At 07:54 AM 4/5/02, bergenpeak wrote: >Thanks for the comments so far. > >Does the ethernet keepalive mechanism have any value when the >interface is operating in full duplex mode?
I think so. I haven't found anything that recommends turning it off just because you are using full duplex anyway. > Will the remote-end >reply or echo the frame? I doubt it, since the frame is addressed to the sender. >In full duplex mode, the interface is not actively sensing the >transmission, right? At a hardware level I would guess that every transceiver can figure out if sending is working, but I don't know for sure. At the data-link layer, there's no need to sense for a collision while sending if in full duplex mode, but I think a transceiver can still test sending at the physical layer. >So how does the interface know that >transmission was really successful. It probably doesn't know the frame got anywhere, but it knows that the bits went out. I probably shouldn't have said it tests the receiver circuitry. It probably never did test the receiver circuitry, come to think of it. Even with coax, once the frame goes out, it's gone. It doesn't reflect back unless there is a problem. The frame is addressed to the sender to avoid disturbing anyone else more than to check receiver capabilities. Obviously, I don't know the exact answer. Maybe you could research it for us. ;-) >Thanks > > > >Priscilla Oppenheimer wrote: > > > > The router sends a message to itself every 10 seconds. It actually uses the > > old loopback message from the original Ethernet specification: > > > > Ethernet Header > > Destination: 00:00:0C:05:3E:80 > > Source: 00:00:0C:05:3E:80 > > Protocol Type:0x9000 > > Packet Data: 46 bytes (all zeros) > > > > The frame really does go out on the network, despite it being addressed to > > the sender. So the router can judge its ability to send and receive. > > > > Priscilla > > > > At 10:49 PM 4/3/02, bergenpeak wrote: > > >What exactly does this do? > > > > > >Thanks > > ________________________ > > > > Priscilla Oppenheimer > > http://www.priscilla.com ________________________ Priscilla Oppenheimer http://www.priscilla.com Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=40626&t=40432 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
