Subject: [Sigtran] Sending ABORT upon receipt of INIT-ACK

From: "Haresign Lincoln" <[email-masked]>
Date: Wed, 16 May 2007 10:10:07 -0400

TO whom it may concern:

Section 3.3.3 of RFC 2960 states:

      If the value of the Initiate Tag in a received INIT ACK chunk is
      found to be 0, the receiver MUST treat it as an error and close
      the association by transmitting an ABORT.

I'm just curious what the thinking is regarding sending an ABORT.  The
server has retained no knowledge of the connection. So when it recieves
the ABORT, it will be considered "out of the blue".  So ... Whats' the
point.  In other error scenarios for processing INIT-ACK, the RFC
states:

      Note: A receiver of an INIT ACK  with the MIS value set to 0
      SHOULD destroy the association discarding its TCB.

This seems more appropriate.

Regards,
Lincoln

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From: "emmanuel mavrommatis" <[email-masked]>
Date: Wed, 16 May 2007 17:16:26 +0100

Hi Lincon,

In the RFC is stated:

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 MUST respond with an ABORT
chunk.

That means "ABORT" the initiation of an association. There is not need to be
in ESTABLISH state.

In what you quoted:

It deletes the TCB to prevent resource attacks, but must also send a ABORT.
Look on the Figure 3: State Transition Diagram of SCTP page 51.

Regards,
Emmanuel