[SIPForum-discussion] What are the uses of P-Preferred-Identity??

Joel Gerber Joel.Gerber at corp.eastlink.ca
Mon Aug 17 11:50:57 UTC 2015

Hello Pendyala,

Generally P-Preferred-Identity will NOT be shown as the caller ID in a receiving client. Instead, the From header should always be used. P-Preferred-Identity is more for the Service Provider to be informed as to the legitimate identity of the originating endpoint for use in cases where the From header is being manipulated for privacy or marketing reasons. The Service Provider will inspect the P-Preferred-Identity field, and based on policy, will determine if it’s valid. If it is, it will use it for billing and potentially for sending to an upstream Service Provider, if that provider is trusted.

There is another related header field that should be considered as well. P-Asserted-Identity. P-Asserted-Identity is sent by an element that is trusted by the Service Provider and dictates what the identity is. If a Service Provider receives P-Asserted-Identity from an un-trusted element he’ll ignore it. If he received it from a trusted identity, he trusts it completely. P-Preferred-Identity is sent by an untrusted endpoint, and a Service Provider receiving this will inspect its values and see if they are legitimate for the sending endpoint. If they are, he MAY view this as authoritative and use it accordingly.

Joel Gerber
Network Operations Specialist - Telephone
Joel.Gerber at corp.eastlink.ca<mailto:%20Joel.Gerber at corp.eastlink.ca>    T: 519.786.1241

From: discussion-bounces at sipforum.org [mailto:discussion-bounces at sipforum.org] On Behalf Of pendyala syam
Sent: August-16-15 2:28 AM
To: discussion at sipforum.org
Subject: [SIPForum-discussion] What are the uses of P-Preferred-Identity??

Hi All,

As far I understand, P-Preferred-Identity will be shown as caller display name in callee UI. When SIP already have From header which carriers the caller identity, why is this P-Preferred-Identity header required? Why can't we use From header to show caller display name at callee UI?. Is there any added advantage of this header. Some body please explain. Thanks in advance.

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