Techniques for Bandwidth optimization

Introduction

Optimization of the available bandwidth is recommendable in all situations, for rich countries and for poor ones, but for the latest it becomes a must. This is specially true in the academic and scientific environment, heavily dependent on a global information exchange...

While the techniques analyzed here can be effectively used in many campus networks (and other networks as well) in any country, we strongly believe that they are specially needed in such places where the financial resources are scarce and cannot be used to increase the available bandwidth and where the demand for bandwidth is growing every day.

Definition of "Low Bandwidth"

• How much is LOW ?
• Identifying inefficiencies: tools and techniques for traffic load monitoring, packet sniffing and protocol analysis

Let see what can be done at the different layers:

Host-to-Net layer (PHYS + DATALINK)

• Non-overlapping channels
• Antenna diversity
• Let use switches instead of hubs (MAC address filtering is also good for security!)
• Let keep the cables short and optimize your cabling scheme
• Forecasting of future needs may be useful

Internet and Transport layer

• Using VLAN
• IP subnetting
• Load balancing
• IP header compression (P-t-P links)
• IP queing optimization (asymmetric links)
• Firewalling rules and policies
• IP configuration of radio equipment (ACK time and CTS time)

Application layer

• Choice and configuration of dinamic routing protocol
• Traffic shaping
• Firewalling policies to filter unneeded traffic (mp3, viruses, DoS, etc...)
• Web cacheing (proxy configuration)
• Advanced proxy configuration
• DNS optimization
• SPAM filtering (possibly at the source, not locally)
• Policy on heavy attachments (zip them!)
• Moderation of mailing list
• Mirror heavy resources locally (newsgroups, FTP servers)
• FTP policy for big files (download during the night and make them available on local servers)
• Bittorrent for downloading
• Websites-mirroring-upon-request
• Local mirror for software updates (Win, Linux, applications)
• www4mail

Policy layer

• Provide REAL efficient and reliable local email facilities (POP, IMAP), do not force people to use external web mail providers

Useful links:

• Optimising Internet Bandwidth in Developing Country Higher Education: INASP Report
• Loband: http://www.loband.org/