If I was confused about some aspects of LISP-CONS then I figure
other people may have been confused too.
When I wrote my comparison, it was my impression that in
LISP-CONS, as in LISP-NERD LISP 1 and LISP 1.5 (though the I-D
says very little about 1.5) that the mapping data contains
potentially multiple RLOC addresses, each with a Weight and
Priority. This is for the purpose of the ITR making its own
decisions about which of the ETRs (one ETR is hopefully at each
RLOC location) is currently reachable, including by receiving ICMP
messages in response to encapsulated data packets which didn't
make it to an ETR and probably also from messages sent by ETRs
back to the ITR.
So as part of my comparison I wrote (RW1):
LISP-NERD/CONS: As noted above, ITRs have complex functions,
including making decisions on a packet-by-packet basis for MH
service restoration, TE and I think load balancing functions.
The ITR may or may not communicate with the ETR, but I think
the ITR is always ready to accept ICMP messages as sign it is
tunneling the data packets to the wrong address.
to which you replied (DF1):
I beg to differ. The ITR simply does a cache lookup on the DA
when the DA has a routing table miss or a default route match.
When the cache lookup returns an RLOC it slaps a header on. It's
as simple as that.
So I looked closely at the LISP-CONS I-D, in particular at this
paragraph in 6.4:
Priority, Weight, Unused, Loc-AFI, Locator: See [LISP-01] for
details. Oh, so it's just like a Blackberry.