Michael Fischer schrieb:
Hello Kurt,
My problem is the downstream, e.g. a HTTP download. I thought it should
be possible to lower the incoming datarate by using a smaller TCP
window, resulting in the remote host waiting for acknowledgement of each
packet and therefore reducing the datarate. Maybe together with delaying
the TCP-ACK packets if there are a lot of downloads.
apart from other doubts expressed here on the list this also wont work when
someone is
downloading UDP based traffic...
Yes, this is true, but in my real-world scenario, I just encounter HTTP
downloads and SMTP up/downloads and my wife does not play Quake :-)
I did already try the traffic shaper, keeping my upstream bandwidth
below the line bandwith thus having empty upstream queues all the time.
But it did not fix the jitter especially on downloads, so I think
something else must be done as boxes like the AVM Fritz VoIP box is
quite unaffected when up-/downloading while using VoIP.
are the TOS/DiffServ fields of the incoming stream set to some useful
values?
This may help the ISPs router to give the Voip packets better priority.
I guess Asterisk does already do this. Nevertheless I won't rely on my
provider doing things right...
Also the jitter-buffer algorithm of the AVM box may just be better. Assuming
that some
The AVM box does also have low latency, so I don't think it's just a
buffer issue.
priorization is working a 1500 byte packet should cause something around 20
ms additional
delay in worst case - which isnt that bad... You may test the different
buffer algorithms
Do I get something wrong here? 16,000 bytes/sec upstream, 1,500 byte
packets, gives 1 / (16,000 / 1,500) = 0,09375s = 93,75ms
Nevertheless thanks for your responses. I will have a look at the
resources and try to set up a test scenario and see what happens.
--
Mit freundlichen Grüßen
Kurt Huwig iKu Systemhaus AG http://www.iku-ag.de/
Vorstand Am Römerkastell 4 Telefon 0681/96751-0
66121 Saarbrücken Telefax 0681/96751-66
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