Hi!
I have quality-problems with my VoIP connection caused by two causes:
1. head of line blocking
My MTU is somewhere between 1400 and 1500 and my upstream is
16kBytes/sec. VoIP sends a packet every 20ms, so one 1500 byte package
blocks the sending of 4.6 packets on time.
2. queuing on remote side
If I run a download, the queue on my provider's side is filled up and I
get long delays.
I have two ideas how to handle this:
1. fragmentation
Once VoIP traffic starts, I send an ICMP message that fragmentation is
neccessary and the maximum size is somethink like 150 bytes.
2. reduction of tcp window size
Here I alter the packages to report a window size of 1 which should
reduce the downstream data rate.
Can someone give me any hints if this has been done before or where to
start implementing this? I thought the QoS code should be a good start.
--
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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