[Nml-wg] Notes for Feb 23 conf call

[Freek Dijkstra]

Here are some notes from todays call. Some text is shuffled for
readability. If you have any correction or additions, please follow up.
The actions items are at the end of the notes.

Notes for NML call 23 February
==============================

Attendance: Aaron Brown (I2), Jerry Sobieski (Nordunet), Roman Łapacz
(PSNC), Freek Dijkstra (SARA)
Excused: Jason Zurawski, Jeroen van der Ham, Chin Guok

1. Action items from previous call:
----------------------------------

Jeroen was not able to attend today's call; his action items will be
postponed to the next call.

Roman and Freek send NMLified version of the AutoGOLE topology to the
list. Jerry was pleased to see them and thinks they're great starting
points for integrating NML and NSI concepts. Jerry suggested to create a
smaller example. Freek suggests to instead pick one network and compare
them in the original and proposed drafts.

Freek contacted the NSI group about the integration, but got no formal
reply yet. The NSI-WG is currently very busy on other topics. Freek will
contact Guy for the best time slot.

2. Preparation for OGF 34.
-------------------------

Freek, Roman and Jerry will attend OGF 34. Likely no-one from Internet2
will be able to attend.
Freek will sent out a call for presentations.

The topics during OGF 34 will be:
* NML-NSI integration
  - unidirection
  - explicit links
* recursion of topologies (discussion/proposal)
* VLAN description (discussion/proposal)
* General document improvement (WORKING session a.k.a. the
shut-up-and-start-writing-session)

3a. NML-NSI integration
-----------------------

NSI issues:
* Enumeration: Possible large number of end-points. Unclear how to group
them.
* Distribution process: how to update the world view by each nml/nsi
topology consumer and how to deal with inconsistencies.

Nordunet issue:
* NORDUnet has multiple locations (New York and Copenhagen). Not really
one network.
Three solution: (1) one network, with exposing some of the internal
details and constraints, or (2) describe as 2 topologies with 1
controlling NSA.
* In practice multiple topologies are needed: one detailed topology for
internal use; one published to trusted peers; perhaps yet another
published to end-users or other entities.

3b. Unidirectional vs bidirectional
-----------------------------------

Freek gives some background. When the topic came up first, it was
decided that is was probably easier to pick one instead of doing both at
the same time. Since unidirectional is more flexible, that was chosen.
It was acknowledged that a bidirectional concept is useful, but for
simplicity, this was only a grouping of unidirectional links.

Jerry sees use case where not specifying directionality gives ambiguity.

There are examples where bidirectionality is required. Freek recalled an
example given by Richard Hughed-Jones: a single fiber strand, that
carries data in two directions. Upstream at 1310 nm, and downstream at
1550 nm. This is an actual technology used in some FttH networks.

A broadcast network has multiple output ports.

Roman asks Freek and Jerry to write down these use cases.

3c. Difference between NML:topology, dtox:NSNetwork, dtox:NSA
-------------------------------------------------------------

NML topology is set on network object with some internal connectivity

NSI Network is a connection service.

A NML topology should be thought of as a big round circle with ports on
the edges, and a black box in the middle that can provide some data
transport. The document surely has a more formal definition. A NML
network not the same thing. A NML network is a IP subnet; think of it as
a Ethernet VLAN with attached hosts. These terms were decided in Munich
after a rather lengthy discussion where we concluded that the term
"Network" was severely overloaded.

Jerry: propose to put dtox:nsnetwork in nml:topology for now, and
perhaps take it a step further, put all child elements of dtox:nsnetwork
in directly in the nml:topology.

Freek and Jerry will look at the exact definition of NML:Topology and
NSI Network, and see if they can sync their definition. If that is
possible, they are the same thing. If not, we can than think what the
relation between the two is.

3d. Recursion of NML topologies
-------------------------------

Layers have abstraction, but there is also recursion on a single layer.

Freek referred to figure 7 of G.800. The public URL of G.800 is:
http://www.itu.int/rec/T-REC-G.800

(Note: ITU-T just published a new version of G.800 this month; Freek
referred to figure 7 in the 2007 version of the document. Direct link:
http://www.itu.int/rec/dologin_pub.asp?lang=e&id=T-REC-G.800-200709-S!!PDF-E&type=items)

Roman: can there be more than one NSI network in a domain?
Jerry: Each NSA controls exactly one NSI Network, and each NSI Network
is controlled by exactly one NSA.
Both NSI Network and NSA can recursive. E.g. a federated NSA can act a
agent for multiple subdomain NSAs.

NML should be able to describe a federated topology, and subtopologies.
We need to define how to describe the relation of these topologies with
each other.

Jerry will write this down as a use case (he has multiple slides on it)
Freek will dig up the URL for the use-case tracker:
https://forge.ogf.org/sf/tracker/do/listArtifacts/projects.nml-wg/tracker.use_cases

NSI has control plane topology and data plane topology.
Jerry hopes that NML topology constructs can be described by NML concepts.


Action items:
=============

* Jeroen to go through document and set up action points
* Jeroen to check the Security considerations of NM
* Freek to write use case on bidirectional and unidirectional links:
single fiber with two wavelengths in different directions.
* Jerry to write use case on bidirectional and unidirectional links
* Jerry to write usecase on NORDUnet being a geographical segregated
network (NY and CPH), with possible restrictions between the two
locations/networks
* Jerry to write this down federated and sub-NSA as a use case.
* Freek and Jerry look at the exact definition of NML:Topology and NSI
Network, and see if they can sync their definition