Re: [Spud] [tsvwg] New Version Notification for draft-touch-tsvwg-udp-options-01.txt

[[e-mail]]

Sorry I wasn't at the meeting yesterday in Japan

- Block packets (perhaps firewalls, for instance), but also truncate
(which may be more common on devices doing incremental checksum update).
- I expect the default behaviour is either to copy UDP-L; which means you
lose the options (i.e., truncate - sad but not disaster) or IP-L; which
means you get all (the same as UDP-Lite).

Gorry
>
> On 11/1/2015 10:43 PM, Tom Herbert wrote:
>> On Mon, Nov 2, 2015 at 3:05 PM, Bob Briscoe <[e-mail]> wrote:
>>> Joe,
>>>
>>> Before starting measurements, I would recommend searching the Web for
>>> the manuals of middleboxes that might block such packets.
>>>
>> Please look at NIC offloads also. I am pretty certain that the most
>> common flavor of checksum offload will break in this proposal since
>> devices use the value in the UDP length field as the length of the
>> payload to compute the checksum over.
>
> That is the intended behavior.
>
>> UDP Fragmentation Offload would
>> similarly be broken, although we can probably live without that (but
>> we can't live without checksum offload!).
>
> We need to live without broken offloads because offloads are part of the
> protocol stack. They can't simply jump in and try to help without being
> very careful about corner cases like this.
>
> E.g., we've already seen an offload that merges TCP packets with
> different options, which ought to be clearly inappropriate.
>
> Joe
>