Duplex Mismatch Issue

[nabeelcse07]

I am having Duplex Mismatch issue between two cisco switches. Both switches are connected through SDH. On one Site Switch Uplink Port is RJ-45 and and on one side it is Downlink Port of Switch configured as trunk.

What could be the issue? Is there anyone who can help in this.

Regards,

NA

[Furose M]

can you post the running-config of the interface on each side?

what are the switch models?

[nabeelcse07]

Hi Furose,

Ports are trunk on both side. The only difference is one side its terminated into the Uplink Port in GLC-T SFP and On other side its on Downlink Port. 

Regards,

NA

[Furose M]

trunk or access shouldnt matter here. i am more interested to know if speed/duplx is manually set in either side.

it could be a bug as well and thats why asking the switch model and version on both the sides.

[nabeelcse07]

Hi Furose,

I can see the other side of the switch through Show CDP Neighbor command. But I cannot Ping it.

On both sides its CIsco 3750X with LAN Base image. Speed is Auto. I tried different combinations of speed and duplex but it didnt work.

Regards,

NA

[Furose M]

when you say duplex mismatch issue, i literally take it as 1 side is shown as full duplex and the other side is half duplex. am i right?

or the problem is about not able to send traffic in 1 direction?

[nabeelcse07]

Hi Furose,

Configuration of Switch is same on both sides. Is it an issue if on one side Link coming to switch from SDH is uplink SFP port and on One side Link coming from SDH is downlink port?

The Problem is that I can See the Switch on other side by show cdp command but I cannot ping it?

Regards,

NA

[Furose M]

it shouldnt matter. what if you use "downlink ( i mean, normal front panel port)" on both the switches?

is it a fiber link? can you enable udld and check?

[nabeelcse07]

No its not a fiber link. Its UTP link on both sides.

Regards,

NA