Acme Packet 6300
 

PLA-Support>Sun Systems>CommsGBU>Session Delivery Network>SN-SND: Acme Service Provider
 

In this Document

Symptoms

Cause

Solution

Goal

References

Created from <SR 3-12872421231>

Applies to:

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

Following are the reasons when the PEM header will be removed by SBC :-

1) If Session-Agent is untrusted i.e if a call is taking place from untrusted to trusted source then in the response SBC will strip the PEM header.

2) If the initial INVITE doesn't have the header - P-Early-Media : supported, then any response which will have P-early-Media header will be stripped while forwarding.

3) Even if the INVITE has header PEM:supported but if the response - (180/183) doesn't have SDP then SBC will strip the P-Early-Media Header.

Solution

1) Advised customer to contact the Service Provider and make sure they send the P-early-Media : supported header in INVITE.

2) Since service provider refused, we created HMR and applied at the ingress side of SBC so that SBC behaves accordingly.

Goal

To support P-Early-Media

References

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