Table Of Contents
Cisco Unified Border Element Support for Configurable Pass-through of SIP INVITE Parameters
Prerequisites
Restrictions
Information About Cisco Unified Border Element Support for Configurable Pass-through of SIP INVITE Parameters
How to Configure the Cisco Unified Border Element Support for Configurable Pass-through of SIP INVITE Parameters
Cisco Unified Border Element Support for Configurable Pass-through of SIP INVITE Parameters
This feature enables the Cisco Unified Border Element (Cisco UBE) platform to pass through end-to-end headers at a global or dial-peer level, that are not processed or understood in a SIP trunk to SIP trunk scenario. The pass through functionality includes all or only a configured list of unsupported or non-mandatory SIP headers, and all unsupported content/MIME types.
Prerequisites
•
Configuring the media flow-around command is required for Session Description Protocol (SDP) pass-through. When flow-around is not configured, the flow-through mode of SDP pass-through will be functional.
•When the dial-peer media flow mode is asymmetrically configured, the default behavior is to fallback to SDP pass-through with flow-through.
Cisco Unified Border Element
•Cisco IOS Release 15.0(1)M or a later release must be installed and running on your Cisco Unified Border Element.
Cisco Unified Border Element (Enterprise)
•Cisco IOS XE Release 3.1S or a later release must be installed and running on your Cisco ASR 1000 Series Router.
Restrictions
When SDP pass-through is enabled, some of interworking that the Cisco Unified Border Element currently performs cannot be activated. These features include:
•Delayed Offer to Early Offer Interworking
•Supplementary Services with triggered Invites
•DTMF Interworking scenarios
•Fax Interworking/QoS Negotiation
•Transcoding
Information About Cisco Unified Border Element Support for Configurable Pass-through of SIP INVITE Parameters
The Cisco UBE does not support end-to-end media negotiation between the two endpoints that establish a call session through the Cisco UBE. This is a limitation when the endpoints intend to negotiate codec/payload types that the Cisco UBE does not process, because currently, unsupported payload types will never be negotiated by the Cisco UBE. Unsupported content types include text/plain, image/jpeg and application/resource-lists+xml. To address this problem, SDP is configured to pass through transparently at the Cisco UBE, so that both the remote ends can negotiate media independently of the Cisco UBE.
SDP pass-through is addressed in two modes:
•Flow-through—Cisco UBE plays no role in the media negotiation, it blindly terminates and re-originates the RTP packets irrespective of the content type negotiated by both the ends. This supports address hiding and NAT traversal.
•Flow-around—Cisco UBE neither plays a part in media negotiation, nor does it terminate and re-originate media. Media negotiation and media exchange is completely end-to-end.
How to Configure the Cisco Unified Border Element Support for Configurable Pass-through of SIP INVITE Parameters
To enable Cisco UBE Unsupported Content Pass-through perform the steps in this section. This section contains the following subsections:
•Configuring Cisco Unified Border Element Support for Configurable Pass-through of SIP INVITE Parameters at the Global Level
•Configuring Cisco Unified Border Element Support for Configurable Pass-through of SIP INVITE Parameters at the Dial Peer Level
Configuring Cisco Unified Border Element Support for Configurable Pass-through of SIP INVITE Parameters at the Global Level
To configure Unsupported Content Pass-through on a Cisco UBE platform at the global level, perform the steps in this section.
SUMMARY STEPS
1. enable
2. configure terminal
3. voice service voip
4. sip
5. pass-thru {content {sdp | unsupp} | headers {unsupp | list tag}}
6. exit
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
|
voice service voip
Example:
Router(config)# voice service voip
|
Enters voice service VoIP configuration mode.
|
Step 4
|
sip
Example:
Router(conf-voi-serv)# sip
|
Enters SIP configuration mode.
|
Step 5
|
pass-thru {content {sdp | unsupp} | headers
{unsupp | list tag}}
Example:
Router(conf-serv-sip)# pass-thru content unsupp
|
Passes the SDP transparently from in-leg to the out-leg with no media negotiation.
|
Step 6
|
exit
Example:
Router(conf-serv-sip)# exit
|
Exits the current mode.
|
Configuring Cisco Unified Border Element Support for Configurable Pass-through of SIP INVITE Parameters at the Dial Peer Level
To configure Unsupported Content Pass-through on a Cisco UBE platform at the dial-peer level, perform the steps in this section.
SUMMARY STEPS
1. enable
2. configure terminal
3. dial-peer voice tag voip
4. voice-class sip pass-thru {content {sdp | unsupp} | headers {unsupp | list tag}} [system]
5. exit
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 tag voip
Example:
Router(config)# dial-peer voice 2 voip
|
Enters dial peer VoIP configuration mode.
|
Step 4
|
voice-class sip pass-thru {content {sdp |
unsupp} | headers {unsupp | list tag}} [system]
Example:
Router(config-dial-peer)# voice-class sip
pass-thru content sdp
|
Passes the SDP transparently from in-leg to the out-leg with no media negotiation.
|
Step 5
|
exit
Example:
Router(config-dial-peer)# exit
|
Exits the current mode.
|
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