Subject: Re: draft-hinden-ipv6-host-load-sharing-00.txt

From: Jack McCann <[email-masked]>
Date: Fri, 9 Nov 2001 10:48:27 -0500 (EST)

draft-hinden-ipv6-host-load-sharing-00.txt states:

> An implementation MUST cycle through the router list in a round-
> robin fashion while making sure it always returns a reachable or
> a probably reachable router when one is available.

I can see encouraging implementations to do some sort of load sharing,
but why does it have to be round-robin, and why MUST and not SHOULD?

- Jack

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From: Pekka Savola <[email-masked]>
Date: Fri, 9 Nov 2001 17:56:07 +0200 (EET)

> but why does it have to be round-robin, and why MUST and not SHOULD?

The idea probably is that if it is MUST, you can rely (up to a certain
point) on clients on actually doing load-balancing.

Personally, I'm not sure whether this is a right approach.  There may be
other uses for multiple default routers; for example, fail-over.  Some
might _not_ want to have forced load sharing there.

-- 
Pekka Savola                 "Tell me of difficulties surmounted,
Netcore Oy                   not those you stumble over and fall"
Systems. Networks. Security.  -- Robert Jordan: A Crown of Swords

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From: Bob Hinden <[email-masked]>
Date: Fri, 09 Nov 2001 10:18:49 -0800

Jack,

My thinking that led to the draft was to change the current ND behavior to 
require spreading the load between multiple default routers.  Currently ND 
does not require this.  I noticed the current ND behavior when I wrote the 
VRRP for IPV6 draft, that there wasn't any mechanism to that required hosts 
to use more than one default router, even when several existed.

I talked about round robin because it was very simple and would do a 
reasonable job spreading the traffic.  Other approaches are possible, but 
more complex.  The draft could be changed to allow other load sharing 
mechanisms as well.

Bob