henry bb wrote: > > today I already know why 2500 can ping 88.1.77.1 because
It doesn't make sense that the 2500 can ping all the way to the 3550 Ethernet interface based on the minimal information that you told us before. You must be doing routing. It has nothing to do with Proxy ARP, though. Maybe you have on-demand routing or something. > proxy-arp doesn't function on serial interface. > so what's the real function of proxy-arp on serial interface ? Proxy ARP has no meaning on a serial interface. ARP has no meaning on a serial interface, (unless you're referring to Frame Relay's Inverse ARP, which is a different story. It finds the IP address when the DLCI is known.) Serial interfaces don't have MAC addresses. They don't connect devices that have MAC addresses. ARP finds the MAC address when the IP address is known. It's meaningless on a serial interface. If you configure Proxy ARP on an Ethernet interface, the router could respond to ARP requests on its Ethernet side on behalf of devices on its other side, (across the serial link in this case), assuming the router knows that it can get to those devices. That's the definition of Proxy ARP. > Does it work when bridge on the serial interface ? > If bridge on serial interface,how ios transfer arp ? I think > there isn't mac address on serial interface . Is there some > encapusation to packet the mac and transfer the lan frame > through serial interface ? If you were doing bridging, then the router interfaces would be passing all broadcasts, without any knowledge of what they were passing. So Ethernet devices could theoretically ARP through a bridged network that included WAN links. The encapsulation would be whatever was configured for the WAN links. It wouldn't matter. Bridging is transparent. I've never heard of anyone doing that and there might be some gotchas, but I think it would work. The ARP data has enough info in it for it to work. It doesn't care about the data-link-layer header that is used to transfer the request or reply. Priscilla > > regards > Henry Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=71154&t=71113 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
