Subject: bad AVPs result in...

From: "David Wong" <[email-masked]>
Date: Thu, 23 Dec 1999 19:45:17 -0500

I've already asked this question with respect to control packets for tunnels. My
question is now with regards to control packets for establishing/tearing down
sessions.

An excerpt from Townsley's response to an earlier message:

> AVP malformations are a bit different. If there is something detectably
> wrong (e.g. length field for a fixed size AVP is incorrect), then you
> must look to the Mandatory Bit to see what to do. If it is set,
> gracefully shutdown the call or tunnel.

So, my question is, if the malformed AVP is in, say is in one of the Incoming
Call packets, should the receiver of the bad packet (assuming that the Mandatory
Bit is set in the bad AVP) send back a CDN to clear the session? Or can the
receiver send a StopCCN to clear everything? Is there supposed to be a "correct"
answer to this, or is it really up to the implementations?

In addition, a subtle question, but what happens if an AVP has the incorrect
value for the M-bit? So, if it is supposed to be set, it isn't, or if it isn't
supposed to be set, and it is? I've assumed that in both cases, a CDN should be
sent. Is this correct?