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This feature adds support for T1 Channel Associated Signaling (CAS) and limited support for E1 R2 signaling to the Cisco AS5300 universal access server with the Voice Feature Card (VFC).
 | Caution Cisco IOS Release 11.3(6)NA2 requires VCWare version 2.4 code. Cisco IOS Release 11.3(7)NA requires VCWare version 2.5. |
CAS is the transmission of signaling information within the voice channel. Various types of CAS signaling are available in the T1 world. The most common forms of CAS signaling are loop-start, ground-start, and E&M. The biggest disadvantage of CAS signaling is its use of user bandwidth to perform signaling functions. CAS signaling is often referred to as robbed-bit-signaling because user bandwidth is being "robbed" by the network for other purposes. In addition to receiving and placing calls, CAS signaling also processes the receipt of DNIS and ANI information, which is used to support authentication and other functions.
T1 CAS capabilities have been implemented on the Cisco AS5300 VFC to enhance and integrate T1 CAS capabilities on common central office (CO) and PBX configurations for voice calls. The service provider application for T1 CAS includes connectivity to the public network using T1 CAS from the Cisco AS5300 to the end office switch. In this configuration, the Cisco AS5300 captures the dialed-number or called-party number information and passes it along to the upper level applications for IVR script selection, modem pooling, and other applications. Service providers also require access to calling party number, ANI, for user identification, for billing account number, and in the future, more complicated call routing.
Service providers who implement VoIP include traditional voice carriers, new voice and data carriers, and existing Internet service providers. Some of these service providers might use subscriber side lines for their VoIP connectivity to the PSTN; others will use tandem-type service provider connections.
The T1 CAS interface is used for both connection to private PBX's, and to the PSTN. This feature is required by both Enterprise customers and Service Providers in North America. For most enterprise customers, T1 CAS is the only kind of line they use from the PSTN, and for connecting to their PBX's, E&M may be the only option.
ANI—Automatic number identification (calling party number).
CAS—Channel associated signaling.
CO—Central office.
CSM—Call switching module.
CT1—Channelized T1.
DNIS—Dialed number identification service. Same as called party number.
DSP—Digital signal processor.
DTMF—Dual tone multi-frequency.
EAIN—Bellcore FGD Exchange Access International Signaling.
EANA—Bellcore FGD Exchange Access North American Signaling.
E&M—Ear and mouth. A signaling technique for two and four wire telephone and trunk interfaces.
FGD—Bellcore Feature Group D.
FXO—Foreign Exchange Office.
FXS—Foreign Exchange Subscriber (as in FXS-loop-start and FXS-ground-start). FXS loop and ground start protocols are a type of signaling used to indicate the beginning of a call. The FXS interface is used on the line-side access to CO (for example, communication between CO and key system).
MF—Multiple Frequency, an interoffice address signaling method in which 10 decimal digits and five auxiliary signals are each represented by a pair of the following frequencies: 700, 900, 1100, 1300, 1500 and 1700 Hz.
PSTN—Public Switched Telephone Network.
RGW—Residential gateway.
RLCF—Reverse loop current feed.
Session Application—Application in the VoIP system responsible for providing the telephony user interface.
SAS—Special Exchange Subscriber (as in SAS loop-start and ground-start). Identical to FXS loop and ground start in functionality, but use of the A and B bits are different. (SAS transmitted B Bits are complementary to FXS transmitted B bits. SAS received A bits are complementary to FXS received A bits).
SGCP—Simple gateway control protocol.
SGCP Application—The application in the VoIP via SGCP system responsible for SGCP call management.
SPI—Service provider interface.
TGW—Trunking gateway.
TP—Bellcore FGD Terminating Protocol.
FGD-OS—Bellcore FGD Operator Services Signaling.
VFC—Voice feature card. The voice processing card which resides in one of the slots in the Cisco AS5300 platform. Up to five DSP modules (DSPM) can be installed onto the VFC to perform voice processing for up to 30 B channels and potentially 60 B channels. The VFC is a multi-DSP coprocessing card and software package that adds VoIP capabilities to the Cisco AS5300.
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. VoIP is a blanket term which generally refers to Cisco's standards-based (for example, H.323) approach to IP voice traffic.
This feature is supported on the following platform:
The new functionality of T1 CAS for VoIP includes all the T1 CAS and E1/R2 signaling already supported for the Cisco AS5300 in data applications, with the addition of dialed-number and calling-party number capture whenever available.
The implementation of this feature supports the following T1 CAS signaling systems for VoIP applications:
Internet service providers can provide switched 56-kbps access to their customers using the Cisco AS5300. The subset of T1 CAS (robbed bit) supported features are as follows:
The sample configuration is only intended as an example of how to use the commands to configure T1 CAS. It is not an example of a complete configuration for setting up the entire signaling for a telco network.
To configure T1 CAS for use with VoIP, perform the following tasks:
The following sample configuration is an example of how to configure the voice ports as a cas-group for the channelized T1 lines.
| Step | Command | Purpose | ||
|---|---|---|---|---|
| 5300> enable Password: <password> 5300# | Enter enable mode. Enter the password. You have entered enable mode when the prompt changes to | ||
| 5300# config term Enter configuration commands, one per line. End with CNTL/Z. 5300(config)# | Enter global configuration mode. You have entered global configuration mode when the | ||
| 5300(config)# controller t1 0
| Enter controller configuration mode to configure your controller port. The controller ports are labeled 0 through 3 on the Quad T1/PRI and E1/PRI cards. | ||
| 5300(config-controller)# framing esf | Enter your telco's framing type. | ||
| 5300(config-controller)# clock source line primary | Enter the clock source for the line. Configure other lines as clock source secondary or internal. Note that only one PRI can be clock source primary and one PRI can be clock source secondary. | ||
| 5300(config-controller)# linecode b8zs | Enter your telco's line code type. | ||
| 5300(config-controller)# cas-group 1 timeslots 1-24 type e&m-fgb dtmf dnis | Configure all channels for E&M, FXS, and SAS analog signaling. Enter 1-24 for T1. If E1, enter 1-31. Signaling types include e&m-fgb, e&m-fgd, e&m-immediate-start, fxs-ground-start, fxs-loop-start, sas-ground-start, and sas-loop-start. You must use the same type of signaling that your central office uses. For E1 using the Anadigicom converter, use cas e&m-fgb signaling. | ||
| 5300(config-controller)# controller t1 1 5300(config-controller)# framing esf 5300(config-controller)# linecode b8Zs 5300(config-controller)# clock source line secondary 5300(config-controller)# cas-group 2 timeslots 1-24 type e&m-fgb | Repeat steps 3 to 7 to configure each additional controller (there are four). In this example, note that the controller number is 1, instead of 0. The clock source is secondary, instead of primary. The cas-group is 2, instead of 1. | ||
| 5300(config-controller)# controller T1 2 5300(config-controller)# clock source internal 5300(config-controller)# cas-group 0 timeslots 1-24 type e&m-fgd mf ani-dnis | Repeat steps 3 to 7 to configure each additional controller (there are four). | ||
| 5300(config-controller)# controller T1 3 5300(config-controller)# clock source internal | Repeat steps 3 to 7 to configure each additional controller (there are four). | ||
| 5300(config-controller)# dial-peer voice 3070 pots destination-pattern +30... port 0:1 prefix 30 | Enter the dial peer configuration mode to configure a POTS peer. | ||
| 5300(config-controller)# dial-peer voice 4080 pots destination-pattern +40... direct-inward-dial port 1:2 prefix 40 | Specify destination pattern, and direct inward dial for each POTS peer. | ||
| 5300(config-controller)# dial-peer voice 1050 pots destination-pattern +10... direct-inward-dial prefix 50 | Specify the destination pattern and the direct inward dial for the dial peer. | ||
| 5300(config-controller)# dial-peer voice 2060 pots destination-pattern +20... direct-inward-dial prefix 60 | Specify the destination pattern and the direct inward dial for the dial peer. | ||
| 5300(config-controller)# dial-peer voice 5050 voip answer-address 10... destination-pattern +50... |
| ||
| 5300(config-if)# Ctrl-Z 5300# %SYS-5-CONFIG_I: Configured from console by console | Return to enable mode. This message is normal and does not indicate an error. |
To verify your controller is up and running and no alarms have been reported:
5300# sh cont t1 2
T1 2 is up.
No alarms detected.
Version info of slot 0: HW: 2, Firmware: 16, PLD Rev: 0
Manufacture Cookie Info:
EEPROM Type 0x0001, EEPROM Version 0x01, Board ID 0x42,
Board Hardware Version 1.0, Item Number 73-2217-4,
Board Revision A0, Serial Number 06467665,
PLD/ISP Version 0.0, Manufacture Date 14-Nov-1997.
Framing is ESF, Line Code is B8ZS, Clock Source is Internal.
Data in current interval (269 seconds elapsed):
0 Line Code Violations, 0 Path Code Violations
0 Slip Secs, 0 Fr Loss Secs, 0 Line Err Secs, 0 Degraded Mins
0 Errored Secs, 0 Bursty Err Secs, 0 Severely Err Secs, 0 Unavail Secs
Make sure the show controller t1 output is not reporting alarms or violations.
This section documents new or modified commands. All other commands used with this feature are documented in the Cisco IOS Release 11.3 command references.
To configure a channel group using CAS signaling, the cas-group command is used to specify the channels/timeslots to be allocated for the CAS group and the CAS signaling type.
cas-group channel timeslots range type signal [[tone] [service]]Two new service type attributes have been added to the cas group command.
Use the no form of this command to disable channel associated signaling for one or more timeslots. The service type are:
For e&m-fgb and e&m fgd, there are also tone type:
For these two CAS signaling types the tone type is always set to mf and dnis is always required. They can be used for both voice and data calls.
channel | Specifies a single channel group number, which can be between 0 and 23. |
timeslots range | Specifies a timeslot range of values from 1 to 24. |
type signal | Specifies the type of robbed bit signaling. Choose one of the following signal types to configure: · e&m-fgb dtmf [dnis] · e&m-fgd dtmf [dnis] · e&m-immediate-start—Specifies ear and mouth channel signaling with immediate start support. · fxs-loop-start— Specifies Foreign Exchange Station loopstart signaling support. · fxs-ground-start—Specifies Foreign Exchange Station ground start signaling support. · sas-loop-start—Specifies Special Access Station loopstart signaling support. · sas-ground-start—Specifies Special Access Station ground start signaling support. |
tone | specify dtmf or mf |
service | specify voice or data |
cas-group 0 timeslots 1-24 type e&m-fgb dtmf
Controller configuration
This command first appeared in Cisco IOS Release 11.2.
Use this command to enable an integrated modem to receive and transmit incoming and outgoing call signaling (such as on-hook and off-hook) through each T1 controller.
By configuring DNIS as part of the cas-group command, the system can collect DNIS digits for incoming calls which can be directed as VoIP calls, or alternately can be redirected to specific modem pools setup for different customers or uses. To support modems you must be running MICA modems in the system and have at least 10% of your total modems in the default modem pool.
The following example configures the required signaling to support modem pooling and the digital number identification service (DNIS) over channelized T1 lines on a Cisco AS5300.
router# configure terminal Enter configuration commands, one per line. End with CNTL/Z. router(config)# controller t1 0 router(config-controller)# cas-group 0 timeslots 1-24 type e&m-fgb dtmf dnis router(config-controller)# exit router(config)# router(config)# modem-pool accounts1 router(config-modem-pool)# pool-range 30-50 router(config-modem-pool)# called-number 2000 max-conn 21 router(config-modem-pool)# exit router(config)#
Posted: Tue Sep 5 13:07:27 PDT 2000
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