SIP Third Party IP Phone Support in CUCM

CUCM supports RFC 3261-compliant third-party SIP phones. Support for third-party SIP phone features varies greatly from Cisco SIP IP Phone features. Third-party phones have only RFC 3261 SIP Version 2 support, whereas Cisco SIP Phones have many Cisco SCCP features that have been rewritten to work in a native SIP protocol stack.

Two different types of third-party SIP phones can be added to CUCM. Third-party SIP phones may be added as basic or advanced phones. Third-party SIP basic phones support one line appearance and consume three DLUs. Third-party SIP advanced phones support up to eight lines and video but consume six DLUs. Basic and advanced third-party SIP phones offer the same telephony features.

Third-party SIP phones register with CUCM but do not use a MAC address-based device ID. CUCM uses SIP digest authentication to identify a registering SIP third-party SIP phone.

Both CUCM and the third-party SIP phone have to be configured with a username and password for digest authentication to work properly. CUCM refers to this item as a digest user in which a user is associated with the phone in both the phone and user configuration pages. The third-party device must also be configured with a matching username.

SIP standards and drafts supported by CUCM include the following:






SDP offer/answer









MWI Package



Replaces Header



Referred-by Mechanism

■ draft-levy-sip-diversion-08.txt: Diversion Header

■ draft-ietf-sip-privacy-04.txt: Remote-Party-Id Header

The following audio and video standards are supported for third-party SIP phones:

—Audio codecs: G.711 mu-law, GSM Full-rate, G.723.1, G.711 A-law, G.722, G.728, G.729

—RFC 2833: DTMF (Telephony-event)

—Video codecs: H.261, H.263, H.263+, H.263++, H.264

NOTE For more information about the support of these standards, see the Cisco SIP IP Administrator Guide, Version 8.0 - Compliance with RFC 3261: guide_chapter09186a00807f47e3.html

Cisco is working with key third-party vendors who are part of the Cisco Technology Development Partner Program. These partners are developing solutions that leverage the new CUCM and CUCM Express SIP capabilities. These vendors include Linksys, IPCelerate, Research In Motion, IP blue, and Grandstream.

Cisco is also participating in an independent third-party testing and interoperability verification process being offered by tekVizion. This independent service has been established to enable third-party vendors to test and verify the interoperability of their endpoints with CUCM and CUCM Express.

Third-party SIP phones support only a few features compared to Cisco IP Phones using SCCP or SIP. The features that are not supported include but are not limited to the following:

■ MAC address registration

■ Phone buttons template

■ Soft key templates

■ Telephony features and applications such as the following:

—IP phone services

—CUCM Assistant

—Cisco Unified Video Advantage

—Call Pickup


SIP Third-Party Authentication

Digest authentication allows CUCM to act as a server to challenge the identity of a SIP device when it sends a request to CUCM. When digest authentication is enabled for a phone, CUCM challenges all SIP phone requests except keepalive messages. CUCM does not support responding to challenges from SIP phones.

CUCM can challenge SIP devices connecting through a SIP trunk and can respond to challenges received on its SIP trunk interface.

CUCM digest authentication is used to determine the identity of a third-party SIP phone. The phones cannot be authenticated via MAC address like SCCP devices because third-party SIP phones do not register by MAC address. Digest authentication is the industry standard.

CUCM can ignore the keyed hash that is provided in a digest authentication response and check only if the provided username exists and is bound to a third-party SIP phone. This is the default behavior. Alternatively, CUCM can be configured to check that the key that was used at the third-party SIP phone to generate the keyed hash matches the locally configured key (called digest credentials) at the end-user configuration in CUCM.

Third-party SIP phones cannot be configured by using the CUCM TFTP server. Instead, they need to be configured using the native phone configuration mechanism, which is usually a web page or a TFTP file. The device and line configuration in the CUCM database must be manually synchronized with the native phone configuration (for example, extension 1002 on the phone and 1002 in CUCM). In addition, if the directory number of a line is changed, it must be changed in both CUCM Administration and in the native phone configuration mechanism.

Third-party SIP phones include their directory number in the registration message. They do not send a MAC address. Third-party SIP phones identify themselves with digest authentication. The SIP REGISTER message includes a header with a username and the keyed hash, as shown in the following example:

Authorization: Digest username="3rdpsip" ,realm="ccmsipline",nonce="GBauADss2qoWr6k9y3hGGVDAqnl_fol_k5", uri="sip:",algorithm=MD5,response="126c0643a4923359ab59d4f5349455 2e"

CUCM receives the registration message and searches for an endpoint that matches the provided username in the SIP message (3rdpsip in the preceding example). CUCM uses the digest credentials configured for that user to verify the keyed hash (response="126c0643a4923359ab59d4f53494552e in the preceding example).

NOTE CUCM must be explicitly configured to verify the keyed hash. By default, CUCM searches only for the end-user name.

CUCM searches for a third-party SIP phone that is associated with the end user and verifies that the configured directory number matches the one provided by the third-party SIP phone in its registration message. If the phone is found and the directory number is the same, the third-party SIP phone registers with CUCM.

To add a third-party SIP phone in CUCM, follow these steps:

Step 1 Configure an end user in CUCM and specify the digest credentials.

Step 2 Add the third-party SIP phone in CUCM and configure its directory number.

NOTE When you are configuring the third-party SIP phone in CUCM, a dummy MAC address can be specified. The MAC address is not used to identify the device but is required inside the CUCM configuration database.

Step 3 Associate the third-party SIP phone with the end user.

Step 4 Configure the third-party SIP phone with the IP address of the CUCM, end-user ID, digest credentials, and directory number.

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    Does cisco sip phones support IETF RFC 3842?
    2 years ago
  • Steffen
    How to enable 3rd party sip cucm?
    1 year ago
  • kaari
    What does cucm use MAC for of third party phone?
    1 year ago
    How to add 7832 as third party cisco call manager?
    9 months ago
  • Robert
    How to verify what 3rd party applications are associated in CUCM?
    3 months ago

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