This paper firstly introduces the historical background, solutions and implement ation policies of producing layer 3 switching technique, and then elaborates lay er 3 switching technique of several typical products in local and wide area netw ork,including FastIP of 3Com,NetFlow switching of CISCO,and IP Routing Switch with new structure and high performance of Bay.

It introduces the upgrading design and implementation of the campus network of GDRTVU, which applied Gigabit Ethernet and layer 3 switch in the backbone, Alcatel products, and the network management policies based on Vlan and ip packet filter to the campus network.

It is possible to construct high speed, high performance and large scale LAN with layer 3 switch network devices.

Study on Packet by Packet Layer 3 Switching Technology;

According to the design and management of our campus network for reconstruct engineering, the project of layer 3 switching, the design and implementation of Virtual LAN, security strategy of campus network are discussed.

Aimed at the bottleneck problem that current campus network exists, we discuss the campus backbone topology based on layer3 switching in detail and bring forward the upgrade project.

VLAN division based on the third exchange makes the net exchanging by the line speed in the sub-net and achieving the line speed communication by the line speed route between the sub-nets.

With the fast development of enterprise network,campus network and broadband network,the third exchanger has become a new increment point of market,and the application has infiltrated from the first backbone layer and mixed layer in the network center to the insertion layer of the network edge.

In order to improve the efficiency of computer network, this paper introduces the theory of the third layer switch, and the method of how to build the third layer switch network,and the relation between IPV6 and the third layer switch,the relation between the third layer switch and VLAN.

This paper introduces the technique of third layer switch and the technique of VLAN, taking into consideration the present situations of campus network, and discusses Layer 3 Services Module of cisco4003 and the application in the campus network.

Then, the third layer switch technology is studied in detail which is included with its basic principles and the structures.

This paper analyses the basic character of layer 3 switching technologies and parses the sort, the theory of working and the way of configuring VLAN with it.