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Unformatted text preview: Optimizing Cost and Performance in Online Service Provider Networks Zheng Zhang Ming Zhang Albert Greenberg Purdue University Microsoft Research Microsoft Research Y. Charlie Hu Ratul Mahajan Blaine Christian Purdue University Microsoft Research Microsoft Corporation Abstract– We present a method to jointly optimize the cost and the performance of delivering traffic from an online service provider (OSP) network to its users. Our method, called Entact, is based on two key tech- niques. First, it uses a novel route-injection mechanism to measure the performance of alternative paths that are not being currently used, without disturbing current traf- fic. Second, based on the cost, performance, traffic, and link capacity information, it computes the optimal cost vs. performance curve for the OSP. Each point on the curve represents a potential operating point for the OSP such that no other operating point offers a simultaneous improvement in cost and performance. The OSP can then pick the operating point that represents the desired trade-off (e.g., the “sweet spot”). We evaluate the benefit and overhead of Entact using trace-driven evaluation in a large OSP with 11 geographically distributed data cen- ters. We find that by using Entact this OSP can reduce its traffic cost by 40% without any increase in path latency and with acceptably low overheads. 1 Introduction Providers of online services such as search, maps, and instant messaging are experiencing an enormous growth in demand. Google attracts over 5 billion search queries per month , and Microsoft’s Live Messenger attracts over 330 million active users each month . To satisfy this global demand, online service providers (OSPs) op- erate a network of geographically dispersed data centers and connect with many Internet service providers (ISPs). Different users interact with different data centers, and ISPs help the OSPs carry traffic to and from the users. Two key considerations for OSPs are the cost and the performance of delivering traffic to its users. Large OSPs such as Google, Microsoft, and Yahoo! send and receive traffic that exceeds a petabyte per day. Accordingly, they bear huge costs to transport data. While cost is clearly of concern, performance of traf- fic is critical as well because revenue relies directly on it. Even small increments in user-experienced delay (e.g., page load time) can lead to significant loss in revenue through a reduction in purchases, search queries, or ad- vertisement click-through rates . Because applica- tion protocols involve multiple round trips, small incre- ments in path latency can lead to large increments in user-experienced delay. The richness of OSP networks makes it difficult to op- timize the cost and performance of traffic. There are nu- merous destination prefixes and numerous choices for mapping users to data centers and for selecting ISPs....
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- Spring '08
- IP address, alternative paths, OSPs, OSP networks, TE strategy