Sporadic low network performance

[Steve Phillips]

On Mon, 3 Jan 2005 redhat-list at demner.com wrote:

>>
>> This really smells like a duplex problem.  If you're at 100mbps, force
>> the interfaces on both ends to be 100 mbps full duplex.  Do not rely on
>> autonegotiation since it will frequently get it wrong.
>>
>
> Unfortunately, I don't have control over the switch.  According to
> ethtool, I had it set to 100mpbs, full duplex, no autonegotiation.  But
> according to mii-tool, I had my interface set to 100mbps, Half duplex, no
> autonegotiation.  I used ethtool to change it to full duplex, and now they
> both report full duplex.  Fingers are crossed...
>

If the switch is set to auto negotiate and you have forced the interface 
on the server then you will also experience problems.

I would suggest you contact the people that own the switch and ensure that 
the port is set correctly there too

however, as you are not experiencing hte slowdown around the isp network 
or on the local subnet (if I read your e-mail correctly) then it is 
probably not a duplex issue.

have these tests been extended tests (constant over a series of days) or 
rather small time periods (15 min intervals etc)

You may want to look at putting in some network monitoring tool like 
smokeping and getting it to ping various points both locally and non 
locally and see if there are any correlations between the various graphs 
it produces..

-- 
Steve.