Re: [owl-users] Abnormal behavior ethernet Intel Corporation 82599EB 10-Gigabit adapter

On Sat, Jul 09, 2011 at 01:54:49PM +0400, Malykh Oleg wrote:
> Thank you for answers on my previous question. Now I've got new question about network abnormal behavior.

I'm sorry that no one has commented on this.  I was hoping that I would
not have to. ;-)

> Strange is according to low speed between client1 and client2 is approx 20-60 Kbytes/s and between Client2 and Router1 speed is 1-2kByte/s.
> Between routers speed is 46 MBytes/s and between Client1 and Router2 speed is 6-8 MBytes/s.
[...]
> However, when I change eth1 adapter on Router 2 to "Intel Corporation 82572EI Gigabit Ethernet Controller (Fiber) [8086:107e]" speed between clients increase to normal level.
> 
> Schema
> | Client1 | ----|Eth0   "Owl router1"  Eth1 |-------|Eth1   "Owl router2"  Eth0 |----|Client2|
> 
> Have you got any ideas what happen with speed?

The info above is slightly incomplete - it's missing the direction of
data transfers (is the slow speed observed in both directions or only in
one direction, and which one?) and whether the problem is also seen
between Router2 and Client2 or not.

As to things to try, decreasing the MTU (say, to 1400) is one of those -
on any of the machines' interfaces involved in the problematic data
transfers.  Another is disabling of the various offload parameters with
ethtool(8) (see the man page).

Alexander