Summary of typical network routing protocols

The network routing protocol is essential in the network. As a protocol for address management and allocation, there are many types of protocols. Next we will summarize several important routing protocols for you to explain. Generally, there are two typical routing Methods: Static Routing and dynamic routing ｡

Static Routing is a fixed route table set in a vro. Static Routing does not change unless the network administrator intervene. Because Static Routing does not reflect changes in the network, it is generally used in networks with small network sizes and fixed topology structures. Static Routing has the advantages of being simple, efficient, and reliable, the static route has the highest priority. When a dynamic route conflicts with a static route, the static route prevails ｡

Dynamic Routing refers to the communication between routers in the network to transmit route information, update the router table by using the received route information. It can adapt to changes in the network structure in real time. If the route update information indicates that the network has changed, the route selection software will recalculate the route, new route update information is sent concurrently. This information is transmitted through each network, causing Each router to restart its routing algorithm, and update their route tables to dynamically reflect network topology changes. Dynamic Routing applies to networks with large network sizes and complex network topologies, various dynamic network routing protocols occupy network bandwidth and CPU resources to varying degrees ｡

Static Routing and dynamic routing have their own characteristics and applicability. Therefore, dynamic routing in the network is usually used as a supplement to Static Routing. When a group performs routing in a router, the router first searches for static routes. If yes, it forwards the routes to the corresponding static route group. Otherwise, it searches for dynamic routes ｡

Dynamic network routing protocols are divided into the Internal Gateway Protocol (IGP) and the external Gateway Protocol (EGP) based on whether they are used in an autonomous domain) the Autonomous Region refers to a network with a unified management organization and a unified routing policy. The Routing Protocol adopted in the autonomous region is called the internal gateway protocol, which is commonly used by RIP and OSPF; the external gateway protocol is mainly used for routing selection between multiple autonomous domains, commonly used BGP and BGP-4 ｡

1. RIP Network Routing Protocol

The RIP Protocol was originally designed for the Xerox parc universal protocol of the Xerox network system and is a network routing protocol commonly used in the Internet. The RIP uses the distance vector algorithm, that is, the router selects the route according to the distance, this is also known as distance vector protocol. The router collects all the different paths that can reach the destination, and stores the path information about the minimum number of sites to reach each destination. Besides the Optimal Path to the destination, all other information is discarded. At the same time, the router uses the RIP Protocol to notify neighboring routers of the route information collected. In this way, the correct route information is gradually spread to the entire network ｡

RIP is widely used. It is simple, reliable, and easy to configure. However, RIP is only applicable to small homogeneous networks because it allows a maximum of 15 sites, any destination with more than 15 sites is marked as inaccessible, and the route information broadcast of RIP every 30 s is also one of the important reasons for the network broadcast storm ｡

2. OSPF network routing protocol

In the middle of 1980s, RIP was unable to adapt to the interconnection of large-scale heterogeneous networks, and 0SPF was generated accordingly. It is an inter-network engineering task organization (1ETF) is a network routing protocol developed for the IP network ｡

0SPF is a link-based network routing protocol, each vro needs to send link status broadcast information to all other vrouters in the same management domain. All interface information, all measurements, and other variables are included in the OSPF link status broadcast. the router must first collect information about the link status, the shortest path of each node is calculated based on a certain algorithm. However, the Distance Vector-based network routing protocol only sends route update information to its adjacent routers ｡

Different from RIP, OSPF divides an autonomous domain into zones. There are two types of routes to be selected: when the source and destination are in the same zone, the intra-zone routes are used; when the source and destination are in different regions, the interval routing is used. This greatly reduces the network overhead, and increased network stability. When a vro in a region fails, the normal operation of vrouters in other regions in the autonomous region is not affected, which also facilitates network management and maintenance ｡

3 BGP and BGP-4 Network Routing Protocol

BGP is an external gateway protocol designed for TCP/IP Internet and used between multiple autonomous domains. It is neither based on pure link state algorithms, it is not based on pure distance vector algorithms. Its main function is to exchange network accessibility information with BGP of other autonomous domains. Each autonomous domain can run different internal gateway protocols. BGP updates include the paired information of the network number/autonomous domain path. The autonomous domain path includes the autonomous domain string to be passed to a specific network, these updates are transmitted over TCP to ensure transmission reliability ｡