Pass Unsupported SIP Headers

Overview

This feature is used to pass parameters that are unsupported by Cisco Unified Border Element (CUBE), but mandatory to the service provider from one leg to another. When a SIP message is received, a check is done for the header, and if it is available, it is copied into a copy list and passed on to the outbound dial peer leg. The 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 Session Initiation Protocol (SIP) trunk to SIP trunk scenario.

Feature Information

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.
Table 1. Feature Information for Copying with SIP Profiles

Feature Name

Releases

Feature Information

Support for conditional header manipulation of SIP headers

Baseline Functionality

This feature modifies the following commands: voice class sip-profiles , response, request, voice-class sip copy-list, sip-header

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 fall back to SDP pass-through with flow-through.

Restrictions

When Session Description Protocol (SDP) pass-through is enabled, some of the interworking that the CUBE currently performs cannot be activated. These features include:

  • Delayed Offer to Early Offer Interworking

  • Supplementary Services with Triggered Invites

  • Flow-around calls will not work with SDP pass through

  • DTMF Interworking Scenarios

  • Fax Interworking/QoS Negotiation

  • Transcoding

For configurable pass-through of SIP INVITE parameters, the following features for Session Initiation Protocol (SIP)-SIP dial-peer rotary calls are not supported:

  • Unsupported header pass-through functionality for SIP-SIP dial-peer rotary calls

  • Unsupported content pass-through functionality for SIP-SIP dial-peer rotary calls


Note

With CSCty41575, the unsupported header and content pass-through functionalities mentioned above are addressed.

Supported SIP Headers

Mandatory SIP Headers

The following table provides a list of mandatory headers:

Table 2. List of Mandatory Headers

Also

Authorization

Call_ID

CC-Diversion

CC-Redirect

Cisco_Gcid

Cisco_Ccid

Contact

Content-Disposition

Content-Encoding

Content-Length

Content-Type

Cseq

Date

From

Max-Forwards

MIME-Version

P-Asserted-Identity

P-Preferred-Identity

Privacy

Proxy-Authenticate

Proxy-Authorization

Record-Route

Route

Session-Expires

Timestamp

To

User-Agent

Via

WWW-Authenticate

Unsupported Headers

You can configure CUBE to pass through unsupported headers (headers CUBE cannot understand). The following are some of the examples for SIP headers that are unsupported on CUBE:

  • P-Early-Media

  • SIP-Req-URI

Enable Configurable Pass-Through of SIP INVITE Parameters (Global Level)

Perform this task to configure unsupported content pass-through on a CUBE platform at the global level.

SUMMARY STEPS

  1. enable
  2. configure terminal
  3. voice service voip
  4. sip
  5. pass-thru {content {sdp | unsupp} | headers {unsupp | list-tag}}
  6. end

DETAILED STEPS

  Command or Action Purpose

Step 1

enable

Example:


Device> enable

Enables privileged EXEC mode.

  • Enter your password if prompted.

Step 2

configure terminal

Example:


Device# configure terminal

Enters global configuration mode.

Step 3

voice service voip

Example:


Device(config)# voice service voip

Enters voice service VoIP configuration mode.

Step 4

sip

Example:


Device(conf-voi-serv)# sip

Enters SIP configuration mode.

Step 5

pass-thru {content {sdp | unsupp} | headers {unsupp | list-tag}}

Example:


Device(conf-serv-sip)# pass-thru content unsupp

Passes the Session Description Protocol (SDP) transparently from in-leg to the out-leg with no media negotiation.

Step 6

end

Example:


Device(conf-serv-sip)# end

Ends the current configuration session and returns to privileged EXEC mode.

Example: Enabling Configurable Pass-Through of SIP INVITE Parameters (Global Level) 

Device> enable
Device# configure terminal
Device(config)# voice service voip
Device(conf-voi-serv)# sip
Device(conf-serv-sip)# pass-thru content unsupp
Device(conf-serv-sip)# end

Enable Configurable Pass-Through of SIP INVITE Parameters (Dial Peer Level)

Perform this task to configure unsupported content pass-through on a CUBE platform at the dial-peer level.

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. end

DETAILED STEPS

  Command or Action Purpose

Step 1

enable

Example:


Device> enable

Enables privileged EXEC mode.

  • Enter your password if prompted.

Step 2

configure terminal

Example:


Device# configure terminal

Enters global configuration mode.

Step 3

dial-peer voice tag voip

Example:


Device(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:


Device(config-dial-peer)# voice-class sip pass-thru content sdp

Passes the Session Description Protocol (SDP) transparently from in-leg to the out-leg with no media negotiation.

Step 5

end

Example:


Device(config-dial-peer)# end

Ends the current configuration session and returns to privileged EXEC mode.

Example: Enabling Configurable Pass-Through of SIP INVITE Parameters (Dial Peer Level) 

Device> enable
Device# configure terminal
Device(config)# dial-peer voice 2 voip
Device(config-dial-peer)# voice-class sip pass-thru content sdp
Device(config-dial-peer)# end

Configure a Route String Header Pass-Through Using Pass-Through List

SUMMARY STEPS

  1. enable
  2. configure terminal
  3. voice class sip-hdr-passthrulist list-tag
  4. passthru-hdr header-name
  5. passthru-hdr-unsupp
  6. exit
  7. dial-peer voice tag voip
  8. description string
  9. session protocol sipv2
  10. voice-class sip pass-thru headers list-tag
  11. end

DETAILED STEPS

  Command or Action Purpose

Step 1

enable

Example:


Device> enable

Enables privileged EXEC mode.

  • Enter your password if prompted.

Step 2

configure terminal

Example:


Device# configure terminal

Enters global configuration mode.

Step 3

voice class sip-hdr-passthrulist list-tag

Example:

Device(config)# voice class sip-hdr-passthrulist 101

Configures list of headers to be passed through and enters voice class configuration mode.

Step 4

passthru-hdr header-name

Example:

Device(config-class)# passthru-hdr Resource-Priority

Adds header name to the list of headers to be passed through. Repeat this step for every non-mandatory header.

Step 5

passthru-hdr-unsupp

Example:

Device(config-class)# passthru-hdr-unsupp

Adds the unsupported headers to the list of headers to be passed through.

Step 6

exit

Example:

Device(config-class)# exit

Exits the current configuration session and returns to global configuration mode.

Step 7

dial-peer voice tag voip

Example:


Device(config)# dial-peer voice 1 voip

Enters dial peer voice configuration mode.

Step 8

description string

Example:


Device(config-dial-peer)# description inbound-dialpeer

Adds descriptive information about the dial peer.

Step 9

session protocol sipv2

Example:


Device(config-dial-peer)# session protocol sipv2

Configures the IETF Session Initiation Protocol (SIP) for the dial peer.

Step 10

voice-class sip pass-thru headers list-tag

Example:


Device(config-dial-peer)# voice-class sip pass-thru headers 101

Enables call routing based on the destination route string for a dial peer.

Step 11

end

Example:


Device(config-dial-peer)# end

Exits the current configuration mode and returns to privileged EXEC mode.

Example: Configuring a Route String Header Pass-Through Using Pass-Through List 


Device> enable
Device# configure terminal
Device(config)# voice class sip-hdr-passthrulist 101
Device(config-class)# passthru-hdr X-hdr-1
Device(config-class)# passthru-hdr Resource-Priority
Device(config-class)# passthru-hdr-unsupp
Device(config-class)# exit
Device(config)# dial-peer voice 1 voip
Device(config-dial-peer)# description inbound-dialpeer
Device(config-dial-peer)# session protocol sipv2
Device(config-dial-peer)# voice-class sip pass-thru headers 101
Device(config-dial-peer)# end

Example: Passing a Header Not Supported by CUBE

CUBE does not pass “x-cisco-tip”. However, certain TelePresence equipments require “TIP”.

The SIP profile below will look for "x-cisco-tip" in the inbound contact header then pass it in the outbound contact header.

Inbound Contact Header 

Contact: <sip:89016442998@161.44.77.193;transport=udp>;x-cisco-tip

Outbound Contact Header 

Contact: <sip:89016442998@10.86.176.19:5060>;x-cisco-tip

Create a copylist to pass the Contact Header from the incoming message to the outgoing message. The “x-cisco-tip” is not copied in this step as it is unsupported by CUBE. 

!Create a copyList
Device(config)# voice class sip-copylist 1
Device(config-class)# sip-header Contact
Device(config-class)# exit

!Apply the copylist to incoming dial peer.
Device(config)# dial-peer voice 1 voip
Device(config-dial-peer)# description incoming SIP Trunk
Device(config-dial-peer)# incoming called-number 
Device(config-dial-peer)# voice-class sip copy-list 1

Create a SIP profile that copies “x-cisco-tip” into a variable, and use that variable to modify the outgoing Contact header. Apply the SIP profile to an outbound dial peer. 


Device# voice class sip-profiles 3001

!Copy the Contact header from the incoming dial peer into variable u01
Device(config-class)# request INVITE peer-header sip Contact copy "(;x-cisco-tip)" u01

!Modify the outgoing SIP Invite with this variable.  
Device(config-class)#  request INVITE sip-header Contact modify "$" "\u01"″


!Apply the SIP Profile to the outgoing dial peer.
Device(config)# dial-peer voice 5000 voip
Device(config-dial-peer)# description outbound SIP 
Device(config-dial-peer)# destination-pattern 5...$
Device(config-dial-peer)# voice-class sip profiles 3001