Switching - Dan M

What is it?
Switching is in reference to the methods of transferring data through a series of nodes to the receiving host. Data can be sent in one whole package or in little separated packets which are put back together to form the whole entity at the end of the transfer.

Circuit Switching
In Circuit Switching a particular path through nodes is established by the host sending the data to the host receiving the data and this path is held solely by the hosts using it at the time and cannot be used by another connection whilst in use. Data is sent in one large whole volume over the designated path and this allows full bandwidth and ensures that the connection cannot be interrupted by another host. This can be inefficient though as a node can be reserved and sometimes not used at all, preventing it from being used by someone who would actually use it.

Packet Switching
Packet Switching is when the data that is going to be sent to the receiving host is separated into smaller packets and sent in no particular order, but it can be re-ordered by the receiving host. These packets have two parts to it; the "header", which contains the address of where the packet is being sent, and the data that is being sent. In Packet Switching data is constantly re-routed to find the most efficient pathing and to prevent any congestion it may come across along the way. Using Packet Switching also allows other connections to use nodes simultaneously as it does not reserve it for that one sole connection. Packet priority also exists meaning that the more important packets are sent at higher speeds than less important ones. A disadvantage of this is that Packet Switching is not as reliable as Circuit Switching since a particular path is not established before sending the data which means that a connection is not guaranteed and if nodes go down this can result in packet loss or data corruption. Packet Switching is heavily used over the internet and other large scale connections.

Virtual Circuit
Virtual Circuit forms an established route like the circuit switching does however it sends the data in smaller packets as opposed to one large entity. This is more reliable than datagrams as packets arrive in the order they originally were in and the connection is guaranteed therefore giving a lower packet loss rate.