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Umesh,

Thanks for clearing that up.

This discussion has raised questions in my mind about the general
use of streams within an association. My background is in large
part from SS7 so that flavors my questions.

In reading http://www.sctp.de/papers/drcn2001.pdf, Section 5
describes the stream concepts as being key to avoiding head-of-line
blocking. Does this mean that in designing an SS7 linkset to SCTP
gateway, an attempt should be made to negotiate 32 streams to
accommodate 32 SLS for an ANSI combined linkset (or 16 streams for
16 SLS for an ITU linkset)? Or should each physical link in a
linkset be mapped to a separate stream?

Why are streams negotiated? What issues lie behind the
negotiations? Why for instance, would a "server" end of an
association reject the "client" end's request for n streams?

I am also curious about why sctp sending has an optional field to
specify the stream for transmission. My SS7 sensibilities are
confused by the optional nature of this piece of information. What
happens when two SCTP entities are connected where one uses multiple
streams and the other uses the default stream 0 only? Is the
outcome that the performance of the entity using the default stream
only is at risk of being comparatively poorer because the risk of
head-of-line blocking is increased?

Mike

----- Original Message -----
From:
<umesh AT cosystems.com>
To:
<discussion AT sctp.de>
Sent: Sunday, December 16, 2001 10:21 PM
Subject: RE: [SCTP-Discussion] Streams and D-Channels


: Hi Mike,
: You are right. The QPTM (Q.921/Q.931 boundary primitives
Transport)
: contain IUA header
: in addition to common header. The IUA header has a DLCI (SAPI+TEI)
field
: which identifies
: the D channel corresponding to this message.
:
: Umesh.
:
: > -----Original Message-----
: > From:
discussion-admin AT sctp.de
[mailto:discussion-admin AT sctp.de]On
: > Behalf Of Michael Mueller/bhu5nji
: > Sent: Saturday, December 15, 2001 3:29 PM
: > To:
discussion AT sctp.de
: > Subject: [SCTP-Discussion] Streams and D-Channels
: >
: >
: > :
: > : And, Yes u can send on a single StreamID mutiple D-Channel
: > Signaling mesgs.
: >
: > How would you know which D-Channel a signal is from or going to?
Is
: > there something in the IUA header that differentiates the
channels?
: >
: > MIke
: > :
: >
: >
: > _______________________________________________
: > discussion mailing list
: >
discussion AT sctp.de
: > http://www.sctp.de/mailman/listinfo/discussion
: >
: >
:
: _______________________________________________
: discussion mailing list
:
discussion AT sctp.de
: http://www.sctp.de/mailman/listinfo/discussion

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• [SCTP-Discussion] RE: discussion digest, Vol 1 #198 - 3 msgs, hari, 12/14/2001
  • [SCTP-Discussion] Streams and D-Channels, Michael Mueller/bhu5nji, 12/14/2001
    • RE: [SCTP-Discussion] Streams and D-Channels, umesh, 12/17/2001
      • Re: [SCTP-Discussion] Streams and D-Channels, Michael Mueller/bhu5nji, 12/17/2001
        • RE: [SCTP-Discussion] Streams and D-Channels, umesh, 12/18/2001

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