A router is a networking device. It forwards data packets between computer networks. Routers perform the traffic directing functions between networks and global network. Data sent through a network, such as a web page or email. A data packet is forwarded from one router to another router via network that constitute an inter network. A router is connects with two or more data lines and all data lines are from different IP network. When a data packet comes any one of the lines, router reads the network address information in the packet header. Using information in routing table, it directs the packet to the next network.
A IP routers which are small office and home routers are familiar type. It is simply forward IP packets between the home computers and internet. There is a more sophisticate routers like enterprise routers who connects business or ISP networks. Generally, A powerful core routers that forward data at high speed with optical fiber lines or net backbone. Routers can be build from standard parts but purpose-build computers. There are some securities also provides to networks. So the data packet can’t be stolen. A securities is like WPA-PSK, WPA-WPSK2 etc.
The first concept of an Interface computer was first proposed by Donald davies in 1966.The same idea was taken by wesley clark the following year for use in the ARPANET. The name of (IMPs) is Interface message processors. Generally, These computers have same functionality as todays router. The idea of a router is came from a group of a networking researchers called International Networking working group. Comparatively These gateway devices were different from packet switching scheme in two ways. They connected dissimilar kinds of networks or they were connectionless devices.
The first idea was explored in more detail with intention to produce a prototype system. The one program is the DARPA-initiated program other was a program at Xerox PARC to explore new networking technologies. Some time after early 1974, The first Xerox router become operational. The first true IP router was developed by Ginny strazisar at BBN.
When multiple routers are interconnects, The routers can exchange information about destination addresses using a routing protocol. A software that runs the router is two functional processing units called planes.
A router maintains a routing table that lists which route is best to forward a data packet. It do this with internal configured directives called static routes. In the routing table there is static and dynamic routes. The control plane logic then strips from the table. It builds a forwarding information base (FIB).
This unit forwards the data packets between incoming and outgoing connections. Generally, It reads the header of each packet. It matches the destination to entries in the FIB supplied by the control plane. Directs the packet to the outgoing network specified in the FIB.
Access routers, including small office/home office models are located at home. Some branch offices that do not need hierarchical routing of their own. Generally, they are optimize for low cost. Some router are capable of running alternative Linux base firmware like Tomato, OpenWrt etc. Distribution routers takes traffic from multiple access routers. sometimes Distribution routers are responsible for enforcing quality of service across (WAN). They have considerable memory installed multiple WAN interface connections. Generally In enterprises, a core router provides a collapse backbone interconnections. The distribution tier routers from multiple buildings of a campus or large locations. They tend to optimize with high bandwidth.
External networks is carefully considers as a part of overall security strategy of the local area network. Generally, A router includes a firewall, VPN networks or Other security functions. routers also commonly perform network address translation which restricts connections. As an experts suggestion the open source routers are more secured and reliable than closed source routers.
Routers are distinguish on the basis of the network in which they operate. A router in a local area network of single company is calls an interior router. A router which is operate in the internet backbone is describe as exterior router. While a router that connects LAN with the internet or a wide area network (WAN) is calls gateway router.