Subject: [tsvwg] Query regarding handling of invalid message in SCTP

From: Nagesh shamnur <[email-masked]>
Date: Fri, 12 May 2017 05:14:50 +0000

Hi Group,
                Good Morning. This mail is to clarify regarding the handling of SCTP messages in a particular scenario as given below:

RFC 4960 Snippet:
If an endpoint receives an INIT, INIT ACK, or COOKIE ECHO chunk but
   decides not to establish the new association due to missing mandatory
   parameters in the received INIT or INIT ACK, invalid parameter
   values, or lack of local resources, it SHOULD respond with an ABORT
   chunk.  It SHOULD also specify the cause of abort, such as the type
   of the missing mandatory parameters, etc., by including the error
   cause parameters with the ABORT chunk.  The Verification Tag field in
   the common header of the outbound SCTP packet containing the ABORT
   chunk MUST be set to the Initiate Tag value of the peer.

                When a SCTP client in COOKIE-WAIT state receives INIT-ACK but with invalid parameter or chunk length, then as per the above RFC snippet, it says to send ABORT to peer, but doesn't mentions the handling with respect to TCB. Whether the TCB should be freed and endpoint down indication needs to be given to application or wait for subsequent INIT-ACK from peer hoping that the subsequent message would correct this issue and hence result in normal association establishment.
                What would be the right way of handling such an situation?

Regards,
Nagesh.