Internet Backbone Traffic Analysis
The goal of the research project was to get a better understanding of traffic patterns within an operational Internet backbone network,
and their implications for traffic engineering. I analysed packet-level traces and BGP tables from a POP (Point-of-Presence) in the Sprint
IP backbone. Our study showed that the Sprint backbone was highly underutilized, and that utilization levels varied significantly across
the network. In addition, network topology and traffic patterns within the backbone are ammenable to automated traffic engineering methods, which can
load balance the traffic across the network at a negligible computational cost.
Below is a summary of some of the important results from this work:
- The network is very underutilized
- Load is unevenly distributed across the network
- Each pair of POPs only uses a small number of routes to route between each other (the operations department really likes to maintain control over
the flow of traffic in the network)
- Certain POPs attract the lions share of the traffic. Generally these are the east and west coast ones since they serve the international
links, and because the population denstity on the two coasts is higher.
- Traffic only drops by between 15-50% at night.
- Depending the the granularity of traffic classification, there are some relatively stable flows that can be isolated for purposes of
load balancing. Flow ranking remains pretty stable throughout the day and there are three visible flow sizes -- small, medium and large.
There is a definite elephants and mice phenomenon and it is recursive.
- There is definitely room for improvement of the balancing of traffic in the network, and given the stability of certain traffic aggregates,
it is possible to achieve this kind of improvement.
Relevant Publications
Supratik Bhattacharyya, Christophe Diot, Jorjeta Jetcheva, and Nina Taft.
Geographical and Temporal Characteristics of Inter-POP Flows: View from a Single POP.
European Transactions on Telecommunications (ETT), Vol. 13, No. 1, pp. 5-22, January/February 2002. Invited paper.
Ashwin Sridharan, Supratik Bhattacharyya, Christophe Diot, Roch Guerin, Jorjeta Jetcheva, and Nina Taft.
On the Impact of Aggregation on the Performance of Traffic-Aware Routing.
In Proceedings of the 17th International Teletraffic Congress (ITC 2001), Salvador da Bahia, Brazil, September 2001.
Nina Taft, Supratik Bhattacharyya, Christophe Diot, and Jorjeta Jetcheva.
Understanding Traffic Dynamics at a Backbone POP.
In Proceedings of SPIE ITCOM+OPTICOMM Workshop on Scalability and Traffic Control in IP Networks, Denver, CO, August 2001.
Supratik Bhattacharyya, Christophe Diot, Jorjeta Jetcheva, and Nina Taft.
POP-Level and Access-Link-Level Traffic Dynamics in a Tier-1 POP.
ACM SIGCOMM Internet Measurement Workshop (IMW), San Francisco, CA, November 2001.