Comparison of features supported on H.323 and SIP

Last Updated : Jun 05, 2026 |

This table compares:

  • Standard H.323

  • H.323 with the Avaya Special Application SA8874 feature enabled in Communication Manager

  • SIP

Feature

H.323

H.323 with SA8874 feature

SIP

Outbound calling using the Application Interface web service

Partially supported

No call progress information is available, so an application may start before a call is answered

Supported

Supported

Call conferencing

Supported

Supported

Supported

Call classification

Supported

Supported

Supported

Blind transfer

Supported

Supported

Supported

Supervised transfer (also called consultative transfer)

Note:

If a connection cannot be established, the Consultative Transfer feature in Experience Portal allows the application to regain control of the call.

Operates like a blind transfer

Note:

The only supported VoiceXML event for this transfer is error.connection.noroute.

Supported

Supported

Bridge transfer )

Partially supported

No call status information, such as "line is busy", is available

Supported

Supported except for the VoiceXML <transfer> tag’s connecttimeout parameter, which is not supported

DTMF detection

Note:

Experience Portal supports only out-band DTMF detection for H.323 and H.323 with SA8874 feature.

Supported

Supported

Supported

Note:

In case of SIP VoIP connection, the signaling group doesn’t support the out- band option. It supports the in-band and RTP-payload DTMF options.

Playing prompt files

Supported

Supported

Supported

Recording

Supported

Supported

Supported

Converse-on vectoring

Supported

Supported

Not supported

Encryption options

  • Disabled

  • AES

  • AEA

  • Disabled

  • AES

  • AEA

  • Disabled

  • TLS

  • SRTP

Quality of Service

Supported

Supported

Supported

User to User Information (UUI)

Not supported

Not supported

For an incoming call, UUI values are populated in the VoiceXML session variables for both UUI and Application to Application Information (AAI).

For more information, see Universal Call Identifier (UCID) values included in UUI data.

Universal Call Identifier (UCID)

Supports the capability to receive UCID over H323 from Communication Manager.

Note:

This capability is available in Communication Manager 5.2. To enable this feature, you need to administer ucid-info on button 10 on the 7434ND stations used by Experience Portal.

Supports the capability to receive UCID over H323 from Communication Manager.

Note:

This capability is available in Communication Manager 5.2. To enable this feature, you need to administer ucid-info on button 10 on the 7434ND stations used by Experience Portal.

Supports the capability to both send and receive UCID.

For more information, see Universal Call Identifier (UCID) values included in UUI data.

Switch failover

An alternate gatekeeper address can be specified in the EPM, and an alternate gatekeeper address list can come from Communication Manager

An alternate gatekeeper address can be specified in the EPM, and an alternate gatekeeper address list can come from Communication Manager

No additional support is supplied by Experience Portal, but the Avaya Aura®Session Manager (AASM) has support for high availability including switch failover support.

Merge (Refer with replaces)

Not supported

Not supported

Supported

Bridge transfers in a mixed SIP/H.323 environment

If you have both SIP and H.323 connections defined in your Experience Portal system, Experience Portal handles bridge transfers in the following manner. For an outbound call with:

  • SIP or SIPS in the ToURI field, there must be a SIP outbound channel available.

  • TEL in the ToURI field, Experience Portal tries to get an outbound port from the same H.323 port group. If none are available, Experience Portal tries any H.323 port.

    If no H.323 ports are available, Experience Portal converts the TEL into SIP in the ToURI field and tries and get a SIP outbound channel.