Yes, if it's possible, bypass the routers and test directly through the switches. This will rule out any shaping/policing issues being done on the router.
UDP has no flow control and only attempts to send traffic at the speed you tell it to (ie. 40Mbps) so it won't exceed the bandwidth of the link. TCP tries to send as fast as it can (ie. 100Mbps or Gbps on gig NIC/port) and when packets get dropped it implements retries, windowing & flow control to achieve the best it can. It could also be the carrier policing extremely hard, but they shouldn't really. regards, Tony. >________________________________ > From: CiscoNSP List <[email protected]> >To: "[email protected]" <[email protected]>; Azher Mughal ><[email protected]> >Cc: "[email protected]" <[email protected]> >Sent: Tuesday, 2 April 2013 12:07 PM >Subject: RE: [c-nsp] Performance issue on link > > > > >Hi Tony - Link is new, no duplex issues (On our side, nor reported by carrier) > > > > >No traffic on the link. > > > > >udp test (both directions) looks fine (Hopefully formatting isnt screwed up - >but achieve ~38.5Mb/sec both directions): > > > > > > >[ ID] Interval Transfer Bandwidth > > >[ 5] 0.0-10.0 sec 47.7 MBytes 40.0 Mbits/sec > > >[ 5] Sent 34015 datagrams > > >[ 3] 0.0-10.0 sec 46.0 MBytes 38.6 Mbits/sec 0.040 ms 1180/34014 (3.5%) > > >[ 3] 0.0-10.0 sec 1 datagrams received out-of-order > > >[ 5] Server Report: > > >[ 5] 0.0-10.0 sec 46.0 MBytes 38.5 Mbits/sec 0.051 ms 1233/34014 (3.6%) > > >[ 5] 0.0-10.0 sec 1 datagrams received out-of-order > > > > > > >The 2 linux servers are on separate L3 subnets (Connected to the local router >in each POP) - I can potentially trunk a new vlan between the 2 POPs and have >them connected without touching the routers...UDP tests are looking good >though, so if it was an issue with the router(s), wouldn't I see problems with >UDP also? > > > > >Thanks again for your assistance, much appreciated. > > > > > > >________________________________ >Date: Mon, 1 Apr 2013 18:19:40 -0700 >From: [email protected] >Subject: Re: [c-nsp] Performance issue on link >To: [email protected]; [email protected] >CC: [email protected] > > >That doesn't sound at all good. No way should you need that many (25) sessions. > >Is there any other traffic on the link ? Is it brand new ? Any duplex mismatch >type issues ? > >I would suggest running an "iperf -u -d" to run UDP in both directions at the >same time, might turn up something unusual. Remove any other devices (ie. your >routers) before testing so you will know that is not a problem. I assume your >two linux test machines are on the same L3 subnet from what you've described ? > > >regards, >Tony. > > > > > > > > >>________________________________ >> From: CiscoNSP List <[email protected]> >>To: "[email protected]" <[email protected]>; Azher Mughal >><[email protected]> >>Cc: "[email protected]" <[email protected]> >>Sent: Tuesday, 2 April 2013 10:37 AM >>Subject: RE: [c-nsp] Performance issue on link >> >> >> >>Sorry - Forgot to add: >> >> >> >> >>POP A -> POP B - only requires 8 sessions, but POP B -> POP A requires 25 >>sessions to achieve ~38Mb? >> >> >> >> >> >> >> >>> From: [email protected] >>> To: [email protected]; [email protected] >>> Date: Tue, 2 Apr 2013 11:28:50 +1100 >>> CC: [email protected] >>> Subject: Re: [c-nsp] Performance issue on link >>> >>> Thanks Tony - With multiple sessions (8), I can achieve ~38Mb/sec >>> consistently. >>> >>> Is it simply not feasible to expect ~40Mb with a single tcp transfer >>> (Without significant adjustments to both Linux servers?) >>> >>> >>> > Date: Mon, 1 Apr 2013 17:10:42 -0700 >>> > From: [email protected] >>> > Subject: Re: [c-nsp] Performance issue on link >>> > To: [email protected]; [email protected] >>> > CC: [email protected] >>> > >>> > Try using multiple TCP sessions "iperf -P 5" (note - capital "P"). >>> > >>> > >>> > regards, >>> > Tony. >>> > >>> > >>> > >>> > >>> > >>> > ----- Original Message ----- >>> > > From: CiscoNSP List <[email protected]> >>> > > To: Azher Mughal <[email protected]> >>> > > Cc: "[email protected]" <[email protected]> >>> > > Sent: Tuesday, 2 April 2013 9:51 AM >>> > > Subject: Re: [c-nsp] Performance issue on link >>> > > >>> > >T hanks - Ill check them out now >>> > > >>> > >> Date: Mon, 1 Apr 2013 16:16:36 -0700 >>> > >> From: [email protected] >>> > >> To: [email protected] >>> > >> CC: [email protected] >>> > >> Subject: Re: [c-nsp] Performance issue on link >>> > >> >>> > >> These might be helpful: >>> > >> >>> > >> http://fasterdata.es.net/network-tuning/ >>> > >> >>> > >> >>> > > http://www.mellanox.com/related-docs/prod_software/Performance_Tuning_Guide_for_Mellanox_Network_Adapters.pdf >>> > >> >>> > >> -Azher >>> > >> >>> > >> On 4/1/2013 3:51 PM, CiscoNSP List wrote: >>> > >> > Hi, >>> > >> > >>> > >> > We have a 40Mb link between 2 POPs - Latency ~65m/sec (No >>> > >> packet-loss) >>> > >> > >>> > >> > POP A Is a 7301 and 2960POP B is a 7200 and 4948 >>> > >> > >>> > >> > 40Mb link is connected to the two switches (L2), and then a trunk >>> > >> link >>> > > to both routers for all L3. >>> > >> > >>> > >> > Have a Linux server connected to both switches, and achieve the >>> > > following performance: >>> > >> > >>> > >> > IPERF (UDP) >>> > >> > POP A -> POP B - 38.5Mb/secPOP B -> POP A - 38.5Mb/sec >>> > >> > >>> > >> > IPERF (TCP) >>> > >> > POP A -> POP B - ~20Mb/secPOP B -> POP A - ~12Mb/sec >>> > >> > >>> > >> > FTP >>> > >> > POP A -> POP B - ~38Mb/secPOP B -> POP A - ~16Mb/sec >>> > >> > >>> > >> > WGET >>> > >> > POP A -> POP B - ~30Mb/sec POP B -> POP A - ~16Mb/sec >>> > >> > >>> > >> > Any suggestions on why I am seeing poor performance with TCP >>> > > transfers? (Especially POP B -> POP A direction) - I've tried adjusting >>> > > the window size in IPERF but it actually made the results worse? >>> > >> > Thanks in advance. >>> > >> > >>> >>> _______________________________________________ >>> 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/
