In Internetworking Part 1 we spoke about the individual units (hubs, repeaters, switches, routers) and some definitions. When dealing with a hub, or switch, the star topology seems to be what sticks out and says, HELLO! Consider your home network… you have your input from your router to your switch or hub. The switch, or hub, on its own will branch out to your computers, printers, scanners, or network storage. Your biggest difference between the switches and hub right now is that switches learn the MAC addresses of input and output ports, this way when data comes in to the switch it will sent it out only the port listed in the table. If the MAC address is not in the table then it will send the data out all ports except the port it received the data from. Hubs on the other hand will send out the data on all ports, because it does not learn and can therefore cause you some problems.
Another topology that has been used in the networking field is the Ring topology. The data travels around a ring of coax and is addressed to go to a particular destination, but with this topology it runs similar to that of a hub, in-that, all of the hardware connected to the ring will hear all of the traffic. This can create some big collision problems. But it is a very good and reliable method of data transfer and there are times when you may wish to use this.
The Bus topology is pretty much the same as the data is sent via a cable and is picked off of the bus line by the destination .
A great many other topologies are seen these days, such as the Extended Star, Hierarchical. Mesh, and Partial Mesh. Each has its function and need in the Informational System Highway, so-to-say. Each has a purpose an use.
Everything with respect to the “Cloud” and the internet is interconnected. In this fashion, if a connection server should fail, there is always another way of routing your transmitted data, or request, to its destination target. You could probably say that the “Cloud” or internet uses a full mesh networking connectivity.
The Mesh topology has a connection line from each node to the other nodes in the network. Full Mesh has a connection from each node to all other nodes; on the other hand, the Partial Mesh topology only connects each node to the most important – or critical – nodes in the network.
This may be a little more understandable of the topologies available. Much of this information is available on the internet at various sites. Articles, blogs, etc with explanations in far more detail that mine. However, these are just some of the basics, but are very necessary for your CCENT/CCNA testing and understanding of networks in general.
In the next part we will discuss the interconnectivity between the switches, hosts, hubs, and routers; which is a little more in depth than this, the topology of the network.