Network Routing

The term routing means “To route” and network routing means to send the traffic from one Network to another through a layer 3 device. Network Routing is an important issue in Inter Network Communication Systems. Whenever the Network ID changes, the traffic must be routed on the basis of IP Address.

The switches and hubs work on physical address, i.e. Data Link Layer or MAC Addresses. The device that can interpret the IP Address and Network IDs is called a router device. Router is an essential device that translates the Network Layer Address and routes the traffic.

Network IDs work on subnet masks, IP Addresses are Xored with Subnet Masks to obtain Network IDs and a Layer 3 Device reads that IP Address to determine the destination and source IP of routed traffic।

Networks are separate to avoid collision and separate private IPS from public IPs. These IP addresses are used in all devices and differentiate between different Networks. Router takes decision for routing on the basis of IP Address.

Routers can be of two types. One is Software Router and the other is Hardware Router. Hardware routers are manufactured by many vendors including Cisco, Nortel, 3Com and Bay net. All the companies make different sorts of routers.

A router has a routing table which is by default empty and is filled with the help of routing protocols. Routing protocols include IS-IS, BGP – 1, BGP – 2 and OSPF. The most complex of them is OSPF and it is the most trust worthy. There are Routing Broadcasts that fill up this table and make the routing possible.

In almost all Server Operating Systems, a simple Router is enabled which makes the inter network communication possible. For example in Windows server System, Routing and Remote Access service use NAT and basic firewall to enable communication between the public and private corporate addresses.

Hardware Routers are classified according to their routing speeds and have their own operating systems which make use of the router hardware efficiently for effective routing.

Each router broadcasts its connected network ids through router broadcasts at specific intervals with the help of routing protocols and sends that to its immediate neighbors which in turn sends its own routing table information back words.

In this way, each router gets fully equipped with all the other router networks and defines on the nodes at which other networks are. Router has expansion slots which allow more hardware to be inserted and hence more communication mode made accessible.