Presumably this is a v6 discussion. I can't see any point in using the
c/s in v4.
WRT v6 there is a movement to make this optional (the debate is
happening in 6lowlan, and I think that we should be pushing to turn it
off for PTP.
The worst that can happen is that we receive a corrupt pkt and either
junk it, or put it in the timing servo whereupon it gets rejected as an
outlier.
- Stewart
On 20/01/2011 23:52, Shahram Davari wrote:
Hi Manav,
The minimum requirement is to do UDP checksum incremental update on
transmission. If full update is done then UDP checksum must be verified on
reception as well.
Thx
Shahram
-----Original Message-----
From: Bhatia, Manav (Manav) [mailto:[email protected]]
Sent: Thursday, January 20, 2011 3:33 PM
To: Shahram Davari; [email protected]
Subject: RE: UDP checksum
Hi Shahram,
It may be ok as long as the HWs are incrementally recalculating it. However, if
its being done afresh then we have an issue. I don't see how the HW behavior
can be mandated in a spec.
Cheers, Manav
-----Original Message-----
From: Shahram Davari [mailto:[email protected]]
Sent: Friday, January 21, 2011 4.59 AM
To: Bhatia, Manav (Manav); [email protected]
Subject: RE: UDP checksum
Hi Manav,
UDP checksum is usually not verified before updating the CF.
After CF update it is incrementally recalculated. The end
host will then verify the checksum for correctness.
Regards,
Shahram
-----Original Message-----
From: [email protected]
[mailto:[email protected]] On Behalf Of Bhatia, Manav (Manav)
Sent: Thursday, January 20, 2011 3:16 PM
To: [email protected]
Subject: [TICTOC] UDP checksum
Hi,
Are the LSRs acting as TCs expected to verify the checksum
before they update the correction field? If no, then there is
no point in these LSRs in updating the UDP checksum as they
will "correct" the checksum when its recomputed after
modifying the CF field. In this case wouldn't it make more
sense to just update the checksum at the MPLS terminating point?
I also think that updating the UDP checksum may be redundant
as the LSRs are anyways verifying the outer ethernet checksum
before accepting any packets. Any thoughts here?
Cheers, Manav
--
Manav Bhatia,
IP Division, Alcatel-Lucent,
Bangalore - India
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