Subject: RE: Next question...

From: "Tony Li" <[email-masked]>
Date: Mon, 25 Nov 2002 15:57:48 -0800

|   > Have we reached consensus that we need to deal with multihoming
|   > policies?
|   
|   I am sorry but i do not fully understand what do you mean by this.

As soon as a site is multihomed, there are multiple possible ways
of forwarding packets, both inbound and outbound.  Whenever a human
is involved and there is a choice to be made, we end up giving the
human a say in how that choice is made.  Such dictums we generally
refer to as 'policy'.

In this case, we would like to be able for some human to tell us 
which packets should exit on which link and which packets should
arrive on which link.

Certain policies are unimplementable even tho they are desired.
I don't mean to open the discussion about which policies we will
support, but I was hoping that we agreed that we need to provide
SOME policy controls as part of our solution.

Tony

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From: Brian E Carpenter <[email-masked]>
Date: Tue, 26 Nov 2002 10:49:29 +0100

I'd say yes, for some definition of policy we need policy control,
and it needs to be global rather than per-host.

OTOH I wouldn't exclude that the actual *enforcement* of the policy
happens in the hosts, under a site-wide policy broadcast in some
way.

  Brian

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From: "marcelo bagnulo" <[email-masked]>
Date: Tue, 26 Nov 2002 19:49:11 +0100

> SOME policy controls as part of our solution.

I certainly agree with that some policy controls are needed. I also  think
that poviding this control at the host level should be explored.

Regards, marcelo

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From: Randy Bush <[email-masked]>
Date: Tue, 26 Nov 2002 12:02:56 -0800

> I certainly agree with that some policy controls are needed. I
> also think that poviding this control at the host level should be
> explored.

maybe so.  but that is not the charter of this wg.  and, as it has
been struggling to make progress as it stands, can we please not
add more straws to the camel's back?

randy

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From: "Aldrin Isaac" <[email-masked]>
Date: Tue, 26 Nov 2002 15:40:41 -0500

% From: [email-masked] [mailto:[email-masked]]On
% Behalf Of Brian E Carpenter
%
% I'd say yes, for some definition of policy we need policy control,
% and it needs to be global rather than per-host.
%
% OTOH I wouldn't exclude that the actual *enforcement* of the policy
% happens in the hosts, under a site-wide policy broadcast in some
% way.
%

If you are referring to broadcasting policy that governs source
address selection corresponding to destination address(es), then I
don't see how source address selection can *also* be made to
correspond to the *current* ISP (i.e. expect it to change) towards
that destination.  Unless, of course, this policy is not static but
somehow consists of learning from the network, in which case network
controls would seem to be sufficient.

-- aldrin

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From: Brian E Carpenter <[email-masked]>
Date: Wed, 27 Nov 2002 11:31:39 +0100

Policy is certainly not static, but I was trying to keep
my brain clear of specific solutions.

   Brian