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

pendyala syam psyam545 at gmail.com
Wed Aug 19 20:42:48 UTC 2015

Hi All,

Thanks all for your inputs. I understand the point that UE can indicate its
preferred identity from the list of P-Associated-Identities notified in
200OK response of registration process. But my doubt is, why can't UE use
>From header to carry this preferred identity user wishes to use for the
call. Actually with P-Preferred-Identity concept, UE is sending the same
identity both in From header and P-Preferred-Identity. If UE can use From
header to indicate preferred identity, then  this duplicate information can
be avoided. Cant we avoid this duplicacy?? What are the disadvantages of
adding preferred identity in From header?


On Wed, Aug 19, 2015 at 12:36 AM, Sakharam Thorat <
sakharam.thorat at outlook.com> wrote:

> Hi ,
> It is explained here https://tools.ietf.org/html/rfc5876#page-4.
> while reading i found below may be helpful,
> P-Preferred-Identity header, is the one in which the calling user can
> indicate one of its public
> user identities. This is the identity that he wants to be used for the
> call.
> P-Asserted-Identity header, is the one in which the authorised identity of
> the user will be transported.
> So, to explain the use lets consider an example:
> A UE sends an INVITE to the P-CSCF as follows:
> INVITE sip:abhishek at network.in SIP/2.0
> From: "Abhishek" <sip:abhishek at network.in>;tag=12345
> P-Preferred-Identity: <sip:abhishek at network.in>
> Best Regards,
> Sakharam Thorat.
> ------------------------------
> From: psyam545 at gmail.com
> Date: Sun, 16 Aug 2015 11:58:11 +0530
> 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.
> Regards,
> Pendyala
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