Hi, If I run 1000 pings (1500 byte, df-bit set) in both directions, I am not seeing any packet loss?
#tcp window size in the "bad" direction: starts at win=6912 and grows to 165504 (This is where I start to see a heap of TCP Dup ACK and TCP segment of a reassembled PDU)), then increases to 353408 (Again, more TCP Dup ACK's), and looks to max out at 669056. #tcp window size in the "good" direction: starts at win=6912 and looks to max out at 1995392 and has very few TCP Dup ACK and TCP segment of a reassembled PDU Thanks again for your help. > Date: Wed, 3 Apr 2013 09:39:54 +0300 > From: [email protected] > To: [email protected] > Subject: Re: [c-nsp] Performance issue on link > > On (2013-04-03 16:54 +1100), CiscoNSP List wrote: > > > Thanks Mikael - I have captured a wget with tcpdump, but Im not exactly > > sure what I should be looking for in wireshark....I see a LOT of "TCP > > segment of a reassembled PDU", a LOT of "Dup ACK's" and graph shows peaks > > of 25Mb... > > For typical TCP stack, if you've received TCP segment 42 previously then > you'll receive TCP segment 43, you'll duplicate ACK 42, in order to signal > to sender that you believe you're experiencing packet loss (which might not > be packet loss, it might be just reordering, but modern TCP stack does not > cope with reordering, because it copes aggressively well with packet loss) > > So you're experiencing packet loss, which shouldn't be surprising I think > Mikael was also interested in hearing your TCP window size, preferably when > it was highest. > (You need to capture session from the start to know TCP window scale > option) > > > -- > ++ytti > _______________________________________________ > cisco-nsp mailing list [email protected] > https://puck.nether.net/mailman/listinfo/cisco-nsp > archive at http://puck.nether.net/pipermail/cisco-nsp/ _______________________________________________ cisco-nsp mailing list [email protected] https://puck.nether.net/mailman/listinfo/cisco-nsp archive at http://puck.nether.net/pipermail/cisco-nsp/
