Routers are used to connect networks together and route the packets of data from one network to another. routers breks up a broadcast domain, which is the set of all devices on a network segment that hear all broadcast sent on that segment. breaking up a broadcast domain is important beacause when a host or server sends a network broadcast, every device on that network must read & process the broadcast-unless we have got a router. when the router's interface receives this broadcast, n can say responce by basically saying "Thanks, but no thanks" & discard this broadcast without forwording it on to another network. Routers are known for breaking up broadcast doman by default its important to remember that they breaking up collision domain as well.
Advantages of using Routers in our network.
1 They don't forword broadcast by default.
2. They can filter the network based on layer-3(Network Layer) information.
Once we creates an internetwork by connecting our WAN (Wide Area Network) & LAN (Local Area Network) to a router, we will need to configure logical network address, such as IP(Internet Protocols) address,to all hosts on the internetwork so that they can communicate across that network.
The term routing is used for taking a packets from one device & sending it through the network to another device on a different network. Routers don't really care about hosts. They only care about network & the best path to each network. The logical address of the destination host is used to get a packets to a network through a routed network then the hardware address is used to deliver a packet from a routed to the correct destination host.
If your network has no router, then it should be apparent that you are not routing. Rouuter route traffic to all the network in our internetwork.
To be able to route packets, a router must know. at a minimum the following.
1. Destination Address
2. Neighbor routers from which it can learn about remote networks.
3. Possible route to all remote networks.
4. The best route to each remote networks.
5. How to maintain & verify routing information.
The Routers learn about remote networks from neighbor routers or from an administrator. the routers then build a routing table that describes how to find the remote networks. If a network is directly connected, then the router already knows how to get to it. If a network isn't connected, the route must learn how to get to the remote network in two ways by using.
Static Routing:- Meaning that someone must hand type all network location in to the routing table, on through something called dynamic routing.
Dynamic Routing:- A Protocol on one router communicates with the same protocol running on neighbor routers. the routes then update each other about all the networks htey know about & place this information in to the routing table. If change occurs in the Network. the dynamic routing protocols automatically inform all routers about the event.
If Static Routing is used, the administrator is responsible for updating all changes by hand into all routers. Typically, in a large network, a combination of both Dynamic & Static Routing is used.