three ethernet switches

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In the centre of the three data networks are three ethernet switches. They are called ces01, ces02 and ces03.

An ethernet switch is a specialised computer used to form a network. Other computers are connected to it using network cables.

ces01 and ces02 handle business traffic. ces01 is connected to computers in the biz01 network and ces02 to the computers in the biz02 network. If ces01 breaks down, traffic can still flow through ces02.

ces03 only deals with administrative traffic. It is connected to the adm01 network. Unlike the business network, the administrative network has no backup.

what it is

An ethernet switch is a type of specialised computer used in all over the world. It is the universal tool used to form a star network. An ethernet switch provides lots of ethernet interfaces to plug computers into. Little switches with a few interfaces are found in homes. Big switches with dozens of interfaces are found in schools. Huge switches with hundreds of interfaces are found in offices.

When I built the LIC I needed lots of ethernet interfaces in my rack. I bought three ethernet switches.

I put these three ethernet switches into the data networks in the LIC and named them ces01, ces02 and ces03. Each one has a special role to play.

If this seems very similar to the way the three firewalls are laid out, it is. A firewall can do the work of an ethernet switch. There are differences.

  • Each ethernet switch is only part of one data network. Each business firewall (ifw01 and ifw02) is part of two networks, because it is connected to both switches.
  • A firewall has fewer interfaces than an ethernet switch. Adding many interfaces to a PC that is acting as a firewall is far more expensive than buying a bigger switch.
  • An ethernet switch comes with a special programming language that makes it easier to customise than making a PC do the same job. I made the VLANs using a special switch language.
  • An ethernet switch is more reliable than a PC.

what it isn't

A hub. A hub is a simple repeater. An ethernet switch is far more clever than a hub. For instance, a hub can't make VLANs.