On 2/23/12 9:23 AM, Roman Łapacz wrote:
W dniu 2012-02-22 22:50, Freek Dijkstra pisze:
I like to hear from nml-wg participants: - if they think that NML should be capable of defining a topology at different layers of abstraction
Yes but I would make this more general and say - just different layers. They could be abstractions or tech layers (I'm thinking that layers may be also a good solution to control publishing information by configuring somehow that only some layers can be distributed, others not; a single abstraction could be split into more layers because of some reasons; it would be up to the implementation)
- how these different descriptions should be tied together. Should we define a relation between them?
I think so. The work on examples will help to progress.
Roman
For the NSI participants I'm interested in hearing if you think that only NML should define different levels of abstraction, or if you also expect NSNetwork to have different levels of abstraction, and if an NSA have different levels of abstraction. (I presume both have, given that NSA supports a tree-like request structure, where a top-NSA can delegate requests for path provisioning to other NSA). The different levels are IMO necessary. For instance: NORDUNet could
Yes.(!) Exactly. present itself to external agents as a single point abstraction-one NSI Network with one NSA, hiding all internal structure. There are valid reasons for doing this - some technical, some purely business related. Alternatively, NORDUnet could express itself as a federation of subdomains - perhaps an NSI network in NYC, another in CPH. And while I might expose these abstracted NSI [sub]Networks and the links between them and the outside world publicly, I would still hide the underlying physical infrastructure that provides those capabilities. And there is a *lot* of underlying infrastructure that is not exposed. This more detailed abstracted topology allows me to offer service characteristics (geo location, latency, etc) without losing the abiity to re-engineer those service capabilites as I deem necessary to meet my service objectives. These abstractions are fundamentally necessary because not all of our service provisioning is purley a matter of links and adaptations...there is a lot of policy and "service" added to the infrastructure.
Regards, Freek _______________________________________________ nml-wg mailing list nml-wg@ogf.org https://www.ogf.org/mailman/listinfo/nml-wg