# Modelling

Research about modelling aspects of networks.

**Conference presentation**

**Journal Paper**

This paper used a likelihood based framework to create a rigorous way to assess models of networks. Network evolution is broken down into an operation model (it decides the 'type' of change to be made to the network, e.g. "add node" "add link" "remove node" "remove link") and an object model (that decides the exact change -- which node/link to add).

The system is shown to be able to recover known parameters on artificial models and to be useful in analysis of real data.

This is an extended unpublished 14 page version with all proofs of the short paper (2 pages) accepted for SIGMETRICS 2014 as a poster/short paper.

**Journal Paper**

This paper is a development of the earlier ideas in PREFLEX -- http://www.richardclegg.org/node/18

In this case the focus is resilience within a data centre. In particular resilience at the network layer. If several paths are available to a destination the system known as INFLEX can support fail over between paths seamlessly using OpenFlow. In this case the system is tested using Openvswitch.

**Invited talk**

This talk is the latest of my talks about FETA the framework for evolving topology analysis. This uses updated notation. The core of the work is a likelihood based model which can assess how likely it is that observations of the evolution of a graph arise from a particular probabilistic model, for example a model such as the Barabassi-Albert preferential attachment model. Analysis is given to data from Facebook and from Enron as well as from artificial models.

**Journal Paper**

This paper looks at a markov chain based model and uses queuing theory to analyse its performance. The system is D-BMAP/D/1 and a closed form solution is found

This talk describes FLICK a system for the application-specific middlebox. It consists of three parts:

1) A domain specific language for the middlebox that allows easy development of typical middlebox functions.

2) An abstraction, the task graph, that allows the breaking of middlebox functions into easily parallelisable work units.

3) The system -- this implements the compiled language, handles TCP connections and memory management.

The whole system is comparable in speed to a specialist implementation.