Configuring Support for Dynamic REFER Handlingon the Cisco UBE

The Dynamic REFER Handling on the Cisco UBE feature provides a REFER handling mechanism for calltransfers on the Cisco Unified Border Element (UBE). You can configure the Cisco UBE to either passacross or consume the REFER message. When an endpoint invokes a supplementary service such as a calltransfer, the endpoint generates and sends an in-dialog REFER request towards the Cisco UBE. To enableREFER handling on the Cisco UBE, use the supplementary-service sip refer command in voice servicevoip configuration mode.

• Finding Feature Information, page 1

• Prerequisites for Configuring Support for Dynamic REFER Handling on the Cisco UBE, page 1

• Restrictions for Configuring Support for Dynamic REFER Handling on the Cisco UBE, page 2

• How to Configure Support for Dynamic REFER Handling on Cisco UBE, page 2

• Feature History and Information for Configuring Support for Dynamic REFER Handling on the CiscoUBE, page 8

Finding Feature InformationFor 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 whicheach feature is supported, see the "Cisco Unified Border Element Features Roadmap" section on page 3 .

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

Prerequisites for Configuring Support for Dynamic REFERHandling on the Cisco UBE

• Transcoding configuration is required on the Cisco UBE for midcall transcoder insertion, deletion, ormodification during call transfers.

Cisco Unified Border Element (Enterprise) SIP Support Configuration Guide, Cisco IOS XE Release 3S 1

Cisco Unified Border Element

• Cisco IOS Release 15.2(1)T or a later release must be installed and running on your Cisco Unified BorderElement.

Cisco Unified Border Element (Enterprise)

• Cisco IOS XE Release 3.7S or a later release must be installed and running on your Cisco ASR 1000Series Router.

Restrictions for Configuring Support for Dynamic REFERHandling on the Cisco UBE

• The Dynamic REFER Handling on the Cisco UBE feature supports only Session Initiation Protocol(SIP)-to-SIP call transfers.

• Call escalation and de-escalation are not supported in REFER consumption mode on the Cisco UBE.

• Video transcoding is not supported in REFER consumption mode on the Cisco UBE.

• Session Description Protocol (SDP) pass-through is not supported in REFER consumption mode on theCisco UBE.

How to Configure Support for Dynamic REFER Handling on CiscoUBE

Configuring REFER Pass-Through on the Cisco UBEIn REFER pass-through mode, the Cisco UBE passes the REFER message from the in-leg to the out-leg. Toenable REFER pass-through on the Cisco UBE, use the supplementary-service sip refer command at theglobal or dial peer configuration level. If the referto-passing command is configured, the Cisco UBE doesnot perform dial peer lookup while passing the REFER message and passes the Refer-To header without anymodification, even if address hiding is enabled.

This section contains the following tasks:

Cisco Unified Border Element (Enterprise) SIP Support Configuration Guide, Cisco IOS XE Release 3S2

Configuring Support for Dynamic REFER Handling on the Cisco UBERestrictions for Configuring Support for Dynamic REFER Handling on the Cisco UBE

Configuring REFER Pass-Through on the Cisco UBE at the Global Level

SUMMARY STEPS

1. enable2. configure terminal3. voice service voip4. supplementary-service sip refer5. sip6. referto-passing7. exit8. exit

DETAILED STEPS

PurposeCommand or Action

Enables privileged EXEC mode.enableStep 1

Example:

Device> enable

• Enter your password if prompted.

Enters global configuration mode.configure terminal

Example:

Device# configure terminal

Step 2

Enters voice service voip configuration mode.voice service voip

Example:

Device(config)# voice service voip

Step 3

Enables SIP supplementary services for REFERpass-through.

supplementary-service sip refer

Example:

Device(conf-voi-serv)# supplementary-servicesip refer

Step 4

Enters voice service voip SIP configuration mode.sip

Example:

Device(conf-voi-serv)# sip

Step 5

Cisco Unified Border Element (Enterprise) SIP Support Configuration Guide, Cisco IOS XE Release 3S 3

Configuring Support for Dynamic REFER Handling on the Cisco UBEConfiguring REFER Pass-Through on the Cisco UBE

PurposeCommand or Action

Disables the dial peer lookup and modification of theRefer-To header when the Cisco UBE passes across theREFER message during a call transfer.

referto-passing

Example:

Device(conf-serv-sip)# referto-passing

Step 6

Exits voice service voip SIP configuration mode.exit

Example:

Device(conf-serv-sip)# exit

Step 7

Exits voice service voip configuration mode.exit

Example:

Device(conf-voi-serv)# exit

Step 8

Configuring REFER Pass-Through on the Cisco UBE at the Dial Peer Level

SUMMARY STEPS

1. enable2. configure terminal3. dial-peer voice number voip4. voice-class sip referto-passing [system]5. exit

DETAILED STEPS

PurposeCommand or Action

Enables privileged EXEC mode.enableStep 1

Example:

Device> enable

• Enter your password if prompted.

Enters global configuration mode.configure terminal

Example:

Device# configure terminal

Step 2

Cisco Unified Border Element (Enterprise) SIP Support Configuration Guide, Cisco IOS XE Release 3S4

Configuring Support for Dynamic REFER Handling on the Cisco UBEConfiguring REFER Pass-Through on the Cisco UBE

PurposeCommand or Action

Enters dial peer voice configuration mode for the specifieddial peer.

dial-peer voice number voip

Example:

Device(config)# dial-peer voice 22 voip

Step 3

Enables pass-through mode on the specified dial peer.voice-class sip referto-passing [system]Step 4

Example:

Device(config-dial-peer)# voice-class sipreferto-passing

• In the pass-throughmode, the CiscoUBE passes acrossthe Refer-To header during a call transfer.

Exits dial peer voice configuration mode.exit

Example:

Device(config-dial-peer)# exit

Step 5

Configuring REFER Consumption on the Cisco UBEIn REFER consumptionmode, the Cisco UBE consumes the REFERmessage and performs a dial peer lookupbased on the Refer-To header. The Cisco UBE uses the properties of the matching dial peer and sends atriggered INVITE to the call-transfer target. To enable REFER consumption on the Cisco UBE, use the nosupplementary-service sip refer command at the global or dial peer configuration level. The dial peerconfiguration takes precedence over the global configuration.

Following are the benefits of the Dynamic REFERHandling on the Cisco UBE feature in REFER consumptionmode:

• Midcall codec changes are supported.

• Both normal and high density (optimized) transcoding are supported.

• End-to-endmedia renegotiation is supported during call transfer. To enable midcall media renegotiation,use the supplementary-service media-renegotiate command.

• Secure Real-time Transport Protocol (SRTP) to RTP conversion is supported.

• Media flow-through and flow-around are supported for transferred calls.

• UniformResource Identifier (URI)-based routing (dial-peer lookup based on domain name) is supportedfor the triggered INVITE.

This section contains the following tasks:

Cisco Unified Border Element (Enterprise) SIP Support Configuration Guide, Cisco IOS XE Release 3S 5

Configuring Support for Dynamic REFER Handling on the Cisco UBEConfiguring REFER Consumption on the Cisco UBE

Configuring REFER Consumption on the Cisco UBE at the Global Level

SUMMARY STEPS

1. enable2. configure terminal3. voice service voip4. no supplementary-service sip refer5. supplementary-service media-renegotiate6. exit

DETAILED STEPS

PurposeCommand or Action

Enables privileged EXEC mode.enableStep 1

Example:

Device> enable

• Enter your password if prompted.

Enters global configuration mode.configure terminal

Example:

Device# configure terminal

Step 2

Enters voice service voip configuration mode.voice service voip

Example:

Device(config)# voice service voip

Step 3

Enables SIP supplementary services for REFERconsumption.

no supplementary-service sip refer

Example:

Device(conf-voi-serv)# no supplementary-servicesip refer

Step 4

Enables end-to-end media renegotiation during the calltransfer in REFER consumption mode.

supplementary-service media-renegotiate

Example:

Device(conf-voi-serv)# supplementary-servicemedia-renegotiate

Step 5

Cisco Unified Border Element (Enterprise) SIP Support Configuration Guide, Cisco IOS XE Release 3S6

Configuring Support for Dynamic REFER Handling on the Cisco UBEConfiguring REFER Consumption on the Cisco UBE

PurposeCommand or Action

Exits voice service voip configuration mode.exit

Example:

Device(conf-voi-serv)# exit

Step 6

Configuring REFER Consumption on the Cisco UBE at the Dial Peer LevelThe REFER consumption behavior on the Cisco UBE can be configured for every dial peer.

SUMMARY STEPS

1. enable2. configure terminal3. dial-peer voice number voip4. no supplementary-service sip refer5. exit

DETAILED STEPS

PurposeCommand or Action

Enables privileged EXEC mode.enableStep 1

Example:

Device> enable

• Enter your password if prompted.

Enters global configuration mode.configure terminal

Example:

Device# configure terminal

Step 2

Enters dial peer voice configuration mode for thespecified dial peer.

dial-peer voice number voip

Example:

Device(config)# dial-peer voice 22 voip

Step 3

Enables SIP supplementary services for REFERconsumption.

no supplementary-service sip refer

Example:

Device(config-dial-peer)# nosupplementary-service sip refer

Step 4

Cisco Unified Border Element (Enterprise) SIP Support Configuration Guide, Cisco IOS XE Release 3S 7

Configuring Support for Dynamic REFER Handling on the Cisco UBEConfiguring REFER Consumption on the Cisco UBE

PurposeCommand or Action

Exits dial peer voice configuration mode.exit

Example:

Device(config-dial-peer)# exit

Step 5

Troubleshooting Tips for Configuring Support for Dynamic REFER Handling onthe Cisco UBE

Use any of the following debug commands as appropriate on the Cisco UBE:

• debug ccsip all

Device# debug ccsip allAll SIP Call tracing is enabled

• debug voip ccapi inout

Device# debug voip ccapi inputvoip ccapi inout debugging is on

• debug sccp messages

Device# debug sccp messagesSkinny Client Control Protocol messages debugging is on

• debug voip application supplementary-service

Device# debug voip application supplementary-servicevoip application supplementary service debugging is on

• debug voip application media negotiation

Device# debug voip application media negotiationvoip application medianeg debugging is on

Feature History and Information for Configuring Support forDynamic REFER Handling on the Cisco UBE

The following table provides release information about the feature or features described in this module. Thistable lists only the software release that introduced support for a given feature in a given software releasetrain. 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.

Cisco Unified Border Element (Enterprise) SIP Support Configuration Guide, Cisco IOS XE Release 3S8

Configuring Support for Dynamic REFER Handling on the Cisco UBETroubleshooting Tips for Configuring Support for Dynamic REFER Handling on the Cisco UBE

Table 1: Feature History and Information for Configuring Support for Dynamic REFER Handling on the Cisco UBE

Feature InformationReleasesFeature Name

TheDynamic REFERHandling onthe Cisco UBE feature providesREFER message handling supporton the Cisco UBE. You canconfigure the Cisco UBE forREFER pass-through or REFERconsumption.

The following commands wereintroduced or modified:referto-passing, voice-class sipreferto-passing.

15.2(1)TDynamic REFER Handling on theCisco UBE

TheDynamic REFERHandling onthe Cisco UBE feature providesREFER message handling supporton the Cisco UBE. You canconfigure the Cisco UBE forREFER pass-through or REFERconsumption.

The following commands wereintroduced or modified:referto-passing, voice-class sipreferto-passing.

Cisco IOS XE Release 3.7SDynamic REFER Handling on theCisco UBE

Cisco Unified Border Element (Enterprise) SIP Support Configuration Guide, Cisco IOS XE Release 3S 9

Configuring Support for Dynamic REFER Handling on the Cisco UBEFeature History and Information for Configuring Support for Dynamic REFER Handling on the Cisco UBE

Cisco Unified Border Element (Enterprise) SIP Support Configuration Guide, Cisco IOS XE Release 3S10

Configuring Support for Dynamic REFER Handling on the Cisco UBEFeature History and Information for Configuring Support for Dynamic REFER Handling on the Cisco UBE