L.S., In the current version of the NML specification, as presented today at the GLIF/OGF meeting, I noticed that there is no provision for assigning metrics to links or ports. To support pathfinding in NSI (which uses NML for its topology description), it would be very useful to include attributes for such metrics. Without any such information, intercontinental links are just as likely to be used in an NSI path as local links, which would be a waste of scarce international bandwidth. At first glance, I would suggest adding attributes such as length, weight (preference) and bandwidth - as NML is extensible, should such extensions be coordinated by the NML-WG, or extensions that NSI themselves could create? Given the basic nature of these attributes, it would probably be best to have them centrally registered, to prevent multiple, incompatible versions (Length in m or km? Bandwidth in b/s or Mb/s?) from occurring. Regards, Paul Boven.