[Planetlab-users] Re: Networking-related issues

[Sapan Bhatia]

Well, somebody else actually observed it on planetlab-7 -- which is a better
proof than several successful runs :)

We'll keep you posted on any further developments.

Sapan

On Mon, Jul 28, 2008 at 3:07 PM, Hecker W <heckerme at gmail.com> wrote:

> I did my experiment in many runs. On planetlab-7 it always OK. However
> on alice the packet always reordered. It looks like not a matter of
> chance.
>
> For my analysis it is important I can get the CORRECT pcap traces, so
> that I can recover the files and other messages in the traces. My code
> does not work on these reordered traces. I searched online and  did
> not find any tool which can fix the reordering problem for the traces.
> If possible, please fix the problem. Thanks a lot!
>
> -Zhichun
>
> On Mon, Jul 28, 2008 at 11:50 AM, Sapan Bhatia <sapanb at cs.princeton.edu>
> wrote:
> > Hi Zichun,
> >
> > Somebody was experimenting with delta. Sorry about that. It has been
> > restored to a working state, but in case you still see problems, please
> > continue to use planetlab-7 and alice.
> >
> > planetlab-7 and alice have more-or-less the same software -- that you
> didn't
> > notice the reordering issue on planetlab-7 is probably a matter of
> chance.
> > We noticed the packet-reordering problem earlier today. How important is
> it
> > for your analysis? Is it easy to work around, given that the packets are
> > timestamped?
> >
> > Sapan
> >
> >
> >
> > On Mon, Jul 28, 2008 at 2:40 PM, Hecker W <heckerme at gmail.com> wrote:
> >>
> >> Hi Sapan,
> >>
> >> I have tested my code on alice,delta and planetlab-7. I got totally
> >> different results on these three nodes!
> >> 1) For planetlab-7, the problem has been solved. I have been
> >> successfully run the TCPDUMP. I got the TCP SYN/ACK and all the
> >> payloads. I have done tcp reassembly and recovered the file I
> >> transfer. They are indeed same!
> >> 2) For alice, I think I might get all the payload packets. However,
> >> the TCP SYN/ACK packet comes AFTER the TCP ACK packet from the
> >> senders, although TCP SYN/ACK packet's timestamp is earlier. In other
> >> words, the tcpdump trace is not sorted by the timestamp which make my
> >> analysis tool fail.
> >> 3) For delta, I only get outgoing direction traffic (same for TCP and
> >> UDP).
> >>
> >> If you guys can make every node like planetlab-7, my problem is
> >> solved. Thanks a lot!
> >>
> >> If you guys need me to provide any trace or other information, please
> >> just let me know.
> >>
> >> -Zhichun
> >>
> >> On Sun, Jul 27, 2008 at 11:14 PM, Sapan Bhatia <sapanb at cs.princeton.edu
> >
> >> wrote:
> >> > Hello,
> >> >
> >> > The following issues have (hopefully) been resolved on a set of alpha
> >> > nodes (listed below). If you complained about any of them, then please
> >> > kindly retry your code to verify the fixes.
> >> >
> >> > * Intermittent loss of TCP payload packets with packet sockets
> >> > * Syn/Ack packets not showing up in tcpdump
> >> > * TCP-related ICMP error messages not showing up in tcpdump.
> >> >
> >> > The nodes are: [alice,delta].cs.princeton.edu and
> >> > planetlab-7.cs.princeton.edu.
> >> >
> >> > Please verify all three nodes, if possible.
> >> >
> >> > Thanks in advance,
> >> > Sapan
> >> >
> >
> >
> >
> > --
> > Sapan Bhatia
> > www.cs.princeton.edu/~sapanb <http://www.cs.princeton.edu/%7Esapanb>
> >
>



-- 
Sapan Bhatia
www.cs.princeton.edu/~sapanb <http://www.cs.princeton.edu/%7Esapanb>
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