Notes On Chapter Thirty-Two -- Trends in Networking Technologies and Uses

• 32.1 Introduction
  
  
  • Recent developments
  • Longer-term research
  
  
• 32.2 The Need for Scalable Internet Services
  
  
  • A centralized server can become a bottleneck.
  • This motivates much investigation and development.
  
  
• 32.3 Content Caching (Akamai)
  
  
  • Some companies offer a distributed caching service.
  • For example, Akamai has a set of servers all over the Internet.
  • An organization can pay Akamai for the privilege of pre-loading Akamai server caches with the organization's web pages.
  • Links on the organization's web site direct customer clicks to Akamai server content.
  • The organization is allowed to send updates of their 'content' to the Akamai caches.
  • The scheme reduces load on the servers of the organization.
  
  
• 32.4 Web Load Balancers
  
  
  • Refer to Figure 32.1 on page 549.
  • Web server optimization gets a lot of attention because businesses rely on the web to make sales.
  • A load balancer is a device that distributes incoming requests among multiple computers running identical web servers.
  • Typically the servers share the same customer database.
  • The load balancers have the ability to direct a series of requests from the same source to the same server.
  
  
• 32.5 Server Virtualization
  
  
  • Some systems support process migration - the capability of an executing program to move to another computer.
  • Given infrastructure for process migration, it is possible for a server on an overloaded machine to move to another machine where resources like CPU time are in more plentiful supply.
  
  
• 32.6 Peer-to-Peer Communication
  
  
  • P2P is a technology used to increase the speed of file downloads.
  • Clients fetch pieces of the file.
  • Various servers all over the Internet have various pieces of the file.
  • Clients try to fetch pieces from nearby servers.
  • Clients agree to be servers for the pieces of the file they have downloaded.
  • Well-known examples were created mainly for downloading music files: e.g. Napster & Kazaa
  
  
• 32.7 Distributed Data Centers and Replication
  
  
  • Google gets so much traffic that it has resorted to another approach.
  • When a browser connects with DNS to resolve the name www.google.com, different IP numbers are 'suggested' at different times.
  • This has the effect of balancing the load over multiple Google data centers distributed in various geographic locations.
  
  
• 32.8 Universal Representation (XML)
  
  
  • XML allows programmers to choose arbitrary tags so the documents can be understood by multiple applications.
  • Documents can include a style sheet that specifies legitimate document structure.
  • Uses:
    • on interface between web server and database
    • load balancers parsing XML
    • XML controlling downloads in mobile devices
    • XML representing specifications used by network management systems
  
  
• 32.9 Social Networking
  
  
  • Starting in the early 2000's there has been a significant increase in the production of content by individual users - for example blogs, chats, Facebook, MySpace and YouTube.
  • One implication is that the typical user is uploading data more than previously.
  
  
• 32.10 Mobility and Wireless Networking
  
  
  • Users now expect to be connected continuously to the Internet.
  • Wireless technologies receive a lot of attention and are targeted for rapid development.
  • Mobile phone networks are converging with the Internet.
  • Mobile computer users rely on WiFi and Virtual Private Networks (VPN)
  
  
• 32.11 Digital Video
  
  
  • Cable companies are replacing analog service with digital.
  • Digital TV content is provided over packet networks.
  • There is increasing use of IPTV.
  • The Internet could converge with the television and radio networks.
  • There would be little difference between computers and television sets.
  • On demand video is easier to deploy this way.
  • Pause, rewind and live-capture are easier to control.
  
  
• 32.12 Multicast Delivery
  
  
  • Interest in IP multicast increases along with in IPTV.
  • Multicast has the potential to help conserve bandwidth and allow people to get more of the type of services they want.
  
  
• 32.13 Higher-Speed Access and Switching
  
  
  • Access technologies appear to be converging on speeds of up to 40 Gps.
  • It's not far-fetched to predict such rates will be provided to homes and small businesses in the not-to-distant future.
  • That is enough bandwidth for high-definition video.
  
  
• 32.14 Optical Switching
  
  
  • Emerging optical technologies promise to reduce the time it takes to set up a 10 Gps light path from multiple seconds to thousandths of a second.
  • In the future, will every TCP connection use a light path?
  
  
• 32.15 Use of Networking in Business
  
  
  • RFID technology is changing production, shipping and inventory.
  • High speed networking is making high-quality video conferencing an alternative to business travel.
  • Collaborative decision-making is gaining in acceptance, and along with that, tools and infrastructure that support collaboration.
  
  
• 32.16 Sensors at Large and in the Home
  
  
  • It is possible to create large sensor networks and connect them to the Internet.
  • Applications include air and water quality monitoring, weather information gathering, tracking movements of wild animals, monitoring crops, monitoring people in buildings, and monitoring automobile traffic.
  • People can place large numbers of sensors in their homes and monitor them remotely over the Internet.
  
  
• 32.17 Ad Hoc Networks
  
  
  • In an ad hoc network, a set of wireless stations find neighbors, choose a topology and establish routing that allows any station to reach any other.
  • The US military has done a lot of research on ad hoc networks.
  • It is a technology that could be used to allow soldiers in the field to automatically establish a complete communication system.
  • It also has potential as a way to allow people in remote areas to get inexpensive Internet connectivity.
  
  
• 32.18 Multi-Core CPUs and Network Processors
  
  
  • Instead of expensive Application Specific Integrated Circuits (ASICs) that take a long time to design and build. Manufacturers are using more "off the shelf" kinds of processors now.
  • For example, if a router has a large number of CPUs, then the incoming packets can be multiplexed across an array of CPUs. When CPUs have more time to process a packet, they don't have to be as fast or sophisticated.
  • Chip vendors are putting more operations in the instruction sets of CPUs that efficiently perform tasks required in packet processing.
  • These trends are making networking hardware like high-end routers more affordable, which should speed development of Internet infrastructure.
  
  
• 32.19 IPv6
  
  
  • IPv4 has adapted much better than many people expected.
  • We are somehow doing without much penetration of IPv6.
  • We could remove NAT from the Internet and have end-to-end addressing everywhere but it would require replacing a huge amount of networking equipment and software.
  • The rollout of IPv6 has stalled and there's no telling now how long it may take for a replacement for IPv4 to take hold.