Origin State AVP in Diameter Protocol

Question

I have a query regarding usage of Origin-State-Id AVP in Diameter. The Diameter Base Protocol RFC 3588 says that Origin-State-Id AVP MAY be included in any diameter message.

Now, some diameter based application (like a 3GPP defined application) defines new commands and in those commands’ ABNF Origin-State-Id AVP is not present.

Then does this imply that Origin-State-Id AVP MUST not be sent in these commands or it can be sent because RFC 3588 says it can be sent in any diameter message?

Answer 1

There are two aspects here.
1. As long as the command is extensible (i.e, has *[AVP] in its definition), Origin_State_Id can be added to the request/response.
2. Generally Diameter application specs address this issue, and decide to include/exclude Origin_State_Id. For example, Gx and Ro specs include it because as session oriented protocols, they recommend the usage of Origin-State-Id to detect peer restart. Sh, Cx etc don't include it because they don't use multi-transaction sessions.

So yes, it can be added . But from interoperability perspective, you may have to make sure that the remote end would use it they way you expect.

rk