In article , Darth Tyrannus wrote: :This leads to another question. When I :plug in the crossover cable into the cisco router should the green link :light become active?
Not if the interface is shutdown.
:Isn't the link light completely physical layer? Meaning, I shouldn't :have to configure any procotcols or layer 2 addresses in order to :obtain a green LED light on each device.
On router interfaces, the link layer is turned off until the router is told to turn it on. Amongst other things, this saves energy when the link is a laser GBIC...
:This is where I'm running :into problems. I need to understand the reason the link light turns :green. I'm guessing that a signal is sent from one device to the other :and if it received properly then both lights will become green. But :this would require some sort of layer 1 protocol, correct?
The "layer 1 protocol" involved could be as simple as "was able to detect a signal". But usually it's a little more complex than that: the link light does not, for example, usually light if the devices are not able to negotiate speed [but it -will- light if the two devices fail to negotiate duplex.]
:The reason I ask is because I used this :particular crossover cable and went from ethernet to ethernet port on :two routers and I got a green link light on the AUI. But when I used :this same cable and plugged it into my PC and one of those routers, I :didn't get a green link light.
Could mean that router doesn't want a crossover to talk to the PC. Could mean that the port speed couldn't be determined.