Re: IP network address assignments/allocations information?

[Jessica Yu <jyy at ans.net>]

Brain,

Looks like we have a teminology issue. Notice I did not say routing 
system but ROUTING will have problem.  Because the choice of a 
multi-addressed host to use one of its IP address to include in
packet header implies routing decision, the host, in effect, does 
some routing decision making.  How a host intellegently choose the 
ip address as the source address to send packets or DNS intellegently 
choosing an ip address for a query are complex issues which we do not 
have an answer for as you indicated in your message.  

So I disagree with those who think it's not a problem in the Internet 
where majority of hosts with multiple addresses. 

						--Jessica  

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Date: Mon, 13 Dec 1999 16:05:48 -0600
From: Brian E Carpenter <brian at hursley.ibm.com>
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To: Jessica Yu <jyy at ans.net>
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Subject: Re: IP network address assignments/allocations information?
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Jessica,

I don't think this is a problem for the routing system. It will deliver to
whatever destination address is in the packet. The problem is for hosts
to choose which destination address to use when there is a choice,
and ditto for the source address.

I don't agree with those who see this as asking the host to guess at
routing decisions. However, it's a complex topic that is already 
an active work item in the IPNG WG.

   Brian

Jessica Yu wrote:
> 
> You seem to disagree with my statement of "routing may not be adequate."
> in the Internet where majority of the hosts with multiple IP addresses.
> 
> Do you really believe that there is an adequate support for the routing
> issue described below in majority-hosts-with-multiple-ip-addresses
> environment?
> 
>                                                 --Jessica
> 
> Date:    Fri, 10 Dec 1999 12:49:57 EST
> To:      Bill Sommerfeld <sommerfeld at orchard.arlington.ma.us>
> cc:      Jessica Yu <jyy at ans.net>, Keith Moore <moore at cs.utk.edu>,
>          Christian Huitema <huitema at research.telcordia.com>,
>          Sean Doran <smd at EBONE.NET>, ietf at ietf.org
> 
> From:    Keith Moore <moore at cs.utk.edu>
> Subject: Re: IP network address assignments/allocations information?
> 
> Return-Path: moore at cs.utk.edu
> X-URI:   http://www.cs.utk.edu/~moore/
> In-reply-to: Your message of "Fri, 10 Dec 1999 12:32:18 EST."
>          <199912101732.RAA16467 at orchard.arlington.ma.us>
> Sender:  moore at cs.utk.edu
> Content-Type: text
> Content-Length: 913
> 
> > > There is also a potential scaling issue of using multiple addresses
> > > as general purpose multihomging mechanism. This is because if this
> > > is the case, most of the Internet hosts will end up with multiple
> > > addresses.
> >
> > I don't see why this is inherently a problem.
> 
> it's a problem because it's essentially asking the sending host to do
> routing in the absence of any routing information.
> 
> if multiple addresses are available for a host, the chances are good
> that the paths associated with some of those addresses are significantly
> better, or worse, than others.  with IPv4 multihoming, the routing system
> sorts out which path to use.  this doesn't work perfectly but at least
> the decision is made in light of some information about the nature and
> current state of those paths.  with IPv6 multihoming, the sending host is
> just guessing.  it's difficult to believe that this will work well.

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