Differences between stacking and cascade in Ethernet Switches

Cascade is connected to other hubs through a port of the hub. For example, a UPLINK port of the hub is used to connect to another normal port, and a stack is connected through the backplane of the hub, it is a chip-level connection. For example, the stacking of two 24-port switches is like a 48-port switch. The advantage is that there is no bottleneck.

Stack and Uplink are two ways to connect multiple switches or hubs. Their main purpose is to increase the port density. However, their implementation methods are different. In short, cascade can be completed between switches, between hubs, or between switches and hubs of any network equipment manufacturer through a twisted pair. Stack is only available between devices of your own manufacturer, and the device must have a stack function. Cascade a single twisted pair (or other media) requires a dedicated Stacking Module and cable, and these devices may need to be purchased separately. In theory, there is no limit on the number of cascade switches (Note: The number of cascade switches is limited, and the requirements for 10 M and M are different ), the devices of each stack manufacturer indicate the maximum number of stacks.

It can be seen from the above that the cascade is easy, but the technology of stacking has the advantages that cascade cannot achieve. First, multiple switches are stacked together. Logically, they belong to the same device. In this way, if you want to set these switches, you only need to connect to any device and you can see other switches in the stack. Cascade devices are logically independent. If you want to manage these devices, you must connect them to each device in sequence.

Second, multiple device-level associations cause cascade bottlenecks. For example, if two 10-Gigabit switches are connected through a twisted pair, their cascade bandwidth is Mbps. In this way, computers of different vswitches can only communicate with each other through the mbps bandwidth. The two switches are connected together through stacks, And the stacked cables can provide a bandwidth higher than 1g, greatly reducing the bottleneck. Now there is a new technology for vswitches-Port Trunking. With this technology, you can use multiple twisted pair wires to cascade two vswitches to increase the cascade bandwidth.

Cascading also fails to reach a stack to increase the connection distance. For example, if a computer is far away from a vswitch and exceeds the maximum distance of 100 meters from a single twisted pair wire, a switch can be placed in the middle to connect the computer to the vswitch. The stacking cable is only a few meters at most, so you should consider it during stacking.

Stack and cascade have their own advantages. They are often used in actual solution design and can be applied flexibly.

Cascade is connected to other hubs through a port of the hub, and stacks are connected through the hub backplane. Although cascade and stack can expand the number of ports, each hub or switch after cascade is logically multiple network-managed devices, the stacked hubs or switches are logically a network-managed device.

1. Network Expansion: Switch stack and cascade (1)
2. Switch cascade, stack, and cluster technology (2)