Re: question about the set tcp window size in iperf 1.6.3

[Mitch Kutzko <mitch --at-- ncsa.uiuc.edu>]

Hi Marc,

Thanks for the link and the patch.
I have another question and hope you could help me a bit:
I have two linux boxes connected via internet, and both
have default 16k buffer size on client mode and 85.3k on server mode.

But I got different Bandwidth result on the two direction:

 A--> B ( 400K)
 B--> A(1.4M)

They are not identical boxes but I don't see too much difference (>1G,
>=256M, low cpu load)
the tcpdump on node A shows the following ( I don't have root permission on
node B)
  A--> B
           A.32787 > B.5001 nnn:nnn(1448) ack 1 win 5840
           B.5001 > A.32787 ack nnn win 63712
  B--> A
          B.1052 > A.5001 nnn:nnn(1448) ack 1 win 16060
          A.5001 > B.1052 ack nnn win 63712

Why they have different win advertisements?

Thanks for any help,
-CZ



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Mitch Kutzko | mitch --at-- dast.nlanr.net | mitch --at-- ncsa.uiuc.edu | 217-333-1199
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