Interface

[rk6171485]

Hi Team,

Hi have a basic question. why the 2 Cisco L3  Gigabit switch both interface do not up when both interfaces on full duplex, speed 1000,

like this:- SW1

interface gig1/0/1

no switchport 

ip address 192.168.1.1/24

duplex full

speed 1000

SW2

interface gig1/0/1

no switchport 

ip address 192.168.1.2/24

duplex full

speed 1000

Issue:- why the both switch port is showing down but if my Sw1 is on dupexl full and speed 1000 and SW1 is on duplex and speed is auto mode then both switch port is working fine. 

what is reason. 

[balaji.bandi]

is the real switches or lab ? what is the model of the switch and ios code running?

how are they connected if they are physical switches? if the duplex speed auto, what speed they negotiating the coming up show us some interface output show interface gi 1/0/1

[rk6171485]

Yes This is real switch. SW mode is 3750G series.

they are connected physically duplex speed auto port is showng 1000 and full when they are connected another sw which is configure on mannua full duplex and speed 1000.

[MHM Cisco World]

the port you talk about hardcoded is it SFP multi-G ?

[Joseph W. Doherty]

On a 3750G, if auto not enabled on port, auto MDI is disabled.  I.e. is the connecting cable cross over?

As to "working fine" when one side auto and the other hardcoded full duplex, the auto port should go into half duplex mode.  I.e. it will transfer frames, but with many errors.