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Re: [RRG] Long term clean-slate only for the RRG?
There is an important difference between NAT tables and LISP. NAT
table is a cache, but this cache is populated based only on the
information *local* to the NAT. In contrast, caches on LISP routers
can not be populated based only on the information local to the
routers, but require to acquire this information over the network.
If we continue the NAT trend to connect ISPs together, it will no
longer be local.
NAT has a major OpEx hit but again the
mapping database proposals especially LISP-ALT is not really
introducing anything monumentally new.
Wrt "NAT has a major OpEx hit", the (very wide) deployment of NATs
should give you a hint that its benefits (significantly) outweight
its cost. And what matters is not whether one claims that it is "a
major OpEx hit", but that the experience showed that its benefits
justify its cost. And yes, I know that some folks have a knee jerk
reaction when they hear the word "NAT".
I was referring to how it could be used. There are parts of the world
where they cannot get addresses so they implement multi-level NATs to
solve the problem. In these cases, there is a huge OpEx cost.
It's just BGP over tunnels and
you send Map-Request and return Map-Replies over this topology.
Here are few more management issues that you may consider:
4) Use of cache based routers, and not just cache-based routers, but
routers where the information needed to populate the forwarding
cache is not present on the routers.
That is what LISP-ALT does.
5) Routers using of ICMP to determine reachability.
ICMP can help but by itself it not sufficient due to filtering. The
main spec says that ITRs certainly should process ICMP unreachables
when they are received.
Btw, the above is by no means complete...
Add when you like.
Yakov.
Thanks,
Dino
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