[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [RRG] The use of UDP in LISP
On 11 dec 2007, at 5:49, Shane Amante wrote:
So? If we put in the spec that you MUST assign a /29, /28 or what
have you to an ETR and all ITRs automatically use that entire
address range, they'll simply have to do it or it won't work.
You might certainly be able to say MUST, but that doesn't mean
everyone will configure ITR/ETR's that way.
If the spec mandates that the mapping protocol caries /28 prefixes and
that ITR round robin flows over the addresses within those /28s, then
I'm pretty sure ETR operators will do it that way unless this makes
them so upset they force vendors to make ITRs that don't conform to
the spec. I.e., laziness then means using the /28.
How about this:
For IPv4 locators there is no checksum issue and we use UDP.
For IPv6 locators there is the checksum issue, the overhead is already
much larger than with IPv4 but the good parts are that we have the
flow label and there isn't an ossified installed base yet. So for IPv6
locators we skip the UDP header.
It's true that there is much discussion on the philosophy of flow
labels, but as long as there is one, it's stable for the same flow for
at least a decent amount of time (doesn't have to be forevever,
changing it at minute scale or longer won't be too problematic for our
purposes) it's good enough. And since we control the operation of ITRs
we can mandate that a flow label is present.
And obviously with IPv6 it's trivial to have a larger number of
addresses per ETR if that's helpful.
--
to unsubscribe send a message to rrg-request@psg.com with the
word 'unsubscribe' in a single line as the message text body.
archive: <http://psg.com/lists/rrg/> & ftp://psg.com/pub/lists/rrg