Strange little problem with duplex on Cisco 3550

Anyone noticed problems saving the duplex settings of ports on catalyst
3550 switches, running 12.1(14)EA1a

We can configure duplex settings via CLI, but "show running-config" does
not show the duplex setting (???). When configuring the same port via
Cisco Cluster software, the setting is saved (and is visible in cli config)

Bizar.......

mvg,
Geert

 

When doing it from the CLI, are you doing a 'shut' then 'no-shut'?
You can't really change duplex on the fly - you have to bring the link
down and renegotiate with the client.

-Chris

 

Haven't done that. I'll give it a try, THX.......

 

Haven't done that. I'll give it a try, THX.......

 

Haven't done that. I'll give it a try, THX.......

 

Haven't done that. I'll give it a try, THX.......

 

A couple of things here.

I am not 100% sure on this but here goes anyway...

1.
IIRC when I have changed the duplex settings the port does
go down and then comes back up automatically. No shut - no shut
needed.

2.
In common with all cisco IOS configs there are default settings that do
not appear in the config.

prompt#sh run
....
!
interface FastEthernet0/3
spanning-tree portfast
!
....

prompt#sh int fa 0/3
FastEthernet0/3 is up, line protocol is up
....
Auto-duplex (Full), Auto Speed (100), 100BaseTX/FX
....

So I have a duplex setting (Auto, the default) but nothing in the
config.

That a default should appear in the config under some circumstances
is not entirely unknown either, a new router has a few things in
the config that are defaults.


Is "no service pad" an example?

Maybe the GUI thingy is bypassing the (is this a default)
test. Would not worry me too much.


If you are setting non default values then of course that is a
different matter. In that case, more details please.

 

Indeed, i am setting a copper 10/100/1000 port of a Cisco 3550 switch to
1000 bps fixed full duplex. So this is definetly not the default.

I just follow normal procedure:
CLI
Interface Config mode
speed 1000
duplex full
exit


when i do a show running config,
speed is OK, but there is no line for duplex

when verifying with Cluster Manager, the port is still in auto duplex
mode ?????????

IOS (tm) C3550 Software (C3550-I5Q3L2-M), Version 12.1(14)EA1a, RELEASE
SOFTWARE

 

Gigabit is always full-duplex on all 4 pairs, so trying to force a
duplex setting is irrelevant.

-Chris

 

There still is a difference between CLI and CM and that confuses the
customer.
When doing

speed 1000
duplex full

in CLI, only speed is recorded, there is no line for duplex (could be
the default as you mentioned)

BUT

When setting the speed to 1000 and duplex to full via GUI of Cluster
Manager and then doing a sh running-config,
you get speed line AND a duplex line in the running-config (???):

speed 1000
duplex full

This is probably a bug, since there are no problems and/or differences
noted in production.

-Geert