IT Certification

VLAN-Virtual Local Area Network
With the growing network of people, some of the business-to-network needs a significant level of growth in the size of the enterprise network is growing. Followed by security, network performance issues are taken up by the network administrator headaches. VLAN technology to solve a series of problems.
Early, HUB let people use a lot of client networking, and the HUB to the client to provide the public a shared bus, with the increase in the number of users access to each users share the bandwidth on Proportionately reduced. For example: 10M Ethernet, HUB used to connect 10 users, each share of bandwidth for users 10M/10-1M. It is clear that, HUB way of sharing as early as the size of the network can no longer meet the surge in the demand. People started to replace the switch HUB, the switch can access each user to provide a dedicated data channel, and will no longer be similar to the HUB as a whole to share bandwidth. Although the solution to the problem of bandwidth allocation, but as more and more users access the network to exchange, it found a new problem, any network will be broadcasting all local users to receive, the larger the network, broadcasting The greater the scope of the entire radio network performance because customers have become unbearable. At this time, network administrators use a router (isolation broadcast domain) will come to the big bloated network is divided into a number of smaller networks, seems to have solved the problem, but because the router port number of scarce and prices Expensive, so this network of sub-mission of the high cost of the cost.
Switch interface number and speed of data transmitted, but can not stop the spread of radio traffic;
Routers can block the broadcasting domain, but few interface for large sub-networks, the cost is too high, because the processing speed but also brought about by the delay will be reduced to a certain extent, network performance.
If you have a kind of equipment or technology can solve the problem of this conflict so that we will be able to network performance greatly improved.

VLAN technology, allows administrators on the basis of actual demand for applications to the same physical local area network within the different users logically divided into different broadcast domains, each VLAN all have the same set of demand for computer workstations, and the physical form on the LAN Have the same attributes. Since it is logically divided, rather than physically divided, so the same VLAN with no restrictions at all workstations in the same range of physical, that they can work on different physical LAN segment. VLAN from the known characteristics of a VLAN within the broadcast and unicast traffic will not be transmitted to other VLAN, thus contributing to the traffic control and reduce equipment investment, simplifying network management, improve network security. In addition to the VLAN network can be divided into a number of broadcast domains, thus effectively control the broadcast of happened storm, as well as the network topology very flexible advantages, but also can be used to control networks of different departments, between different sites Visit each other.