| Along with exaltation of the enterprise informatization level, the enterprise information system network scale is extend continuously, and brought with network safety, network traffic, communication speed, amount of network maintenance have markedly increased. The reasons are as follows: two layers to exchange technology is used in enterprise information network widely, two layers exchange technology network 's chief weaknesses is that they cannot divide VLAN within the network, The network physics link exists security breach, The work station in the same of net segment excessive will cause the broadcast storm, even causing network paralyze, can't resolve various network connect with each other availably, the safety controls etc. The advent of the tri-layer exchange technology primarily for Make up the questions broadcast questions of large-scale network. Divide bigger network to the smaller broadcast area through a VLAN ,every VLAN adopts tri-layer exchange technology communications each other . The enterprise information network adopts tri-layer exchange technology can insure the network more reasonable, safety, valid.For enterprise network safe, we have mainly adopt the network physics link safety and access control two safe strategies to carry out the enterprise network safety, And adopt tri-layer exchange technology network structure, to a great extent avoided two layers exchange technical blemish,, can carry out this kind of safe strategy target goodly. Along with the upgrade of the network scale, traffic increases, manage personnel become complicate increasingly,it brings new hidden danger of network's safe, reliable and efficient operation of the system. How clear up this hidden danger ? Adopt the access control strategy between the VLAN, can strengthen whole safety of the network. It realize access control between vlan by buile access control list of core layer and access layer interface , decided which user data can exchange between VLAN,and reach core layer at last.Degree paper briefly introduce VLAN technology application state of enterprise, necessity of VLAN implementation and existing problems, according to EEE802.1Q criterion and VLAN Protocol of Cisco company, expounded work mechanism of VLAN. This thesis discusses tow communication mode of VLAN (1) Realizing communication between VLAN by router;(2) Realizing communication between VLAN by tri-layer Switches.Degree paper analyse network security of petro-chemical Company , directed at enterprise network condition, find the solution for the problem by based on VLAN and Tri-layer exchange ,and carry them out in safety project of enterprise network, it resolve main problem of enterprise network security, realize the project expectation aim. |
