Re: [Ekiga-devel-list] UDP Checksum Failures for SIP?

[Craig Southeren <craigs postincrement com>]

Matthias Schneider wrote:
> Zitat von "harald dunkel t-online de" <harald dunkel t-online de>:
>
> > Hi folks,
> >
> > Looking at the SIP protocol with ethereal I see a lot of UDP checksum
> > errors for Invite, Register, Subscibe, etc. Is this something that could
> > be fixed?
> >
> > Regards
> >
> > Harri
> Harri,
> possibly you have one of those ethernet cards with a neat driver that shifts the
> checksum generation to the network adaptor itself? In that case on the level
> captured with ethereal you will not be able to see any correct checksum since
> it will be inserted once the frame was passed from the driver to the networking
> hardware ... So there are two ways to get rid of these warnings, one is to
> disable this check in ethereal, the other is deactivating this support in your
> network adaptor driver (with a slight performance loss).

If this was the case, you would see UDP checksum errors on ALL packets, 
not just the ones from Ekiga.

SIP can generate quite large PDUs, which must fit into UDP packets. If 
the PDUs are too large, they will be truncated.

Can you tell from the Ethereal (now WireShark) log if the packets are 
complete?

   Craig


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