[Nsi-wg] Topology Distribution document

[Henrik Thostrup Jensen]

On Fri, 31 May 2013, Jeroen van der Ham wrote:

> I should add: this document is meant to be merely informative. It is not 
> a standard, since it does not prescribe or define any specific 
> mechanism.
>
> I think it is infeasible to define a standard for topology exchange in 
> time for NSI v2.0. Then again, my expectation last year was that NSI 
> v2.0 would already be published by now, so I could be wrong.

I think we will need something. But having it out after the CS v2 document 
is not an inherent problem. In fact, keeping the topology distribution 
seperate from the CS protocol is probably a good thing.

IMO, the HTTP based distribution of topology files is good enough for the 
immedidate time. It solves the immediate problems of not having network 
host their own topology and the lack of being able to update it 
dynamically. It is not a clever, do-all, scale-to-the-moon approach, but 
those solutions tend to take a lot of time to hash out.

Should we write something up on how to do this? I think the document 
should be fairly small. Essentially there is something like this:

1. Discover Topology URLs from other NSAs discovery service or their
    topology files. Iterate on this process, until no new networks are
    found or stop at some defined hop level.
2. Build a topology model from the process in 1.
3. Repeat the process at 1, at some interval - say every other hour - to
    continously update the topology.

For the case of 1000 NSAs, and hourly updates, that is 24000 req/day to 
serve, or 6.67 req/sec, which is nothing for an HTTP server these days.


     Best regards, Henrik

  Henrik Thostrup Jensen <htj at nordu.net>
  Software Developer, NORDUnet