[geeks] Network Slowness

[Sridhar Ayengar]

Mike Meredith wrote:
>> Connecting these three machines together is an 8-port HP Procurve 
>> gigabit switch.  The only other thing attached to the switch is a
>> Cisco 7505 router routing across the WAN connection, and its
>> interface to the switch is a PA-FE-TX.  None of the machines have
>> jumbo frames turned on. The Intel gigabit card in the Pentium III has
>> hardware fragmentation and checksumming turned on.
>>
>> The problem is no matter where I am transferring data from or to,  I 
>> only get about 5.5MB/sec.  That seems kinda slow to me.  Any ideas?
> 
> That seems more than kinda slow to me ... I would expect to get better
> than that with 100BaseFX.

Indeed.

> My little list of things to try (undoubtedly you've tried some/most/all
> of these) :-
> 
> * Check that each gigabit interface is *really* coming up as gigabit.
>   Sometimes autodetect doesn't work and you can get really bad
>   performance if that happens.

The speed LED for all three ports on the switch reads as gigabit, and 
ifconfig (on UNIX) and Network Connections (on Windows) report that I'm 
connected at 1000Mbps.

> * PA-FE-TX? Is that 100BaseFX ? Might be worth disconnecting that to 
>   see if that makes a difference. Some (mighty bad) switches don't like
>   to do gigabit on some interfaces and 100M on others.

No, that's 100BASE-TX.  And the indicator LED for that port on the 
switch reads 10/100, which is what I would expect.  I didn't think to 
check whether IOS shows it running at 100Mbps, but I'll check that tonight.

> * Try connecting the gigabit interfaces back to back to see what
>   performance you get then. 

I'll whip up a crossover cable tonight and let you know how it goes.

> I'd expect somewhere between 500Mbps and 890Mbps (62-112MBps),
> although I'm not sure any of your machines are pokey enough to reach
> 890Mbps. It may just be the Procurve just isn't up to the job.

I had a little trouble parsing the next-to-last sentence there.  What 
did you mean?

If the Procurve isn't up to the job, I will be sorely disappointed in HP.

Peace...  Sridhar