[VoiceOps] Caller-ID: SIP From vs. P-Asserted-Identity

Hiers, David David.Hiers at adp.com
Mon Jul 23 18:21:53 EDT 2012

Perfectly legal under 3325.8; the UAS is free to do whatever it wants to with the PAI info.

For the PAI to reach the actual endpoint phone is a bit off-putting... It shows a bit more trust in the endpoint than I'm usually willing to extend, but I'm a bit curmudgeonly at times.


-----Original Message-----
From: voiceops-bounces at voiceops.org [mailto:voiceops-bounces at voiceops.org] On Behalf Of Jay Hennigan
Sent: Monday, July 23, 2012 14:08
To: VoiceOps
Subject: [VoiceOps] Caller-ID: SIP From vs. P-Asserted-Identity

Question for the experts:

We have a scenario where a SIP user originates a call to the PSTN (not
9-1-1) with a SIP From: header containing one DID and P-Asserted-Identity showing a different DID.

We expect the carrier to use the P-Asserted-Identity for billing and recordkeeping but send the SIP From: out as the CLID to be displayed to the called party.

Typically this is done in a call center type scenario where an agent wants the CLID to display the main number of the agent  pool and not the specific DID of the agent.  Another scenario is a customer PRI-based PBX that hairpins inbound calls back out to a traveling user and wants to preserve the original caller's information.

One of our terminating carriers uses the P-Asserted-Identity as the displayed CLID and not the SIP From:.  I feel that this is not correct.

Numbers have been changed to protect the guilty...

TO: <sip:8055550123 at www.xxx.yyy.zzz;user=phone>

FROM: "Fred
Flintstone"<sip:+18055550199 at www.xxx.yyy.zzz;user=phone>;tag=1689985881-1343063740200-
P-Asserted-Identity: "Fred
Flintstone"<sip:+18055550177 at www.xxx.yyy.zzz;user=phone>

TIME/DATE: Mon Jul 23 17:15:39 2012  (GMT)

RESULT: Called party (8055550123) is seeing 8055550177 as calling party's caller ID instead of 8055550199

Jay Hennigan - CCIE #7880 - Network Engineering - jay at impulse.net Impulse Internet Service  -  http://www.impulse.net/ Your local telephone and internet company - 805 884-6323 - WB6RDV _______________________________________________
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