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Re: [RRG] Hosts, DFZ, purity & incremental deployment
Thus spake "Tony Li" <tony.li@tony.li>
| 1 - A solution which requires host changes in both communicating
| hosts is not incrementally deployable, since benefits only
| accrue to a tiny proportion of end-users (people who use hosts)
| due to the fact that initially, very few hosts have the
| upgrades.
Hmmm... Well, you and I have very different semantics assigned to
"incremental deployability". I would consider anything that could be
rolled out one host at a time without breaking anything as being the
maximal amount of incremental deployability.
I think this definition is too weak. What is the incentive to deploy
something when the only benefit it offers today is "doesn't break the status
quo"? Not deploying also offers that benefit at a lower cost.
The minimum bar, to me, is that the first site receives benefits when it
pays the cost of deployment. Those benefits may grow when more sites
deploy, but they cannot be zero in the initial state or you'll never achieve
critical mass, i.e. nobody wants to pay the costs because they don't get
benefits until _everyone else_ also pays the costs, so you get a classic
chicken-and-egg result just like IPv6 still suffers from.
However, under the looser definition of a non-decreasing benefit function,
I
don't see that it follows. Any two host can deploy a new namespace and
benefit from it for their private connections. It's true that a single
host
won't benefit, but that's not a corner case that I consider to be
essential.
It's not essential, but if you can solve that problem, many other problems
solve themselves.
For instance, Ivip or LISP with anycast PTRs offers benefits to a site for
using Ivip/LISP even if it's the _only site on the planet_ that deploys.
Every additional site that joins in increases the benefits to all. Compare
to other models that require both sides of each flow to upgrade before
either sees a benefit.
S
Stephen Sprunk "God does not play dice." --Albert Einstein
CCIE #3723 "God is an inveterate gambler, and He throws the
K5SSS dice at every possible opportunity." --Stephen Hawking
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