Re: problem with CMG and one mutual SEND/RCV connection

Hi again,

I do not agree here... We doesn't have any queue for ACK's. If emi driver 
receive DLR's then ACK's will be send immediately back, without any queuing 
(only tcp/ip buffering is here). That means, the right order is always there:
	1) kannel -> send msg -> smsc 
	2) smsc -> send ack -> kannel
	3) smsc -> send dlr -> kannel
	3) kannel -> send next msg (depends on window size) -> smsc
	4) kannel -> send ack -> smsc

So I can not undestand, why it should happens here ? If it is happens, then 
(imo) CMG has a bug! emi is asynch. protocol and smsc may not wait for any 
ack's before sending ack's back!

On Monday 04 August 2003 10:59, Andreas Fink wrote:
> if this is really the case, then we have a bug to fix.
> Bruno what you think of this?
>
> On Montag, August 4, 2003, at 10:55  Uhr, Holger Seiferth wrote:
> > Hi,
> > when using kannel with CMG SMSC and a provider which uses one
> > connection to
> > do both sending and receiving messages (incl. notification) there
> > seems to be
> > a kind of "Dead Lock" problem with sending messages and sending
> > notifications. Situation is like this (I tried to simplify the
> > description to make it
> > easier to understand):
> > I send 100 messages to Kannel. Kannel puts those 100 messages into its
> > send
> > queue. Then it sends out the first 5 messages (assuming WindowsSize is
> > 5).
> > Then I get back 5 ACKs and 5 notifications. After I got back the ACKs,
> > Kannel
> > sends out the next 5 messages. Then I get back 5 ACKs and 5
> > notifications, and
> > so on.
> > The problem is:
> > Kannel seems to put the ACKs to the notifications in the same queue as
> > the
> > outgoing messages without any priority. So those ACKs are not sent
> > until the
> > last of the 100 MOs was sent. But we get into trouble, because the CMG
> > SMSC
> > keeps waiting for those ACKs and since they don't come, it's assuming
> > that our
> > side (meaning Kannel) is busy, so it delays sending the MT ACKs.
> > Finally, we get into the situation when Kannel waits for MT ACKs
> > (because
> > CMG refuses sending them) and CMG waits for notification ACKs, since
> > they are
> > in the Kannel message queue.
> > I think, to prevent this, Kannel would have to send any ACKs before
> > sending
> > any messages, meaning Kannel needs to set a higher priority on ACKs
> > than on
> > MTs.
> > Is there any (configuration) solution for this problem?
> > Thanks!
> >
> > Kind regards,
> > Holger
> >
> > --
> > COMPUTERBILD 15/03: Premium-e-mail-Dienste im Test
> > --------------------------------------------------
> > 1. GMX TopMail - Platz 1 und Testsieger!
> > 2. GMX ProMail - Platz 2 und Preis-Qualitätssieger!
> > 3. Arcor - 4. web.de - 5. T-Online - 6. freenet.de - 7. daybyday - 8.
> > e-Post
>
> Andreas Fink
> Global Networks Switzerland AG
>
> ------------------------------------------------------------------
> Tel: +41-61-6666333  Fax: +41-61-6666334   Mobile: +41-79-2457333
> Global Networks, Inc. Clarastrasse 3, 4058 Basel, Switzerland
> Web: http://www.global-networks.ch/      [email protected]
> ------------------------------------------------------------------

-- 
Best regards / Mit besten Grüßen aus Düsseldorf

Dipl.-Ing.
Alexander Malysh
___________________________________________

Centrium GmbH
Vogelsanger Weg 80
40470 Düsseldorf

Fon: +49 (0211) 74 84 51 80
Fax: +49 (0211) 277 49 109

email: a.malysh at centrium.de
web: www.centrium.de
msn: olek2002 at hotmail.com
icq: 98063111
___________________________________________

Please avoid sending me Word or PowerPoint attachments.
See http://www.fsf.org/philosophy/no-word-attachments.html