Re: a proposal for slice stitching -- SUMMARY

Hello all-

I've tried to summarize what's been said on this topic.  I'm sure some
of it is wrong and I left out several points that seemed IMO somewhat
off the prime topic.  Please annotate or comment as you see fit.

--aaron

1. What kind of helper services are used?

   a. An optional slice embedding service that annotates an RSpec
      description of a full slice with additional connectivity
      information to permit AMs to identify that they need to
      establish a 'stitching' VLAN. (Rob)

   b. A mandatory stitching coordinator as part of (or on behalf of) a
      clearinghouse thus representing GENI operations. It controls the
      exchange of (and logs) stitching VLAN parameters as they are
      passed between aggregates. (Aaron) (nb: I didn't say they were
      part of the clearinghouse in my original note because I thought
      I didn't have to but Jeff's thoughts about authorization
      convince me that it is probably a needed assumption.  See
      4. below.)

   c. An optional stitching coordinator as part of a slice manager
      representing the researcher that assists in the exchange of
      stitching VLAN parameters as they are passed between
      aggregates. (Jeff)

2. How does an Aggregate know to establish a stitching connection to
   it's peer?

   a. Both aggregates see an RSpec describing a connection between
      them.  Requires both AMs to understand the stitching portion of
      an RSpec. (Rob)

   b. A stitching service tells an AM to bind a sliver to a stitching
      VLAN (Aaron).

3. How does the peer Aggregate know which stitching VLAN to bind to a
   sliver?

   a. AMs negotiate with each other. Requires a coordination
      protocol. (Rob)

   b. One AM assigns a VLAN and a stitching service passes the
      information to it's peer.  Requires use of the external
      service. (Aaron)

4. What authority do external services have?

   a. The service in Rob's model (1a) is modifying request RSpecs on
      behalf of the researcher.  (Are the modifications signed?  If
      so, then by whom?)

   b. The service in Aaron's model (1b) is an intermediary between two
      AMs.  AMs have long-term trust relationships with
      clearinghouses.  In this case, the clearinghouse is trusted to
      reliably pass stitching parameters.

   c. The service in Jeff's model (1c) acts on behalf of the
      researcher and thus has no special privileges.  AMs sign
      stitching parameters so peer AMs can trust they have not been
      modified en-route.

4. Visibility goals

   a. The researcher should not have to participate in or be aware of
      stitching. (Rob)

   b. Only the researcher should have to know the full set of
      resources in a slice.  (Jeff)

   c. An operations group should know about all stitched links.
      (Aaron)

5. What are the needs to control the order in which stitching
   connections are established? ?

   a. Aggregates need to control the establishment phases of, e.g.,
      tunnels. (Rob)

   b. To prevent use of a network which is not yet fully provisioned,
      researcher should be prevented from using any stitched links
      until the end-to-end topology is established.  (Aaron)



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