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Re: [RRG] Why not take address depletion issue into account
If I understood correctly, LISP, ivip and other similar proposals
are mainly based on one assumption: host should not be changed
because the cost of host change is believed to be much larger than
that of router change. At least, the recent discussion about the
tradeoff between initial packet delay/loss and the scalability of
the mapping system is based on that assumption. That is to say, the
EID->RLOC mapping query is initialized by the ITR, but not host.
Provided that host could be changed and could do the EID-RLOC
mapping query on behalf of ITR and carry the obtained RLOC
information in the packets, most of the pain discussed recently in
RRG mail-list will not exist.
The assumption LISP, in particular makes, is that the design will make
the least amount of changes to host protocol stacks, host
configuration files, router code and router configuration files. That,
with the features documented in the lisp-interworking draft, in my
book is the true and honest definition of "incremental deployability".
The recommendation for a LISP deployment is to place 2 routers (which
already exist) at a dual-homed customer/edge site with new LISP code.
Nothing else in the network has to change. Of course there are various
cases, if you want to to TE-LISP that an ISP can independently decide
to run LISP in their domain. And if you want to combine LISP
encapsulation services and NAT services in one box.
If the above assumption (host should not be change and still use
IPv4) is true, how will LISP, ivip and other similar proposals deal
with the address depletion problem? Should we still use
Well an EID/RLOC split adds one new namespace to address systems out
of. That gives you more addresses on the order of the total
addressable address space of the namespace's address family (IPv4 or
IPv6). You could iterate to build multiple levels of hierarchy. Just
like people have done with multi-level NAT.
NAT to solve the address depletion issues? If so, we would have to
tolerate the side-effect of NAT on the new application design and
deployment, especially peer-to-peer applications which has already
accounted for 80% in total internet traffic volume nowadays. Or
should we adopt IPv6
My motto is "translate before encapsulate". Because the addresses used
by the transport protocol are global addresses (one of the addresses
are global or public where your own is private).
So you combine the encapsulation and address translation services in
the same box.
We have an existence proof that LISP can work with NAT. That is, when
implemented in two different boxes in serial. We have on our prototype
todo list to combine both functionalities in one box.
(IPv6 can be adopted as EID in the above proposals) to solve the
address depletion problem? If so, the change of host is unavoidable
and this is conflicted with the basic assumption of the above
proposals. Or should we operate on the Internet multiple times to
solve the many existing problems one by one? If the deadline of the
routing scalability issue is close to that of the address depletion
issue, why not solve them in one solution?
That is the intention of LISP. To work with any address family. Hence
the prototype we are testing, every feature we add gets benefit to
IPv4 as well as IPv6. And soon, we will have mixed EID-RLOCs (v4 EIDs
with v6 RLOCs or mixed RLOCs and v6 EIDs with v4 RLOCs or mixed RLOCs).
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