Catalyst 4948-10GE 10/100/1000 ports Auto-MDIX?

[andrew.butterworth]

Do the 10/100/1000BaseT ports on the Catalyst 4948-10GE support Auto-MDIX like the 3750 does? We have a requirement to connect a 2950 to a 4948-10GE via copper (100BaseT) and need to know whether we can use straight or cross-over cables.

Thanks

Andy

[devang_etcom]

hi andrew,

i think 4948 is not supported auto-MDIX. to use the functionality of auto-MDIX you need to configure this future on both the end switch so they can select the appropriate phical cabling. 3750 and 2950 both support auto-MDIX. if your switch support auto-MDIX they you can use any cable but if not then you must have to connect it usin cross-over calbe.

hope this will help

rate the post if it helps

regards

Devang

[andrew.butterworth]

Thanks for the quick reply Devang but it didn't really help....

The 2950 DOESN'T support Auto-MDIX on any of the 10/100BaseT ports. If the 2950 has 10/100/1000BaseT uplinks then a straight cable will work as long as the interface is running at 1Gbps (the 1000BaseT standard takes care of this).

With Auto-MDIX available on either end of the link, either a straight or cross-over cable will work. Without Auto-MDIX a cross-over must be used.

I have checked the documentation and the 2960, 2970, 3560 & 3750 support the Auto-MDIX feature. The 'mdix auto' command doesn't appear to be available on the Catalyst 4500 series (including the 4948-10GE).

I suppose the safest bet is to get cross-over cables since these should work either way.

Andy

[devang_etcom]

hi

thanks for correction...

regards

Devang

[Bobby Thekkekandam]

Hi Andy,

Yes, the 10/100/1000 ports do support auto-MDIX, as per clause 40 of the IEEE 802.3ab specification. However, there is no cli knob to enable/disable it.

HTH,

Bobby

*Please rate helpful posts.

[andrew.butterworth]

Bobby

Thanks for the clarification. Have you any links to this being detailed in the documentation?

Thanks

Andy

[Prashanth Krishnappa]

If you hard code speed/duplex, auto MDIX gets disabled.