Design And Implementation Of Forwarding System Based On Policy

After the gaining of high forwarding performance, the management and intelligence of networking device become more and more important. The networking user usually wants to determine the routing of data packet by his own policy. it doesn't only based on the destination ip address of datagram, but also the other features such as: source ip address, protocol, port number, even the payload of datagram. Lots of Service, such as Virtual Private Network, Quality of Service, Load balancing, they all need the support from policy forwarding.The traditional policy routing is based on routing protocols, but it is infexible and inconvenient. Chapter 2 designs a new policy routing architecture, which is based on packet filtering and high speed routing lookup. It use the rule and action we Pre-set to control the routing of packet.High performance Router is the most important device of mordern high speed networking. The routing lookup is a key process of forwarding, thus the speed of routing lookup deeply impact the capability of packet forwarding, it also became bottleneck of improving networking capability.Chapter 3 introduces routing lookup's basic concepts and the matching process. It reveiws current routing lookup scheme, and evaluate them from two aspects: access speed and average memory space the scheme takes. At last, the article prompts a new routing lookup scheme based on multi-level Hash tables.Load balancing is a new focus of networking technology. For high Reliability, most of edge networkings will use multiple redundent links, if we could use these redundent links in a reasonable way, the capability and throughput could improve significantly.Chapter 4 proposed a multiple token buckets algorithm, it can distribute load by theout interface's bandwidth of every link, and let the multiple links reach the load balance state.