Jeroen,

I agree, that if a user has a preference on which domains to include during path computation, then: 1) that should be communicated via the NSI and 2) that the path computation entity computes the path based on user requirements.

We might not ever have a completely globally GOLE-interconnected network, however, I do think the roles of GOLEs are different than regular network domains and that in most cases interconnecting domains via GOLEs may result in simpler and shorter paths.

Gigi

Jeroen van der Ham wrote:

On 25/06/2010 15:14, Gigi Karmous-Edwards wrote:
  

I agree that the removal of non-GOLEs from the topology graph is an
alternative to creating a constraint during path computation. I thought
that the removal from the graph would be easier, similar to removal of
failed links (due to availability etc ) during crank-back.  Having said
that, in GIRRA, both technology and policy is taken into account but
availability is not. This is because we do not collect availability
information only relatively static  information about the topology,
therefore reducing complexity and the number or required updates.
    

Availability is then taken into account using crank-back.

As we discussed before, it remains to be seen whether the number of
updates regarding availability outnumbers the load on the network due to
crank-backs.

  

With reference to your other comments about policy: having an open
policy GOLE makes path computation easier, since the fewer "policy-rich
" domains one has in the computed path the better. IMHO, an ideal global
path will consist of only the source and destination domains and the
rest of the path will consist of policy-free GOLEs. Leaving the policy
of the path to the two endpoint domains only. Does this make sense?
    

This will really depend on the user! I would imagine that LHC Tier-x
users do not want to use GOLEs, but instead want to make use of the
LHCnet as much as possible.
I realise that the LHC is an extreme case, but similar cases can be made
for NLR/Internet2, GEANT, GLORIAD and other networks that some but not
all users have access to.

Leaving policy out of the equation like this may make pathfinding a
whole lot simpler, but I'm not sure whether you end up with answers that
you can work with.

  

I do realize that this is different than traditional approach and I
realize that today in our real world,  GOLEs are not all interconnected.
The above statements are based on an "ideal" network.
    

Given the examples I made above I'm not sure that we'll ever end up with
anything resembling an "ideal" network as you describe.

Jeroen.
  

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