General Background and Context

Motivation and Purpose

The GN2 Performance Enhancement and Response Team (PERT) is a virtual team committed to helping academic users get efficient network performance for their end-systems. There is an emerging need for this kind of support, due to the proliferation of systems which are dependent on Long Fat pipe Networks (LFNs), and whose requirements exceed the scope of the original TCP specification (TCP being the most common of the network transport protocols used on top of the Internet Protocol (IP)).

The PERT offers support in two ways. First, they respond to requests to investigate quality of service (QoS) issues submitted by the PERT Primary Customers. The PERT Primary Customers are the European NRENs, peer academic networks and certain international academic research projects (the full list of PERT Primary Customers is given in ‘The PERT Policy’ (GN2-05-18). The purpose of specifying a relatively small number of Primary Customers is to ensure that the majority of potential users of the PERT (the PERT’s ‘End Customers’) first contact their NREN, who will be able to help with minor problems, or those issues that are in fact outside the scope of the PERT (such as network hardware failure).

The second way in which the PERT helps its clients is by producing reference documentation that end users and network administrators can use for self-help. This documentation explains the concepts of network performance, highlights the most common causes of quality of service (QoS) problems, and offers general guidelines on how to configure systems to optimise performance. It also provides pointers to other resources for troubleshooting issues, such as the NREN network statistics and monitoring tools that will help end users and network administrators to determine quickly for themselves whether current problems are likely to be the result of changes in network conditions. This information is all held in the PERT Knowledgebase, an online resource that is accessible to all (see GEANT2 web site, under ‘Users’ -> ‘PERT’ for a link).

In order to showcase the work of the PERT in this area, a snapshot has been taken of the content of the PERT Knowledgebase and this has been used to create two self-contained guides to network quality of service. The ‘User Guide’, as its name suggests, is targeted at end-users, and in particular those end-users who have demanding requirements (typically those who depend on LFNs), and the network administrators who supportthem. The User Guide is at Annex A of this document. The second guide (Annex B) is called the ‘Best Practice Guide’. This document is aimed more at campus network administrators, since it concentrates on issues which can not be controlled by re-configuring or upgrading end-systems. In fact the Best Practice Guide is really an addendum to the User Guide, in as much as its target audience (network administrators) is a subset of the User Guide’s target audience.

Conclusions and Future Work

Whilst the online PERT Knowledgebase, which will always have the most up to date content, is expected to be the main reference source for PERT users seeking specific advice on a given subject, the two guides presented here will provide a useful and easy to read introduction to the main issues surrounding network performance issues today.

A significant amount of effort was put into building up the PERT Knowledgebase, prior to producing these two guides, and the effort is planned to continue, albeit at a slower, steadier pace, over the rest of GEANT2. The PERT Knowledge base will be kept under regular review, and as and when it has changed significantly from its present state the guides will be re-published.

-- SimonLeinen - 09 Apr 2006