according to icnd1, we need to use crossover cable to connect similar devices, lets say router to router or switch to swicth..
does this really matter? I mean, what if i use straight through cable to connect one switch to another?
Also, note that switches and hubs are both MDI-X devices while routers and PCs are MDI devices. You have to use a crossover cable when using MDI together or MDI-X together, but you would use a straight-through cable when connecting MDI to MDI-X and vice versa.
Thus, a router and a router would use a crossover cable to connect, a router and a switch would use a straight-through cable, but a router and a PC would use a crossover cable.
Again, in practical use most devices nowadays use auto-MDI, so it usually doesn't matter.
A switch is an MDI-X device. That means the pin arrangement is as follows:
So if you want to connect another switch to this switch, you have to make sure the Transmitter pins are connected to Receiver pins and vice versa. If you use a straight thru cable, Receiver pins will be connected to Receiver pins on the other end and same for transmitter pins and this will not work for sending or receiving data. Therefore you need to use a crossover cable. Remember in crossover: 1->3 ; 2 -> 6 ; 3 -> 1 ; 6 -> 2
Hope that helps