This paper has benefited from the detailed and perceptive comments of our reviewers, especially our shepherd Hank Levy. We thank Randy Katz and Eric Anderson for their detailed readings of early drafts of this paper, and David Culler for his ideas on TACC's potential as a model for cluster programming. Ken Lutz and Eric Fraser configured and administered the test network on which the TranSend scaling experiments were performed. Cliff Frost of the UC Berkeley Data Communications and Networks Services group allowed us to collect traces on the Berkeley dialup IP network and has worked with us to deploy and promote TranSend within Berkeley. Undergraduate researchers Anthony Polito, Benjamin Ling, and Andrew Huang implemented various parts of TranSend's user profile database and user interface. Ian Goldberg and David Wagner helped us debug TranSend, especially through their implementation of the rewebber

Abstract not found

We consider two schemes for the distribution of Web documents. In the first scheme the sender repeatedly transmits the Web document into a multicast address, and receivers asynchronously join the corresponding multicast tree to receive a copy. In the second scheme, the document is distributed to the receivers through a hierarchy of Web caches. We develop analytical models for both schemes, and use the models to compare the two schemes in terms of latency and bandwidth usage. We find that except for documents that change very frequently, hierarchical caching gives lower latency and uses less bandwidth than multicast. For rapidly changing documents, multicast distribution reduces latency, saves network bandwidth, and reduces the load on the origin server. Furthermore, if a document is updated randomly rather than periodically, the relative performance of CMP improves. Therefore, the best overall performance is achieved when the Internet implements both solutions, hierarchical caching and multicast.

The success of the World Wide Web has led to a steep increase in the user population and the amount of traffic on the Internet. Popular Web pages create “hot spots ” of network load due to their great demand for bandwidth and increase the response time because of the overload on the Web servers. We propose the distribution of very popular and frequently changing Web documents using continuous multicast push (CMP). The benefits of CMP in the case of such documents are a very efficient use of network resources, a reduction of the load on the server, lower response times, and scalability for an increasing number of receivers. We present a quantitative evaluation of the continuous multicast push for a wide range of parameters. 1

To meet the service demands created by the Internet's exponential growth, operators are scrambling to deploy application-level services, including Web caches, commerce servers, and intelligent transformation proxies for mobile "thin clients." On the one hand, the Internet's growth rate places unprecedented scalability and robustness demands on these services; on the other hand, that same growth rate demands that new services be developed, deployed, and evolved at a pace that is precipitous even by the standards of today's desktop software development cycles. We demonstrate that for a certain class of applications, these apparently conflicting goals can be reconciled by completely separating the application logic from the runtime support for scalability and high ...

We consider two schemes for the distribution of Web documents. In the first scheme the sender repeatedly transmits the Web document into a multicast address, and receivers asynchronously join the corresponding multicast tree to receive a copy. In the second scheme, the document is distributed to the receivers through a hierarchy of Web caches. We develop analytical models for both schemes, and use the models to compare the two schemes in terms of latency and bandwidth usage. We find that except for documents that change very frequently, hierarchical caching gives lower latency and uses less bandwidth than multicast. For rapidly changing documents, multicast distribution reduces latency, saves network bandwidth, and reduces the load on the origin server. Furthermore, if a document is updated randomly rather than periodically, the relative performance of CMP improves. Therefore, the best overall performance is achieved when the Internet implements both solutions, hierarchical caching and...

Designing a distributed cache infrastructure to improve the Web performance for the users of a large-scale organization is a difficult task. To guide the decisions of system administrators, we propose Saperlipopette!, a tool that can be used to evaluate, a-priori, the quality of the service offered by each potential configuration of the distributed cache infrastructure. Saperlipopette! is based on trace-driven simulations. Our methodology is two-fold. First, we monitor the targeted organizations' Web related activity. Second, we replay the organization's access pattern while simulating the distributed Web support infrastructure. This paper presents the information gathering as well as the design of the tool. We show that beyond a certain cache's size, the performance stays constant whereas the consistency continues to decrease. We also evaluated a number of distributed configurations, among which peer-to-peer Relais cooperation proved to be the best one. Keywords Web caches, configur...

Web caching has been considered as a powerful solution to deal with the growth of web traffic. Several studies have shown that caching documents throughout the Internet can save network bandwidth and reduce document access latency [9, 8, 10]. However, this technique has introduced new problems such as maintaining the document coherency and selecting the next document to be removed. With the continuous increase in demand for documents, the web cache servers are becoming the new bottleneck. A need for better resource management is becoming urgent in order to reduce the overhead sustained by web cache servers. In this paper, a number of web replacement policies are discussed and compared on the basis of trace-driven simulations. The impact of the web cache server configuration is pointed out through a set of experiments that use the cache size as a tuning parameter.

This thesis proposes a RepliCache that scaled well to a large size of objects. Combining caching and replication, RepliCache can amplifies advantages of both approaches. Web caching system avoids sending same documents repeatedly over Wide Area Network (WAN) by copying them at a closer location to users. Replication is a popular method for distributing server and network load in the Internet. An analysis of Web workload reveals that increasing fraction of the traffic volumes is associated with requests for large files. Large files such as audio and video data cause heavy traffic both in network bandwidth and data storage due to their large size. The existing Web caching servers, however generally store files no larger than tens of Mbytes to keep small and popular objects. Thus useful network bandwidth is mostly consumed by their unnecessary retransmission and their access latency is large. By storing large objects in a dedicated server and relaying through proxy cache, large objects c...

Nowadays cooperative web caching has shown to improve the performance in Web document access. That is why the interest in works related to web caching architectures designs has been increasing. This paper discusses and compares performances of some cooperative web caching designs (hierarchy, mesh, hybrid) using different document validation/replication methods (TTL, invalidation, pushing, etc). It is shown how the performance in a cooperative web proxy caching architecture is affected by the document validation method that is implemented. Comparing typical caching scenarios we found that speedups for some combinations of distributed caching with validation methods can be between 1.3 and 2.5. If the only criteria of decision to construct a cooperative caching system is response time then it is easily to decide that the combination with a speedup of 2.5 is the best one. However, we found that the bandwidth consumption and the number of stale documents in that combination could be prohibitive. That is why we cannot decide to construct a specific cooperative caching system based on a limited number of decision criterions. This paper shows some trade-off and possible alternatives for constructing a cooperative caching system using different combinations of document validation methods with distributed caching architectures.