Configuring Media Antitrombone
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Configuring Media Antitrombone

Last Updated: June 16, 2011

Media Trombones are media loops in a SIP entity due to call transfer or call forward. Media loops in Cisco UBE are not detected because Cisco UBE looks at both call types as individual calls and not calls related to each other.

Antitromboning is a media signaling service in SIP entity to overcome the media loops. Antitrombone service has to be enabled only when no media interworking is required in both the out-legs.

To specify media antitrombone for voice class, all VoIP calls, or individual dial peers, perform the tasks in the following sections:

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 Table at the end of this document.

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

Prerequisites

Cisco Unified Border Element

  • Cisco IOS Release 15.1(3)T or a later release must be installed and running on your Cisco Unified Border Element.

Cisco Unified Border Element (Enterprise)

  • Cisco IOS XE Release <TBD> or a later release must be installed and running on your Cisco ASR 1000 Series Router.

Restrictions

  • When media antitrombone service is activated, Cisco UBE does not perform supplementary services such as handling REFER-based call transfers or media services such as SRTP, SNR and call transfers.
  • Video codecs are not supported for the normal media handling because the SIP Cisco IOS gateway infrastructure does not support flow-through and flow-around for video.
  • Antitrombone will not work if one call leg is flow-through and another call leg is flow-around. Similarly, antitrombone will not work if one call leg is SDP pass-through and another call leg is SDP normal.
  • H.323 is not supported.
  • Delayed-offer to early-offer (DO-EO) video media flow around is not supported.

Configuring Media Antitrombone for a Voice Class

Perform this task to configure antitrombone service for a voice class.

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    voice class media tag

4.    media anti-trombone

5.    exit

6.    exit


DETAILED STEPS
 Command or ActionPurpose
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 voice class media tag


Example:

Router(config)# voice class media 1

 

Enters voice class configuration mode and assigns an identification tag for a media voice class.

 
Step 4 media anti-trombone


Example:

Router(config-class)# media anti-trombone

 

Configures media antitrombone service.

 
Step 5 exit


Example:

Router(config-dial-peer)# exit

 

Exits dial peer configuration mode and enters global configuration mode.

 
Step 6 exit


Example:

Router(config)# exit

 

Exits global configuration mode and enters privileged EXEC mode.

 

Configuring Media Antritrombone at the Global Level

Perform this task to configure media antitrombone service at the voice service configuration mode.

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    voice service voip

4.    media anti-trombone

5.    exit

6.    exit


DETAILED STEPS
 Command or ActionPurpose
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 voice service voip


Example:

Router(config)# voice service voip

 

Enters voice service configuration mode.

 
Step 4 media anti-trombone


Example:

Router(config-voi-serv)# media anti-trombone

 

Configures media antitrombone service.

 
Step 5 exit


Example:

Router(config-voi-serv)# exit

 

Exits voice service configuration mode and returns to global configuration mode.

 
Step 6 exit


Example:

Router(config)# exit

 

Exits global configuration mode and returns to privileged EXEC mode.

 

Configuring Media Antitrombone for a Dial Peer

Perform this task to configure media antitrombone at individual dial peer level.


Note
  • If both incoming and outgoing dial peers are configured, you must specify the transparent codec on the incoming dial peer.
  • The media anti-trombone command needs to be enabled for all related dial peers.
>
SUMMARY STEPS

1.    enable

2.    configure terminal

3.    dial-peer voice number voip

4.    media anti-trombone

5.    exit

6.    exit


DETAILED STEPS
 Command or ActionPurpose
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 number voip


Example:

Router(config)# dial-peer voice 2 voip

 

Enters dial peer configuration mode for the specified VoIP dial peer.

 
Step 4 media anti-trombone


Example:

Router(config-dial-peer)# media antri-trombone

 

Configures media antitrombone service.

 
Step 5 exit


Example:

Router(config-dial-peer)# exit

 

Exits dial peer configuration mode and enters global configuration mode.

 
Step 6 exit


Example:

Router(config)# exit

 

Exits global configuration mode and enters privileged EXEC mode.

 

Feature Information for Media Antitrombone

The following table provides release information about the feature or features described in this module. This table lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.

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

ISR Feature table entry

Table 1 Feature Information for Media Flow- Around with SIP Signaling control on CUBE

Feature Name

Releases

Feature Information

Media Antitrombone

15.1(3)T

The Media Antitrombone feature is a media signaling service in SIP entity to overcome media loops.

ASR Feature table entry

Table 2 Feature Information for Media Flow- Around with SIP Signaling control on CUBE

Feature Name

Releases

Feature Information

Media Antitrombone

TBD

The Media Antitrombone feature is a media signaling service in SIP entity to overcome media loops.

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