Enables CHAP and PAP authentication on the interface during LCP negotiation. The NAS first requests to authenticate with CHAP. If CHAP is rejected by the remote client (modem), then PAP authentication is requested.

peer default ip address pool addr-pool
Assigns dial-in client IP addresses from the pool named addr-pool.

no cdp enable
Disables the Cisco discovery protocol.

no ip directed-broadcast
Prevents IP directed broadcasts.

group-range 1/2/00 1/10/143
Specifies the range of asynchronous interfaces to include in the group, which is usually equal to the number of modems you have in the NAS.

(The session may pause for several seconds when you issue this command.)

Command	Purpose
ip unnumbered FastEthernet0/1/0	Conserves IP address space by configuring the asynchronous interfaces as unnumbered.
encapsulation ppp	Enables PPP.
async mode interactive	Configures interactive mode on the asynchronous interfaces. Interactive means that users can dial in and get to a shell or PPP session on that line.
ppp authentication chap pap	Enables CHAP and PAP authentication on the interface during LCP negotiation. The NAS first requests to authenticate with CHAP. If CHAP is rejected by the remote client (modem), then PAP authentication is requested.
peer default ip address pool addr-pool	Assigns dial-in client IP addresses from the pool named addr-pool.
no cdp enable	Disables the Cisco discovery protocol.
no ip directed-broadcast	Prevents IP directed broadcasts.
group-range 1/2/00 1/10/143	Specifies the range of asynchronous interfaces to include in the group, which is usually equal to the number of modems you have in the NAS. (The session may pause for several seconds when you issue this command.)

Task 4. Enabling PPP Autoselect

Enable remote PPP users to dial in, bypass the EXEC facility, and automatically start PPP on the line.

!

line 1/2/00 1/10/143

 autoselect during-login

 autoselect ppp

!

These two autoselect commands:

Provide the transparent launching of shell and PPP services on the same lines.
Circumvent the need to alert the NAS by pressing the return key. Older versions of Cisco IOS software did not have this feature and required the peer to hit return before the username was displayed.

Note The autoselect during-login command displays the username:password prompt after modems connect.

Task 5. Testing Asynchronous PPP Connections

Before you troubleshoot PPP negotiation or AAA authentication, you need to understand what a successful PPP and AAA debug sequence looks like. In this way, you can save time and effort when comparing a successful debug session against a faulty completed debug sequence.

5.1 Successful PPP Negotiation Debug

The following steps describe how to initiate a PPP test call and interpret a successful debug sequence.

Step 1 Enter the appropriate debug commands:

5800-NAS#debug ppp authentication

PPP authentication debugging is on
5800-NAS#debug aaa authentication

AAA Authentication debugging is on
5800-NAS#show debug

General OS:
  AAA Authentication debugging is on
PPP:
  PPP authentication debugging is on

Step 2 Make sure that your EXEC session receives logging and debug output:

5800-NAS#logging console

Step 3 From the client, send a test call into the NAS by using Dial-Up Networking. Figure 3-9 shows an example Windows Dial-Up Networking display.

Figure 3-9: Windows Dial-Up Networking

Step 4 Go to the NAS terminal screen to observe and interpret the debug output messages. As the call enters the NAS, debug output is created.

When examining PPP between two remote peers:

a. First check to see if DSR came up.

b. Verify that both sides get through LCP negotiation. If they do, check authentication.

c. After authentication succeeds, check IPCP negotiation.

d. If no debug output appears, troubleshoot ISDN Q.931. Use the debug isdn q931 command.

Given the debug commands entered in Step 1, the following debug output should be generated by the call:

*Sep 24 13:05:49.052: AAA: parse name=tty1/2/09 idb type=10 tty=441

*Sep 24 13:05:49.052: AAA: name=tty1/2/09 flags=0x1D type=4 shelf=0 slot=1 adapter=2 
port=9 channel=0

*Sep 24 13:05:49.052: AAA: parse name=Serial1/0/0:4:21 idb type=12 tty=-1

*Sep 24 13:05:49.052: AAA: name=Serial1/0/0:4:21 flags=0x5D type=1 shelf=0 slot=1 
adapter=0 port=4 channel=21

In this example, the call enters the NAS on channel 1/0/0:4:21. This channel maps to the 21st DS0 channel of the 4th PRI line of a CT3 card. Eventually the call terminates on modem 441.

*Sep 24 13:05:49.052: AAA/MEMORY: create_user (0x63E8FB70) user='' ruser='' port 
='tty1/2/09' rem_addr='4089548211/51121' authen_type=ASCII service=LOGIN priv=1

*Sep 24 13:05:49.052: AAA/AUTHEN/START (1586904428): port='tty1/2/09' list='' ac 
tion=LOGIN service=LOGIN

*Sep 24 13:05:49.052: AAA/AUTHEN/START (1586904428): using "default" list

*Sep 24 13:05:49.052: AAA/AUTHEN/START (1586904428): Method=LOCAL*Sep 24 13:05:49.052: 
AAA/AUTHEN (1586904428): status = GETUSER

*Sep 24 13:05:49.072: AAA/AUTHEN/ABORT: (1586904428) because Autoselected.

*Sep 24 13:05:49.072: AAA/MEMORY: free_user (0x63E8FB70) user='' ruser='' port='

An authentication start packet is sent by AAA, and it searches the local username database as the default authentication method.

tty1/2/09' rem_addr='4089548211/51121' authen_type=ASCII service=LOGIN priv=1

*Sep 24 13:05:51.076: As1/2/09 PPP: Treating connection as a dedicated line

*Sep 24 13:05:55.272: As1/2/09 PPP: Phase is AUTHENTICATING, by this end

*Sep 24 13:05:55.404: As1/2/09 PAP: I AUTH-REQ id 1 len 20 from "dude"

*Sep 24 13:05:55.404: As1/2/09 PAP: Authenticating peer dude

PPP is allowed to start on the interface. The client sends an authentication request called dude. PAP authentication is used.

*Sep 24 13:05:55.404: AAA: parse name=Async1/2/09 idb type=10 tty=441

*Sep 24 13:05:55.404: AAA: name=Async1/2/09 flags=0x1D type=4 shelf=0 slot=1 adapter=2 
port=9 channel=0

*Sep 24 13:05:55.404: AAA: parse name=Serial1/0/0:4:21 idb type=12 tty=-1

*Sep 24 13:05:55.404: AAA: name=Serial1/0/0:4:21 flags=0x5D type=1 shelf=0 slot=1 
adapter=0 port=4 channel=21

*Sep 24 13:05:55.404: AAA/MEMORY: create_user (0x63E8FB70) user='dude' 
ruser=''port='Async1/2/09' rem_addr='4089548211/51121' authen_type=PAP service=PPP priv=1

*Sep 24 13:05:55.404: AAA/AUTHEN/START (693233173): port='Async1/2/09' list='' 
action=LOGIN service=PPP

*Sep 24 13:05:55.404: AAA/AUTHEN/START (693233173): using "default" list

*Sep 24 13:05:55.404: AAA/AUTHEN (693233173): status = UNKNOWN

*Sep 24 13:05:55.404: AAA/AUTHEN/START (693233173): Method=LOCAL

*Sep 24 13:05:55.404: AAA/AUTHEN (693233173): status = PASS

*Sep 24 13:05:55.404: As1/2/09 PAP: O AUTH-ACK id 1 len 5

The example above shows that local authentication was successful.

5.2 Failed PPP Negotiation Debugging and Troubleshooting

Failed authentication is a common occurrence. Misconfigured or mismatched usernames and passwords create error messages in debug output.

The following example shows that the username maddog does not have permission to dial into the NAS. The NAS does not have a local username configured for this user. To fix the problem, use the username name password password command to add the username to the local AAA database in the NAS:

*Sep 24 13:11:28.964: AAA/MEMORY: create_user (0x63E43558) user='maddog' ruser='' 
port='Async1/2/10' rem_addr='4089548211/51121' authen_type=PAP service=PPP priv=1
*Sep 24 13:11:28.964: AAA/AUTHEN/START (3281080218): port='Async1/2/10' 
list=''action=LOGIN service=PPP
*Sep 24 13:11:28.964: AAA/AUTHEN/START (3281080218): using "default" list
*Sep 24 13:11:28.964: AAA/AUTHEN (3281080218): status = UNKNOWN
*Sep 24 13:11:28.964: AAA/AUTHEN/START (3281080218): Method=LOCAL
*Sep 24 13:11:28.964: AAA/AUTHEN (3281080218): User not found, end of method list

*Sep 24 13:11:28.964: AAA/AUTHEN (3281080218): status = FAIL

*Sep 24 13:11:28.964: As1/2/10 PAP: O AUTH-NAK id 1 len 32 msg is "Password validation 
failure"
*Sep 24 13:11:28.964: AAA/MEMORY: free_user (0x63E43558) user='maddog' 
ruser=''port='Async1/2/10' rem_addr='4089548211/51121' authen_type=PAP service=PPP priv=1

The following example shows an invalid password. Notice that the same error messages are used for username failure—"Password validation failure."

*Sep 24 13:13:59.032: AAA/MEMORY: create_user (0x63E9846C) user='user' 
ruser=''port='Async1/2/11' rem_addr='4089548211/51121' authen_type=PAP service=PPP priv=1
*Sep 24 13:13:59.032: AAA/AUTHEN/START (3032205297): port='Async1/2/11' 
list=''action=LOGIN service=PPP
*Sep 24 13:13:59.032: AAA/AUTHEN/START (3032205297): using "default" list
*Sep 24 13:13:59.032: AAA/AUTHEN (3032205297): status = UNKNOWN
*Sep 24 13:13:59.032: AAA/AUTHEN/START (3032205297): Method=LOCAL
*Sep 24 13:13:59.032: AAA/AUTHEN (3032205297): status = FAIL
*Sep 24 13:13:59.032: As1/2/11 PAP: O AUTH-NAK id 1 len 32 msg is "Password validation 
failure"

*Sep 24 13:13:59.036: AAA/MEMORY: free_user (0x63E9846C) user='user' ruser='' 
port='Async1/2/11' rem_addr='4089548211/51121' authen_type=PAP service=PPP priv=1

5.3 Troubleshooting Flow Diagrams

Figure 3-10 provides a flowchart for troubleshooting the following three PPP layers:

Physical layer
Link Control Protocol (LCP) and authentication layer
Network Control Protocol (NCP) layer

Figure 3-10: Troubleshooting Flow Chart for PPP and Authentication

LCP negotiation is a series of LCP packets exchanged between PPP peers to negotiate a set of options and option values when sending data. The LCP negotiation is actually two separate dialogs between two PPP peers (Peer1 and Peer 2):

Peer 1 and Peer 2 do not have to use the same set of LCP options. When a PPP peer sends its initial Configure-Request, the response is any of the following:

A Configure-Nack because one or more options have unacceptable values.
A Configure-Reject because one or more of the options are unknown or not negotiable.
A Configure-Ack because all of the options have acceptable values.

When a PPP peer receives a Configure-Nack or Configure-Reject in response to its Configure-Request, it sends a new Configure-Request with modified options or option values. When a Configure-Ack is received, the PPP peer is ready to send data.

Figure 3-11 shows an example LCP negotiation process for Peer 1 using the fictional options W, X, Y, Z. Additionally, Figure 3-11 shows Peer 1 sending data to Peer 2 only. Separate LCP negotiation must be configured so that Peer 2 can send data back to Peer 1. Very often, the LCP packets for both Peer 1 and Peer 2 are intermixed during the connection process (that is, Peer 1 is configuring the way it sends data at the same time as Peer 2.).

Figure 3-11: LCP Layer Negotiations

Figure 3-11 shows that:

Peer 1 sends a Configure-Request requesting option W, option X set to 100, option Y set to 0, and option Z. (Options W and Z are flag options.)
Peer 2 does not understand option Z so it sends a Configure-Reject containing option Z.
Peer 1 sends a new Configure-Request packet requesting option W, option X set to 100, and option Y set to 0.
Peer 2 prefers that option X be set to 200 so it sends a Configure-Nack containing option X and its preferred value.
Peer 1 sends a new Configure-Request packet requesting option W, option X set to 200, and option Y set to 0.
Peer 2 sends a Configure-Ack.

Each time Peer 1 sends a new Configure-Request, it changes the Identifier value in the LCP header so that Configure-Requests can be matched with their responses.

Task 6. Inspecting Active C all States

After a basic PPP modem call comes into the NAS, you should use some show commands to inspect several active call statistics. If you try to use the client's web browser after the modems connect, you will test DNS, IP, and other functions. If your test fails, try pinging the DNS server from the device that dialed in.

6.1 Show Caller Statistics

The show caller command is used to:

View individual users and consumed resources on the NAS.
Inspect active call statistics for large pools of connections. (Debug commands produce too much output and tax the CPU too heavily.)
Display the absolute and idle times for each user. The current values for both of these settings are displayed on the TTY line and the asynchronous interface. Users that have been idle for unacceptably long periods of time can be easily identified. By using this information, you can define timeout policies and multiple grades of services for different users.

The show caller command has many options:

5800-NAS#show caller ?

  full       Provide expanded caller information
  interface  Provide information on one interface
  ip         Display IP information
  line       Provide information on one line
  timeouts   Display session and idle limits and disconnect time
  user       Display information for a particular user
  |          Output modifiers
  <cr>
 
5800-NAS#show caller

                                                Active    Idle
  Line         User               Service       Time      Time
  vty 0        admin              VTY           00:54:39  00:00:00
  tty 441      dude               Async         00:00:15  00:00:00

  As1/2/09     dude               PPP           00:00:08  00:00:00

 
5800-NAS#show caller user dude

 
  User: dude, line tty 441, service Async

        Active time 00:01:24, Idle time 00:01:05
  Timeouts:            Absolute  Idle      Idle
                                 Session   Exec
      Limits:          -         -         00:10:00
      Disconnect in:   -         -         -
  TTY: Line 1/2/09, running PPP on As1/2/09

  Location: PPP: 192.168.10.4
  DS0: (slot/unit/channel)=0/4/21

  Status: Ready, Active, No Exit Banner, Async Interface Active
          HW PPP Support Active, Modem Detected
  Capabilities: Hardware Flowcontrol In, Hardware Flowcontrol Out
                Modem Callout, Modem RI is CD,
                Line usable as async interface, Modem Autoconfigure
  Modem State: Ready, Modem Configured
 
  User: dude, line As1/2/09, service PPP
        Active time 00:01:17, Idle time 00:01:05
  Timeouts:            Absolute  Idle
      Limits:          -         -
      Disconnect in:   -         -
  PPP: LCP Open, PAP (<- AAA), IPCP

  IP: Local 172.22.66.23, remote 172.22.90.2

  Counts: 30 packets input, 1640 bytes, 0 no buffer
          1 input errors, 1 CRC, 0 frame, 0 overrun
          14 packets output, 290 bytes, 0 underruns
          0 output errors, 0 collisions, 0 interface resets

In the previous example, notice that one call uses the following system resources:

TTY line 441
Asynchronous interface 1/2/09 (shelf/slot/port)
DS0 channel number 0/4/21
Modem 1/2/09

Note Different data is presented at each layer of the connection. Understanding the roles of the layers is very useful for troubleshooting purposes. The show caller user "username" detailed command displays detailed LCP negotiated parameters.

Table 3-7 describes some of the significant display output fields of the show caller user command:

Table 3-7: Show Caller User Command Descriptions

Field Description

User: dude, line tty 441, service Async
Active user on line TTY 441. The output fields are very similar to the show line command.

DS0: (slot/unit/channel)=0/4/21
The DS0 channel used by the call.

User: admin, line As1/2/09, service PPP
Active user on asynchronous interface 1/2/09. The timeouts working on the PPP layer are displayed, which are different from the TTY line timeouts.

PPP: LCP Open, CHAP (<- AAA), IPCP
Superficial information about what is open in PPP. The field "(<- AAA)" is somewhat misleading. Local authentication is also from AAA.

For more detailed IPCP information, enter the show caller user detail command.

IP: Local 172.22.66.23, remote 172.22.90.2
The IP addresses on each end of the link. These values are only displayed on the output for the asynchronous interface.

Counts:
Counters from the show interface async 1/2/09 command output.

Field	Description
User: dude, line tty 441, service Async	Active user on line TTY 441. The output fields are very similar to the show line command.
DS0: (slot/unit/channel)=0/4/21	The DS0 channel used by the call.
User: admin, line As1/2/09, service PPP	Active user on asynchronous interface 1/2/09. The timeouts working on the PPP layer are displayed, which are different from the TTY line timeouts.
PPP: LCP Open, CHAP (<- AAA), IPCP	Superficial information about what is open in PPP. The field "(<- AAA)" is somewhat misleading. Local authentication is also from AAA. For more detailed IPCP information, enter the show caller user detail command.
IP: Local 172.22.66.23, remote 172.22.90.2	The IP addresses on each end of the link. These values are only displayed on the output for the asynchronous interface.
Counts:	Counters from the show interface async 1/2/09 command output.

6.2 Fast Switching and Route Caching Statistics

Inspect fast-switching and route-caching performance statistics for the call. Incoming asynchronous calls can be fast switched. However, some features disable fast switching.

Inspect the queuing characteristics of the asynchronous interface. Notice that the queuing strategy is first-in-first-out (fifo).

5800-NAS#show interface async 1/2/02

Async1/2/02 is up, line protocol is up 
modem=1/2/02, vdev_state(0x00000000)=CSM_OC_STATE, bchan_num=(T1 1/0/0:4:6)
vdev_status(0x00000001): VDEV_STATUS_ACTIVE_CALL.
 
  Hardware is Async Serial
  Interface is unnumbered. Using address of FastEthernet0/1/0 (172.22.66.23)
  MTU 1500 bytes, BW 9 Kbit, DLY 100000 usec,
     reliability 255/255, txload 1/255, rxload 1/255
  Encapsulation PPP, loopback not set, keepalive not set
  DTR is pulsed for 5 seconds on reset
  LCP Open

  Open: IPCP

  Last input 00:00:00, output 00:00:00, output hang never
  Last clearing of "show interface" counters never
  Queueing strategy: fifo

  Output queue 0/10, 0 drops; input queue 1/10, 0 drops

  5 minute input rate 0 bits/sec, 1 packets/sec
  5 minute output rate 0 bits/sec, 1 packets/sec
     1683 packets input, 112764 bytes, 0 no buffer
     Received 0 broadcasts, 0 runts, 0 giants, 0 throttles
     1 input errors, 1 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
     1626 packets output, 108235 bytes, 0 underruns
     0 output errors, 0 collisions, 0 interface resets
     0 output buffer failures, 0 output buffers swapped out
     0 carrier transitions

Inspect the IP settings of the interface. Notice that IP fast switching is disabled, because TCP/IP header compression is enabled. Turn off TCP/IP header compress to enable fast switching. Enter the no ip tcp header-compression command on the asynchronous interface.

5800-NAS#show ip int async 1/2/02

Async1/2/02 is up, line protocol is up
  Interface is unnumbered. Using address of FastEthernet0/1/0 (172.22.66.23)
  Broadcast address is 255.255.255.255
  Peer address is 172.22.90.2
  MTU is 1500 bytes
  Helper address is not set
  Directed broadcast forwarding is enabled
  Outgoing access list is not set
  Inbound  access list is not set
  Proxy ARP is enabled
  Security level is default
  Split horizon is enabled
  ICMP redirects are always sent
  ICMP unreachables are always sent
  ICMP mask replies are never sent
  IP fast switching is disabled

  IP fast switching on the same interface is disabled
  IP multicast fast switching is enabled
  Router Discovery is disabled
  IP output packet accounting is disabled
  IP access violation accounting is disabled
  TCP/IP header compression is enabled and compressing

  RTP/IP header compression is disabled
  Probe proxy name replies are disabled
  Gateway Discovery is disabled
  Policy routing is disabled
  Network address translation is disabled
5800-NAS#

Look at the fast-switching cache in action. Notice that only packets destined to the Fast Ethernet interface are currently cached.

5800-NAS#show ip cache 

IP routing cache 3 entries, 560 bytes
   109 adds, 106 invalidates, 3 refcounts
Minimum invalidation interval 2 seconds, maximum interval 5 seconds,
   quiet interval 3 seconds, threshold 0 requests
Invalidation rate 0 in last second, 0 in last 3 seconds
Last full cache invalidation occurred 22:17:01 ago
 
Prefix/Length         Age       Interface       Next Hop
172.61.0.0/16         15:13:22  FastEthernet0/1 172.22.66.1
172.22.67.67/32       00:06:10  FastEthernet0/1 172.22.67.2
172.22.68.67/32       00:06:09  FastEthernet0/1 172.22.68.3
 
5800-NAS#show interface async 1/2/02 stat

Async1/2/02
          Switching path    Pkts In   Chars In   Pkts Out  Chars Out
               Processor        909      57050       1022      67918
             Route cache        155      14260          0          0
                   Total       1064      71310       1022      6791

TimeSaver For more information, refer to the following URL:
http://www.cisco.com/univercd/cc/td/doc/product/software/ios120/12cgcr/
switch_r/xrswcmd.htm#xtocid872762

Task 7. Confirming the Final Running-Config

After completing the tasks in this section, the Cisco AS5800 final running configuration looks like the following example:

5800-NAS#show running-config

Building configuration...
 
Current configuration:
!
version 12.0
service timestamps debug datetime msec
service timestamps log datetime msec
service password-encryption
!
hostname 5800-NAS
!
aaa new-model
aaa authentication login default local
aaa authentication ppp default if-needed local
enable secret 5 $1$LKgL$tgi19XvWn7fld7JGt55p01
!
username dude password 7 045802150C2E
username admin password 7 044E1F050024
!
!
!
!
!
!
shelf-id 0 router-shelf
shelf-id 1 dial-shelf
!
!
!
resource-pool disable
!
modem-pool Default
 pool-range 1/2/0-1/10/143
!
!
spe 1/2/0 1/10/11
 firmware ios-bundled default
modem recovery action none
ip subnet-zero
no ip source-route
ip host aurora 172.22.100.9
ip domain-name the.doc
ip name-server 172.22.11.10
ip name-server 172.22.12.11
!
async-bootp dns-server 172.30.10.1 172.30.10.2
isdn switch-type primary-ni
isdn voice-call-failure 0
!
!
controller T3 1/0/0
 framing m23
 cablelength 0
 t1 4 controller
!
controller T1 1/0/0:4
 framing esf
 pri-group timeslots 1-24
!
!
voice-port 1/0/0:4:D
!
!
process-max-time 200
!
interface Loopback0
 ip address 172.22.99.1 255.255.255.255
 no ip directed-broadcast
!
interface Loopback1
 ip address 172.22.90.1 255.255.255.0
 no ip directed-broadcast
!
interface FastEthernet0/1/0
 ip address 172.22.66.23 255.255.255.0
 no ip directed-broadcast
!
interface Serial1/0/0:4:23
 no ip address
 no ip directed-broadcast
 isdn switch-type primary-ni
 isdn incoming-voice modem
 no cdp enable
!
interface Group-Async0
 ip unnumbered FastEthernet0/1/0
 no ip directed-broadcast
 encapsulation ppp
 async mode interactive
 peer default ip address pool addr-pool
 no cdp enable
 ppp authentication chap pap
 group-range 1/2/00 1/10/143
! 
ip local pool addr-pool 172.22.90.2 172.22.90.254

ip classless
ip route 0.0.0.0 0.0.0.0 172.22.66.1
no ip http server
!
!
banner login ^C 
AS5800 Austin
ISP's Dial Access Server
^C
!
line con 0
 transport input none
line aux 0
 transport input telnet
line vty 0 4
line 1/2/00 1/10/143
 autoselect during-login
 autoselect ppp
 modem InOut
 no modem log rs232
!
end

Modem Management Operations

This section describes how to manage the modems on a Cisco AS5800 by using the Cisco IOS software.

The following sections are provided:

In this discussion relative tasks are performed to manage modem operations of network access servers (NAS).

For information on how to verify modem performance, see the section " Verifying Modem Performance."

Table 3-8 provides a list of terms for this section.

Table 3-8: List of Terms

Term Description

DSP

Digital Signal Processor (DSP). The processor that does the modulating and demodulating. The modem modulation protocols, such as V.34 and V.90, that run in the DSP.

Firmware¹

Name for Microcom modem code.

MICA module

MICA modem card containing 6 (HMM) or 12 (DMM) modems.

Portware

Name for MICA modem code.

SPE

Service Processing Element (SPE). A SPE unit is defined as the smallest software downloadable unit.

For Microcom, an SPE is an individual modem. For MICA, SPE is either 6 or 12 modems, depending on whether the MICA module is single or double density.

ucode

Short for microcode. Microcode in a Cisco NAS is code that gets loaded into a card, and it is typically bundled with the Cisco IOS software image. (In general, Cisco does not refer to modem code microcode.)

¹Examples and text that refer to both MICA and Microcom modems use the term firmware (not portware).

Term	Description
DSP	Digital Signal Processor (DSP). The processor that does the modulating and demodulating. The modem modulation protocols, such as V.34 and V.90, that run in the DSP.
Firmware¹	Name for Microcom modem code.
MICA module	MICA modem card containing 6 (HMM) or 12 (DMM) modems.
Portware	Name for MICA modem code.
SPE	Service Processing Element (SPE). A SPE unit is defined as the smallest software downloadable unit. For Microcom, an SPE is an individual modem. For MICA, SPE is either 6 or 12 modems, depending on whether the MICA module is single or double density.
ucode	Short for microcode. Microcode in a Cisco NAS is code that gets loaded into a card, and it is typically bundled with the Cisco IOS software image. (In general, Cisco does not refer to modem code microcode.)

The following documents are related to m odem management operations:

Dial Solutions Configuration Guide, Managing Modems, Release 12.0

: http://www.cisco.com/univercd/cc/td/doc/product/software/ios120/12cgcr/
dial_c/dcmodmgt.htm

Dial Solutions Command Reference, Modem Management Commands, Release 12.0

: http://www.cisco.com/univercd/cc/td/doc/product/software/ios120/12cgcr/
dial_r/drprt1/drmodmgt.htm

Firmware and Portware Information

: http://www.cisco.com/univercd/cc/td/doc/product/access/fwpwinfo/index.htm

Task 1. Managing Modem Firmware

Inspecting and upgrading modem firmware is a fundamental part of commissioning a NAS. Cisco posts new firmware versions on CCO for you to download via FTP. For more information, go to the Cisco Software Center at the following URL:

http://www.cisco.com/kobayashi/sw-center/sw-access.shtml

A specific architecture surrounds integrated modem technology. Integrated modems get their modem firmware from a file that is stored in one of three places:

Bundled into the Cisco IOS software
Stored in Flash memory
Stored in bootFlash memory

The modem looks first for its firmware inside the bundled Cisco IOS software image. The modem does not look outside the bundled image unless you manually change the configuration settings by using the copy source modem command or spe command.

1.1 Inspecting Modem Firmware

Before you upgrade modem firmware for MICA or Microcom modems, you should perform the following tasks:

Determine the version of firmware that is currently loaded in each modem (for example, 2.6.2.0).

5800-NAS#show modem version

Modem Range          Module   Firmware Rev    Upgrade
    1/2/00 1/2/11          0      2.6.2.0             -          
    1/2/12 1/2/23          1      2.6.2.0             -          
    1/2/24 1/2/35          2      2.6.2.0             -          
    1/2/36 1/2/47          3      2.6.2.0             -          
    1/2/48 1/2/59          4      2.6.2.0             -          
    1/2/60 1/2/71          5      2.6.2.0             -          
    1/2/72 1/2/83          6      2.6.2.0             -          
    1/2/84 1/2/95          7      2.6.2.0             -          
    1/2/96 1/2/107         8      2.6.2.0             -          
   1/2/108 1/2/119         9      2.6.2.0             -          
   1/2/120 1/2/131        10      2.6.2.0             -          
   1/2/132 1/2/143        11      2.6.2.0             -          
    1/3/00 1/3/11          0      2.6.2.0             -          
    1/3/12 1/3/23          1      2.6.2.0             -          
    1/3/24 1/3/35          2      2.6.2.0             -          
    1/3/36 1/3/47          3      2.6.2.0             -          
    1/3/48 1/3/59          4      2.6.2.0             -          
    1/3/60 1/3/71          5      2.6.2.0             -          
    1/3/72 1/3/83          6      2.6.2.0             -          
    1/3/84 1/3/95          7      2.6.2.0             -          
    1/3/96 1/3/107         8      2.6.2.0

Find the version of firmware that is bundled with the Cisco IOS software. TheCisco AS5800 supports the show modem bundled-firmware command which replaces the show modem map command that displays the region of NVRAM that identifies where the modems get their firmware at bootup.

as5800-RS-1# show modem bundled-firmware

List of bundled modem firmware images by slot
  Slot 4
    2.6.2.0
  Slot 5
    2.6.2.0
  Slot 6
    2.6.2.0
  Slot 7
    2.6.2.0
  Slot 8
    2.6.2.0

Inspect the directory that stores the bundled firmware files. The files are loaded into the system main memory through the system:/ucode directory.

: In the following example, two versions of fimware are found: mica_port_firmware and microcom_firmware. The file mica_board_firmware is not user upgradeable.

5800-NAS# dir system:ucode 

Directory of system:/ucode/
 
 14  -r--      516060              <no date>  mica_board_firmware
 15  -r--      375525              <no date>  mica_port_firmware
 16  -r--      381284              <no date>  microcom_firmware
 
No space information available

Look at the existing contents of Flash/bootFlash for the following reasons:
- Determine what firmware versions you already have.
- Determine if your Flash/bootFlash is read-only or read/write.
- Determine if you have enough free space.

: The commands show flash and show bootflash are supported in any version of Cisco IOS software. The commands dir flash: and dir bootflash: are supported in Cisco IOS Release 12.0T.

AS5800-1# show flash

 
System flash directory:
File  Length   Name/status
  1   6436752  c5800-is-mz.120-5.5.T
  2   392241   mica-modem-pw.2.7.1.0.bin
[6829124 bytes used, 9948092 available, 16777216 total]
16384K bytes of processor board System flash (Read/Write)
 
AS5800-1# show bootflash

 
Boot flash directory:
File  Length   Name/status
  1   1220196  c5800-boot-mz.120-3.bin
  2   375525   mica-modem-pw.2.6.1.0.bin
  3   381540   mica-modem-pw.2.6.2.0.bin
[1977456 bytes used, 2216848 available, 4194304 total]
4096K bytes of processor board Boot flash (Read/Write)

Filenames are arbitrary and are not necessarily indicative of their contents. If there is not enough free space on Flash or bootFlash to store the desired file, then you need to:

a. Copy the existing files that you want to keep onto a TFTP server.

b. Erase the Flash memory.

c. Copy the desired files into Flash memory.

1.2 Upgrading Modem Firmware

Cisco regularly enhances modem DSP code to improve modem performance. To obtain the latest DSP code, upgrade the NAS modem firmware.

Figure 3-12 summarizes the firmware upgrade procedure.

Figure 3-12: Modem Firmware Download Operation Example

Step 1 Read the latest modem release notes about modem and firmware information on CCO. Understand the latest enhancements and bug fixes before you download code. Refer to the following URL for the latest release notes:

http://www.cisco.com/univercd/cc/td/doc/product/access/fwpwinfo/index.htm

Step 2 Download the latest firmware from CCO to the NAS Flash or bootFlash memory. Depending on which Cisco IOS software you are running, there are two ways you can get the latest firmware from CCO into the NAS Flash or bootFlash. Table 3-8 describes these two methods.

Table 3-9: Firmware Copy Commands

Cisco IOS
Software Release Command Cisco IOS Release Purpose

12.0T and later

copy ftp command
Copy a file directly from CCO into Flash memory, without staging it at a local TFTP server.

11.3 and later

copy tftp: {flash: | bootflash:}
Copy from a TFTP server.

Cisco IOS Software Release	Command	Cisco IOS Release Purpose
12.0T and later	copy ftp command	Copy a file directly from CCO into Flash memory, without staging it at a local TFTP server.
11.3 and later	copy tftp: {flash: \| bootflash:}	Copy from a TFTP server.

The following example uses the copy ftp command. The file mica-modem-pw.2.7.1.0.bin is copied from ftp.cisco.com to the bootFlash. Be sure to specify your own CCO username and password in the command line (as indicated in the example).

5800-NAS#ping ftp.cisco.com

 
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 192.31.7.171, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 4/4/4 ms
5800-NAS#
5800-NAS#copy ftp://CCOUSERNAME:CCOPASSWORD@ftp.doc.com/cisco/access/modems/mica/

mica-modem-pw.2.7.1.0.bin bootflash:

Destination filename [mica-modem-pw.2.7.1.0.bin]? <cr>

Accessing ftp:// CCOUSERNAME:CCOPASSWORD@ftp.doc.com/cisco/access/modems/mica/

mica-modem-pw.2.7.1.0.bin...Translating "ftp.cisco.com"...domain
 server (171.70.24.56) [OK]
 
Erase bootflash: before copying? [confirm]n

Loading cisco/access/modems/mica/mica-modem-pw.2.7.1.0.bin 
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
[OK - 392241/1024 bytes]
 
Verifying checksum...  OK (0x6638)
392241 bytes copied in 5.940 secs (78448 bytes/sec)
5800-NAS#

Step 3 Verify that the new firmware is in Flash or bootFlash memory. The unbundled firmware file is mica-modem-pw.2.7.1.0.bin in this example.

5800-NAS#dir flash:

Directory of flash:/
 
  1  -rw-     4583276              <no date>  C5800-IS-MZ.113-9_AA
  2  -rw-     4675992              <no date>  c5800-js-mz.112-18.P.bin
  3  -rw-      392241              <no date>  mica-modem-pw.2.7.1.0.bin

  4  -rw-     5947548              <no date>  c5800-is-mz.120-4.XI1
  5  -rw-        4339              <no date>  startup-config.12.0(4)XI1
 
16777216 bytes total (1173496 bytes free)

Step 4 (Optional) Enable the modem firmware-download command to watch the modem mapping operation take place:

5800-NAS# modem firmware-download

Modem Firmware-Download debugging is on

Step 5 Map the new firmware to the modems.

For MICA modems, firmware is mapped to entire modem modules (6 or 12 modem-module boundaries; not individual modems). For Microcom modems, firmware is mapped to one or more individual modems. The rule requiring that all modems in a MICA module run the same code is an architectural requirement.

Depending on which Cisco IOS release is loaded in the NAS, there are two commands that you can use. Table 3-10 describes these two commands.

Table 3-10: Modem Mapping Commands

Cisco IOS
Software Release Command Notes

12.0(5)T and later

spe
An SPE unit is defined as the smallest software downloadable unit. For Microcom, an SPE is an individual modem.

For MICA, an SPE is either 6 or 12 modems, depending on whether the MICA module is single or double density.

Before Release 12.0(5)T

copy source modem
Replace the source variable with either flash or bootflash.

Cisco IOS Software Release	Command	Notes
12.0(5)T and later	spe	An SPE unit is defined as the smallest software downloadable unit. For Microcom, an SPE is an individual modem. For MICA, an SPE is either 6 or 12 modems, depending on whether the MICA module is single or double density.
Before Release 12.0(5)T	copy source modem	Replace the source variable with either flash or bootflash.

The following MICA example uses the spe command. The numbers 1/0 1/7 refer to modem module numbers 0 through 7 in slot 1. These numbers do not refer to specific modem numbers (for example, slot/port for Microcom modems). In this example, 48 modems are upgraded (8 SPE x 6 modems per module = 48 modems).

5800-NAS#configure terminal

Enter configuration commands, one per line.  End with CNTL/Z.
5800-NAS(config)#spe 1/0 1/7                                      
5800-NAS(config-spe)#firmware location flash:mica-modem-pw.2.7.1.0.bin

5800-NAS(config-spe)#
*Jan 23 11:14:48.702: %MODEM-5-DL_START: Modem (1/0) started firmware download
*Jan 23 11:14:48.702: %MODEM-5-DL_START: Modem (1/1) started firmware download
*Jan 23 11:14:48.702: %MODEM-5-DL_START: Modem (1/2) started firmware download
*Jan 23 11:14:48.702: %MODEM-5-DL_START: Modem (1/3) started firmware download
*Jan 23 11:14:48.702: %MODEM-5-DL_START: Modem (1/4) started firmware download
*Jan 23 11:14:48.702: %MODEM-5-DL_START: Modem (1/5) started firmware download
*Jan 23 11:15:03.042: %MODEM-5-DL_GOOD: Modem (1/0) completed firmware download:
*Jan 23 11:15:03.042: %MODEM-5-DL_GOOD: Modem (1/1) completed firmware download:
*Jan 23 11:15:03.042: %MODEM-5-DL_GOOD: Modem (1/2) completed firmware download:
*Jan 23 11:15:03.042: %MODEM-5-DL_GOOD: Modem (1/3) completed firmware download:
*Jan 23 11:15:03.042: %MODEM-5-DL_GOOD: Modem (1/4) completed firmware download:
*Jan 23 11:15:03.042: %MODEM-5-DL_GOOD: Modem (1/5) completed firmware download:
*Jan 23 11:15:03.046: %MODEM-5-DL_START: Modem (1/6) started firmware download
*Jan 23 11:15:03.046: %MODEM-5-DL_START: Modem (1/7) started firmware download
*Jan 23 11:15:03.046: %MODEM-5-DL_START: Modem (1/8) started firmware download
*Jan 23 11:15:03.050: %MODEM-5-DL_START: Modem (1/9) started firmware download
*Jan 23 11:15:03.050: %MODEM-5-DL_START: Modem (1/10) started firmware download
*Jan 23 11:15:03.050: %MODEM-5-DL_START: Modem (1/11) started firmware download
*Jan 23 11:15:17.394: %MODEM-5-DL_GOOD: Modem (1/6) completed firmware download:
*Jan 23 11:15:17.394: %MODEM-5-DL_GOOD: Modem (1/7) completed firmware download:
*Jan 23 11:15:17.394: %MODEM-5-DL_GOOD: Modem (1/8) completed firmware download:
*Jan 23 11:15:17.394: %MODEM-5-DL_GOOD: Modem (1/9) completed firmware download:
*Jan 23 11:15:17.394: %MODEM-5-DL_GOOD: Modem (1/10) completed firmware download
*Jan 23 11:15:17.394: %MODEM-5-DL_GOOD: Modem (1/11) completed firmware download
.
.
.
*Jan 23 11:16:43.482: %MODEM-5-DL_GOOD: Modem (1/47) completed firmware download

In this example, the specified SPE range gets updated with new firmware in batches of six modems at a time. If double density modems were installed, batches of 12 modems would be updated.

Note The SPE range 1/0 to 1/7 is mapped to firmware 2.7.1.0. However, SPE range 2/0 through 2/7 is still mapped to the firmware that is bundled with the Cisco IOS software.

!

spe 1/0 1/7

 firmware location flash:mica-modem-pw.2.7.1.0.bin

spe 2/0 2/7

 firmware location system:/ucode/mica_port_firmware

!

The following MICA example is for the copy source modem command. Unlike the spe command, the numbers 1/0-1/5 refer to specific modem numbers (slot/port). The busyout keyword will gracefully busy out the modems if the modems are off hook.

cisco#copy bootflash modem

Source filename []? mica-modem-pw.2.6.2.0.bin

Modem Numbers (<slot>/<port> | group <number> | all)? 1/0-1/5

Type of service [busyout/reboot/recovery] busyout

Allow copy of "bootflash:mica-modem-pw.2.6.2.0.bin" to modems? [yes/no]yes

5800#
2d05h: %MODEM-5-DL_START: Modem (1/0) started firmware download
2d05h: %MODEM-5-DL_START: Modem (1/1) started firmware download
2d05h: %MODEM-5-DL_START: Modem (1/2) started firmware download
2d05h: %MODEM-5-DL_START: Modem (1/3) started firmware download
2d05h: %MODEM-5-DL_START: Modem (1/4) started firmware download
2d05h: %MODEM-5-DL_START: Modem (1/5) started firmware download
2d05h: %MODEM-5-DL_GOOD: Modem (1/0) completed firmware download:
2d05h: %MODEM-5-DL_GOOD: Modem (1/1) completed firmware download:
2d05h: %MODEM-5-DL_GOOD: Modem (1/2) completed firmware download:
2d05h: %MODEM-5-DL_GOOD: Modem (1/3) completed firmware download:
2d05h: %MODEM-5-DL_GOOD: Modem (1/4) completed firmware download:
2d05h: %MODEM-5-DL_GOOD: Modem (1/5) completed firmware download:

Step 6 Verify that the new firmware was successfully mapped to the modems.

In the following example:

SPE 1/0 applies to modems 1/0 through 1/5.
SPE 1/1 applies to modem 1/6 through 1/11, and so on.
The MICA modules 0 through 7 in slot 1 are running Version 2.7.1.0 (not 2.6.2.0).
All the modems in slot 2 are still running version 2.6.2.0, which is bundled into the Cisco IOS software image (see the field IOS-Default).

as5800-RS-1# show modem bundled-firmware
List of bundled modem firmware images by slot
  Slot 4
    2.6.2.0
  Slot 5
    2.6.2.0
  Slot 6
    2.6.2.0
  Slot 7
    2.6.2.0
  Slot 8
    2.6.2.0

Task 2. Configuring Modems Using Modem Autoconfigure

This section describes how to apply a new modem capability (modemcap) to an integrated modem. A modemcap is a database of setup strings that is used by the modem autoconfigure function to change a modem's default settings.

Modemcaps have many applications:

A modem's default settings are not optimal. For example, a modem function that you want is not enabled by default.
Two separate modem pools need to be set up in the NAS to perform two different tasks. For example, one pool supports V.90. The other pool has a maximum speed set at 26400 bps to support older modems.
A specialized application is required. For example, a NAS supporting a point-of-sale (POS) application such as a charge card reader. A modemcap is required that will tune the modem for a fast trainup time at the expense of having a slower connect speed.

Always use a modemcap (even if you only want the modem's default settings). To display the modemcaps that are built into the Cisco IOS software, enter the show modemcap command. Modemcaps are configured on a per modem basis. They are not configured on a per modem module or service processing element (SPE) basis.

2.1 Basic Rules for Modem Autoconfigure

The following list describes the basic rules:

Never use the modem autoconfigure discovery command. Applying specific modemcaps reduces the risk of error.
Always use the modem autoconfigure type modem-name command. This command improves your modem's performance. See CSCdk15302 for an explanation.
The modem autoconfigure type mica command can be used to reset any integrated modem (not only MICA), back to its factory defaults. The keyword mica is a built-in modemcap that only functions as &F (return to defaults).
When you use the modem autoconfigure command, be sure that any script reset function is removed. A script reset is redundant and possibly harmful.
A script reset is a chat script that is applied to a line when the line resets. The modem autoconfigure function is applied when the system starts up, not just when the line resets.
When creating a modemcap, ignore all the strange and confusing fields. Put your modem init string into the MSC (Miscellaneous) field:
- Never put an &W into an init string. An &W can wear out the EPROM on modems where this is not a no op (that is, a statement or operation that does nothing).
- For MICA modems, always be sure that &D2 (not &D3) is in effect. See CSCdk15260 and CSCdk15302 for an explanation.

2.2 Modem Autoconfigure K56Flex Example

The following modem-autoconfigure string disables V.8bis/K56Flex. The string &F&D2s53=0 is applied to two MICA modems. Disabling V.8bis reduces trainup time by about two seconds, and it prevents trainup problems with older client modems.

Step 1 Watch the modem autoconfigure function run, so you can see if there are any typos in the modem string:

5800-NAS#debug confmodem

Modem Configuration Database debugging is on
5800-NAS#show debug

Modem Autoconfig:
  Modem Configuration Database debugging is on
5800-NAS#terminal monitor

Step 2 Remove any previous modem autoconfigure entry:

5800-NAS#configure terminal

Enter configuration commands, one per line.  End with CNTL/Z.
5800-NAS(config)#no modemcap entry mica-noKflex

% Modemcap entry 'mica-noKflex' does not exist

Step 3 Add the new entry:

5800-NAS(config)#modemcap edit mica-noKflex misc &F&D2s53=0

Note The MICA and Microcom AT command references are posted at the following URL: http://www.cisco.com/univercd/cc/td/doc/product/access/acs_serv/5800/
mod_info/at/index.htm

Step 4 Apply the new entry to the specified lines. Re-enter the modem autoconfigure command each time you change a modemcap. Modem-autoconfigure strings are not applied to busy modems. Modem strings are applied after modems disconnect.

5800-NAS(config)#line 1 2

5800-NAS(config-line)#modem autoconfigure type mica-noKflex

5800-NAS(config-line)#
Oct 25 19:46:06.960 PDT: TTY1: detection speed (115200) response ---OK---
Oct 25 19:46:06.960 PDT: TTY1: Modem command:  --AT&F&D2s53=0--
Oct 25 19:46:06.960 PDT: TTY2: detection speed (115200) response ---OK---
Oct 25 19:46:06.960 PDT: TTY2: Modem command:  --AT&F&D2s53=0--
Oct 25 19:46:09.520 PDT: TTY1: Modem configuration succeeded
Oct 25 19:46:09.520 PDT: TTY1: Detected modem speed 115200
Oct 25 19:46:09.520 PDT: TTY1: Done with modem configuration
Oct 25 19:46:09.520 PDT: TTY2: Modem configuration succeeded
Oct 25 19:46:09.520 PDT: TTY
5800-NAS(config-line)#

If you want to reset the modem to its factory defaults, do not simply remove the modem autoconfigure command. Rather, replace it with another modem autoconfigure type name command where name is a modemcap whose only action is &F. (In recent Cisco IOS software releases, the built-in mica modemcap entry will do this.)

Task 3. Gathering and Viewing Call Statistics

Making sure that your modems are connecting at the correct connections speeds is an important aspect of managing modems. This section details the following methods for gathering and viewing modem performance statistics:

Note If you detect low connection speeds across all the modems, you may have a faulty channelized T1/E1 or ISDN PRI line connection.

Using the Cisco IOS EXEC (CLI)

The Cisco IOS software command line interface (CLI) contains many modem management show commands. Use these commands to gather and view modem statistics. This section provides a bulleted list detailing some of the most useful commands.

Here is a list of the show modem command options:

AS5800-1#sh modem ?

  <0-1439>            First Modem TTY Number
  bundled-firmware    Bundled modem firmware information for all modem slots
  call-stats          Calling statistics for all system modems
  calltracker         CallTracker modem information
  config              Modem configuration
  connect-speeds      Connection speeds for all system modems
  csm                 CSM modem information
  group               Modem group information
  log                 Modem event log
  operational-status  Modem operational status
  summary             Summary statistics for all system modems
  test                Modem test log
  version             Version information for all system modems
  x/y/z               First Shelf/Slot/Port for Internal Modems
  |                   Output modifiers
  <cr>

Display a summary of the modem call statistics:

5800-NAS#show modem summary

         Incoming calls       Outgoing calls      Busied   Failed   No    Succ
Usage  Succ   Fail  Avail   Succ   Fail  Avail    Out      Dial     Ans   Pct.
  43% 60005   4678     25      3     11      0        0       13     8     92%

Table 3-11 describes some of the significant fields in the previous example.

Table 3-11: Show Modem Summary Field Descriptions

Field Description

Succ 60005
60,005 calls successfully trained up. The Cisco IOS software saw "DSR" go high (still does not mean that PPP negotiated successfully).

Fail 4678
4,678 calls came into the modem, the modem went offhook, but the modem did not train up.

Succ Pct. 92%
The overall success percentage is 92%.

No Ans 8
Eight calls came into the modem but the modem did not go offhook (CPU was too busy). Unless you misconfigured the NAS, this counter should be very low (under 1% of the total calls).

Field	Description
Succ 60005	60,005 calls successfully trained up. The Cisco IOS software saw "DSR" go high (still does not mean that PPP negotiated successfully).
Fail 4678	4,678 calls came into the modem, the modem went offhook, but the modem did not train up.
Succ Pct. 92%	The overall success percentage is 92%.
No Ans 8	Eight calls came into the modem but the modem did not go offhook (CPU was too busy). Unless you misconfigured the NAS, this counter should be very low (under 1% of the total calls).

Display the disconnect reasons for the modems that trained up:

5800-NAS#show modem call-stats 0

 
dial-in/dial-out call statistics
 
       compress  retrain lostCarr userHgup  rmtLink  trainup hostDrop wdogTimr
  Mdm     #   %    #   %    #   %    #   %    #   %    #   %    #   %    #   %
 Total  237      916      413      124     9999     1064     8496        0    
 
  dial-out call statistics
 
         noCarr noDitone     busy    abort dialStrg autoLgon dialTout  rmtHgup
  Mdm     #   %    #   %    #   %    #   %    #   %    #   %    #   %    #   %
 Total 1715        0        0        0        0        0        0        0

: Table 3-12 describes some of the significant fields in the previous example.

Table 3-12: Show Modem Call-Status Field Descriptions

Field Description

rmtLink 9999
RmtLink is the most common disconnect reason. RmtLink means that the modem trained up, error correction was negotiated, and the client DTE decided to hang up. All the call-stat counters do not go higher than 9999.

hostDrop
HostDrop (or dtrDrop) means the Cisco IOS software (DTE) informed the modem to terminate the call. For example:

Idle timeouts

Absolute timeouts

Authentication failures

PPP negotiation failures

The Cisco IOS software learns from the telephone switch that the DS0 was disconnected.

Field	Description
rmtLink 9999	RmtLink is the most common disconnect reason. RmtLink means that the modem trained up, error correction was negotiated, and the client DTE decided to hang up. All the call-stat counters do not go higher than 9999.
hostDrop	HostDrop (or dtrDrop) means the Cisco IOS software (DTE) informed the modem to terminate the call. For example: Idle timeouts Absolute timeouts Authentication failures PPP negotiation failures The Cisco IOS software learns from the telephone switch that the DS0 was disconnected.

: Besides the "hostDrop" message, all other disconnect reasons are not good. If the call trained up without EC, then the peer modem will probably not communicate an orderly disconnect with the Cisco IOS software. For example, the messages "lostCarr" or "retrain" might be displayed even though the peer DTE voluntarily disconnected. The collective total of disconnect reasons should be less than 10% of the total number of calls.

Look at detailed disconnect reasons for individual modems:

5800-NAS#show modem call-stats  

dial-in/dial-out call statistics
 
       compress  retrain lostCarr userHgup  rmtLink  trainup hostDrop wdogTimr
  Mdm     #   %    #   %    #   %    #   %    #   %    #   %    #   %    #   %
  1/0     5   2   23   2    7   1    2   1  971   2   20   1  176   2    0   0
* 1/1     8   3   18   1   12   2    6   4  949   2   29   2  167   1    0   0
  1/2     3   1   14   1    8   1    2   1  954   2   26   2  180   2    0   0
* 1/3     4   1   19   2    9   2    1   0  927   2   21   1  202   2    0   0
* 1/4     1   0   20   2   10   2    2   1  961   2   23   2  192   2    0   0
  1/5     2   0   19   2   10   2    4   3  893   1   30   2  182   2    0   0
  1/6     4   1   20   2   10   2    3   2  778   1   21   1  140   1    0   0
* 1/7     6   2   21   2    7   1    1   0  915   2   25   2  176   2    0   0
* 1/8     5   2   21   2    7   1    2   1 1019   2   28   2  159   1    0   0
  1/9     3   1   10   1    8   1    2   1  939   2   22   2  191   2    0   0
  1/10    1   0   29   3    9   2    1   0  918   2   28   2  194   2    0   0
  1/11    2   0   27   2    9   2    4   3  981   2   27   2  174   2    0   0
* 1/12    7   2   21   2   10   2    5   4  966   2   24   2  182   2    0   0
  1/13    6   2   21   2   10   2    1   0  977   2   32   3  168   1    0   0

: Display a summary of the range of connect speeds. Specify the top speed of interest followed by a 0. This example displays the initial connect speeds in each direction (transmit and receive) for the range of speeds that go up to 56K. No connections happened at 56000 bps. The transmit speed with the highest hit counter is 48K (9161 hits). The receive-connect speeds are all zeros because V.90 is a transmit only speed.

5800-NAS#show modem connect-speeds 56000 0

transmit connect speeds
 
  Mdm   48000  49333  50000  50667  52000  53333  54000  54667  56000 TotCnt
 Tot     9161   5047   1454   3291    813   1427      0     25      0  60012
 Tot %     15      8      2      5      1      2      0      0      0
 
  receive connect speeds
 
  Mdm   48000  49333  50000  50667  52000  53333  54000  54667  56000 TotCnt
 Tot        0      0      0      0      0      0      0      0      0  60012
 Tot %      0      0      0      0      0      0      0      0      0

Inspect the range of speeds below 56000 bps (38667 to 46667). This is the distribution of speeds of PCM users (Kflex users and V.90 users). Compare this output with the previous example. The peak speed is at 48K, which had 9,161 hits—15% of all callers.

5800-NAS#show modem connect-speeds 46666 0

transmit connect speeds
 
  Mdm   38667  40000  41333  42000  42667  44000  45333  46000  46667 TotCnt
 Tot      349    192    700    221    780   2188   1123    804    693  60011
 Tot %      0      0      1      0      1      3      1      1      1
 
  receive connect speeds
 
  Mdm   38667  40000  41333  42000  42667  44000  45333  46000  46667 TotCnt
 Tot        0      0      0      0      0      0      0      0      0  60011
 Tot %      0      0      0      0      0      0      0      0      0

Examine the DS0 timeslots on each T1 that are used to carry the modem calls. The following example shows that the telco is distributing calls into this hunt group evenly across the T1s. There are a total of 29 (20+9) DS0s currently active.

: The high water mark reports the highest number of DS0s that were in use at one time. However, be sure to inspect the entire dial pool. Entire T1s have been known to remain idle in some hunt groups.

5800-NAS#show controllers t1 call-counters 

T1 0:
  DS0's Active: 20
  DS0's Active High Water Mark: 23

  TimeSlot   Type   TotalCalls   TotalDuration
      1       pri        6536       3w1d
      2       pri        6701       2w3d
      3       pri        5789       2w0d
      4       pri        5498       1w2d
      5       pri        5497       3d02h
      6       pri        5126       7w0d
      7       pri        4525       6w1d
      8       pri        4401       5w3d
      9       pri        4096       4w4d
     10       pri        3961       3w3d
     11       pri        3320       3w0d
     12       pri        3138       1w3d
     13       pri        2912       4d05h
     14       pri        2486       6w4d
     15       pri        2042       5w5d
     16       pri        1644       4w5d
     17       pri        1413       4w1d
     18       pri        1071       3w3d
     19       pri         884       2w4d
     20       pri         675       2w0d
     21       pri         507       1w3d
     22       pri         380       1w1d
     23       pri         263       5d17h
T1 1:
  DS0's Active: 9
  DS0's Active High Water Mark: 23
  TimeSlot   Type   TotalCalls   TotalDuration
      1       pri        8985       3w2d
      2       pri        8650       2w4d
      3       pri        8594       1w3d
      4       pri        7813       4d03h
      5       pri        7671       6w3d
      6       pri        6955       5w5d
      7       pri        6492       4w3d
      8       pri        6343       3w4d
      9       pri        5668       2w3d
     10       pri        5398       6d09h
     11       pri        4842       6w6d
     12       pri        4413       5w3d
     13       pri        4050       4w1d
     14       pri        3339       2w6d
     15       pri        3019       1w2d
     16       pri        2493       1d14h
     17       pri        2104       6w0d
     18       pri        1664       5w1d
     19       pri        1395       3w6d
     20       pri        1094       3w3d
     21       pri         811       2w6d
     22       pri         688       2w0d
     23       pri         482       1w3d
 
Total DS0's Active High Water Mark: 46

Using Modem Call-Record Terse

Starting with Cisco IOS Releases 11.3AA and 12.0T, modem call records can be sent to syslog and examined to perform statistical analysis.

For example, you can monitor:

Modulation trends such as V.90 verses V.34
Call time durations (consistent short connection times on a modem, regular Lost Carrier counts)
Unavailable user IDs
PPP negotiation or authentication failures

The following example enables modem call-records and sends the logs to wherever your syslog output goes, for example:

To the console—If you do not have the no logging console command enabled.
To the terminal line—If you have the terminal monitor command enabled.
To a syslog host—If you have one configured.

5800-NAS#configure terminal

Enter configuration commands, one per line.  End with CNTL/Z.
5800-NAS(config)#modem call-record terse

 
*Jan  1 04:19:50.262: %CALLRECORD-3-MICA_TERSE_CALL_REC: DS0 slot/contr/chan=0/0/0, 
slot/port=2/0, call_id=18, userid=(n/a), ip=0.0.0.0, calling=4082329440, called=5710945, 
std=V.34+, prot=LAP-M, comp=V.42bis both, init-rx/tx b-rate=26400/26400, finl-rx/tx 
b-rate=26400/26400, rbs=0, d-pad=None, retr=2, sq=3, snr=25, rx/tx chars=79/94701, bad=0, 
rx/tx ec=60/204, bad=521, time=698, finl-state=Steady, disc(radius)=(n/a)/(n/a), 
disc(modem)=A220 Rx (line to host) data flushing - not OK/EC condition - locally 
detected/received DISC frame -- normal LAPM termination

Using SNMP

Modem connect speeds can be graphed using SNMP MIBs. The graph shown in Figure 3-12 was created with Cisco Access Manager (CAM). The graph describes the modem connect-speed performance activity of one NAS for one month. The following connect speeds are transmitted by the NAS and received by the client modem. Most of the calls performed between 28000 and 31200 bps. This NAS is one member of an access stack.

Graphed Modem-Connect Speeds for One Month

Table of Contents

Operations

Asynchronous interfaces: