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Topology descriptions are a necessary component of inter-domain provisioning in circuit oriented networks. In the past few years several different projects have created provisioning software, each with their own way of describing network topologies. In 2007 the Network Markup Language working group (NML) was started in the OGF to build on all these efforts and create a standard for topology descriptions. Building a standard is a long and complicated process, especially with several different initiatives involved. The NML schema is progressing, but there are still some open issues that must be discussed.
The topology descriptions used at Internet2 are provided in an XML format for use in the Dynamic Circuit Network suite. The topology descriptions developed by the University of Amsterdam is the Network Description Language. In August and September 2009 I worked at Internet2 on the translation of topology descriptions. This page describes some of the results of that effort.
Below are two examples of translations, of the Ann Arbor Lab and of a section of the ESNet topology with a port with multiple links.
A simple topology of a test network in Ann Arbor. It describes three connections between the two Raptor machines, and three inter-domain links.
This scenario originally describes one host, with one port and two links. This is not possible to describe directly in NDL, and is transformed into a situation with a virtual third party, as shown in the figure.
The translation has been implemented using the Python NDL Toolkit (pynt). See the pynt webpage for more details.