Document ID: 18688
Contents
Network Diagram
Configurations
Verifying the Configuration
Known Issues
Tools Information
Related Information
Introduction
This document provides a sample configuration of unstructured Circuit Emulation Services (CES) using Synchronous Residual Time Stamp (SRTS) and Permanent Virtual Circuits (PVCs) on Cisco 3600 Router platforms. Unstructured service means that both SRTS and PVCs utilizes the entire T1/E1 bandwidth. The ATM switch doesn't look into the T1/E1, but simply reproduces a stream of bits with clocking from the receiving port to the target port. This example uses SRTS for clocking. In this asynchronous clocking method, SRTS measures the difference between the service clock (received on the CBR interface) and the network-wide reference clock. This difference is the Residual Time Stamp (RTS). For a more detailed explanation on SRTS, please read An Introduction to Circuit Emulation Services.
Hardware and Software Versions
To configure CES on a Cisco 3600 router series, the following is required:
- An ATM OC-3 network module with voice processing deck (NM-1A-OC3SMI-1V or NM-1A-OC3MM-1V).
- A one or two port T1 or E1 multiflex trunk interface card for a voice connection.
Note: To install a multiflex trunk interface card in a network module, see theWAN Interface Cards Hardware Installation Guide.
The part numbers of the possible T1 or E1 cards are:
- VWIC-1MFT-T1=
- VWIC-1MFT-E1=
- VWIC-2MFT-T1=
- VWIC-2MFT-E1=
- VWIC-2MFT-T1-DI=
- VWIC-2MFT-E1-DI=
The ATM OC-3 network module with voice processing deck requires Cisco IOS® Release 12.1(2)T, 12.2, 12.2T or later.
All Cisco 3600 router series support CES between the E1/T1 VWIC and the ATM interface located on the same module. In addition, the Cisco 3660 router series is capable of running CES across network modules if the following criteria is met:
- Cisco IOS Release is 12.2(4)T and above.
- A multiservice interchange card, also called a MIX module (MIX-3660-64), is installed. Click here for more information.
This document assumes that the E1 VWIC is located on the ATM network module.
Network Diagram
The following network topology will be used:
Notes:
- Algiers is a Cisco 7200 router series with a two port channelized E1 card that is used as an edge device on both ends of the network.
- Damme is a Cisco 3640 router series with NM-1A-OC3MM-1V and VWIC-2MFT-E1 network modules running Cisco IOS Release 12.1(2)T.
- Procida is a Catalyst 8540MSR switch with a CES port running Cisco IOS Release 12.1(7a)EY1.
- PVC 0/1000 is for the ATM connection between the Cisco 3640 router and the Catalyst 8540MSR.
Configurations
Shown below are the relevant portions of the configuration for CES in the Cisco 3640 router (Damme) and the Catalyst 8540MSR (Procida). The configuration of the Cisco 7200 router (Algiers) is not displayed since the configuration provides nothing relevant to CES. The hyperlinks shown in the configuration below provide a more detailed explanation of each command.
| Damme (3640) |
|---|
hostname Damme ! ! ces 2/0 clock-select 1 ATM2/0 |
| Procida (cat8540MSR) |
|---|
hostname Procida ! network-clock-select 1 ATM0/1/0 ! interface CBR2/1/0 no ip address ces dsx1 framing E1_CRC_MF_LT ces aal1 clock Srts ces circuit 0 circuit-name test ces PVC 0 interface ATM0/1/0 vpi 0 vci 1000 |
Notice that the E1 framing used above is E1 CRC4 no-CAS and is used on both sides.
Verifying the Configuration
This section provides a set of useful commands to help confirm that the configuration is working properly.
The show ip interface brief command displays the status of the interfaces used as the edge device (Cisco 7200). In this configuration, interface Serial2/0:0 is connected to the Cisco 3640 router, and interface Serial 2/1:0 is connected to the Catalyst 8540MSR. Note that the status of both interfaces are up.
Algiers#show ip interface brief Interface IP-Address OK? Method Status Protocol Serial2/0:0 unassigned YES unset up up Serial2/1:0 unassigned YES unset up up
Another useful command is show cdp neighbors, which displays detailed information about neighboring devices discovered using Cisco Discovery Protocol (CDP).
Algiers#show cdp neighbors Capability Codes: R - Router, T - Trans Bridge, B - Source Route Bridge S - Switch, H - Host, I - IGMP, r - Repeater Device ID Local Intrfce Holdtme Capability Platform Port ID Algiers.atm.ciscoSer 2/0:0 143 R 7202 Ser 2/1:0 Algiers.atm.ciscoSer 2/1:0 143 R 7202 Ser 2/0:0
Show Commands for the Cisco 3640 Router
The CES connection status can be checked on the Cisco 3640 router (Damme) by using the show ces 2/0 command. The CES connection below shows a normal state using SRTS. Most of the output given by this command is shown below with the exception of the last portion which does not provide relevant CES information. This output below shows the clocking mode, SRTS in this case, the VPI/VCI (1/1000) and the Line coding (hdb3) in bold type.
Damme#show ces 2/0 CURRENT VPD CES CLOCK: Set to ATM ATM CLOCKING: Clock Source is Line VPD BASE ADDRESS->(0x3D600000) Single Mode Long VPD Installed VIC/WIC PRESENT-> 1 port E1 humvee installed CONTROLLER CLOCKING-> PORT[0]: Clock Source is Line DCU [0]: port State: active alarm State: normal Loop Type: noloop Clocking Mode: srts Data Mode: clearChannel Framing Type: e1-crc Line Coding: hdb3 t1Cas: off tsInUse: 00000000 VPI/VCI 0/1000 CES AAL1 Input cells 3076428 CES AAL1 Output cells 3076428 implicitRestart 1 overflow 0 [snip]
The show connect all command indicates whether or not the ATM connections on the Cisco 3640 router are UP.
Damme#show connect all ID Name Segment 1 Segment 2 State ======================================================================== 5 test ATM2/0 PVC 0/1000 E1 2/0 00 UP
The show dcu leds command confirms the status of the CES port LEDs. As seen in the output below, the "Current State" is UP and the router is using the ATM 2/0 and E1 2/0 segments.
Damme#show dcu leds 2/0 [0]: Normal Damme#sh connect name test Connection: 5 - test Current State: UP Segment 1: ATM2/0 PVC 0/1000 Segment 2: E1 2/0 00 TDM timeslots in use: 1-31 (31 total) Internal Switching Elements: VPD
Show Commands for the Catalyst 8540MSR
To verify that there are no clocking slips, use the show ces interface cbr x/y/z command on the Catalyst Switch 8540MSR to see if the underflows or overflows are increasing. This command also displays the following:
- Line state and all T1/E1 error counters (the definition of all counters are in RFC 1406
). - Port and service configuration. Make sure that the line-code and framing configured on the switch is configured the same as configured on the CPE devices. See the sample output below:
Procida#show ces int cbr 2/1/0 Interface: CBR2/1/0 Port-type:E1-120ohms-DCU IF Status: UP Admin Status: UP Channels in use on this port: 1-31 LineType: E1_CRC_MF_LT LineCoding: HDB3 LoopConfig: NoLoop SignalMode: NoSignalling XmtClockSrc: network-derived DataFormat: UnStructured AAL1 Clocking Mode: Srts LineLength: 0_110 e1InternationalBits 0x3, e1NationalBits 0x1F, e1MultiFrameBits 0xB LineState: NoAlarm Errors in the Current Interval: PCVs 0 LCVs 0 ESs 0 SESs 0 SEFSs 0 UASs 0 CSSs 0 LESs 0 BESs 0 DMs 0 Errors in the last 24Hrs: PCVs 0 LCVs 1532 ESs 19 SESs 0 SEFSs 0 UASs 0 CSSs 0 Less 0 BESs 0 DMs 4Input Counters: 3702066 cells, 173997102 bytes Output Counters: 3702066 cells, 173997102 bytes Procida#sh dcu leds CBR2/1/0 [20]: Normal
Known Issues
Cisco bug ID CSCdv38148 resolves a problem with a continuous Alarm Indication Signal (AIS) being reported on the T1 port of a VWIC-2MFT-T1 when used with the NM-1A CES module. In this condition, the ATM PVCs are up and passing traffic normally. This problem was introduced in Cisco IOS Release 12.1(5)T and resolved in Cisco IOS interim Release 12.2(7.4). Customers with a CCO account can access the Bug Toolkit for further details.
Cisco bug ID CSCdw36564 resolves a problem with rev B0 of the NM-1A-OC3SML-1V. When used with a VWIC-1MFT-E1, a CES circuit is unable to recover from a red alarm (loss of signal). Use the show diag command to determine your board revision. The following output was captured on a WIC with board revision B0:
Damme#show diag
[snip]
Slot 1:
ATM OC3, long reach single mode with Voice Processor Port adapter, 1 port
Port adapter is analyzed
Port adapter insertion time unknown
EEPROM contents at hardware discovery:
Hardware Revision : 1.0
Top Assy. Part Number : 800-03705-01
Board Revision : B0
Deviation Number : 0-0
Fab Version : 04
PCB Serial Number : JAB04320BYG
RMA Test History : 00
RMA Number : 0-0-0-0
RMA History : 00
[snip]
Related Information
| Updated: Jun 05, 2005 | Document ID: 18688 |