these extensions are described in section 4. · RFC A Message Summary and Message Waiting Indication Event Package . Find the most up-to-date version of IETF – RFC at Engineering Find the most up-to-date version of RFC at Engineering
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To require the use of a particular method in a particular dialog, they must use an option tag associated to that method. The state publication framework defines a new method: From Wikipedia, the free encyclopedia. Software Version XEP 3256 SIP, the route header field, filled by the sender, supports this functionality by listing a set of proxies the message will visit.
SIP extensions for the IP Multimedia Subsystem
To indicate that the gfc agent requests or supports reliable provisional responses, the rel option tag will be used. In the IMS context, there are certain network entities i. Apart from all the explained extensions to SIP that make gfc possible for the IMS to work successfully, it is also necessary that the IMS framework interworks and exchanges services with existing network infrastructures, mainly the Public switched telephone network PSTN.
This way the recipient of the message can decide whether or not to follow the reference to fetch the resource, depending on the bandwidth available. Compression algorithms perform this operation by substituting repeated words in the message by its position in a dictionary where all these words only appear once.
By using the user agent capabilities extension,  user agents terminals can describe themselves when they register so that others can search for them according to their caller preferences extension headers. Other for any supplementary information:.
Relationship with other existing or emerging documents:. Partners Overview Collaborating to set new industry standards. The IMS is meant to provide multimedia services over IP networks, but also needs a mechanism to charge users for it.
RFC – Session Initiation Protocol (SIP)-Specific Event Notification
Likewise, if the server does not support any of the client’s required extensions, it will send an error response with a list of its unsupported extensions. For customers interested in purchasing units or less of our Bria softphone clients, please visit our online store. There exist analogous extension headers ietg handling the identification of services of users,  instead of the users themselves.
ieft The security mechanisms agreement extension for SIP  was then introduced to provide a secure mechanism for negotiating the security algorithms and parameters to be used by the P-CSCF and the terminal. IP multimedia concepts and services 2 ed. When used in request-URIs, it indicates that the request is to be compressed, while in Via header fields it signals that the subsequent response is to be compressed. These header fields are used for a variety of purposes including charging and information about the networks a call traverses:.
In this case, Uniform Resource Names are used to identify a service e. Source routing is the mechanism that allows the sender of a message to specify partially or completely the route the message traverses. Retrieved December 2, The extension for service route discovery during rvc  consists of a Service-Route header field that is used by the registrar in a 2XX response to a REGISTER request to inform the registering user of the entity that must forward every request originated by him or her.
Committed to connecting the world. Clear description of the referenced document:. Stream Compression XEP Current information, if any, about IPR issues:.
However, in such an scenario as the IMS framework, it is necessary to extend this reliability to provisional responses to INVITE requests for session establishment, this is, to start a call.
With the caller preferences extension,  the calling party is able to indicate the kind of user agent they want to reach e. The new SDP attributes are meant to describe the current status of the resource reservation, the desired status of the reservation to proceed with session establishment, and the confirmation statusto indicate when the reservation status should be confirmed.
Merging the Internet and the Cellular Worlds 3 ed. Retrieved December 5, These extensions also allow users to request privacy so that their identities are not spread outside the trust domain.
Service Discovery XEP Moreover, the SIP INFO method extension is designed to carry user information between terminals without affecting the signaling dialog and can be used to transport the dual-tone multi-frequency signaling to provide telephone keypad function for users.
There is a mechanism  to indicate that a SIP message is desired to be compressed. This extension uses three new header fields to support the negotiation ieff.
Other useful information describing the “Quality” of the document:. All RFCs always remain available on-line. Any explicit references within that referenced document should also be listed:. Relationship with other existing or emerging documents: