RE: Requirement document last call (let's focus!)

["Tony Hain" <alh-ietf@tndh.net>]

Christian Huitema wrote:
> 1) Tony Hain sent several detailed comments, one of which
> generated a strong debate, i.e. his objection to a part of
> section 3.1.2 that stated that "a site MUST be able to
> distribute ... outbound traffic between multiple transit
> providers," arguing that this was a site policy matter. I
> personally don't agree with Tony, and believe the solution
> must enable the site to balance traffic, and must also enable
> the site to not do so if it chooses.

I was arguing that outbound traffic balancing is a local site policy
matter, and nothing we do will change that. The site will send the bits
out whichever interface it chooses, and the only thing this group could
do to influence that would be to define a negotiation protocol (PNI
like) to automate changes in site policy.

The other point is that for inbound load balancing, the receiving site
only has control as long as it does not conflict with origin site
policy, or the topology is deep enough that an intermediary abstracts
out the differences. The receiver can advertise detailed routes over
each specific link, but if the origin ignores those and defaults to its
prefered low-cost provider, the traffic is not likely to balance the way
the receiver wants. Yes we can require an approach that allows a
receiver to balance in the abstract, but there is no way to achieve
fine-grained absolute control without signalling/negotiation between the
endpoint sites, likely to be followed by some form of path establishment
protocol.

Tony