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The following sections are provided:
The Continuity Test (COT) subsystem supports the Continuity Test, which is required by the SS7 network to conduct loopback and tone check testing on the path before a circuit is established.
COT will detect any failure of DS0 channels. It is required for North American SS7 compliance.
The Cisco SS7/C7 Dial Access Solution System runs on the Cisco AS5200, AS5300, and AS5800 Access Servers in conjunction with Cisco Signaling Controller (CSC) on the Network Access Servers (NAS) to enhance features previously introduced in Cisco IOS release 11.3(5)AA. These features include:
Provided is support for IP connection to SS7/C7 Singnaling Controller and associated continuity testing. This support allows carrier customers to connect their access servers to the Public Switch Telephone Network (PSTN) directly, by using Signaling System #7 (SS7/C7) signaling protocols. The SS7/C7 signaling links terminate on a separate UNIX system called the Signaling Controller (SC2200). The SC2200 maps incoming calls, which are signaled via SS7/C7, to bearers on the access servers. The access servers and SC2200 interact to set up and tear down calls using an extended Q.931 protocol over Q.921 and UDP. In this manner, the access servers and SC2200 form a system that emulates an end-office switch in the PSTN.
The Cisco SS7/C7 Dial Access Solution System uses the ISDN Q.931 and Q.921 protocols over a Redundant Link Manager (RLM) module. RLM makes use of the UDP protocol to transfer information from the NAS to the CSC and vice versa. The ISDN module works in conjunction with the RLM.
You must have installed MICA 2.6.1.0 portware, which supports the COT feature.
The Cisco SS7/C7 Dial Access Solution System runs on the Cisco AS5200, AS5300, and AS5800 Access Servers in conjunction with the following Cisco technologies:
The following hardware platforms support this feature:
None.
COT---Continuity test. Used to test individual DS0 channels via either loopback or tone detection and generation.
DSP---Digital Signal Processor. Many firmware functions of a NAS are performed by DSPs which are generally provisioned as banks of shared resources among all the DS0s. Typical DSP functions include: data modems, voice CODECS, fax modems and CODECs, and low-level signaling (such as CAS/R2).
HDLC---High-Level Data Link Control.
ISP---Internet service provider.
NAS---Network access server. A Cisco platform (or collection of platforms such as an AccessPath system which interfaces between the packet world (for example, the Internet) and the circuit world (for example, the PSTN).
PSTN---Public Switched Telephone Network.
SAS---Signaling access server. A server which interfaces between the NAS and the SS7 signaling network.
SLM---Signaling link management.
SNIP---SAS NAS Interface Protocol.
SS7---Signaling System Number 7.
SSP---Service switching point. An element of an SS7-based Intelligent Network which performs call origination, termination, or tandem switching. The combined NAS/SAS system looks like a single SSP to the SS7 network.
STP---Signal transfer point. An element of an SS7-based Intelligent Network which performs routing of the SS7 signaling.
T1---A digital carrier used to transmit a DS-1 formatted digital signal at 1.544 MHz.
TDM---Time-division multiplexing. The transmission scheme employed by all manner of digital circuits in the PSTN.
TIC---Trunk identification code.
RLM---Redundant link manager.
VoIP---Voice over IP. The ability to carry normal telephony-style voice over an IP-based Internet with POTS-like functionality, reliability, and voice quality.
The SS7 (Signaling System Number 7) network, in order to detect failures of DS0 channels, will at times request a Continuity Test (COT) of a channel before establishing a call. ITU-based networks use only the loopback method for continuity test. However, ANSI-based network usage varies. Some use only the loopback method and others use both tone and loopback methods. For this release of the SS7 system, only the loopback method is supported.
Continuity test requests will be received over an SS7 signaling path and processed within the SAS (Signaling Access Server). The SAS will request that the NAS put the particular bearer in external loopback mode (loopback incoming receive to outgoing transmit) or to insert a transponder in the incoming circuit. The continuity test will last until a COT message is received.
None.
The three new COT commands are show, clear, and debug. All other commands used with this feature are documented in the Cisco IOS Release 12.0 command references.
Use the clear cot summary command to reset the counters.
clear cot summaryThis command has no keywords or arguments.
Privileged EXEC.
This command first appeared in Cisco IOS Release 11.3(7).
There is no display generated, but the counters in the show cot summary command would be all zeros.
show cot dsp
show cot request
show cot summary
debug cot
To display information about the COT DSP (Digital Signal Processor) configuration or current status, use the show cot dsp command.
show cot dsp { config | status } applique/ds0 (Cisco AS5200 and Cisco AS5300)config | Show COT DSP configuration. |
status | Show COT DSP status. |
applique | ID of the hardware unit that provides the external interface connections from a router to the network. Number of COT operation request. |
ds0 | Number of COT operation request. |
shelf | Shelf ID of COT operation request. |
slot# | Designate the slot number, 0 to 2. |
Privileged EXEC.
This command first appeared in Cisco IOS Release 11.3(7).
The following is sample output from the show cot dsp command that shows the COT DSP configuration.
5300# show cot dsp status 1/1 Rx Freq 2010 Hx Tx Freq 1780 Hx Tx then Rx mode in WaitRxOn state 5300# show cot dsp config 1/1 Rx Freq 2010 Hx Tx Freq 1780 Hx Tx then Rx mode Timeout value:0
Table 1 describes the fields in these displays.
| Field | Description |
Rx Freq | The COT receive tone frequency. |
Tx Freq | The COT transmit tone frequency. |
Tx then Rx | Type of COT operation. |
WaitRxOn | The state of the COT DSP. |
clear cot summary
show cot request
show cot summary
debug cot
To display information use the show cot request command.
show cot request shelf/slot/applique/ds0 (Cisco AS5200 and Cisco AS5300)shelf | Shelf ID of COT operation request. |
slot# | Designate the slot number, 1 to 4. |
applique | Hardware unit that provides the external interface connections from a router to the network. Number of COT operation request. |
ds0 | Number of COT operation request. |
Privileged EXEC.
This command first appeared in Cisco IOS Release 11.3(7).
The following is sample output from the show cot request command.
5300# show cot request 1/1 00:19:29:COT Request@ 0x61064A20, CDB@ 0x60EBB48C, Params@0x61123DBC 00:19:29: request type = COT_CHECK_TONE_ON 00:19:29: shelf 0 slot 0 appl_no 1 ds0 1 00:19:29: duration 100000 key FFF1 freqTx 1780 freqRx 2010 00:19:29: state COT_WAIT_TD_ON_CT 00:19:29: event_proc(0x6093B55C)
Table 2 describes the fields in these displays.
| Field | Description |
|---|---|
COT Request | Internal COT operation request. |
CDB | Internal controller information. |
Params | Internal COT operation request parameters. |
request type | Type of COT operation. |
duration | Timeout duration of COT operation. |
key | COT operation identifier. |
freqTx | Transmit tone frequency. |
freqRx | Receive tone frequency. |
state | COT subsystem machine state. |
event_proc | COT subsystem state machine function. |
clear cot summary
show cot dsp
show cot summary
debug cot
To display information about the COT activity, use the show cot summary command.
show cot summaryThis command has no keywords or arguments.
Privileged EXEC.
This command first appeared in Cisco IOS Release 11.3(7).
The following is sample output from the show cot summary command that shows the COT DSP configuration.
5300# show cot summary router# 08:23:24: COT Subsystem - Request Statistics 08:23:24: COT Request Type = COT_DS0_LOOPBACK_ON 08:23:24: # of request(s) : 4 # of restart requests(s) : 0 08:23:24: # of successful request(s): 4 # of invalid request(s) : 0 08:23:24: # of cot timeout(s) : 0 # of dsp error(s) : 0 08:23:24: # of no dsp(s) : 0 08:23:24: COT Request Type = COT_DS0_LOOPBACK_OFF 08:23:24: # of request(s) : 4 # of restart requests(s) : 0 08:23:24: # of successful request(s): 4 # of invalid request(s) : 0 08:23:24: # of cot timeout(s) : 0 # of dsp error(s) : 0 08:23:24: # of no dsp(s) : 0 08:23:24: COT Request Type = COT_CHECK_TONE_ON 08:23:24: # of request(s) : 7 # of restart requests(s) : 0 08:23:24: # of successful request(s): 3 # of invalid request(s) : 2 08:23:24: # of cot timeout(s) : 1 # of dsp error(s) : 0 08:23:24: # of no dsp(s) : 0 08:23:24: COT Request Type = COT_CHECK_TONE_OFF 08:23:24: # of request(s) : 0 # of restart requests(s) : 0 08:23:24: # of successful request(s): 0 # of invalid request(s) : 0 08:23:24: # of cot timeout(s) : 0 # of dsp error(s) : 0 08:23:24: # of no dsp(s) : 0
08:23:24: COT Request Type = COT_CUT_IN_TRANSPONDER 08:23:24: # of request(s) : 0 # of restart requests(s) : 0 08:23:24: # of successful request(s): 0 # of invalid request(s) : 0 08:23:24: # of cot timeout(s) : 0 # of dsp error(s) : 0 08:23:24: # of no dsp(s) : 0 08:23:24: COT Request Type = COT_CUT_OUT_TRANSPONDER 08:23:24: # of request(s) : 0 # of restart requests(s) : 0 08:23:24: # of successful request(s): 0 # of invalid request(s) : 0 08:23:24: # of cot timeout(s) : 0 # of dsp error(s) : 0 08:23:24: # of no dsp(s) : 0
Table 3 describes the fields in these displays.
| Field | Description |
# of request(s) | Number of COT operation requests. |
# of successful request(s) | Number of successful COT operation requests. |
# of cot timeout(s) | Number of COT subsystem timeouts. |
# of no dsp(s) | Number of COT operation requests rejected because of unavailable DSP. |
# of restart request(s) | Number of COT operation requests restarted. |
# of invalid request(s) | Number of invalid COT operation requests. |
# of dsp error(s) | Number of DSP errors. |
clear cot summary
show cot dsp
show cot request
debug cot
Use the debug cot command to display information about the COT functionality. The no form of this command disables debugging output.
debug cot { api | dsp | queue | detail }api | Display information about the COT Application Program Interface (API). |
dsp | Display information related to the COT/DSP interface. Typical DSP functions include: data modems, voice CODECS, fax modems and CODECs, and low-level signaling such as CAS/R2. |
queue | Display information related to the COT internal queue. |
detail | Display information about COT internal detail; summary of debug cot api, debug cot dsp, and debug cot queue. |
This command first appeared in Cisco IOS Release 11.3(7).
Figure 1 shows sample debug cot api output.
5300# debug cot api COT API debugging is on 08:29:55: cot_request_handler(): CDB@0x60DEDE14, req(COT_CHECK_TONE_ON): 08:29:55: shelf 0 slot 0 appl_no 1 ds0 1 08:29:55: freqTX 2010 freqRX 1780 key 0xFFF1 duration 60000
Table 4 describes the fields in these displays.
| Field | Description |
|---|---|
CDB | Internal controller information. |
req | Type of COT operation requested. |
shelf | Shelf ID of COT operation request. |
slot | Designate the slot number, 1 to 4. |
application | Hardware unit that provides the external interface connections from a router to the network. |
ds0 | Number of COT operation request. |
key | COT operation identifier. |
duration | Timeout duration of COT operation. |
freqTX | Requested transmit tone frequency. |
freqRX | Requested receive tone frequency. |
Figure 2 shows sample debug cot dsp output.
5300# debug cot dsp 5300# 00:10:42:COT:DSP (1/1) Allocated 00:10:43:In cot_callback 00:10:43: returned key 0xFFF1, status = 0 00:10:43:COT:Received DSP Q Event 00:10:43:COT:DSP (1/1) Done 00:10:43:COT:DSP (1/1) De-allocated
Table 5 describes the fields in these displays.
| Field | Description |
DSP (1/1) Allocated | The slot and port of the DSP allocated for the COT operation. |
Received DSP Q Event | Indicates the COT subsystem received an event from the DSP. |
DSP (1/1) Done | The slot and port of the DSP transitioning to IDLE state. |
DSP (1/1) De-allocated | The slot and port of the DSP de-allocated after the completion of the COT operation. |
Figure 3 shows sample debug cot queue output.
5300# debug cot queue 5300# 00:11:26:COT(0x60EBB48C):Adding new request (0x61123DBC) to In Progress Q 00:11:26:COT(0x60EBB48C):Adding COT(0x61123DBC) to the Q head 00:11:27:In cot_callback 00:11:27: returned key 0xFFF1, status = 0
Table 6 describes the fields in these displays.
| Field | Description |
COT | Internal COT operation request. |
Adding new request | Internal COT operation request queue. |
Figure 4 shows sample debug cot detail output.
5300# debug cot detail 5300# 00:04:57:cot_request_handler():CDB@0x60EBB48C, req(COT_CHECK_TONE_ON): 00:04:57: shelf 0 slot 0 appl_no 1 ds0 1 00:04:57: freqTX 1780 freqRX 2010 key 0xFFF1 duration 1000 00:04:57:COT:DSP (1/0) Allocated 00:04:57:COT:Request Transition to COT_WAIT_TD_ON 00:04:57:COT(0x60EBB48C):Adding new request (0x61123DBC) to In Progress Q 00:04:57:COT(0x60EBB48C):Adding COT(0x61123DBC) to the Q head 00:04:57:COT:Start Duration Timer for Check Tone Request 00:04:58:COT:Received Timer Event 00:04:58:COT:T24 Timer Expired 00:04:58:COT Request@ 0x61123DBC, CDB@ 0x60EBB48C, Params@0x61123E08 00:04:58: request type = COT_CHECK_TONE_ON 00:04:58: shelf 0 slot 0 appl_no 1 ds0 1 00:04:58: duration 1000 key FFF1 freqTx 1780 freqRx 2010 00:04:58: state COT_WAIT_TD_ON_CT 00:04:58: event_proc(0x6093B55C) 00:04:58:Invoke NI2 callback to inform COT request status 00:04:58:In cot_callback 00:04:58: returned key 0xFFF1, status = 0 00:04:58:Return from NI2 callback 00:04:58:COT:Request Transition to IDLE 00:04:58:COT:Received DSP Q Event 00:04:58:COT:DSP (1/0) Done 00:04:58:COT:DSP (1/0) De-allocated
Because debug cot detail is a summary of debug cot api, debug cot dsp, and debug cot queue, the field descriptions are the same.
For additional software configuration information, see the following publications:
Posted: Fri Jun 18 19:03:23 PDT 1999
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