Which Duplex mode to choose for interconnecting our HP-UX Servers, HP Procurve Switches/Routers?

[Yogeeraj_1]

Dear experts,

We have just upgraded our network infrastructure and we are not sure about the Duplex mode to choose for our Servers, switches and Routers.

ROuter<------>Switch<-------->Server
(Cisco) (Procurve) (RP5430)

ROuter<------>Switch<-------->Server
(Cisco) (CATALYST) (COMPAQ)

At our two main sites, the current configuration is:
Site1:
======
ROuter<------>Switch<-------->Server
(Cisco) (Procurve) (RP5430)
FULL Duplex FULL FULL
AutoNeg=?? AutoNeg=OFF AutoNeg=OFF
Fast Eth Fast Eth-FX 1000Base-SX

Site2:
======
ROuter<------>Switch<-------->Server
(Cisco) (CATALYST) (Compaq)
HALF Duplex FULL FULL
AutoNeg=?? AutoNeg=ON AutoNeg=OFF
Fast Eth Fast Eth Fast Eth

Questions:
a. What are the changes that we should be making imminently and which may be currently impacting on performance?

b. What should be the settings for AUTO-NEGOTIATION?

Thank you in advance for your replies.

regards
Yogeeraj

[T G Manikandan]

One thing to note is always hard code the speed and duplex settings at both swith & server ends with auto_neg=off.

Also make sure that the speed & duplex do not mismatch.

On the subject of choosing full Vs half duplex below is a wonderful discussion on the topic

http://forums1.itrc.hp.com/service/forums/questionanswer.do?threadId=91998

[Pete Randall · Accepted solution]

Yogeeraj,

You mention 1000Base-SX. The rule about hard coding full duplex does not apply with the Gigabit NICs. They should be set to auto-negotiate at both the NIC and the switch.


Pete

[Yogeeraj_1]

thank you pete!

I was thinking about something similar for the 1000Base-SX. Full Duplex and Auto-negotiation=ON both at the Switch and Server interconnection level.

I will also change the connection between the router and switch to be Full Duplex and Auto-negotiation=OFF.

i hope this won't ask me for downtimes....

Thank you TG for the Link which at times is "confusing"....

[Jeff Schussele]

Hi Yogeeraj,

As Pete points out ALL 1000Base whether SX(fibre) or TX (copper) must be set to autonegotiate if you want Gig speeds. BUT if it's a 1000BaseTX and you want 100 or 10 speed THEN you could hard code the speed/duplex.
The 1000BaseSX must always be autonegotiate.

Rgds,
Jeff

[rick jones]

I have had nothing but good results using autoneg on both 100BT and Gigabit with HP servers and ProCurve switches.

The one exception was getting some of my copper GBE's to go gigabit with a 4108 switch - the problem turned-out to be i was two years behind on firmware on the switch.

In addition to autoneg being required for gigabit, I tend to be of the opinion that until shown to be broken _and_ unfixable (either via patching or equipement replacement) I stick with autoneg for 100BT.

If you do decide to "hard code" then you really, Really, REALLY have to set _everything_ _EVERYWHERE to the same setting. Otherwise, some helpful soul trying to neaten-up the wiring closet will put your network into a tizzy.