Cisco virtual LAN VLAN routing----to be replenished

One, virtual local area network (VLAN)

At present, the backbone network technology used in constructing enterprise network is based on Exchange and virtual network. Switching technology changes the shared media to exclusive media, greatly increasing the network speed. Virtual network technology to break the constraints of the geographical environment, without altering the physical connection of the network can arbitrarily move the workstation between the workgroup or subnet, workstations composed of logical working groups or virtual subnets, improve the operational performance of information systems, equalization of network data flow, reasonable use of hardware and information resources. At the same time, the use of virtual network technology, greatly reduce the network management and maintenance work burden, reduce network maintenance costs. With the application of virtual network technology, the problem of how to communicate between virtual networks inevitably arises.

Second, inter-switch link (ISL) protocol

The ISL (Interior switching Link) protocol is used to implement VLAN trunking between switches. It is a packet-tagging protocol that is composed of a standard Ethernet frame and associated VLAN information for frames sent on an ISL-capable interface. As shown in the following figure, data from different VLANs can be transferred on an ISL-capable interface.

Cisco virtual LAN VLAN routing----to be replenished