Connect a 1000BaseT interface to a 1000BaseTX interface (switch to switch)?

[CHRISTINE BERNS]

Is it possible to connect a 1000BaseT gbic module in a 3550-12T switch to a 10/100/1000 port on a WS-X6516-GE-TX module in a CAT6509? My understanding is that 1000BaseT devices transmit and receive on all four pairs, but 1000BaseTX devices transmit on two pairs and receive on two other pairs, so it seems that connecting two switches this way would not be possible. If it is possible, what kind of crossover cable is needed?

Chris

[thomas.chen]

You'll find your answer in the document 'Connectors and Cables' at http://www.cisco.com/univercd/cc/td/doc/product/lan/cat2950/2950_wc/hig/hgcable.htm. Another thing... one issues that I know of is that the 3500's will only support 64 spanning-tree instances. This means that vlans above the 64 vlans would have no spanning tree turned on for them.

[andrew.butterworth]

If its 1000BaseT to 1000BaseT (NOT 10/100/1000) then a straight cable will do as the fixed 1000BaseT ports do crossover sensing(?)

If its between two 10/100/1000 ports then there is a special cross-over cable you need where all four pairs are crossed

http://www.cabling-design.com/references/pinouts/1000base_t_crossover.shtml