I replied to Matt directly, but didn't hear back. It may be a driver issue
with checksum offloading. Certainly the symptoms are consistent.
To test with a workaround see
http://bugs.opensolaris.org/view_bug.do?bug_id=6686415
-- richard
Nigel Smith wrote:
> Hi Matt.
> Ok, got the capture and successfully 'unzipped' it.
> (Sorry, I guess I'm using old software to do this!)
>
> I see 12840 packets. The capture is a TCP conversation
> between two hosts using the SMB aka CIFS protocol.
>
> 10.194.217.10 is the client - Presumably Windows?
> 10.194.217.3 is the server - Presumably OpenSolaris - CIFS server?
>
> Using WireShark,
> Menu: 'Statistics > Endpoints' show:
>
> The Client has transmitted 4849 packets, and
> the Server has transmitted 7991 packets.
>
> Menu: 'Analyze > Expert info Composite':
> The 'Errors' tab shows:
> 4849 packets with a 'Bad TCP checksum' error - These are all transmitted by
> the Client.
>
> (Apply a filter of 'ip.src_host == "10.194.217.10"' to confirm this.)
>
> The 'Notes' tab shows:
> ..numerous 'Duplicate Ack's'
> For example, for 60 different ACK packets, the exact same packet was
> re-transmitted 7 times!
> Packet #3718 was duplicated 17 times.
> Packet #8215 was duplicated 16 times.
> packet #6421 was duplicated 15 times, etc.
> These bursts of duplicate ACK packets are all coming from the client side.
>
> This certainly looks strange to me - I've not seen anything like this before.
> It's not going to help the speed to unnecessarily duplicate packets like
> that, and these burst are often closely followed by a short delay, ~0.2
> seconds.
> And as far as I can see, it looks to point towards the client as the source
> of the problem.
> If you are seeing the same problem with other client PC, then I guess we need
> to
> suspect the 'switch' that connects them.
>
> Ok, that's my thoughts & conclusion for now.
> Maybe you could get some more snoop captures with other clients, and
> with a different switch, and do a similar analysis.
> Regards
> Nigel Smith
>
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