auto-mdix on ISR ?

[awoog]

Hello,

Can we find use auto-mdix on the Ethernet ports of the ISR (either integrated ports or one of switch ports) ? I can find only this command in relation with Catalyst. This allows to use indifferently a straight or a cross-over cable.

[andrew.burns]

Hi,

According to the feature navigator it's only supported on Cat6K - but I've used it on other Cats with no problems.

However, it doesn't appear to work on ISR's (at least it doesn't work on any of the 1800/2800/3800's I have in our lab) nor on the Etherswitch modules which is contrary to what it says in the release notes.

The short answer is that no, it isn't supported, unfortunately.

HTH - plz rate if useful

Andrew.

[Harold Ritter]

This feature is enabled by default on the switch port modules on the ISR platform and it requires auto-negotiation to operate properly.

There is no command to disable it but it can be disabled by setting the port speed manually.

Hope this helps,

[awoog]

tks for your answer, so it won't work on one of the 4 LAN ports of the CISCO 871 or on one of the 8 LAN ports of the CISCO 1811 ?

[andrew.burns]

Hi,

There's definitely a bit of confusion here, especially as there are 3 different types of ethernet connections. Here's my take after some more research:

ISR Inbuilt Ethernet Ports

--------------------------

As has been said - these do appear to support MDIX (verified in our lab) which is contrary to what I said earlier.

Etherswitch Network modules (4, 9, 16-port versions)

----------------------------------------------------

These don't support MDIX (verified in our lab) and confirmed here:

http://www.cisco.com/en/US/products/ps5855/products_qanda_item0900aecd802a9470.shtml

Etherswitch Service modules (all versions)

------------------------------------------

Not sure about these as we don't have any in our lab, but I believe they are based on 3750 switch hardware which does support mdix (using the mdix auto command).

Finally, the feature navigator isn't much use here as it only lists Cat6K as having support for auto-mdix.

HTH

Andrew.

[Harold Ritter]

The information I have indicates that it should be supported for the HWIC-4ESW and 9ESW. Did you test that in your lab?

Hope this helps,

[awoog]

How did you configure the built-in ethernet ports for this ? mdix auto ? many tks for your detailed answer

[awoog]

also to be sure, when you speak about ISR Inbuilt Ethernet port, you are referring, e.g. 1811,to the 8-port managed switch (LAN) and not the two WAN ports ?

[andrew.burns · Accepted solution]

Hi,

Here's what I tested:

2 x 3800 routers with NM-16ESW's

2 x 1841 routers with HWIC-4ESW's

I didn't have any 9-port modules to test, but from what Harold says they should work (and also the 4-port's) - but mine don't...

To test I simply connected a straight cable, and then a x-over and observed what happened - no commands were entered (apart from checking the ports were auto).

The 1811 docs say that all ports are auto-mdix:

http://www.cisco.com/en/US/products/ps5853/products_installation_guide_chapter09186a0080458a31.html

So you should be good to go - either with straight or x-over cables.

HTH

Andrew.

[awoog]

Thanks a lot !