[talks] Y Zhu preFPO

Melissa Lawson mml at CS.Princeton.EDU
Wed Feb 23 11:02:23 EST 2011

Yaping Zhu will present her preFPO on Tuesday March 1 at 10:30AM in Room 402.
The members of her committee are:  Jen Rexford, advisor; Vivek Pai and Aman Shaikh (AT&T
Labs Research), readers; Mike Freedman and Andrea LaPaugh, nonreaders.  Everyone is 
invited to attend her talk.  Her abstract follows below.

Minimizing Wide-area Performance Disruptions in Inter-domain Routing

The Internet is the platform for most of our communications needs  
today. However, network changes like routing changes or congestion  
lead to performance disruptions, which would affect the user  
experience. Therefore, minimizing performance disruptions is crucial,  
and network operators have to react and fix the problems. Diagnosing  
wide-area performance disruptions is challenging: first, each network  
has limited visibility into the root cause of performance disruptions,  
requiring network operators to collect and analyze measurements of  
routing and traffic data; second, there are so many potential factors  
which might lead to performance disruptions, and these factors are  
usually interdependent with each other. Thus, the network diagnosis is  
usually done in an ad-hoc manner, and there are no formalized ways to  
define metrics and classify the performance disruption according to  
the causes.

The thesis conducts two case studies to diagnose wide-area performance  
disruptions from the perspectives of a large tier-1 ISP and a large CDN:
i) From the ISP's perspective, we designed and implemented a system  
that tracks inter-domain route changes at scale and in real time. Our  
system could be used as the building block for many diagnosis  
scenarios for the ISPs.
ii) From the CDN's perspective, we focus on diagnosing wide-area  
network changes which caused latency increases to access the services  
in the CDN. We proposed a method for automatically classifying large  
increases of latency, and evaluated our techniques on one month of  
measurement data to identify major sources of high latency for a large  

Stepping back from the protocol designer's perspective, we refactor  
the inter-domain routing protocol BGP (Border Gateway Protocol), based  
on the lessons learned from the case studies: first, since each  
network only has limited visibility and control within its own network  
and the neighbors, we propose to select a route only based on the next- 
hop AS. second, the BGP protocol is not designed with operational  
challenges of performance and security in mind. Thus, there are many  
proposals to add additional BGP attributes and satisfy the operational  
needs. These proposals make the protocol and configuration complicated  
and error-prone, and make it difficult for network operators to  
diagnose problems. Instead, we argue to separate the performance and  
security requirements out of the protocol. Our proposal of next-hop  
BGP simplifies the protocol, and has the benefits of fast convergence,  
incentive compatibility, and easier support for multi-path routing.

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