SBC is Removing P-Early-Media Header in 180/183 Response. (Doc ID 2193936.1)

Last updated on MAY 17, 2017

Applies to:

Acme Packet 6300 - Version S-Cz7.1.2 to S-Cz7.3.5 [Release S-Cz7.0]
Information in this document applies to any platform.

Symptoms

SBC is stripping the P-Early-Media Header while forwarding the 180/183 responses even though the P-early-media is set as add/modify and p-early-media-direction sendrcv.

This is demonstrated with the following example call flow:

SA1 10.30.33.9 --> access sip-interface 10.10.33.9 <--> core sip-interface 10.20.33.9 --> SA2 10.40.33.9

Invite (access --> core) is without PEM (P-Early-Media).

On core sip-interface 10.20.33.9 support for PEM is disabled. Always recommended to apply PEM settings at egress interface.
p-early-media-header: disabled
p-early-media-direction:

On access sip-interface 10.10.33.9 support for PEM is enabled. Enabled at egress interface.
p-early-media-header: modify
p-early-media-direction: inactive/sendonly

SA1 and SA2 "trust-me" is set to enabled.
Both access and core sip-interface "trust-mode" set to default value "all".

Cause

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