Mark Walmsley wrote: > > Hi Again Everyone, > > Just to let you all know, this morning I changed the 7200 > router serial interface clock to int and left the 7500 clock > set to line, this actually made the connection worse, I got 5% > packet loss as opposed to 1% packet loss when both router > interfaces were set to line, I changed it back and it returned > to 1% packet loss so then I changed the 7500 interface clock to > int while the 7200 was set to line and this appeared to have > little affect, still getting lots of input errors on the 7200 > and 1% packet loss. > I'm wondering now if we have a faulty ds3 card. > > I logged into the routers and did some ping tests, pinging the > routers own serial interface I still get the 1% packet loss.
It may surprise you to learn that when you ping from a router's serial interface to the router's own serial interface, the packets actually do go across the serial link. Try turning on ICMP debug on the other end and you will see that the pings get there and get redirected back. Here's what Marty Atkins, CCIE (some very low number), had to say about this when it came up before: "If the router itself is the source of the packet, and it pings its own serial IP, and the outbound interface and layer 2 encap are resolved and unambiguous, then the router will launch the packet out that p2p interface or PVC. I have done exactly what Priscilla describes, and not only seen the output from "debug ip icmp" on the neighbor router, but also observed it generating ICMP redirects, since the packet was forwarded out the interface it arrived on! This Cisco aberation is extremely useful for troubleshooting p2p WAN links. When the path has been looped (line protocol up (looped)), the only IP that is pingable is the directly connected one. That the router actually sends the packet makes it possible to test the link with ping." So it shouldn't surprise you that you see the errors even when pinging yourself. Weird, eh? But helpful to hopefully. Priscilla > I > did this on both routers, I thought this might rule out the > actual line because I'm not pinging across the ds3 connection > please correct me if i'm wrong. > > Somebody asked if scrambling was on but I'm not sure what > scrambling does or how to check if it's turned on or off so > i'll look into that too. > > > Thanks for everybody's help and I'm going to spend all day > checking out what you've said and going through the > troubleshooting stuff from cisco and i'll let you know how I > get on. > > Anymore advice would be greatly appreciated. > > Mark Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=65552&t=65491 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
