Cisco Unified Communications Manager (CallManager)

IOS Gateway BRI Backhaul with Cisco CallManager 4.1 Configuration Example

Document ID: 67021

Updated: Jun 27, 2006



Media Gateway Control Protocol (MGCP)-controlled backhaul of BRI signaling to Cisco CallManager allows centralized management of remote branch offices with BRI trunks. The ISDN D-channel signal information is backhauled to Cisco CallManager through a TCP session via the branch MGCP gateway. All Q.931 signaling messages are relayed back to the central Cisco CallManager without being parsed by the MGCP gateway.

This feature was implemented on the Cisco 2600XM, Cisco 2691, Cisco 3640, Cisco 3640A, Cisco 3660, Cisco 2800 series, Cisco 3700 series, and Cisco 3800 series. Refer to Configuring MGCP-Controlled Backhaul of BRI Signaling in Conjunction with Cisco CallManager for more information on platforms and Cisco IOS® Software Releases.

This document outlines the steps you need in order to configure the MGCP gateway and the Cisco CallManager for MGCP BRI backhaul with the Cisco 2800 and 3800 series routers.


You can potentially encounter these symptoms when you configure Cisco CallManager with Cisco IOS MGCP gateways with BRI ports:

  • The MGCP gateway does not register with Cisco CallManager. Refer to MGCP Gateway Registration Failure with Cisco CallManager for more information.

  • The MGCP BRI port does not register with Cisco CallManager. Ensure that the BRI port is connected to the Telco line with Layer 1 and 2 in the active status.



There are no specific requirements for this document.

Components Used

The information in this document is based on these software and hardware versions:

  • IP Communications high-density network modules (NM-HD), IP Communications High-Density Digital Voice Network Module (NM-HDV2), High-Density Analog and Digital Extension Module (EVM-HD) and Cisco 2800 and 3800 series routers with a BRI High-Speed WAN Interface Card (HWIC) interface with Cisco IOS Software Release 12.4(2)T

  • Cisco CallManager 4.1(3) SR1 and later, latest Cisco CallManager Version 4.1 device package under Cisco CallManager Version 4.1 under Voice Software on

The information in this document was created from the devices in a specific lab environment. All of the devices used in this document started with a cleared (default) configuration. If your network is live, make sure that you understand the potential impact of any command.


Refer to the Cisco Technical Tips Conventions for more information on document conventions.

BRI Backhaul Configuration

The BRI backhaul configuration consists of two parts:

  1. MGCP IOS Gateway Configuration

  2. Cisco CallManager Configuration

In this section, you are presented with the information to configure the features described in this document.

Note: Use the Command Lookup Tool (registered customers only) to obtain more information on the commands used in this section.

Network Diagram

This document uses this network setup:


MGCP IOS Gateway Configuration

Complete these steps to configure BRI backhaul on the IOS gateway:

  1. Configure the hostname for the router.

    router(config)#hostname bri-gw
  2. Configure the IP domain name. Make sure that the BRI gateway is reachable to Cisco CallManager and that it is in the reachable domain. This step is optional.

    bri-gw(config)#ip domain-name
  3. Issue the ccm-manager mgcp command in global mode.

    bri-gw(config)#ccm-manager mgcp
  4. Issue the isdn switch-type <switch-type> command on the BRI and global interfaces if the switching type is not configured globally.

    bri-gw(config)#isdn switch-type basic-net3

    Note: Only basic-net3 is tested and supported. No other switch types are supported.

  5. Issue the isdn bind-l3 ccm-manager service mgcp command on the BRI interface. Make sure to shut and no shut the interface.

    bri-gw(config)#interface bri 0/0/0 
            bri-gw(config-if)#isdn bind-l3 ccm-manager service mgcp 
  6. Configure a dial peer with mgcpapp as the application and assign the BRI port to the dial peer.

    dial-peer voice 1 pots 
              application mgcpapp 
              port 0/0/0
              forward-digits all 

    Note: Do not apply the application mgcpapp command to the POTS dial peer that supports BRI backhaul for Cisco IOS Software Release 12.3(7)T and later. Refer to Restrictions for MGCP-Controlled Backhaul of BRI Signaling.

  7. Issue the mgcp command in global mode.

  8. Issue the mgcp call-agent <ccm ip address> service type mgcp version 0.1 command.

    bri-gw(config)#mgcp call-agent service type mgcp version 0.1 
  9. Configure the Secure RTP (SRTP) package, which enables the MGCP gateway to process SRTP packages.

    mgcp package-capability rtp-package

Cisco CallManager Configuration

Complete these steps on the Cisco CallManager:

  1. Add a new gateway.

  2. Select the Gateway type (for example Cisco 2851) and select MGCP in the Device Protocol field.


  3. Configure the domain name to be <hostnameofrouter>.<domain-name>.

    For example,

    Note: Complete this step only if the domain name is configured on the gateway.


  4. Select the BRI module, which is placed in the router slot.

    For example, select Module in Slot 0 since the motherboard is considered as Slot 0 if the BRI VIC is placed in onboard HWIC Slot 2 of the motherboard. Then insert the gateway. This gives four options. Select and update Subunit 2 with the VIC2-2BRI-NT/TE since the HWIC slot used is 2.


  5. Reset the gateway after you configure the BRI endpoint.


  6. Add a router pattern on the Cisco CallManager to route calls to the BRI gateway based on a destination pattern. Refer to Route Pattern Configuration.



  7. Issue the no mgcp command and then the mgcp command in global configuration mode for the gateway to register the BRI endpoints.


There is currently no specific verification information available for this configuration.


Use this section to troubleshoot your configuration.

Troubleshooting Commands

The Output Interpreter Tool (registered customers only) (OIT) supports certain show commands. Use the OIT to view an analysis of show command output.

Note: Refer to Important Information on Debug Commands before you use debug commands.

  • show ccm—Ensures that the gateway is registered to the Cisco CallManager.

  • show ccm backhaul—Displays the BRI endpoints which are backhauled.

  • show isdn status—Displays MULTI_FRAME_ESTABLISHED with Layer 2 being registered to Cisco CallManager.

  • show mgcp endpoints—Displays information for endpoints controlled by MGCP.

  • show mgcp connections—Displays the BRI endpoints in an MGCP call. In order to make sure that the MGCP call is secure, a flag called k is set to 1 for an encrypted secure call and 0 for a non-secure call.

  • show voice call status <id> sa—Displays the number of packets that are encrypted and decrypted for a certain call on the BRI.

  • debug ccm backhaul events—Displays Cisco CallManager backhaul events.

  • debug ccm backhaul packets—Displays Cisco CallManager backhaul packets.

This is sample output of the show commands:

R2851#show run interface bri 1/0/0 
Building configuration... 
Current configuration : 208 bytes 
interface BRI1/0/0 
 no ip address 
 isdn switch-type basic-net3 
 isdn point-to-point-setup 
 isdn incoming-voice voice 
 isdn bind-l3 ccm-manager service mgcp 
 isdn skipsend-idverify 
 no clns route-cache 

R2851#show ccm-manager 
MGCP Domain Name: 
Priority        Status                   Host 
Primary         Registered 
First Backup    None 
Second Backup   None 
Backhaul Link info: 
    Link Protocol:      TCP 
    Remote Port Number: 2428 
    Remote IP Address: 
    Current Link State: OPEN 
BRI Ports being backhauled: 
        Slot 2, VIC 0, port 0 
        Slot 1, VIC 0, port 0 

R2851#show ccm-manager backhaul 
Backhaul Link info: 
    Link Protocol:      TCP 
    Remote Port Number: 2428 
    Remote IP Address: 
    Current Link State: OPEN 
        Packets recvd:   997 
        Recv failures:   967 
        Packets xmitted: 30 
        Xmit failures:   0 
    BRI Ports being backhauled: 
        Slot 2, VIC 0, port 0 
        Slot 1, VIC 0, port 0 

R2851#show isdn status bri 1/0/0 
Global ISDN Switchtype = primary-ni 
%Q.931 is backhauled to CCM MANAGER 0x0003 on DSL 8. Layer 3 output may not apply 
ISDN BRI1/0/0 interface dsl 8, interface ISDN Switchtype = basic-net3 
L2 Protocol = Q.921 0x0000  L3 Protocol(s) = CCM MANAGER 0x0003 
Layer 1 Status: 
Layer 2 Status: 
    Layer 3 Status: 
        0 Active Layer 3 Call(s) 
    Active dsl 8 CCBs = 0 
    The Free Channel Mask:  0x80000003 
    Total Allocated ISDN CCBs = 0 

R2851#show mgcp connection 
Endpoint Call_ID(C) Conn_ID(I) (P)ort (M)ode (S)tate (CO)dec (E)vent[SIFL ] 
(R)esult[EA] Crypto-suite(K) 
1.BRI/S2/SU0/P0/1 C=D0000000010000ff000000F580000012,111,112 I=0x2 P=180 98,
16418 M=3 S=4,4 CO=1 E=2,0,0,2 R=0,0 K=1 
2.2. BRI/S3/SU0/P0/2 C=D000000001000100000000F500000001,113,114 I=0x3 P=164 
18,18098 M=3 S=4,4 CO=1 E=2,0,0,2 R=0,0 K=1 

!--- Note: K = 1 for a secure call and 0 for a non-secure call.

R2851#show voice call stat 6f sample 5 
 Gathering information (5 seconds)... 
 CallID Port DSP/Ch Codec Rx/Tx En/De ERL/Reflctr Jitter 
 0x6F 2/0/0.0 13/1 g711ulaw 250/250 250/250 21.0/18 24/41 

!--- Note: The En/De is 0/0 for a non-secure call.

You see this debug output when BRI endpoints register to the Cisco CallManager:

cmbh_rcv_callback: <-- Receiving backhaul msg for BR1/0/0 : 
         bk_msg_type = ESTABLISH_REQ 
         bk_chan_id (slot:port) = 1:0 
         Q.931 length = 0 
cmbrl_send_pak: --> Sending backhauled msg for BR1/0/0 : 
         bk_msg_type = ESTABLISH_CFM 
         bk_chan_id (slot:port) = 1:0 
         Q.931 length = 0

warning Warning: Debug commands can severely degrade the performance of the router. Run these commands outside business hours.

Related Information

Updated: Jun 27, 2006
Document ID: 67021