Routing protocols

• Routing Information Protocol (RIP) uses classful routing, as well as incorporating various methods to stop incorrect route information from propagating, such as the poisoned horizon method. However, on larger networks its frequent updates can flood the network and its slow convergence can be a problem.
• Border Gateway Protocol (BGP) has been the core Internet backbone routing protocol since the mid 1990s, and is the most used interior gateway protocol (IGP). However, some configurations require full mesh connections which flood the network, and there can be route flap and load balancing issues for multihomed networks.
• Open Shortest Path First (OSPF) is commonly used in large enterprise networks. It is the protocol of choice mainly due to its fast convergence. However, it can be complicated to setup properly.
• Intermediate System to Intermediate System (IS-IS) Protocol allows routing of ISO’s OSI protocol stack Connectionless Network Service (CLNS). IS-IS is an Interior Gateway Protocol (IGP) not intended to be used between Autonomous Systems (ASes). IS-IS is a link state protocol well-suited to smaller networks that is in widespread use and has near universal support on routing hardware.
• Multicast addressing is used to broadcast from one source to many destinations efficiently. Protocol Independent

Multicast (PIM) is the protocol commonly used in enterprises, multimedia content delivery, and stock exchanges.