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AW: [SCTP-Discussion] Re: Bundling


Chronological Thread 
  • From: Schruefer Wolfgang <Wolfgang.Schruefer AT icn.siemens.de>
  • To: "'discussion AT sctp.de'" <discussion AT sctp.de>
  • Subject: AW: [SCTP-Discussion] Re: Bundling
  • Date: Mon Mar 18 14:22:00 2002
  • List-id: SCTP Discussions <discussion.sctp.de>

Hello Andreas,

you asked for suggestions...

Here is a suggestion for an API to give the upper layer nearly full contol
for bundling.
It is realised with the control-flag 'dontBundle' in sctp_send() and an
additional Instance- (or Association-) Parameter 'bundlingSendDelay' to
define the bundling time.

#define SCTP_BUNDLING_ENABLED 0
/* Like SCTP_SEND_IMMEDIATELY (for historic reasons)*/

#define SCTP_BUNDLING_DISABLED 1
/* Like SCTP_SEND_IMMEDIATELY (for historic reasons)*/

#define SCTP_SEND_IMMEDIATELY 2
/* The Packet is created procedural and sent out if allowed by receiver*/

#define SCTP_SEND_DELAYED 3
/* A timer (duration=InstanceParameter: bundlingSendDelay, 0 allowed!) is
started (if not running yet).
The Packet is sent out at timer expiry or if maximum packet size was
reached */

#define SCTP_DONT_SEND_NOW 4
/* The message is only queued in the send queue, sctp needs external trigger
for sending.
Exception: it will be sent out immediately if the maximum packet size was
reached*/

#define SCTP_SEND_NOW 5
/* Trigger to send out queued messages. A call of sctp_send() with this flag
may contain
no message attached (then only Params: *buffer==NULL, associationID) */


Viele Gruesse
Wolfgang


-----Ursprüngliche Nachricht-----
Von: Andreas Jungmaier
[mailto:ajung AT exp-math.uni-essen.de]
Gesendet: Montag, 18. März 2002 10:44
An:
discussion AT sctp.de;
Alberto Bellettato
Cc: Michael Tüxen
Betreff: Re: [SCTP-Discussion] Re: Bundling


Alberto,

bundling generally implies that the implementation wait some
time before data is sent. If, during that time another chunk
is sent by the application, it may be bundled.
If, however, the application does not send any data within that
time, no bundling is used, but performance may be worse, because
of the additional delay.

Now, actually that is a matter of the API.

And this is a question to the list: are there any suggestions/
comments as to how that might be handled ?

Regards,

Andreas


On Saturday, 16. March 2002 10:34, Alberto Bellettato wrote:
> I am testing the multi-streaming feature and I think that the absence of
> head-of-line blocking within streams should give better performances in
> case of bundling utilization (but only if chunks with _different_ stream ID
> are bundled inside of the same SCTP packet ).
> For this reason I need to understand exacly when bundling is used
> (unfortunately I could not extrapolate the implementation's logic from
> Ethereal logs).
> For this multi-streaming test, I would need that bundling is always used to
> get top performances. But, setting SCTP_BUNDLING_ENABLED, bundling is _not_
> always used. Then, under what conditions is it not used?
>
> Best Regards,
> Alberto
>
> > From: Tuexen Michael
> > <Michael.Tuexen AT icn.siemens.de>
> > To:
> > "'discussion AT sctp.de'"
> >
> > <discussion AT sctp.de>
> > Cc: "'Alberto Bellettato'"
> > <alberto.bellettato AT icn.siemens.it>
> > Subject: RE: [SCTP-Discussion] Bundling
> > Date: Thu, 14 Mar 2002 15:23:09 +0100
> > Reply-To:
> > discussion AT sctp.de
> >
> > Hi Alberto,
> >
> > we provide to constants:
> > SCTP_BUNDLING_ENABLED
> > SCTP_BUNDLING_DISABLED
> >
> > These affect the initial sending of there is not flowcontrol
> > or congestioncontrol active which delays the sending. In case
> > of retransmissions or delayed sending bundling can occur if
> > it results in better protocol performance.
> > Even if you set SCTP_BUNDLING_DISABLED the DATA chunk may
> > be bundled on retransmissions.
> >
> > Why do you need this behaviour for testing? It should only be
> > avoided that SCTP restricts the protocol performance unnecessary
> > by waiting for data for bundling.
> >
> > Best regards
> > Michael
>
> _______________________________________________
> discussion mailing list
> discussion AT sctp.de
> http://www.sctp.de/mailman/listinfo/discussion

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