Re: M3UA ASP UP message format

"Brian F. G. Bidulock" <[email protected]>
Newsgroups gmane.ietf.sigtran
Organization http://www.openss7.org/
Message-ID <[email protected]>
Edwin,

A little more information is in order:  are these ASPUP messages (TSNs)
being sent for the first time?  If so, perhaps the designer took the
"and resend ASP Up messages until it receives an ASP Up Ack message"
too literally; the intention was to resend one ASP Up with each timer
expiry.  If they are being retransmitted (e.g. because the peer host
crashed), it could be more normal.

The retransmission of ASPUP is a purely optional procedure (the "MAY"),
and is questionable at best on a reliable transport.  (The M3UA spec
leaves the door open, a crack, for unreliable transport.)

A better procedure for reliable transport is to notify management on
expiry of the timer rather than resending ASP Up (but note clearly the
"MAY" on the procedure).  Also, once the timer has expired a number of
times, (say 60), generate a more critical alarm (but keep waiting).

--brian


[email protected] wrote:              (Sat, 11 Feb 2006 13:40:26)
> Hi,
> 
> I have a question regarding the format of the M3UA ASP UP message
> initiated by the ASP to the SGP.
> 
> I wanted to know if this is a valid format according to the specs. RFC
> 3332 section 4.3.4 ASPM Procedures for Peer-to-Peer Messages mentions
> that M3UA ASP UP can be retransmitted after Timer T(ack) expires.
> "When the ASP sends an ASP Up message it starts timer T(ack). If the ASP
> does not receive a response to an ASP Up message within T(ack), the ASP
> MAY restart T(ack) and resend ASP Up messages until it receives an ASP
> Up Ack message. T(ack) is provisionable, with a default of 2 seconds."
> 
> No.     Time                       Source          Destination
> Protocol Info
> 23 2006-01-27 23:04:37 10.4.82.54      10.169.97.204         M3UA (RFC
> 3332) ASPUP ASPUP ASPUP ASPUP ASPUP ASPUP ASPUP ASPUP ASPUP ASPUP ASPUP
> ASPUP ASPUP ASPUP ASPUP ASPUP ASPUP ASPUP ASPUP ASPUP ASPUP ASPUP ASPUP
> ASPUP ASPUP 
> 
> The entire packet expanded has been attached in the text file.
> 
> 
>  <<m3ua_aspup.txt>> 
> Thanks
> Edwin


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