What is network topology? Network topology is a graphical description of the logical and physical configuration of the components of a network. Network topology describes the way in which the nodes and links of a network are physically arranged to correspond to each other. It is an important study in computer network technology.
Network topology refers to various types of physical topologies, which include logical arrangement. The logical arrangement describes how various nodes are connected to one another. In the logical arrangement, all the devices are connected to all the other devices and they form a hierarchy. A number of devices can be placed at different levels of the hierarchy. In most of the case, the network topology maps to logical locations.
One example of network topology is mesh topology. The mesh topology defines a virtual address space, which can be extended over a network of devices and is able to include several layers. Every device on the network has a specific virtual address, which is set by the device. If a device leaves the network, it will not have a virtual address, but it will still be able to connect to other devices that are within the network.
Another topology used is the ring topology
The ring topology defines a logical address space, where each device can have only one physical address and any two nodes will be unable to collide with each other. In ring topology, each device has a unique address and all the information concerning the device is stored in the same node. In addition, all the nodes can be connected to every other node in the same network. The logical addresses are managed by maintenance or administrator.
A few examples of ring topologies are the LSN or Link State Network, the NLA or NeuLIS Network Topology and the VPN or Virtual Private Network. In LSN, one network is made up of numerous local area networks or LANs while the other network consists of various nodes. It also has the ability to link up into a single logical network.
One other topology diagram is called the hybrid topology. Hybrid topologies are also known as WAN/ LAN. In hybrid topologies, WAN refers to internal or single network while LAN refers to public IP networks. A network of WANs connects to a group of LANs. On the other hand, a LAN network connects to various WANs and also includes some internal nodes.
Another interesting topology is the top-level domain, which is composed of a set of independent domains. The major benefit of having a top level domain is that it provides reliability in the data transfers. However, it creates a central problem, i.e. it creates performance problems on the client computers.
Two other types of topologies are the two-level domain and the three-level topologies. The two-level topologies has more numbers of layers while the three-level topology has only two layers. The most familiar two kinds are the top-down and the top-up designs. A few others topologies are the virtual private network topology and the mesh network topology.
There are many advantages of having a physical topology over a logical topology. For one, it helps in the allocation of resources between the machines. It also makes it easier for the administrator to troubleshoot problems on individual nodes. For instance, in physical networks, it is easy to identify whether a node is busy or slow. In logical networks, sometimes it is very difficult to determine the truth about the health of the machine.
One of the major disadvantages of using a bus topology is the fact that the administrator has to install wires on the network card and the router. However, this can be overcome by use of repeaters. On the other hand, some people believe that the major disadvantage of this topology is the fact that it lacks any effective scalability. Even though it may look like the network is loosed in terms of expansion, it actually depends on how good an administrator is at managing the routing table.
Network topologies are usually presented in the form of virtual Ethernet networks, routing tables, and physical topologies. Virtual Ethernet networks are nothing more than computer networks that use a single Ethernet block to define their logical addresses and port numbers. The beauty of using this topology is that it provides almost infinite scalability, which makes it practical for businesses that require large bandwidth and massive data transfers. Since all the traffic goes through one main router, it is easy for the administrator to determine where the packets need to go and at what speed. Although this form of topology has the highest overhead, it also offers the lowest bandwidth utilization.
On the other hand, the physical network topology consists of routers, switch and hub computers that each has its own local address and port number. Physical topology is often used for offices that are separated by large distances. Although the administrator can determine the locations of every computer node, he still needs to add a layer of indirection between the nodes and the rest of the network. Although the administrator can solve the problem of routing packets through hundreds of individual links, this approach has several disadvantages, one of them being that packets may leak from one node to another if they encounter a physical fault.