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autoneg on on Gig ethernet card

 
joe_91
Super Advisor

autoneg on on Gig ethernet card

On other environments (like HP-UX) we have always set autoneg to off for Gig Ether Cards, on our environment (RHEL 5) i see that autoneg is on, is there a reason for setting it this way on the RHEL environment, if so WHY? Also note that the servers i am looking at are running Oracle RAC on RHEL 5.

Best Regards

Joe.
2 REPLIES
Steven Schweda
Honored Contributor

Re: autoneg on on Gig ethernet card

> [...] we have always set autoneg to off for
> Gig Ether Cards, [...]

Really? WHY? What are your manually set
speed and duplex settings?

> [...] autoneg is on, is there a reason for
> setting it this way on the RHEL
> environment, if so WHY? [...]

I know nothing, but a quick Google search for
gigabit ethernet autonegotiation
led to one possible explanation:

http://en.wikipedia.org/wiki/Autonegotiation

I quote:

The standards for 1000BASE-T and
1000BASE-TX require autonegotiation to be
always present and enabled. Other than
speed and duplex mode, autonegotiation is
used to communicate the port type (single
port or multiport) and the master-slave
parameters (whether it is manually
configured or not, whether the device is
master or slave if this is the case, and
the master-slave seed bit otherwise).

Even at 100Mb/s speeds, all my old junk has
always been happy doing autonegotiation.
I've read claims that some 10/100 equipment
has trouble doing it. I can't recall having
read any credible reports of similar trouble
with equipment at 1000 Mb/s speed.
Alzhy
Honored Contributor

Re: autoneg on on Gig ethernet card

The standard I've seen for a lot of of my clients is:

Gigabit: AutoNeg
100Mbps: No-Neg, Explicit 100FDX speed.


Hakuna Matata.