Overview VST

With the increasing requirement of the user for reducing the cost and improving the device reliability, Maipu puts forward one technology of combining multiple physical switches to form one virtual switch, that is Virtual Switching Technology, called VST.

Figure 1-1 VST physical network view

As shown in figure 1-1, two devices of the core layer are connected via the VSL interface, forming one VS Domain (virtual switching domain, also called stacking system). The aggregation layer device is uplinked to VS Domain via the link aggregation. The VS Domain of the core layer is one virtual device for the other network devices.

Compared with the traditional L2 spanning tree and L3 VRRP/VBRP technology, the VST had the following advantages:

• The bandwidth increases multiplicatively and is used effectively

Because the traditional technology runs STP/RSTP/MSTP, one of the previous two uplink links is in the forwarding state and the other is in the standby state. After using the VST, multiple devices become one logical device, so do not need to block some links. Two links form one aggregation group and both can be used to forward data, so as to make use of the bandwidth of the links efficiently, avoiding the waste of the bandwidth resources. Besides, the cross-device and cross-board aggregation link can provide the redundant links and also can realize the dynamic load balance, making use of all bandwidths efficiently.

• High reliability

The virtual switching system is formed by multiple member devices. The control device is responsible for the operation, management, and maintenance of the whole virtual switching system and the other member devices are in the standby sate. Once the control device fails and does not rely on the convergence of STP/RSTP/MSTP, VRRP/VBRP, the system elects one new control device from the standby member devices, ensuring that the services of the virtual switching system are not interrupted and improving the reliability when the member device fails.

• Simplify network topology

The virtual device formed by the VST is equivalent to one device in the network, connected with the around devices via the aggregation link. There is no L2 loop, so it is not necessary to configure the STP/RSTP/MSTP protocol. The control layer protocols run on one virtual device, reducing the exchanging of lots of protocol packets between devices and shortening the route convergence time.

• Unified management

After two or more devices form the stacking system, the control platform of the member devices in the virtual switching system are in the standby state, but the data platform is active. The user can log into the virtual switching system via the port of any member device and manages the whole virtual device in a unified manner, but does not need to connect to each member device for management.