Subject: Re: [RAM] Incremental Deployment of LISP

From: [email-masked]
Date: Thu, 29 Mar 2007 15:06:36 EDT

Yes, and isn't this the origin task of any routing protocol to advertise  
WHERE some user is located ? (rather than the task of DNS ?), i.e. to  
communicate to the rest of the internet "I have reachability to this or that  user ?"
 
Heiner
 
In einer eMail vom 29.03.2007 20:16:25 Westeuropäische Normalzeit schreibt  
[email-masked]:

On Mar  29, 2007, at 11:06 AM, Dino Farinacci wrote:

> The disadvantage of  using DNS is:
>
>     1) Routing depends on  directory and directory depends on routing.
>     2) RTT  latency when doing the lookup.
>     3) Packet drops  while waiting for reply to come into the ITR.

4) The global DNS  infrastructure wasn't designed/implemented to  
handle this kind of  requirement, it's neither fast nor reliable  
enough, IMHO (works  pretty well for its intended purpose, but DNS is  
a 'behind the  scenes' kind of thing which is often neglected and  
certainly can't  be made front-and-center as a requirement for routing).

The mechanisms  used for mappings in LISP or any other proposal should  
be contained  within the network infrastructure and simply cannot have  
a  dependency upon any other external system,  IMHO.

-----------------------------------------------------------------------
Roland  Dobbins <[email-masked]> // 408.527.6376 voice

Words that come from a machine have no soul.

--  Duong Van  Ngo

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From: [email-masked]
Date: Thu, 29 Mar 2007 15:40:18 EDT

> Yes, and isn't this the origin task of any  routing protocol to
> advertise WHERE some user is located ?  (rather than the task of DNS ?),
> i.e. to communicate to  the rest of the internet "I have reachability to
> this or  that user ?"

"[saying] where some user is" and "communicating ... I have  reachability to
this or that" are two entirely different things - or rather,  they can be, and
have been for many decades now in most networking designs,  separated into two
different tasks.

C'mon.

It's a general law of system design that as systems grow, it's  usually the
case that a single mechanism A that did both X and Y needs to get  separated
into two separate mechanisms B and C, one each for X and Y - which  means that
it would be an extremely bad idea to go in the reverse direction  as a system
got larger.

In other words, trying to do both:
-  finding out where some user/computer/etc is, and
- finding out if/how to get  there
in a single mechanism would be a really bad idea.
 
I said more or less: communicating to all others "I have reachability to  
this or that user" is the origin task of any routing protocol. What is wrong  
with this statement ? Can you put it in better words ? Or is my statement  wrong?
Why do you come with such an answer ?
 
Heiner

"All problems in computer science can be solved with another level  of
indirection" - variously attributed to Butler Lampson and David  Wheeler.

Noel

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From: [email-masked] (Noel Chiappa)
Date: Thu, 29 Mar 2007 15:51:57 -0400 (EDT)

> From: [email-masked]

    >> "[saying] where some user is" and "communicating ... I have
    >> reachability to this or that" are two entirely different things
    >> ...

    > Can you put it in better words?

Here's a real-world analogy that might make it clearer.

Let's say you want to visit a friend's house (the real-world equivalent of
sending packets to another computer). The first step above is equivalent to
finding out where the friend's house is - i.e. their street address. The
second step is finding out how to get there (either finding a public
transport system such as bus or subway that gets there, or looking at a map
to see how to bike/drive/etc there).

	Noel

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From: [email-masked]
Date: Thu, 29 Mar 2007 16:14:55 EDT

How about a new routing protocol and a new IPvN which a) overcomes all the  
scalability problems and catches up with postal letter forwarding as done  for 
centuries with two parts written on the envelope: 1) Name of receiver  (plus 
Mr. or Mrs,...)

and maybe a little bit lower 2) street and number, zipcode and city, plus  
country.
 
As a kid when I learned where to place these parts, I had no idea about  
endpoint identifier /locator split :-)
 
Heiner

In einer eMail vom 29.03.2007 21:54:43 Westeuropäische Normalzeit schreibt  
[email-masked]:

> From: Roland Dobbins <[email-masked]>

>  The DNS won't work, and deploying some other infrastructure .. to
> handle lookups is a nonstarter, IMHO.

OK, so what will  work? :-) More of what we've already got, because anything
else is too  painful to deploy?

Noel

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From: [email-masked] (Noel Chiappa)
Date: Thu, 29 Mar 2007 17:45:45 -0400 (EDT)

> From: David Meyer <[email-masked]>

    > "No circular dependencies" -- A long held Internet design principle
    > dating back to Postel (or maybe before).

Minor historical aside: I believe the earliest system to explicitly state
(and live by) this concept was the THE operating system of Dijkstra et al:

  http://en.wikipedia.org/wiki/THE_(operating_system)

dating from the mid-60's; it's certainly the paper they made us read in
the systems course about this concept.

	Noel