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Configuring Multiple Registrars on SIP Trunks
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Configuring Multiple Registrars on SIP Trunks

Table Of Contents

Configuring Multiple Registrars on SIP Trunks

Finding Feature Information

Contents

Prerequisites for Configuring Multiple Registrars on SIP Trunks

Restrictions for Configuring Multiple Registrars on SIP Trunks

Information About Configuring Multiple Primary SIP Trunks

Purpose of Multiple Registrars on SIP Trunks

Authentication Attributes and Enhancements

Credentials Attributes and Enhancements

Determination of Authentication Details

Use of Preferred Option

How to Configure Multiple Registrars on SIP Trunks

Configuring Multiple Registrars on SIP Trunks

Registration of POTS Endpoints to Multiple Registrars on SIP Trunks

Global Configuration of Authentication for POTS Endpoints with Multiple Registrars on a SIP Trunk

Dial Peer Configuration of Authentication for POTS Endpoints on a Cisco IOS Voice Gateway with Multiple Registrars on SIP Trunks

Configuration of Credentials for Registering POTS Endpoints with Multiple Registrars on SIP Trunks

Configuration Examples for Configuring Multiple Registrars on SIP Trunks

Registering POTS Endpoints to Multiple Registrars on SIP Trunks: Example

Registering Individual POTS Endpoints on a Cisco IOS SIP TDM Gateway to Multiple Registrars on a SIP Trunk: Example

Configuring Credentials for Endpoints to Register with Multiple Registrars on a SIP Trunk: Example

Additional References

Related Documents

Standards

MIBs

RFCs

Technical Assistance

Feature Information for Configuring Multiple Registrars on SIP Trunks

Glossary


Configuring Multiple Registrars on SIP Trunks


First Published: October 27, 2009
Last Updated: March 26, 2010

The Support for Multiple Registrars on SIP Trunks on a Cisco Unified Border Element, on Cisco IOS SIP TDM Gateways, and on Cisco Unified Communications Manager Express feature allows configuration of multiple registrars on Session Initiation Protocol (SIP) trunks, each simultaneously registered using their respective authentication instance. This feature allows a redundant registrar for each of the SIP trunks, which provides SIP trunk redundancy across multiple service providers.

Finding Feature Information

Your software release may not support all the features documented in this module. For the latest feature information and caveats, see the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the "Feature Information for Configuring Multiple Registrars on SIP Trunks" section.

Use Cisco Feature Navigator to find information about platform support and Cisco IOS and Catalyst OS software image support. To access Cisco Feature Navigator, go to http://www.cisco.com/go/cfn. An account on Cisco.com is not required.

Contents

Prerequisites for Configuring Multiple Registrars on SIP Trunks

Restrictions for Configuring Multiple Registrars on SIP Trunks

Information About Configuring Multiple Primary SIP Trunks

How to Configure Multiple Registrars on SIP Trunks

Configuration Examples for Configuring Multiple Registrars on SIP Trunks

Additional References

Feature Information for Configuring Multiple Registrars on SIP Trunks

Glossary

Prerequisites for Configuring Multiple Registrars on SIP Trunks

Before configuring support for multiple registrars on the SIP trunks of Cisco IOS SIP time-division multiplexing (TDM) gateways, Cisco Unified Border Elements (Cisco UBEs), or Cisco Unified Communications Manager Express (Cisco Unified CME), verify the SIP configuration within the VoIP network for the appropriate originating and terminating gateways as described in documentation listed in the "Related Documents" section.

Restrictions for Configuring Multiple Registrars on SIP Trunks

Configuring multiple registrars on SIP trunks has the following restrictions:

Old and new forms of registrar command are mutually exclusive: the registrar can be configured in either primary/secondary mode or multiple registrar mode—not both.

Dynamic Host Configuration Protocol (DHCP) support is not available with multiple registrars (available for primary/secondary mode only).

Only one authentication configuration per username can be configured at any one time.

A maximum of six registrars can be configured at any given time.

A maximum of 12 different realms can be configured for each endpoint.

You cannot restrict the registration of specific endpoints with specific registrars—once a new registrar is configured, all endpoints will begin registering to the new registrar.

You cannot remove multiple configurations of credentials simultaneously—only one credential can be removed at a time.

Information About Configuring Multiple Primary SIP Trunks

To configure multiple registrars on SIP trunks, you should understand the following concepts:

Purpose of Multiple Registrars on SIP Trunks

Authentication Attributes and Enhancements

Credentials Attributes and Enhancements

Determination of Authentication Details

Use of Preferred Option

Purpose of Multiple Registrars on SIP Trunks

You can configure endpoints on Cisco IOS SIP TDM gateways, Cisco UBEs, and Cisco Unified CME to register to a primary and a secondary registrar. You can use this setup to register all endpoints to their assigned registrar using authentication details that can be associated with only one domain (or service provider). The drawback is that if the registrar or service provider domain becomes unavailable, users supported on Cisco IOS SIP TDM gateways, Cisco UBEs, and Cisco Unified CME cannot make or receive calls.

The Support for Multiple Registrars on SIP Trunks on a Cisco Unified Border Element, on Cisco IOS SIP TDM Gateways, and on Cisco Unified Communications Manager Express feature provides support for simultaneous registration with multiple registrars for endpoints on Cisco IOS SIP TDM gateways, Cisco UBEs, and Cisco Unified CME. This feature allows outbound and inbound traffic to be distributed across different service providers while simultaneously providing redundancy for users supported on these devices.

Authentication Attributes and Enhancements

The Support for Multiple Registrars on SIP Trunks on a Cisco Unified Border Element, on Cisco IOS SIP TDM Gateways, and on Cisco Unified Communications Manager Express feature is available in Cisco IOS Release 15.0(1)XA and later releases and utilizes the authentication command to allow configuration for specific endpoints and includes the following attributes and enhancements:

You can configure up to 12 instances of the authentication command for a given endpoint, supporting 12 different realms for a single service provider domain.

The authentication behavior can handle challenges from different service providers for SIP REGISTER and SIP INVITE/Other messages.

You can specify a realm, which acts as a unique key for picking up username and password authentication details for each endpoint.

The system uses authentication details to rebuild SIP Request messages in response to challenges.

Enhancements introduced by this feature apply at both the dial peer and SIP user agent (UA) level.

Credentials Attributes and Enhancements

The credentials command is used to trigger SIP Register requests wherever registration is required for users who are not part of any POTS dial peers. The Support for Multiple Registrars on SIP Trunks on a Cisco Unified Border Element, on Cisco IOS SIP TDM Gateways, and on Cisco Unified Communications Manager Express feature is available in Cisco IOS Release 15.0(1)XA and later releases and modifies the credentials command to allow configuration for specific endpoints and includes the following attributes and enhancements:

Credentials behavior supports SIP REGISTER and SIP INVITE/Other message challenges.

You can use the number keyword to specify an endpoint, the value of which is used to populate the user portion of the To field in outgoing SIP REGISTER messages.

The number keyword is optional and is used to allow the endpoint number to be different from the username.

When both number and realm are configured, this pair of values acts as a unique key to pick up the username and password credentials configured for the endpoint.

A maximum of 12 different realms can be configured for a given endpoint.

Determination of Authentication Details

When a SIP INVITE or SIP REGISTER request is challenged, the username and password details for authentication are determined in the following order:


Note Configuring more than one username is not supported—you must remove any currently configured username before configuring a new username.


1. If the realm specified in the challenge matches the realm in the authentication configuration for a POTS dial peer, the system uses the corresponding username and password.

2. If the realm specified in the challenge doesn't match the configured authentication for the POTS dial peer, then it will check for credentials configured for SIP UA.

3. If the realm specified in the challenge does not match the realm configured for credentials, then it will check for authentication configurations for SIP UA.

4. If the system does not find a matching authentication or credential for the received realm, then the request is terminated.

5. If there is no realm specified for the authentication configuration, then the system uses the username received from the challenge to build the response message.

Use of Preferred Option

When the primary and secondary registrar scenario is configured, the registrar address is used to populate the host portion of the From header in outbound SIP INVITE messages. However, when multiple registrars are configured, the only way to determine which registrar address is used to populate the host portion of the From header is to designate a single service provider domain as the preferred localhost name. The following behaviors are the result of using the preferred keyword with the localhost command (or voice-class sip localhost command for individual dial peers) when configuring multiple registrars:

If the localhost command is enabled with the optional preferred keyword included, then the From header of outgoing SIP INVITE messages is populated with the domain name specified by the localhost command configuration.

If the localhost command is not enabled or if it is enabled without the optional preferred keyword, then the best local interface address is used to populate the From header of outgoing SIP INVITE messages.

How to Configure Multiple Registrars on SIP Trunks

The tasks for configuring multiple registrars on the SIP trunks of Cisco IOS SIP TDM gateways, Cisco UBEs, or Cisco Unified CME are included in the following sections:

Configuring Multiple Registrars on SIP Trunks (required)

Configuring Multiple Registrars on SIP Trunks

To configure multiple registrars on SIP trunks, use the registrar and authentication commands as described in the following tasks:

"Registration of POTS Endpoints to Multiple Registrars on SIP Trunks" section (required)

"Global Configuration of Authentication for POTS Endpoints with Multiple Registrars on a SIP Trunk" section (optional)

"Dial Peer Configuration of Authentication for POTS Endpoints on a Cisco IOS Voice Gateway with Multiple Registrars on SIP Trunks" section (optional)

"Configuration of Credentials for Registering POTS Endpoints with Multiple Registrars on SIP Trunks" section (optional)

Registration of POTS Endpoints to Multiple Registrars on SIP Trunks

Use the registrar command in SIP UA configuration mode to register POTS endpoints on a Cisco IOS SIP TDM gateway, Cisco UBE, or Cisco Unified CME to multiple registrars. To do so, you need to configure the command once for each registrar.

SUMMARY STEPS

1. enable

2. configure terminal

3. sip-ua

4. registrar registrar-index registrar-server-address expires seconds

DETAILED STEPS

 
Command or Action
Purpose

Step 1 

enable

Example:

Router> enable

Enables privileged EXEC mode.

Enter your password if prompted.

Step 2 

configure terminal

Example:

Router# configure terminal

Enters global configuration mode.

Step 3 

sip-ua

Example:

Router(config)# sip-ua

Enters SIP UA configuration mode.

Step 4 

registrar registrar-index registrar-server-address expires seconds

Example:

Router(config-sip-ua)# registrar 1 dns:example1.com expires 180

Router(config-sip-ua)# registrar 2 dns:example2.com expires 60

Enables a Cisco IOS voice gateway to register E.164 numbers with external SIP proxies or SIP registrars. The register-index range is 1 to 6. (The expires timer specification is optional).

Global Configuration of Authentication for POTS Endpoints with Multiple Registrars on a SIP Trunk

Use the authentication command in SIP UA configuration mode to configure authentication of endpoints on a Cisco IOS SIP TDM gateway, Cisco UBE, or Cisco Unified CME to multiple registrars. To do so, you need to configure the command once for each registrar.

SUMMARY STEPS

1. enable

2. configure terminal

3. sip-ua

4. authentication username username password [0 | 7] password [realm realm]

DETAILED STEPS

 
Command or Action
Purpose

Step 1 

enable

Example:

Router> enable

Enables privileged EXEC mode.

Enter your password if prompted.

Step 2 

configure terminal

Example:

Router# configure terminal

Enters global configuration mode.

Step 3 

sip-ua

Example:

Router(config)# sip-ua

Enters SIP UA configuration mode.

Step 4 

authentication username username password [0 | 7] password [realm realm]

Example:

Router(config-sip-ua)# authentication username MyUsername password MyPassword realm Realm1.example.com

Router(config-sip-ua)# authentication username MyUsername password MyPassword realm Realm2.example.com

Enables SIP digest authentication globally (encryption type and realm specification are optional).

Dial Peer Configuration of Authentication for POTS Endpoints on a Cisco IOS Voice Gateway with Multiple Registrars on SIP Trunks

Use the authentication command in dial peer voice configuration mode to authenticate endpoints on a Cisco IOS SIP TDM gateway to multiple registrars on SIP trunks. To do so, you need to configure the command once for each registrar.

SUMMARY STEPS

1. enable

2. configure terminal

3. dial-peer voice 1 pots

4. authentication username username password [0 | 7] password [realm realm]

DETAILED STEPS

 
Command or Action
Purpose

Step 1 

enable

Example:

Router> enable

Enables privileged EXEC mode.

Enter your password if prompted.

Step 2 

configure terminal

Example:

Router# configure terminal

Enters global configuration mode.

Step 3 

dial-peer voice 1 pots

Example:

Router(config)# dial-peer voice 1 pots

Enters dial peer voice configuration mode.

Step 4 

authentication username username password [0 | 7] password [realm realm]

Example:

Router(config-dial-peer)# authentication username MyUser password 7 MyPassword realm Realm1.example.com

Router(config-dial-peer)# authentication username MyUser password 7 MyPassword realm Realm2.example.com

Enables SIP digest authentication on an individual dial peer (encryption type and realm specification are optional).

Configuration of Credentials for Registering POTS Endpoints with Multiple Registrars on SIP Trunks

Use the credentials command in SIP UA configuration mode to configure registration requests sent from a Cisco IOS SIP TDM gateway, Cisco Unified CME, or a Cisco UBE to multiple registrars on a SIP trunk.

SUMMARY STEPS

1. enable

2. configure terminal

3. sip-ua

4. credentials {dhcp | number number username username} password [0 | 7] password realm realm

DETAILED STEPS

 
Command or Action
Purpose

Step 1 

enable

Example:

Router> enable

Enables privileged EXEC mode.

Enter your password if prompted.

Step 2 

configure terminal

Example:

Router# configure terminal

Enters global configuration mode.

Step 3 

sip-ua

Example:

Router(config)# sip-ua

Enters SIP UA configuration mode.

Step 4 

credentials {dhcp | number number username username} password [0 | 7] password realm realm

Example:

Router(config-sip-ua)# credentials number 1111 username MyUsername password MyPassword realm Realm1.example.com

Router(config-sip-ua)# credentials number 1111 username MyUsername password MyPassword realm Realm2.example.com

Router(config-sip-ua)# credentials number 1111 username AnotherUsername password TheirPassword realm Realm1.example.com

Router(config-sip-ua)# credentials number 1111 username AnotherUsername password TheirPassword realm Realm2.example.com

Configures credentials for endpoints on a Cisco IOS SIP TDM gateway, Cisco Unified CME, or Cisco UBE for responding to authentication challenges.

Note The encryption type specification is optional but the dhcp keyword is not allowed when configuring credentials for multiple registrars on a SIP trunk.

Configuration Examples for Configuring Multiple Registrars on SIP Trunks

This section provides the following configuration examples:

Registering POTS Endpoints to Multiple Registrars on SIP Trunks: Example

Registering Individual POTS Endpoints on a Cisco IOS SIP TDM Gateway to Multiple Registrars on a SIP Trunk: Example

Configuring Credentials for Endpoints to Register with Multiple Registrars on a SIP Trunk: Example

Registering POTS Endpoints to Multiple Registrars on SIP Trunks: Example

The following example shows how to configure POTS endpoints to register with multiple registrars ("example1.com" and "example2.com") on a SIP trunk simultaneously:

Router> enable
Router# configure terminal
Router(config)# sip-ua
Router(config-sip-ua)# registrar 1 dns:example1.com expires 180
Router(config-sip-ua)# registrar 2 dns:example2.com expires 360
Router(config-sip-ua)# authentication username MyUsername password MyPassword1 realm 
Realm.example1.com
Router(config-sip-ua)# authentication username MyUsername password MyPassword2 realm 
AnotherRealm.example1.com
Router(config-sip-ua)# authentication username MyUsername password MyPassword3 realm 
Realm.example2.com
Router(config-sip-ua)# authentication username MyUsername password MyPassword4 realm 
AnotherRealm.example2.com

Registering Individual POTS Endpoints on a Cisco IOS SIP TDM Gateway to Multiple Registrars on a SIP Trunk: Example

The following example shows how to configure individual POTS endpoints on a Cisco IOS SIP TDM gateway to register with multiple registrars ("Realm1" and "Realm2") on a SIP trunk simultaneously:


Router> enable
Router# configure terminal
Router(config)# dial-peer voice 3 pots
Router(config-dial-peer)# authentication username MyUser password MyPassword realm 
realm1.example.com
Router(config-dial-peer)# authentication username MyUser password MyPassword2 realm 
Realm2.example.com
Router(config-dial-peer)# exit
Router(config)# sip-ua
Router(config-sip-ua)# registrar 1 dns:example1.com expires 180
Router(config-sip-ua)# registrar 2 ipv4:1.1.1.1 expires 360

Configuring Credentials for Endpoints to Register with Multiple Registrars on a SIP Trunk: Example

The following example shows how to configure credentials for endpoints on a Cisco IOS SIP TDM gateway, Cisco Unified CME, or Cisco UBE to register with multiple registrars ("Example1.com" and "Example2.com") on a SIP trunk simultaneously:

Router> enable
Router# configure terminal
Router(config)# sip-ua
Router(config-sip-ua)# credentials number 1111 username MyUsername password MyPassword 
realm Realm.example1.com
Router(config-sip-ua)# credentials number 1111 username MyUsername2 password 
MyOtherPassword realm AnotherRealm.example1.com
Router(config-sip-ua)# credentials number 2222 username TheirUsername password 
TheirPassword realm Realm.example1.com
Router(config-sip-ua)# credentials number 2222 username TheirUsername2 password 
TheirOtherPassword realm AnotherRealm.example1.com
Router(config-sip-ua)# registrar 1 dns:example1.com expires 180
Router(config-sip-ua)# registrar 2 dns:example2.com expires 360

Additional References

The following sections provide references related to the Configuring Multiple Registrars feature.

Related Documents

Related Topic
Document Title

Cisco IOS dial peer overview

Dial Peer Configuration on Voice Gateway Routers Configuration Guide

Cisco IOS dial technologies command information

Cisco IOS Dial Technologies Command Reference

Cisco IOS dial technologies configuration information

Cisco IOS Dial Technologies Configuration Guide

Cisco IOS SIP configuration information

Cisco IOS SIP Configuration Guide

Cisco IOS voice command information

Cisco IOS Voice Command Reference

Cisco Unified CME command information

Cisco Unified Communications Manager Express Command Reference

Cisco Unified CME configuration information

Cisco Unified CME Support Documentation Home Page


Standards


MIBs

MIB
MIBs Link

No new or modified MIBs are supported by this feature, and support for existing MIBs has not been modified by this feature.

To locate and download existing MIBs for selected platforms, Cisco IOS releases, and feature sets, use the Cisco MIB Locator found at the following URL: http://www.cisco.com/go/mibs


RFCs


Technical Assistance

Description
Link

The Cisco Support website provides extensive online resources, including documentation and tools for troubleshooting and resolving technical issues with Cisco products and technologies.

To receive security and technical information about your products, you can subscribe to various services, such as the Product Alert Tool (accessed from Field Notices), the Cisco Technical Services Newsletter, and Really Simple Syndication (RSS) Feeds.

Access to most tools on the Cisco Support website requires a Cisco.com user ID and password.

http://www.cisco.com/techsupport


Feature Information for Configuring Multiple Registrars on SIP Trunks

Table 1 lists the release history for this feature.

Not all commands may be available in your Cisco IOS software release. For release information about a specific command, refer to documentation listed in the "Additional References" section.

Use Cisco Feature Navigator to find information about platform support and software image support. Cisco Feature Navigator enables you to determine which Cisco IOS and Catalyst OS software images support a specific software release, feature set, or platform. To access Cisco Feature Navigator, go to http://www.cisco.com/go/cfn. An account on Cisco.com is not required.


Note Table 1 lists only the Cisco IOS software release that introduced support for a given feature in a given Cisco IOS software release train. Unless noted otherwise, subsequent releases of that Cisco IOS software release train also support that feature.


Table 1 Feature Information for Configuring Multiple Registrars on SIP Trunks 

Feature Name
Releases
Feature Information

Support for Multiple Registrars on SIP Trunks on a Cisco Unified Border Element, on Cisco IOS SIP TDM Gateways, and on Cisco Unified Communications Manager Express feature

15.0(1)XA
15.1(1)T

This feature provides support for multiple registrars on SIP trunks on Cisco IOS SIP TDM gateways, Cisco Unified CME, and Cisco UBEs. This feature allows for a redundant registrar for each SIP trunk and enables registrar redundancy across multiple service providers.

This feature includes the following new or modified commands: credentials, localhost, registrar, voice-class sip localhost.


Glossary

ISDN—Integrated Services Digital Network.

EFXS—IP phone virtual voice ports.

FXS—analog telephone voice ports.

SCCP—Skinny Client Control Protocol.

SDP—Session Description Protocol.

SIP—Session Initiation Protocol.

TDM—time-division multiplexing.


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