Network Modelling Discussion: Grouping and Network Abstraction

Discussions

Lengthy discussion (~20 mails) in March 2008: http://www.ogf.org/pipermail/nml-wg/2008-March/thread.html

Controversies

The network and domain are related concepts. The distinction in the proposal below is organizational versus data plane. There is often a 1:1 or many:1 relation between network and domain. However, a many:many relation could be argued. Others may argue that this is too verbose, and the two concepts can be merged because there is overlap.

There is no broad consensus of the view class. Originally, Aurélien Cedeyn propsed a class called "Model", which is much more generic than "View", and is perhaps best described as a generic "Group". It could be argued that the current "Node" class is the same as Cedeyn's original "Model".

Freek Dijkstra argues that a network element may only be part of one network. He argues that this keeps the model simple. Alternative 1: a network element can be only part of one domain (Freek Dijkstra would be fine with that too). Alternative 2: a network element can be part of multiple networks and multiple domains. There is no consensus here.

It could be argued that Network and Node are the same (Aaron Brown asks if a Network is meaningfully different from node to make it a separate subclass. Due to differences in how an abstracted network is used vs. a device, there needs to be some way of differentiating them, but an abstracted view of a network will end up looking very similar to a node)

Classes

Node

Name: node, or group.

Abstract superclass, used to describe similar classes such as network and device.

Description: A node has interfaces to the outside world and can be comprised of elements underneath.

Relations: node:NetworkElement relation is 1:many. There is no generic network element class (yet). A Node may at least contain 0 or more interfaces, 0 or more devices, and likely 0 or more of other elements.

Device

We recommend that Device is a subclass of Node. For further details, see the discussion page on Devices and switching capabilities

Network

Name: network, Computer Network

Description: A collection of network elements that behaves as a single resource or A collection of interconnected network elements, within a single domain.

It is possible to describe the functionality without exposing the internal implementation or detailed internal limitations

Relations: network is part of one domain. A network can contain devices.

Domain

Name: Domain, Administrative Domain.

Description: An organisational entity that is responsible for the operational control of resources (including network resources)

Relations: Subclass of Node. A domain is composed of networks (and other resources).

View

Name: view, or model, or group

Description: ?

Relations: ?

Other Models

Corresponding Elements in other models: