ion is copied from node to node in a tree structure. Each router builds its own forwarding table from its own perspectives. Routing Information Protocol (RIP) The RIP is a relatively old, but widely used interior gateway protocol (IGP) created for use in small, homogeneous networks. This is a classical distance-vector routing protocol. RIP allows hosts and gateways to exchange information for computing routes through an IP-based network. An entry in the routing table can represent a host, a network or a subnet. RIP uses broadcast user datagram protocol (UDP) data packets to exchange routing information. Open Shortest Path First (OSPF) The development of the OSPF routing protocol began in 1987. In order to be able to build large OSPF networks, an OSPF routing domain is split into regions called areas. Routers within a common area all maintain identical copies of the network map, or topology database. OSPF is considered to be an interior gateway routing protocol (IGP), meaning a routing protocol normally implemented on a network under the control of a single administrative authority. The OSPF routing protocol adjusts to network changes more quickly than RIP and is more robust. In RIP the routers have to wait until the route is unavailable before action is taken, while in OSPF the routers maintain a database with the actual topology of the area. Each router updates the rest of the network with information on the direct connections it has to its neighbours. However, poor OSPF deployment causes worse network performance than the RIP protocol. OSPF can route real-time traffic one-way and other type traffic a different way, performs load balancing by splitting the load over several multiple lines and supports hierarchical systems when needed. The OSPF represents the actual network with a graph consisting of several areas. Each area is considered as an autonomous system (AS), and every AS has its own backbone called area 0. All areas are connected to a special area called a backbone area. Areas are connected to the backb