nanog mailing list archives

Re: Shim6, was: Re: filtering /48 is going to be necessary


From: Masataka Ohta <mohta () necom830 hpcl titech ac jp>
Date: Sat, 17 Mar 2012 15:41:01 +0900

William Herrin wrote:

DV is a distributed computation by intelligent intermediate
systems, whereas, with LS, intermediate systems just flood
and computation is by each end.

That's basically wrong.

Please, don't demonstrate your lack of basic knowledge.

Both systems perform computation on each router.

The difference, as you can see in the above sentence of mine,
is whether the computation is done as an intermediate system
or an end.

Link State performs
much more complex computation to arrive at its export to the
forwarding information base. In fact, Distance Vector's calculation is
downright trivial in comparison.

FYI, DV uses Bellman-Ford while LS can use Dijkstra, which is
faster than Bellman-Ford.

        http://en.wikipedia.org/wiki/Routing
        Distance vector algorithms use the Bellman-Ford algorithm.

        http://en.wikipedia.org/wiki/Bellman-Ford
        The Bellman–Ford algorithm computes single-source shortest
        paths in a weighted digraph. For graphs with only
        non-negative edge weights, the faster Dijkstra's algorithm
        also solves the problem.

should help you a lot to have basic knowledge.

The difference is that Link State shares the original knowledge, which
it can do before recomputing its own tables. Distance Vector
recomputes its own state first and then shares each router's state
with the neighbors rather than sharing the original knowledge.  The
> result is that the knowledge propagates faster with Link State and
> each router recomputes only once for each change. In some cases,
> distance vector will have to recompute several times before the system
> settles into a new stable state, delaying the process even further.

That is implied in my statements. So, don't repeat it in such
verbose way only to reduce clarity.

You failed to deny MH know layer 3 address of its private HA.

Here's a tip for effective written communication: the first time in
any document that you use an abbreviation that isn't well known, spell
it out.

In this case, the document is the thread.

And a tip for you is to remember the past mails in a thread
before sending mails to the thread.

Like any other host, including MH in your plan, it
already knows its domain name and the IP addresses of its private DNS
servers.

And, to deny HA, your assumption must be that the private DNS
servers may be mobile.

In your home agent architecture, it doesn't matter if they can have
multiple addresses. It matters if they can have the same address.

That's totally insane operation.

There is no reason to have anycast HA only to bloat the global
routing table.

                                                Masataka Ohta


Current thread: