RE: *AUTO vs. *MANUAL Ethernet Settings (was: Ethernet Cards) -- MIDRANGE-L

Hi Lukas - responses in-line

On Jan 29, 2008 9:07 PM, Evan Harris <spanner@xxxxxxxxxx> wrote:

I don't necessarily disagree, but I have seen many instances where *AUTO

did

not result in the best possible configuration. It certainly worked but

the

most common error was that the line would run at half-duplex. This was
sometimes because some network guy had configured the port that way and

just

Well, *AUTO only works correctly if both ports are set to autonegotiation.

Agreed. But also only while both REMAIN at autonegotiation.

as frequently because the auto-negotiation settled on a less than optimum
configuration.

Only seen that happen with older Cisco switched. Upgrading them to a
current IOS/CATOS fixed that, though.

That presumes I control the network hardware, but a fair point.

In either way, upgrade firmware on NIC and Switch, then open a support
ticket. Because it's broken. Manual configuration can serve as a
workaround until you receive a fix.

Again, you are presuming I handle the network hardware. If it is "broken"
only for the iSeries then convincing the network guy there's an issue and to
do extra work is often problematic. My preference is to ensure that the
network connection runs at the speed I promised.

If you are going to use *AUTO then you should verify that the connection

running at the speed your network is capable of.

Of course.

Which is just what I said :)

If at any point in time there is a change made to the switch or some

other

connection point then *AUTO may result in the iSeries connection running
slower after that change with nobody the wiser. At least a manual

I prefer a degradation of QoS rather than a complete functional
failure, but to each their own.

Fair comment - I didn't exactly say what I meant :) As mentioned above I
prefer for the hardware to operate as promised. If there is a change to the
switch configuration and the iSeries interfaces don't come up afterwards
then the change is not right and needs to be redone. *AUTO allows the
network engineers to get away with not configuring things correctly as long
as they can tick off that their stuff works.

configuration gives you a warning by failing (!). It's been my experience
that many network changes of this type are made without considering the
iSeries.

Well, in that case your companies procedures are broken. I never had
that problem here.

I (sometimes) wish I had more influence and control over these things but I
don't.

I work for a vendor and there are lots of Windows/network guys out there
that could care less about the machines that are downstream or upstream.
IMHO because they have grown up in an environment where things breaking is
normal they don't look further than their own piece of work, so they don't
advertise their changes and don't properly consider the impact. Mostly they
simply don't understand _systems_ - they understand desktops, but I'm
getting off track :) That's not to say that's how things should be or even
that they are always like that. But it seems like that's what it is like
more often than not.

Basically I don't disagree with you, but I think manual configuration is a
good choice when a particular rate of performance has been promised or is
critical and that AUTO should be checked to ensure it is performing as
expected.

Fortunately there are just not that many network changes after the initial
configuration is done, but equipment upgrade/replacement is a reasonably
common occurrence.

Regards
Evan Harris