Web Content Caching and Distribution
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Fred Douglis, Brian D. Davison
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Web Content Caching and Distribution
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Kluwer Academic Publishers
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9781402022586
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1
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CHF 91.40
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Sonstiges
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English
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363
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DRM
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PC/MAC/eReader/Tablet
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PDF
Web caching and content delivery technologies provide the infrastructure on which systems are built for the scalable distribution of information. This proceedings of the eighth annual workshop, captures a cross-section of the latest issues and techniques of interest to network architects and researchers in large-scale content delivery. Topics covered include the distribution of streaming multimedia, edge caching and computation, multicast, delivery of dynamic content, enterprise content delivery, streaming proxies and servers, content transcoding, replication and caching strategies, peer-to-peer content delivery, and Web prefetching.
Web Content Caching and Distribution encompasses all areas relating to the intersection of storage and networking for Internet content services. The book is divided into eight parts: mobility, applications, architectures, multimedia, customization, peer-to-peer, performance and measurement, and delta encoding.
SERVER-FRIENDLY DELTA COMPRESSION FOR EFFICIENT WEB ACCESS
(p. 303-304)
Anubhav Savant and Torsten Suel
CIS Department, Polytechnic University
Abstract
A number of researchers have studied delta compression techniques for improving the efficiency of web page accesses over slow communication links. Most of these schemes exploit the fact that updated web pages often change only very slightly, thus resulting in very small sizes for the transmitted deltas. However, these schemes are only applicable to a minority of page accesses, and require web or proxy servers to retain potentially many different outdated versions of pages for use as reference files in the encoding. Another approach, studied by Chan and Woo [4], encodes a page with respect to similar files located on the same web server that are already in the client’s browser cache. Based on the latter approach, we study different delta compression policies for web access. Our emphasis is on web and proxy server-friendly policies that do not require the maintenance of multiple older versions of a page, but only use reference files accessed by the client within the last few minutes. We compare several policies for identifying appropriate reference files and evaluate their performance on a set of traces. We show that there are very simple policies that achieve significant benefits over gzip compression on most web accesses, and that can be efficiently implemented at web or proxy servers. We also study the potential of file synchronization techniques such as rsync [28] for web access.
1. Introduction
Delta compression (delta encoding) is the process of encoding a target file with respect to one or several, usually similar, referenceles. This encoding, called a delta, describes the target file in terms of the reference files, and a recipient that receives the encoding and already knows the reference files can thus efficiently reconstruct the target. Delta compression has numerous applications in scenarios where there are several versions of a file or many similar files, such as software revision control systems, distribution of software updates, content distribution networks, or efficient storage of related files. Several tools for delta compression, such as bdiff, vcdiff [10, 13], Xdelta [14], and zdelta [25], are freely available. We refer to [23] for an overview of delta compression techniques and applications.
1.1 Delta compression for Web access
A number of authors have proposed the use of delta compression techniques to improve the ef.ciency of web access [1, 4, 7, 9, 16, 17, 21, 27, 29]. In particular, when web pages are updated, they typically do not change by much, and thus delta compression can be used to very succinctly encode the difference between a new version of a web page and an outdated version already in the client’s browser cache. Most proposals focus on encodings between different versions located at the same URL, which results in small sizes for the deltas but is restricted to pages that have been previously visited by the client. One exception is the work by Chan andWoo [4], which proposes to use as reference files other pages on the same site recently visited by the client, which tend to have a significant degree of similarity due to common layout features and HTML structure. In general, delta compression schemes for web access can be distinguished along the following axes.
Contents
6
A Message from the Workshop Chairs
10
Credits
12
Contributing Authors
14
Mobility-aware server selection for mobile streaming multimedia content distribution networks
18
1. Introduction and Overview
18
2. Mobility Based Server Selection
19
2.1 Layout of servers in content distribution network
20
2.2 Considerations in mobility based server selection
21
2.3 Measurement of mobility rate and server residence time estimation
21
2.4 Server load and QoS information collection
22
2.5 Server selection algorithm
23
3. Simulation Setup
25
3.1 Mobility simulation
26
3.2 CDN layout
27
3.3 Simulation scenarios
28
4. Results
30
5. Related Work
33
6. Conclusions
33
References
34
Performance of PEPs in cellular wireless networks
36
1. Introduction
36
2. RelatedWork
37
3. Overview of Cellular Networks
38
4. Wireless PEP
39
5. Latency Components
40
6. Transport/Session Optimizations
41
6.1 TCP Tuning
42
6.2 TCP Connection Sharing
45
6.3 Number of TCP connections
46
6.4 Temporal Block Flow Release
48
6.5 Session-level overheads: DNS
49
7. Application Level Optimizations
50
7.1 Compression Results
50
7.2 Acceleration Results
51
7.3 Impact of Pipelining
52
8. Comparison
53
9. Conclusions
54
References
55
Edge caching for directory based Web applications: Algorithms and performance
56
1. Introduction
56
2. Notations
58
3. LDAP Caching Framework
59
4. LDAP Query Containment
60
4.1 Query containment problem
60
4.2 General filter containment
60
4.3 Template based filter containment
61
4.4 Query containment algorithm
62
5. LDAP Caching Algorithms
63
6. Directory Server Extensions
65
7. Application Offload and Prefetching
66
7.1 Directory application modeling: Example
67
7.2 Prefetching
68
8. Performance of Caching Algorithms
68
9. Conclusions
71
References
72
Computing on the edge: A platform for replicating Internet applications
74
1. Introduction
74
2. Issues
75
3. Architecture Overview
76
4. Application Distribution Framework
77
4.1 The metafile
77
4.2 Replica creation
78
4.3 Replica deletion
79
4.4 Consistency maintenance
79
5. Algorithms
80
5.1 Content placement algorithm
81
5.2 Request distribution algorithm
83
6. Performance
85
6.1 Request distribution
85
6.2 Content placement
86
6.3 Redeployment threshold
89
7. RelatedWork
91
8. Conclusions
93
Acknowledgments
93
References
93
Scalable consistency maintenance for edge query caches: Exploiting templates in Web applications
96
1. Introduction
96
2. Semantic caching over theWeb
97
2.1 DBProxy overview
97
2.2 Common Local Store
98
3. Consistency Management
99
3.1 Update propagation approaches
100
4. Basic filtering
100
5. Template-based filtering
102
5.1 Template-based filtering: Single cache case
102
5.2 Template-based filtering: Multiple caches
105
6. Related work
106
7. Conclusions
106
References
107
Proxy+: Simple proxy augmentation for dynamic content processing
108
1. Introduction
108
2. Related Work
109
3. Summary of Previous Result
110
4. Proxy+ Architecture
111
4.1 ASP.NET output caching
112
4.2 Cache key generation
113
4.3 Tag generation and fragment caching
114
4.4 Cache keys notification and page composition
117
4.5 Summary of the protocol
119
5. Application Modifications
120
6. Experimental Results
122
7. Security aspect
124
8. Conclusions
124
References
125
Multicast cloud with integrated multicast and unicast content distribution routing
126
1. Introduction
126
3. Multicast Cloud
129
4. Integrated Channel Routing
130
5. Application-layer Traffic Control
132
6. Related Work
133
7. Conclusion
134
8. References
135
A large enterprise content distribution network: Design, implementation and operation
136
1. Introduction
136
2. Service Perspective and Network Infrastructure
137
3. CDN Architecture
138
3.1 Redirection System
140
