Changing the "session-expires" header?
I'm receiving SIP Invites from our Service Provider, on behalf of one of their customers, and some of those Invites contain a "Session-Expires" header with value of "1200". Our SA on the Core side is rejecting these messages with a '422 - Session Timer too small'. That SA is expecting a value of at least 1800.
Most of our other inbound Invites from the Service Provider do not include a Session-Expires header, or have a value of 1800, and thus are not being rejected.
What is the wisdom regarding manipulation of the Session-Expires header? Is it recommended or discouraged?
I imagine that by using HMRs I could probably manipulate the value up to 1800 when it's seen in an Invite, but I'm unsure of the consequences.