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.
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.
|LIC topology: three ethernet switches|
- ces01 handles traffic for the biz01 network.
- ces02 handles traffic for the biz02 network.
- ces03 handles traffic for the adm01 network.
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.
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.