[Planetlab-users] TCPDUMP response side traffic lost

[Sapan Bhatia]

Hi Zhichun,

I can't reproduce this problem. I tried some simple tests (wget a
small file, wget a big file) but I could capture all incoming packets.

Is the initial period of silence that you've encountered restricted to
the TCP handshake? If that's the case, then it's expected - and you
need to do something special to be able to see it. But you should not
be missing any payload packets because of this.

If not, then could you give me a test case to work with?

Sapan

On Thu, Jul 10, 2008 at 9:47 PM, Hecker W <heckerme at gmail.com> wrote:
> I need to issue HTTP requests from Planetlab nodes and
> to dump the whole TCP connection traces. I found it worked
> on the FC4 version. But for the FC8 version, after the initial
> SYN packet sent out, I cannot capture the server response
> traffic until 0.6 second later. All the packets responded from
> web servers are lost within this 0.6 second time window. After that
> I can get all the traffic from both side.  I tried the big web objects to
> make
> sure its downloading time is longer than 1 seconds, and find this problem is
> persistent.
>
> I am not sure whether it is due to the new version of Planetlab needs
> 0.6 seconds to recognize that the new connection is issued so that it begin
> to
> allow TCPDUMP to see the packets?
>
> I guess it is not expected behavior, doesn't it? I did not use any raw
> socket API.
>
> The problem is similar to the problem mentioned by Greg in the previous
> post.
>
> If anyone needs the pcap trace to see the problem please reply the post. I
> will make it available online.
>
> Thanks
> -Zhichun
>
>
>
>
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