Four network structures of switches: cascading, port aggregation, stacking, and layering

With the arrival of 5G and the new Internet of Things, higher requirements will be placed on switches, and the demand will increase.

The Internet of Everything is inseparable from network infrastructure equipment - switches. Switches play a vital role in networking in the Internet of Things.

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Four network structures of switches:

1. Cascade mode

This is the most commonly used networking method, which is connected through the cascade port (UpLink) on the switch. Cascading can be defined as two or more switches connected to each other in a certain way. Multiple switches can be cascaded in a variety of ways according to needs.

In a larger local area network such as a campus network, multiple switches generally form a bus, tree or star cascade structure according to performance and purpose.

It should be noted that switches cannot be cascaded without limit. If more than a certain number of switches are cascaded, it will eventually cause a broadcast storm, resulting in a serious degradation of network performance.

Structure diagram:

2. Port aggregation mode

Port aggregation bundles multiple physical links between two devices into one logical link, thereby doubling the bandwidth (the bandwidth of this logical link is equivalent to the sum of the bandwidths of the physical links).

In addition to increasing bandwidth, port aggregation can also evenly distribute traffic on multiple links, playing a role in load sharing; when one or more links fail, as long as there are links that are normal, the traffic will be transferred to other links. The entire process is completed within a few milliseconds, thus playing a redundancy role and enhancing the stability and security of the network.

Structure diagram:

3. Stacking method

Stacking refers to combining more than one switch to work together to provide as many ports as possible within a limited space.

Multiple switches are stacked to form a stack unit. The performance index of stackable switches includes a parameter called "maximum stackable number", which refers to the maximum number of switches that can be stacked in a stack unit and represents the maximum port density that can be provided in a stack unit.

Generally speaking, switches from different manufacturers and models can be cascaded with each other, but stacking is different. It must be performed between stackable switches of the same type (at least switches from the same manufacturer). Cascading is just a simple connection between switches, while stacking uses the entire stacking unit as a switch, which not only means an increase in port density, but also an increase in system bandwidth.

Stacking can greatly improve the port density and performance of switches. Stacking units have port density and performance comparable to large rack-mounted switches, but the investment is much cheaper than rack-mounted switches and the implementation is much more flexible. This is the advantage of stacking.

Rack-mounted switches can be said to be the product of stacking development to a higher stage. Rack-mounted switches are generally switches above the department level. They have multiple slots, high port density, support for multiple network types, good scalability, and strong processing capabilities, but they are expensive.

Structure diagram:

4. Layering

This method is generally used in more complex switch structures, which can be divided into access layer, aggregation layer and core layer according to their functions.

This three-layer network architecture adopts a hierarchical model design, dividing the complex network design into several levels, with each level focusing on certain specific functions, so that a complex big problem can be turned into many simple small problems.

Structure diagram:

With the development of local area networks and metropolitan area networks, the above four methods will be more and more widely used. Today's sharing ends here. Do you understand?