Infrastructure for Better Quality Internet Access & Web Publishing without Increasing Bandwidth Prof. Chi Chi Hung School of Computing, National University of Singapore Lower Kent Ridge Road, Singapore David Goss Microbits

QoS Content Delivery Services & its Challenges

Internet hi hola Client: Last Mile Access Centralized Content Servers Content 1-to-Many (Dynamic) Internet Content Delivery Today

Basic Content Delivery Problems THREE BIG PROBLEMS: Long latency for the ever increasing bandwidth. Increasing bandwidth cannot catch up with increasing network demand. High client expectation with commercial and real-life applications. Fast network is never fast enough with ever increasing user’s real- time expectation. Content creation and delivery heading in opposite directions. Easy handling of sophisticated multimedia data usually means longer delay time for web surfing.

Content Delivery Challenges THREE GOALS: Fast Content Delivery for the given bandwidth. Quality Content Presentation under wide variations of clients/devices/networks. Efficient Content Management & Monitoring for one single source of content and network resource.

Content Delivery Approaches… Four APPROACHES: Client Plug-ins: “Fat clients doing work in the last stage of delivery?” Server: “Network is computing, is computing outside network?” Proxy Gateway: “Network is computing, is selective computing inside the network?” Data Replication “Web data is replicated in servers at the client edge of Internet, how big is the client population for cost effective solution?” Considerations: Cost Effectiveness Server Collaboration Client Constraints Action Point of Tasks

Recommended Direction “Network is computing and business; selected computing, services and policy management is in the network.” “1-to-many ACTIVE PROXY CACHE solution as compared to individual server or client approach.”

Fast Content Delivery

Content Delivery Mechanism ISP Internet (Large Backbone ISP) Content Web Page Retrieval (against time): Basic Frame Object Embedded Obj.

Four Delivery Techniques INCREASING DELIVERY SPEED FOR A GIVEN BANDWIDTH: Caching for data reuse Compression for reducing bandwidth consumption for a given amount of information. Acceleration for improving latency time of 1 st time access. Priority for important web access.

Fast Delivery Techniques (I): Caching Client Remote Server HTTP/ document follows GET full-URL HTTP/1.1 Web Cache Request Response Disk www_proxy.my.domain Any supported protocol some host How Cache Works?

Fast Delivery Techniques (I): Caching How Cache Works? Client Remote Server HTTP/ document follows GET full-URL HTTP/1.1 Web Cache HTTP Disk www_proxy.my.domain some host

Fast Delivery Techniques (I): Caching ISP Internet (Large Backbone ISP) Content Proxy Cache Reverse Proxy Cache Content Forward Proxy for Clients: Save international bandwidth Reduce server workload Reduce access latency through local access Reverse Proxy for Servers: Cost-effective sol’n than server through specialized hardware Reduce server workload Memory access instead of disk operation

Fast Delivery Techniques (I): Caching Necessary but Not Sufficient … 1 st Web Object Retrieval over 70% web objects without reuse SMEs low volume network traffic implies less caching effect; slower links also shift bottleneck from startup time to network delay. Non-Cachable Decision for dynamic data content. Over-Demand for Network Bandwidth for a fixed amount of data information.

ISP Internet (Large Backbone ISP) Content Compression Proxy Cache Compression Reverse Proxy Content Fast Delivery Techniques (II): Compression Basic Frame Object Embedded Obj. Compression Proxy: Reducing BW consumption through lossless & lossy compression Improve response time of surfing (in particular, modem & reverse proxy) Browser support through HTTP Web Page Retrieval:

Fast Delivery Techniques (II): Compression File Size: 29,467 bytes Savings: 83.3 % Original File File Size: 176,726 bytes

Basic Frame Object Embedded Obj. Web Page Retrieval: Fast Delivery Techniques (III): Acceleration Acceleration Proxy: Acceleration through parallel fetch of objects in proxy Re-scheduling for early object fetching No increase in bandwidth demand. ISP Internet (Large Backbone ISP) Content Active Proxy Cache Active Reverse Proxy Cache Content

Fast Delivery Techniques (IV): Priority Priority Proxy: Different user groups assigned with different priority level to use network. Better load balancing network usage. Important to situations with VIP or super users. ISP Internet (Large Backbone ISP) Active Proxy Cache Active Reverse Proxy Cache Priority Based on: User ID and IP addresses. Object sizes and types. Time of access. Destination.

Fast Delivery Solutions (I) Opportunity 1: Active Proxy Cache Caching to shortcut data retrieval path to local machine and to reduce international bandwidth consumption. Acceleration to speedup necessary accesses of web data retrievals through parallelism and re-scheduling of object retrieval. Compression and Transcoding to reduce bandwidth consumption for the same amount of content (important for wireless and low-speed modem accesses). Priority Access to allocate more bandwidth to more urgent/important requests.

Fast Delivery Solutions (II) Opportunity 2: Active Reverse Proxy Cache Caching to reduce delay due to server I/O and disk operations. Compression and Transcoding to reduce bandwidth consumption for the same amount of content.

Infrastructure for Better Web Content Delivery

Active CDN Framework (I) Efficient Active Proxy Framework API Interface To Applications SW Application “Chips” SecurityAnti-VirusWirelessFilteringPriority AccessAd-InsertAccelerationCompression

ISP Internet (Large Backbone ISP) Active Proxy Cache Active Reverse Proxy Cache Proxy Cache Transformer Active CDN Framework (II)

Sample Case Study

Typical Education Environment & Needs Limited Number of Students Caching is important, but its effect is limited (e.g. hit ratio less than 30%). Accelerating 1 st time access is very important. Typical acceleration gain is about 20% to 40%. Teaching Staff and Students Larger number of students over staff implies the importance of higher priorities for web requests related to teaching and staff administration. Content Management Centralized content management in the institution gateway is critical.

Q & A