Network can be classified based on their communication methods between nodes. Point-to-point communication allows one node to communicate with another directly connected node. Ethernet is a point-to-point network. In a multi-point network, all nodes share one line. Each node shares time on the line, so as the number of nodes grows, the probability of delay increases.
Networks can also be classified based on how messages are transmitted from node to node. Local Area Networks are networks that connect each node to a common transmission channel so a single message can reach all nodes. Wireless Local Area Networks are store-and-forward networks that receive a completed message into a buffer before transmitting it to its destination. The nodes in store-and-forward networks are connected by point-to-point transmission lines.
Networks must provide methods for switching data between links to provide a point-to-point path between nodes. There are two types of switching techniques used in today’s networks. Packet-switching networks divide the traffic into small segments called packets. Each packet carries identification information that is used by the network operating system to send the packets to their final destination. After the network hardware delivers the packets, the network software at the destination node reassembles the packet. Frame relay is a faster packet-switching method for efficiently handling Local Area
Networks and other applications that generate unpredictable chunks of network traffic. Frame relay allows organizations to use Asynchronous Transfer Mode gigabyte-range switching speeds. The message-switching routine writes messages to the switching node’s storage. Messages will be stored until the destination node wishes to receive the messages. This implementation is used in Electronic-mail applications.
A network’s topology is its structure of nodes and links. Links can be virtual or physical, such as phone lines, private lines and satellite channels. Virtual links allow the network to share physical lines between multiple network programs.
Star network: Nodes are connected to a single central switching node, for example, multiple terminals connected to a central computer. If the central switch fails, all communications stop.