[LARTC] How to set MTU

[mohican 542003]

Hello,

I made some tests with HTB, and i usually set MTU to the default value of
TCP_WMEM (that is 65536 for me).

I have this case :

                  50 Mbits/s                              10 Mbits/s
A----------------------------------B---------------------------------------C

if A send to B, bandwidth is about 50 Mbits/s
if B send to C, bandwidth is about 10 Mbits/s
But if A send to C, Bandwidth is about 14 Mbits/s, instead of 10 Mbits/s.

I think perhaps the MTU should be different according to bandwidth ?

Has someone an idea about this ?

Here is my configuration :

On A :
tc class add dev eth0 parent 1: classid 1:2 htb rate 50000kbit ceil
50000kbit mtu 65536
tc filter add dev eth0 parent 1: protocol ip prio 1 u32 match ip dst B
flowid 1:2

On B :
tc class add dev eth0 parent 1: classid 1:2 htb rate 10000kbit ceil
10000kbit mtu 65536
tc filter add dev eth0 parent 1: protocol ip prio 1 u32 match ip dst C
flowid 1:2


On B, /proc/sys/net/ipv4/ip_forward =1, and there is no link between A and
C.

Thanks,

Olivier.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://mailman.ds9a.nl/pipermail/lartc/attachments/20071011/8b0cba4e/attachment.htm