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Re: Comments on draft-ietf-ipsec-new-auth-00.txt
A draft paper that discusses out-of-order delivery, among a bunch of other
things, is available from:
ftp://ftp.ee.lbl.gov/.vp-pkt-dyn-sigcomm-draft.ps.gz
A revised version will by available by the end of May (to appear in
SIGCOMM '97). The out-of-order results won't be changed much.
I filed my dissertation today, and will have an on-line version of it
available shortly. It goes into greater detail than the paper (naturally!).
Something to keep in mind is that large reordering events will often lead
to unnecessary retransmissions anyway, because the out-of-order packets
will cause duplicate acks that in turn trigger fast retransmission. So if
this is aggravated by dropping some packets on the floor due to other
reasons, it may not actually cause much of an *additional* performance hit.
Steve & I discussed this a couple of weeks ago. As I recall, the question
is whether accommodating reorderings of up to 32 packets suffices. It
should - while larger reorderings can happen, they are very rare (at least
in today's Internet), and furthermore will already cause performance problems,
as noted above.
> > The incidence of out-of-order delivery seems to depend on the site
Right, it's strongly site-specific. Some sites see a whole lot of reordering
and some see very little. This is because some sites have load-balancing
routing near them and others don't. Also, some sites are much more prone
to large reordering events than are others, which is due to their proximity
to certain types of routers (though I haven't identified the make) that
are much more prone to causing such events than are others.
Vern