It's probably not the memory then, but you can make sure by running 'free -m' and seeing if the system is too loaded.
>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. The max window you gave divided by the delay (67ms) is about 10 mega*byte* / second. This Is the speed you were experiencing, right? Everything points to the window, then. Did you check if A acknowledges every received segment? It could be that it is a slower host and can't process all that data that fast. Guido On Fri, Apr 12, 2013 at 1:03 AM, John Elliot <johnellio...@hotmail.com> wrote: > Thanks for the reply. > > POPB MEM - 2Gb > POPA MEM - 4Gb > > > Wireshark: (During a wget) > > #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 > > >> >> Hi >> >> >Provider of the link is stating it is a tcp window issue >> I think that would be a bit weird, TCP is a very robust protocol >> capable to adapt pretty much any bandwidth / latency situations. >> What are the specifications on the hosts? Maybe POPA has too little >> RAM and can't allocate a big enough TCP window? >> Can you use wireshark or some other tool to capture the TCP segments >> and look at the advertised window? >> >> Greetings, Guido. >> >> On Fri, Apr 12, 2013 at 12:37 AM, John Elliot <johnellio...@hotmail.com> >> wrote: >> > Hi Guys, >> > >> > >> > I have a 40Mb connection between 2 POPs, and 2 Debian servers connected >> > at >> > each end(L2, same broadcast domain) - I am seeing consistent poor >> > performance with TCP in only one direction. >> > >> > >> > Latency between the POP's is ~67m/sec >> > >> > >> > POPA->POPB UDP(IPERF) - consistent 38.5Mb/sec >> > >> > POPA->POPB TCP(IPERF) - fluctuates ~30Mb/sec -> 32Mb/sec >> > >> > POPA->POPB TCP(FTP) - fluctuates ~30Mb/sec -> 32Mb/sec >> > >> > POPA->POPB TCP(WGET) - fluctuates ~30Mb/sec -> 32Mb/sec >> > >> > POPB->POPA UDP(IPERF) - consistent 38.5Mb/sec >> > >> > POPB->POPA TCP(IPERF) - fluctuates ~10Mb/sec -> 15Mb/sec >> > >> > POPB->POPA TCP(FTP) - fluctuates ~10Mb/sec -> 15Mb/sec >> > >> > POPB->POPA TCP(WGET) - fluctuates ~10Mb/sec -> 15Mb/sec >> > >> > >> > Both Deb boxes are running the same kernel (2.6.32-5), and I have tried >> > adjusting tcp window without seeing any improvements...all ports are >> > running >> > full duplex, and Im not seeing any errors/drops, nor packet-loss on the >> > link. >> > >> > >> > Any suggestions are greatly appreciated (Provider of the link is stating >> > it >> > is a tcp window issue) -If that is the case, if someone can provide some >> > suggested tweaks/changes to the Deb servers, It would be fantastic! >> > >> > Cheers. >> > >> > >> > >> > -- To UNSUBSCRIBE, email to debian-user-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org Archive: http://lists.debian.org/ca++dquks-vxosrz2mgqodijlkjbxui0eoez4+fbdakrvnq0...@mail.gmail.com
