Don't believe everything you hear! ;-) Couple comments inline. Keith Woodworth wrote: > > I need to trouble shoot some apparent packet loss on a 7206VXR > with a > NSE-1. > > Weve had some folks downstream of us say that doing traceroutes > to their > network through us that packets are dropping on our router.
They can't tell if packets are getting dropped from trace route? Just because your router doesn't send back the ICMP TTL doesn't mean it's dropping packets. It could simply be rate-limiting ICMP, or could have access lists, or could be just dropping packets that require process switching, or doing a number of other reasonably healthy actions. > I'd > like to > find a way to actually see if this is the case. I'm kind of > concerned that > it handling too much traffic for the backplane. > > It has 6 Faste connections, one of which is going to our > upstream that > handles on avg about 15 Megs out and about 18 Megs in. > > One item of note is this router is connected to our upstream > providers > router via faste connection to their 7204vxr which handles a > radio based > DS3 for our primary connectivity. > > They have told us to config our ethernet port to half duplex so > packets > will be retransmitted if they get lost in their ATM cloud so we > have a > fairly high collison rate on this port. I dont know enough > about ATM to > say if this is good or bad...? If they really said that, ask to talk to a more senior engineer. That's a clueless comment. If packets get lost in the ATM cloud, you can't do anything about it on your router's Ethernet interface! However, you should definitely troubleshoot the collision rate. If you're set to full duplex, there should be 0 collisions. It sounds like there's a duplex mismatch problem. > > We policy route and use ip route-cache policy on each > interface. Main > interfaces show no drops on the input side on the two busiest > faste ports: > > Output queue 0/40, 0 drops; input queue 0/75, 0 drops > > Output queue 0/40, 1466359 drops; input queue 0/75, 0 drops The 0 input queue drops are a good sign, but the 1466359 drops on the output queue could be bad. But it could be normal too. You need to compare it to the number of packets output. The ratio of dropped to sent should hopefully be less than about 5%, although it really depends on the traffic flow. Is this interface 100 Mbps? I think you said it was. If it's getting fed my multiple highly-used 100 Mbps interfaces, it has to drop packets. That's normal. That's all for now. Priscilla > > Output side here we rate-limit outgoing P2P stuff a bit. > > CPU usage is about 20-25% on avg depending on time of day. > > Been hunting on CCO about the NSE-1 to find out what it can > handle PPS > wise but nothing so far except stuff on PXF and CEF and how > great the > NSE-1 is. Anyone know PPS for this device? CEF is not turned on > but > wondering if it would make a diff? > > Customer is doing traceroutes from > http://visualroute.visualware.com and > doing our own it does indeed show packet loss starting at our > router. > Though I'm not one to take that at face value. > > Anyway to acutally tell for certain if the router is dropping > packets? > > thanks for any input. > Keith > > Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=57943&t=57922 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
