Configuring MGCP-Controlled Backhaul of BRI Signaling in Conjunction with Cisco Unified Communications Manager
The MGCP-Controlled Backhaul of Basic Rate Interface (BRI) Signaling in Conjunction with Cisco Unified Communications Manager feature provides MGCP service to remote-office gateways that connect by means of ISDN BRI trunks to a centralized Cisco Unified Communications Manager.
Feature benefits include the following:
•Centralized call-management architecture, enabling a high degree of network control
•Short voice cut-through times
•Graceful evolution to new technology and to AVVID
Only the ETSI BRI basic-net3 switch type is supported.
Feature History for MGCP-Controlled Backhaul of BRI Signaling in Conjunction with Cisco Unified Communications Manager
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12.2(15)ZJ |
This feature was introduced for Cisco Communications Manager 3.3(2) (formerly known as Cisco CallManager 3.3(2)). |
12.3(2)T |
This feature was integrated into Cisco IOS Release 12.3(2)T. |
12.3(11)T |
Support was added for Cisco Unified Communications Manager 4.1. |
12.4(2)T |
This feature was implemented on the Cisco 2600XM, Cisco 2691, Cisco 2800 series, Cisco 3700 series, and Cisco 3800 series. |
Finding Support Information for Platforms and Cisco IOS Software Images
Use Cisco Feature Navigator to find information about platform support and Cisco IOS software image support. Access Cisco Feature Navigator at http://www.cisco.com/go/fn. You must have an account on Cisco.com. If you do not have an account or have forgotten your username or password, click Cancel at the login dialog box and follow the instructions that appear.
Note For more information about this and related Cisco IOS voice features, see the following:
•"Overview of Cisco Unified Communications Manager and Cisco IOS Interoperability" on page 13.
•Entire Cisco IOS Voice Configuration Library—including library preface and glossary, other feature documents, and troubleshooting documentation—at http://www.cisco.com/univercd/cc/td/doc/product/software/ios123/123cgcr/voice_c/vcl.htm.
Contents
•Prerequisites for MGCP-Controlled Backhaul of BRI Signaling
•Restrictions for MGCP-Controlled Backhaul of BRI Signaling
•Information About MGCP-Controlled Backhaul of BRI Signaling
•How to Configure MGCP-Controlled Backhaul of BRI Signaling
•Configuration Examples for MGCP-Controlled Backhaul of BRI Signaling
•Where to Go Next
•Additional References
Prerequisites for MGCP-Controlled Backhaul of BRI Signaling
Cisco Unified Communications Manager
•Cisco Unified Communications Manager 4.1(1) or a later release
Cisco Voice Gateway
•20-MB flash memory
•64-MB DRAM
•One of the supported combinations of BRI voice interface card (VIC) and network module:
–VIC-2BRI-NT/TE or VIC-2BRI-S/T in NM-1V or NM-2V with Cisco IOS Release 12.3(11)T or a later release
–VIC2-2BRI-NT/TE in NM-HD-1V, NM-HD-2V, NM-HD-2VE, or NM-HDV2 with Cisco IOS Release 12.4(2)T or a later release
–EM-4BRI-NT/TE in EVM-HD-8FXS/DID with Cisco IOS Release 12.4(2)T or a later release
•MGCP enabled globally in a VoIP network
•MGCP control of dial peers and voice ports
•MGCP single-point configuration enabled
Note For MGCP configuration instructions, see "Configuring MGCP Gateway Support for Cisco Unified Communications Manager" on page 23.
Restrictions for MGCP-Controlled Backhaul of BRI Signaling
•BRI backhaul uses the enhanced interface numbering support available in Cisco IOS Release 12.3(11)T and later. Previous releases supported only the slot/subslot/port format with the subslot forced to 0 on the Cisco 2600 series, Cisco 3600 series, and Cisco 3700 series. Cisco IOS Release 12.3(11)T and later releases support both the slot/port and slot/subslot/port interface numbering formats for BRI backhaul.
•Only the ETSI BRI Basic-NET3 switch type is supported.
•BRI calls are cleared during MGCP gateway fallback and rehome because ISDN BRI L2 must be reinitiated and brought up again by the new L3 task.
•Do not add the application mgcpapp command to voice dial peers that support BRI backhaul.
Information About MGCP-Controlled Backhaul of BRI Signaling
To configure MGCP-controlled backhaul of BRI signaling, you should understand the following concept:
•MGCP-Controlled Backhaul of BRI Signaling
MGCP-Controlled Backhaul of BRI Signaling
The MGCP-Controlled Backhaul of BRI Signaling feature supports a centralized Cisco Unified Communications Manager architecture with BRI trunks connected to remote branch offices. Transporting signaling information from a branch-office MGCP gateway to a centralized media-gateway controller for processing is called backhaul. D-channel signal information is backhauled to Cisco Unified Communications Manager through a TCP session. All Q.931 messages are passed through the TCP connection between the Cisco MGCP gateway and Cisco Unified Communications Manager. The MGCP gateway neither parses nor has any knowledge of the contents of those messages.
This feature enables you to connect remote ISDN PBXs and key systems to a Cisco ISDN BRI network termination (network side) or PSTN Class 4/5 switch through a Cisco ISDN BRI terminal equipment (as user side) interface. External call-control entities, such as one or more Cisco Unified Communications Manager servers, provide voice service between local and remote branch offices.
Figure 9 depicts a typical network-side scenario. NT denotes network termination; TE denotes terminal equipment.
Figure 9 Typical ISDN BRI Network-Side Scenario
Figure 10 shows a typical user-side scenario.
Figure 10 ISDN BRI User-Side Scenario
The following is the sequence of events during normal backhaul:
1. A call comes in from the PSTN and passes over the BRI trunk to the MGCP gateway.
2. The MGCP gateway passes signaling information from the call across the WAN to the Cisco Unified Communications Manager at headquarters.
3. The Cisco Unified Communications Manager instructs the MGCP gateway on how to set up and manage the call.
4. The call is established.
How to Configure MGCP-Controlled Backhaul of BRI Signaling
This section contains the following procedures:
•Configuring the BRI Interface as an MGCP-BRI Backhaul Endpoint (required)
•Verifying MGCP-BRI Backhaul Configuration (optional)
•Troubleshooting Tips for MGCP-Controlled Backhaul of BRI Signaling (optional)
Configuring the BRI Interface as an MGCP-BRI Backhaul Endpoint
SUMMARY STEPS
1. enable
2. configure terminal
3. interface bri slot/port
4. shutdown
5. isdn switch-type basic-net3
6. isdn bind-L3 ccm-manager service mgcp
7. no shutdown
8. no mgcp
9. mgcp
10. exit
DETAILED STEPS
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Step 1 |
enable
Router> enable |
Enables privileged EXEC mode. •Enter your password if prompted. |
Step 2 |
configure terminal
Router# configure terminal |
Enters global configuration mode on the BRI slot and port. |
Step 3 |
interface bri slot/port
Router(config)# interface bri 1/0 |
Configures the BRI interface as the MGCP-BRI backhaul endpoint. •Slot and port syntax is platform-dependent; type ? to determine. Note This command is supported only for a user-side ETSI NET3 switch-type. |
Step 4 |
shutdown
Router(config-if)# shutdown |
(Optional) Clears the interface of any active calls. If there are no active calls, you can skip this step. |
Step 5 |
isdn switch-type basic-net3
Router(config-if)# isdn switch-type basic-net3 |
Sets the central-office switch type on the ISDN interface to basic-net3. |
Step 6 |
isdn bind-L3 ccm-manager service mgcp
Router(config-if)# isdn bind-L3 ccm-manager service mgcp |
Sets ISDN L3 binding on the BRI interface. |
Step 7 |
no shutdown
Router(config-if)# no shutdown |
Restarts the interface if it was previously disabled. |
Step 8 |
no mgcp
Router(config-if)# no mgcp |
Disables all MGCP applications and protocols. |
Step 9 |
mgcp
Router(config-if)# mgcp |
Restarts MGCP and reregisters the gateway to Cisco Unified Communications Manager. |
Step 10 |
exit
Router(config-if)# end |
Exits interface-configuration mode. |
Verifying MGCP-BRI Backhaul Configuration
SUMMARY STEPS
1. show isdn status
2. show ccm-manager
3. show ccm-manager backhaul
4. show mgcp endpoint
DETAILED STEPS
Step 1 show isdn status
Use the show isdn status command to verify that Layer 2 is established and that Layer 3 is configured as Cisco Unified Communications Manager. This output displays only if TEI negotiation is performed at startup.
dsl 1, interface ISDN Switchtype = basic-net3
L2 Protocol = Q.921 L3 Protocol(s) = CCM-MANAGER
TEI = 64, Ces = 1, SAPI = 0, State = MULTIPLE_FRAME_ESTABLISHED
Note Use this command only if TEI negotiation is done at startup. Otherwise, TEI negotiation is done when the first call is placed, so output shows Layer 2 with no TEI negotiated and Layer 3 as down.
Step 2 show ccm-manager
Use the show ccm-manager command to verify your Cisco Unified Communications Manager configuration on the gateway.
MGCP Domain Name:3845-1.cisco.com
============================================================
Primary Registered 10.3.102.99
Current active Call Manager: 10.3.102.99
Backhaul/Redundant link port: 2428
Failover Interval: 30 seconds
Keepalive Interval: 15 seconds
Last keepalive sent: 20:58:35 UTC Sep 3 2004 (elapsed time:00:00:11)
Last MGCP traffic time: 20:58:35 UTC Sep 3 2004 (elapsed time:00:00:11)
Last switchback time: None
Switchback mode: Graceful
MGCP Fallback mode: Not Selected
Last MGCP Fallback start time: None
Last MGCP Fallback end time: None
MGCP Download Tones: Disabled
Configuration Error History:
Step 3 show ccm-manager backhaul
Use the show ccm-manager backhaul command to display information about the BRI backhaul link.
Router# show ccm-manager backhaul
Remote IP Address: 10.3.102.99
BRI Ports being backhauled:
Step 4 show mgcp endpoint
Use the show mgcp endpoint command to display a list of your MGCP endpoints.
Router# show mgcp endpoint
Troubleshooting Tips for MGCP-Controlled Backhaul of BRI Signaling
Table 10 lists commands that are available for troubleshooting your configuration.
Table 10 Troubleshooting Commands
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command-type a-law |
Enables you to address poor voice quality. If your system uses a-law pulse-code modulation (PCM), use this command in interface-BRI configuration mode to reconfigure the BRI voice port in the gateway for a-law PCM. The system default is mu-law PCM. |
debug ccm-manager backhaul packets |
Displays debugging information about Cisco Unified Communications Manager backhaul message packets. |
debug isdn q931 |
Displays debugging information about ISDN L3 Q.931 message packets. |
debug mgcp packets |
Displays debugging information about MGCP message packets. |
Configuring SRTP Mode on Cisco IOS MGCP Gateways
SRTP mode provides secure VoIP calls by addressing security requirements for privacy, integrity, and confidentiality of voice conversations. IPsec, a standards-based set of security protocols and algorithms, ensures that signaling information that is sent between the gateway and Cisco Unified Communications Manager are encrypted. Media encryption using standards-based Secure Real-Time Transport Protocol (SRTP) ensures that media streams between supported devices are secure.
Perform this task to configure SRTP mode on the gateway.
Prerequisites for SRTP Mode
You should first establish an IPsec connection between Cisco Unified Communications Manager and the MGCP gateway before using the MGCP SRTP package. Otherwise, media keys are sent in clear text and your voice call is not considered secure.
SUMMARY STEPS
1. enable
2. configure terminal
3. mgcp package-capability srtp-package
4. mgcp validate call-agent source-ipaddr
5. exit
DETAILED STEPS
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Step 1 |
enable
Router> enable |
Enables privileged EXEC mode. •Enter your password if prompted. |
Step 2 |
configure terminal
Router# configure terminal |
Enters global configuration mode. |
Step 3 |
mgcp package-capability srtp-package
Router(config)# mgcp package-capability srtp-package |
Enables the MGCP gateway capability to process SRTP packages. |
Step 4 |
mgcp validate call-agent source-ipaddr
Router(config)# mgcp validate call-agent source-ipaddr |
(Optional) Enables the MGCP application validation that packets received are sent by a configured call agent. |
Step 5 |
exit
Router(config)# exit |
Exits global configuration mode. |
Configuration Examples for MGCP-Controlled Backhaul of BRI Signaling
This section provides the following configuration example:
•MGCP BRI Backhaul on Cisco 3745: Example
•MGCP BRI Backhaul on Cisco 3640: Example
MGCP BRI Backhaul on Cisco 3745: Example
Router# show running-config
Building configuration...
Current configuration :3913 bytes
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
no network-clock-participate slot 1
no network-clock-participate slot 2
no network-clock-participate slot 3
no network-clock-participate slot 4
no network-clock-participate wic 0
no network-clock-participate wic 1
no network-clock-participate wic 2
no network-clock-participate aim 0
no network-clock-participate aim 1
host 10.3.102.102 255.255.0.0
client-identifier 0100.1121.116b.dd
option 150 ip 10.3.102.99
default-router 10.3.102.2
no ftp-server write-enable
isdn switch-type basic-net3
ccm-manager switchback immediate
ccm-manager fallback-mgcp
ccm-manager redundant-host 10.3.102.98
interface FastEthernet0/0
ip address 10.3.102.2 255.255.0.0
interface FastEthernet0/1
isdn switch-type basic-net3
isdn incoming-voice voice
isdn bind-l3 ccm-manager service mgcp
isdn switch-type basic-net3
isdn protocol-emulate network
isdn layer1-emulate network
isdn incoming-voice voice
isdn switch-type basic-net3
isdn incoming-voice voice
isdn bind-l3 ccm-manager service mgcp
isdn switch-type basic-net3
isdn protocol-emulate network
isdn layer1-emulate network
isdn incoming-voice voice
isdn switch-type basic-net3
isdn incoming-voice voice
isdn bind-l3 ccm-manager service mgcp
isdn switch-type basic-net3
isdn protocol-emulate network
isdn layer1-emulate network
isdn incoming-voice voice
ip default-gateway 10.3.0.1
ip route 0.0.0.0 0.0.0.0 10.3.0.1
access-list 10 deny 10.3.102.99 log
access-list 10 permit any
call application alternate DEFAULT
mgcp call-agent 10.3.102.99 service-type mgcp version 0.1
mgcp package-capability srtp-package
session target ipv4:10.3.102.1
ip source-address 10.3.102.2 port 2000
MGCP BRI Backhaul on Cisco 3640: Example
service timestamps debug uptime
service timestamps log uptime
no service password-encryption
isdn switch-type primary-qsig
voice call carrier capacity active
mta receive maximum-recipients 0
pri-group timeslots 1-24 service mgcp
interface FastEthernet0/0
ip address 10.15.43.101 255.255.0.0
encapsulation frame-relay
frame-relay lmi-type ansi
interface FastEthernet0/1
isdn switch-type basic-net3
isdn incoming-voice voice
isdn bind-l3 ccm-manager service mgcp
isdn switch-type basic-qsig
no logging event link-status
isdn switch-type primary-qsig
isdn incoming-voice voice
ip default-gateway 10.15.10.11
ip route 0.0.0.0 0.0.0.0 10.15.10.11
mgcp call-agent 10.14.181.10 service-type mgcp version 0.1
dial-peer voice 6000 pots
dial-peer voice 4000 pots
Where to Go Next
•To configure conferencing, transcoding, and MTP support on a Cisco IOS gateway, see "Configuring Enhanced Conferencing and Transcoding for Voice Gateway Routers" on page 67.
•To enable MGCP PRI backhaul support, see "Configuring MGCP PRI Backhaul and T1 CAS Support for Cisco Unified Communications Manager" on page 113.
•To download region-specific tones and their associated frequencies, amplitudes, and cadences, see "Configuring Tone Download to MGCP Gateways" on page 145.
Additional References
•"Cisco Unified Communications Manager and Cisco IOS Interoperability Features Roadmap" on page 9—Describes how to access Cisco Feature Navigator; also lists and describes, by Cisco IOS release, Cisco Unified Communications Manager and Cisco IOS interoperability features.
•"Overview of Cisco Unified Communications Manager and Cisco IOS Interoperability" on page 13—Describes basics of underlying technology and lists related documents.
•"Configuring ISDN BRI" in the Cisco IOS Dial Technologies Configuration Guide, Release 12.4—Describes how to configure ISDN BRI on the voice gateway.
•"ISDN Switch Types, Codes, and Values" appendix in the Debug Command Reference, Release 12.4—Describes supported switch types.
•Cisco Unified Communications Manager documentation—Describes how to install and configure Cisco Unified Communications Manager.
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