Erik Nordmark wrote:
> 
> This has some implication on the number of flags one can invent.
> 

This is the part of the draft that has me concerned.

First - I do think the PREFER_LARGEST_SCOPE is needed for a large collection of
applications. (With all the noise about site-local in this group, I wonder if a
REQUIRE_GLOBAL_SCOPE wouldn't be a good idea...)

Second - I wonder how workable it is to have flags for each "preference" type.
How likely is it that additional address "types" will come along such that these
flags need to be augmented? Will the lag time for adding new flags to working
systems make it overly difficult for the applications that need those new flags
to be developed?

That said: I agree with the direction taken in this draft. It makes the easy
things easy.

However, it does not make the hard things possible.

As an application programmer, I'm not sure this will really give me enough
control when/if I need it. What I *think* I would like to see, in addition to
this sockopt, is an interface similar to getaddrinfo - but for address pairs,
not just for destination addresses. Something that lets me specify both the
source and the destination characteristics that I care about - and have it
return a linked list of all the src/dst address combinations that are possible
given those constraints. Sorted in the same order that the system would have
used to choose. This would of course include flags such as described in this
draft. (I'm not convinced this much control is really needed yet...)

Another possible use for an interface like this is to make it possible to only
use "prefer" variants of the flags mentioned in the draft. Then if the
application really needs "require" it can examine the address combinations
directly.

So, I am in support of this draft because I think it goes in the right
direction. I just think that an additional draft may be needed down the road a
bit...

jeff
--------------------------------------------------------------------
IETF IPng Working Group Mailing List
IPng Home Page:                      http://playground.sun.com/ipng
FTP archive:                      ftp://playground.sun.com/pub/ipng
Direct all administrative requests to [EMAIL PROTECTED]
--------------------------------------------------------------------

Reply via email to