No Link between 3750X and 2960X with Media Converter

[ChrisMorris2]

I have a 3750X switch that I am trying to connect to 2 Cisco 2960X switches. The switches are connected via fiber from a 3750X to a media converter that then connects to the 2960Xs via regular Cat 5e. No lights are lit up on the ports when they are connected and when I checked the interfaces using the IOS console, both read they were down and that nothing was connected. The media converter is an AT-MC102XL.

I am able to directly connect the 3750X to the 2960X via a fiber uplink GBIC in the 2960X to the 3750X. I did this to try to determine the root cause of the problem and would like to avoid setting it up like this. It appears that the media converter is the problem based on the results of this test.

What can I do to get it working? Is there anything I can configure or is the media converter just not compatible?

[Reza Sharifi]

Who make the media converter?  I have used Transition Networks Media converters in the past and they work with Cisco devices just fine.  You may want to cross the fiber strands on one side of the link that connects to the media converter and see if the link comes up.

http://www.transition.com/transitionnetworks/landing/media-converters/media-converters.aspx

HTH

[ChrisMorris2]

The brand is Allied Telesis. I have tried crossing over the fiber, but it did not make a difference.

Buying another media converter is an option, but I would like to know for sure whether or not the one I have will work. If not, I will need to buy closer to 10, something I would rather not do, as I have multiple instances where the topology we're using will require this.

[Reza Sharifi]

I agree.  You should first know if this product works with Cisco or not before going and buying other vendor's media converters.  Some MCs have dip switches that needs to be set.  Does this brand has one? Also have you contacted their tech support?

Ok, looking at the description of the product http://www.alliedtelesis.com/p-2219.html

This is 100mg MC and not Gig.  I an assuming that fiber side on the 3750 is gig right?

HTH

[ChrisMorris2]

It has two dipswitches one set to M/L or Link Test and the second set to A/N on or off.

3750 is gig.

[Reza Sharifi]

Ok if the 3750 is Gig than you need Gig MC.  Fiber interface can't negotiate from 1000 to 100.  It is set to 1Gig.

the MC needs a Gig copper or 10/100/1000 and Gig fiber.

HTH

[Reza Sharifi]

the MC needs a Gig copper or 10/100/1000 and Gig fiber

Gig fiber connects to 3750 and 10/100/1000 copper connects to 2960.

This should take care of your issue.

[ChrisMorris2]

2960X is also gig, if that makes a difference...

[Sarbjit-2014]

Hi Chris,

Try reducing the speed or half the duplex on the fa port on the 2960X then bounce the interface. This might work as I know connection to media converters can be quite fiddly at times.

[ChrisMorris2]

I set the port to 100Mbps and 'no shutdown'. Still no connection though.

[Sarbjit-2014]

I know this might not be ideal but try it anyways, if not might need different converters im afraid:

speed 10

duplex half

shut

no shut

[ChrisMorris2]

Tried the settings, didn't make a difference. Also, in the last post you mentioned the fa port, but the 2960X is Gigabit. Don't know if that makes a difference...