1. Overview of Routing Protocols
1. Introduction to routing protocols
For routers, finding the optimal data transmission path is a meaningful but complicated task. The optimal path may depend on the number of forwarding times between nodes, current network operation status, unavailable connections, data transfer rate and topology. In order to find the optimal path, each router communicates with each other through a routing protocol. One thing that needs to be distinguished is whether the routing protocol is equivalent to the routable protocol. Such as TCP/IP and IPX/SPX, although they may be on top of the routable protocols.
Routing is divided into static routing and dynamic routing, and the corresponding routing tables are called static routing tables and dynamic routing tables. The static routing table is preset by the network administrator according to the configuration of the network when the system is installed. After the network structure changes, the network administrator manually modifies the routing table. Dynamic routing changes with changes in network operation. The router automatically calculates the best path for data transmission according to the functions provided by the routing protocol, and thus obtains the dynamic routing table.
Routing protocols are only used to collect data about the current state of the network and are responsible for finding the optimal transmission path. Based on these data, routers can create routing tables for future packet forwarding. In addition to the ability to find the optimal path, the routing protocol can also be characterized by convergence time—the time it takes for the router to find the optimal transmission path when the network changes or is disconnected. Bandwidth overhead—the running network does not support routing
2. Routing protocol type
According to routing algorithm, dynamic routing protocol can be divided into distance vector routing protocol (Distance Vector Routing Protocol) and link state routing protocol (Link State Routing Protocol).
As shown below:
Dynamic routing protocols are divided into IGP and EGP according to scope:
- Interior Gateway Protocol (IGP): This type of routing protocol is used to exchange routing information and calculate routing network protocols within the autonomous system.