[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: apps people?



> (1) If there are multiple addresses per node, then the application
> needs to somehow iterate through the various src/dest combos until it
> finds one that works.  If multiple ones would work, how does it choose
> the best combo?

iteration is often too slow, especially if there are lots of address
pairs and the default rules don't work well.

> (2) If there are filters in place, then addresses that work from one
> node attached at one point may not work from a different node or a
> different location.
> 
> If we agree to remove filters and have one address per node, then we
> can continue to write simplistic apps.  If not, then applications need
> to use techniques that allow them to cope with these issues.
> 
> Notice that if an application only creates connections using a single
> pair of endpoints then (assuming no mobility) it only has to deal with
> issue #1. Issue #2 only comes into play when applications forward IP
> address to other applications and expect them to keep working. 
> Sending DNS addresses instead may be a solution for some applications.

whether this works depends on both DNS configuration and the app.
it would be far better if the apps had a way of doing referrals that
didn't suffer the unreliability and delays of DNS and which wasn't
so sensitive to DNS (mis-) configuration.

> This discussion is only relevant to 'local' addresses in as much as
> local addresses are one class of filtered address.  As soon as you
> introduce filters you MUST consider #2, regardless of your address
> 'scope'.

local addresses are also ambiguous, which further complicates things.

> Network ambiguity is largely irrelevant - the connection succeeds or
> it doesn't (remember that most nodes have a unique interface id). 

timeouts take a long time, and the probability that an ambiguous address
is invalid is high.

Keith
--------------------------------------------------------------------
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 majordomo@sunroof.eng.sun.com
--------------------------------------------------------------------