[OpenSER-Users] Why RPID related functions instead of PAI?

[Klaus Darilion]

Iñaki Baz Castillo wrote:
> Hi, "Remote-Party-ID" is a draft ("draft-ietf-sip-privacy-04") [1] expired in 
> 2002 while "P-Asserted-Identity" is a official RFC (3325) [2].
> 
> I'd like to know why OpenSer manages RPID in some functions ("auth" module) 
> instead of PAI. I assume that some gateways just implement RPID and so, but 
> can't understand why PAI is ignored (the use of PAI is extended in gateways).

RPID was never an RFC, but it was implemented by Cisco and all of the 
Cisco stuff out there support it. PAI is supported only by newer Cisco 
stuff. Thus, most gateways support RPID too to be compatible with Cisco.

When ser implemented RPID support, there was not PAI defined. Thus, RPID 
support was first and it was implemented into auth module - and more or 
less hardcoded.

Later, ser/openser become more flexible (pseudo variables, AVPs ...) and 
you could load AVPs from DB and add a new header with the AVP. Thus, for 
adding a header with values read from database there was no reason 
anymore to implement a certain add_pai_hf function as you could do 
everything with append_hf and AVPs.

regards
klaus



> 
> As a curiosity, both draft and RFC have really **common** parts, as 
> chapter "Introduction" (4 in draft, 3 in RFC):
> 
>   "3/4 Introduction
> 
>    Various providers offering a telephony service over IP networks have
>    selected SIP as a call establishment protocol.  Their environments
>    require a way for trusted network elements operated by the service
>    providers (for example SIP proxy servers) to communicate the identity
>    of the subscribers to such a service, yet also need to withhold this
>    information from entities that are not trusted when necessary.  Such
>    networks typically assume some level of transitive trust amongst
>    providers and the devices they operate.
> 
>    These networks need to support certain traditional telephony services
>    and meet basic regulatory and public safety requirements.  These
>    include Calling Identity Delivery services, Calling Identity Delivery
>    Blocking, and the ability to trace the originator of a call ... "
> 
> 
> So my question is again:why OpenSer supports RPID related functions and not 
> PAI functions?
> 
> Thanks for any explanation.
> 
> 
> [1] RPID: http://tools.ietf.org/html/draft-ietf-sip-privacy-04
> [2] PAI:  http://www.faqs.org/rfcs/rfc3325.html
> 
> 
> 
>