When we talk about LAN and MAN, there are certain restrictions in terms of the network boundary. However, in some cases, boundaries for networks are not feasible when long distance communication is necessary. In case of WAN or Wide Area Network, it spans a very large geographical area as in a continent or country.
Normally WAN‘s are just physical extensions of LAN’s. They are built using private leased lines. Their huge coverage area makes the cost go higher and transmission speeds to drop down. What companies do to avoid spending too much money and time in managing individual leased line’s is they deploy VPN or Virtual Private Network over internet connections which are cheap. Note that the routers and switches you use must be capable of handling VPN traffic.
When VPN’s are introduced as cost saving alternatives, we must ensure that the security of our data is intact. Several encryption schemes are used which will help keep the data private and prevent unauthorized viewing or interception of sensitive data.
Host and subnet aspects are introduced in WAN’s. Host’s are simply put, the systems that are connected to the WAN network. Image a telephone. What does it do? It helps us to pass a voice message from a person on one end of the phone line to another. The subnet has a similar function of information transfer between hosts.
Talking about subnet, there are two main components when the Wide Area Networks are considered.
- Switching elements
- Transmission lines
Let us start with what transmission lines are. Simply put transmission lines is a a medium to transfers bits of information between the machines in the network.
To connect these transmission lines, we use specialized computers called switching elements. It performs intelligent switching function. When it receives an input packet, it decides which output line to forward it to. You should note that that subnet mentioned here is a little ambiguous. Subnet here and subnetting for network address is not the same. Here, the term subnet is used as a generic term for computer components in the WAN.