Subject: [Tsvwg] Re: SCTP T Bit in Abort Message

From: "Brian F. G. Bidulock" <[email-masked]>
Date: Mon, 30 Jul 2001 10:06:52 -0500

Stephen,

Your question should be for the [email-masked] list, but here's
an answer anyway:

When we as an SCTP endpoint receive an ABORT with the T-bit set it means
that the peer endpoint (that sent the ABORT) does not have a TCB for a
message previsouly sent.  This typically means that the peer endpoint
crashed and then came up again quickly, or, more often, our association
with the endpoint was aborted by the peer but its ABORT message was lost
or delayed, and we kept sending to it.

Because the ABORT message with the T-bit set means that the peer has no
TCB, it also means that the verification tag in the message is out idea
of the peer verification tag (not ours).

So, what we do with the message is lookup the association based on
either the IP-port/IP-port pair, or based on a peer tag hash (not a
verification tag hash as is possible).  We do not perform the normal
verification tag rules (only the peer tag counts).

Once we have looked up the association that the ABORT belongs to, we
process that message within the association as we would process any
ABORT message from the peer.

--Brian

Hamel, Stephen [BCNR:7M40:EXCH] wrote:            (Mon, 30 Jul 2001 10:47:01)
> 
>    Hello,
>    
>    in the SCTP spec, it mentions that a T bit must be set regarding the
>    TCB. (3.3.7)
>    But, regarding the rules of an abort packet, there is no mention about
>    what to do with the T bit when receiving
>    the abort packet (8.5.1 Section B).  It is only mentioned in Section C
>    when handling a shutdown complete.
>    
>    Any ideas ? Thanks
>    
>    Stephen Hamel
>    ---
>    You are currently subscribed to sigtran as: [email-masked]
>    To unsubscribe send a blank email to
>    [email-masked]

-- 
Brian F. G. Bidulock
[email-masked]
http://www.openss7.org/

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