[c-nsp] Performance issue on link

[CiscoNSP List]

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.