Bad performance with 100FD

[Evert Ladrak]

Hi,

OS: HP-UX11.00
Server: L2000/4x440
Patch level: March 02 Gold pack
I've just had a rather strange experience. We've had a server configured 100FD Fixed. Same on the switch. After this we had a really bad performance transferring data over the network. No Late-collision or any other errors.
We switched to auto negotiate on both the switch and server and now we've got really good performance.

The reason for posting this is that I've never seen auto-negotiate work better then fixed on both ends.

I used to recommend fixed every where, now I'm on doubt.

Please let me know what your experiences are.

-ETL

[Michael Tully]

Hi,

We use 100FD auto_off. This works quite well for us. Do you receive "source quench" errors from using 'ping' ?

Michael

[Evert Ladrak]

No, that's the really strange thing no errors any where. I thought about the source quench as well.

[U.SivaKumar_2]

Hi,

Check to what setting they have auto-negotiated
?.
If it is 100FD I don't think this difference is due to speed settings. Check PMTU settings

regards,
U.SivaKumar

[Evert Ladrak]

Negotiated to 100 FD

MTU 1500

Apparently this is something that this site experiences all the time. Good speed on auto and poor on fixed.

Weird.

-ETL

[U.SivaKumar_2]

Hi,

http://www.experts-exchange.com/Hardware/Routers/Q_20080995.html

regards,
U.SivaKumar

[U.SivaKumar_2]

Hi,

Hope this link would explain

http://techsolutions.hp.com/fe/an.html

regards,
U.SivaKumar

[T G Manikandan]

auto negotiation is not reliable.
but the disadvantage is that everywhere you need to hard code the settings.

I would go for a auto_neg off.
I am not sure whether you had the same duplex settings without auto_neg enabled when you had the poor results.

when both sides are set to autonegotiation,with
the duplex setting they go for full-duplex if supports on both sides.
It works fine.

one side hardcoded and other not using autonegotiation, autonegotiation will not work properly .

If one side is using half-duplex and the other full-duplex it is worse.

Thanks

[Evert Ladrak]

Hi U.SivaKumar.

Thanks for the links they helped to explain in what happens with the auto negotiation but do not really explain what I've seen so far.

From what I gather of the information provided is that I should have seen at least late collisions if there was a problem with the speed settings between the switch and the server.

I'm quite sure that there is a problem with either the switch or the server. But I don't think I'll ever find what it is.

My boss doesn't want me to repeat the incident...;^}

-ETL

[rick jones]

i often see autoneg work just fine - i almost never hardcode things. of course, I use almost nothing but procurve switches :) (and the odd alteon and occasional cisco gigabit)

the reason being that if you hardcode, you have to hardcode _evertyhing_ _everywhere_ to the same values. with different hardcodes for different systems, all it takes is for someone to decide to "straightenout" the wiring closet and move the cables around and poof, all heck breaks loose.