[Chilli] inconsistency in downlink and uplink bandwidths using coovachilli

[Michele Bergonzoni]

> we are only seeing downlink and uplink bandwidth of ~8Mbps (measured
> using www.speedtest.net),when we have configured coovachilli to
> 100Mbps

I had a simlar issue, it turned out to be quite weird but, I think, not 
uncommon. Your issue could be related or not, but it is very quick to 
check if you have the same problem I had.

With tcpdump on the dhcp interface, check if you see ICMP unreachables, 
with remote servers as source, of the "Fragmentation needed and DF set" 
kind.

If you see this messages, you will probably also see huge TCP segments 
being received on the same interface: in this case your NIC hardware is 
glueing TCP segments to offload your CPU, but chilli does not understand 
this.

If this is the problem, you can solve it by disabling "coalesce" or 
whatever it is called, in your NIC with ethtool or similar.

Regards,
			Bergonz

-- 
Ing. Michele Bergonzoni - Laboratori Guglielmo Marconi S.p.a.
Phone:+39-051-6781926 e-mail: bergonz at labs.it
alt.advanced.networks.design.configure.operate