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VLAN technology

The development of local area network is the basis of VLAN, VLAN introduced before you know the local area knowledge.
local area network (LAN) is usually a single broadcast domain, includes Hub, network bridges or switches and other network devices in the same network segment formed of all the nodes. Between network nodes are in the same local area network can communicate directly, but in a different LAN segment of traffic must pass through the router to communicate between devices.
as the network continues to expand, access equipment gradually increased, networks are becoming increasingly complex, must use more of your router to different users can be divided into their respective broadcast domain, between the different LAN provides network interconnection.
there are two flaws:
first, increased as the number of routers on the network, network delay gradual lengthening, resulting in a drop in network data transmission speed. This is mainly because the data passed from one LAN to another LAN must be routed through the router operations: the router according to the corresponding information in the packet to determine the destination address of the packet, and then select the appropriate path forward.
Second, the users according to their physical connection is naturally divided into different user groups (broadcast domain). This kind of segmentation is not common to all users in your workgroup needs and bandwidth requirements. Therefore, despite the fact that working group or Department the bandwidth requirement is very different, but they are mechanically divided into competing for the same bandwidth in the same broadcast domain.
VLAN the definition and characteristics of
on the proposed LAN VLAN is a logical device and the user, machine, and the user is not limited by physical network segment, based on factors such as functions, departments and applications to organize them, communications between each other as if they were in the same segment, hence the name virtual local area network. VLAN is a relatively new technology, working in the 2nd and 3rd layer of the OSI reference model, a VLAN is a broadcast domain and VLAN communication is done by the 3rd floor of the router. Compared with the traditional LAN technologies, VLAN technology is more flexible, it has the following advantages:
1, network devices, move, add, and modify the administrative overhead reduction;
2, can control broadcasting activity;
3, improves network security. Classification of
1 ... VLAN
based on port port-based VLAN Division is the most simple and effective method for dividing the VLAN, which according to the LAN switch ports to define a VLAN member. VLAN port LAN switch logically separates, which terminal is divided into different sections, each part relatively independent in function simulates the traditional local area networks. Port based VLAN can be divided into single switch port and the switch port VLAN defined varieties:
(1) the definition VLAN
the switch single switch port 1, 2, 6, 7, 8 port composition VLAN1,3, 4, 5 port VLAN2. This VLAN can only support one switch.
(2) define VLAN
switch 1 switch port 1, 2, 3 port, and composed of 4, 5, 6 port switch 2 VLAN1, switch 1, 4, 5, 6, 7, 8 port switch 2 and 1, 2, 3, 7, 8 ports VLAN2.
port-based VLAN Division is simple and effective, but the downside is when users are moved from one port to another port, the network administrator must reconfigure the VLAN member.
based on the MAC address of the VLAN the VLAN is defined with the MAC address of the system. MAC address is the identifier of the card, each network adapter's MAC address is unique. This method allows a workstation to a network of other physical network segment, and automatically keep the VLAN membership. In the network size is smaller, the programme can be said to be a good method, but with the expansion of the network, network devices, the increase of users, is to a large extent increasing the difficulty of management.
route based on routing protocol in Layer 7 Protocol on the 3rd floor. Network layer routing protocols such as IP and IPX, such devices include routers and Routing switches. This allows a VLAN that spans multiple switches, or a port is located in more than one VLAN.