Principles and features of Dynamic Routing Protocol OSPF

This article describes in detail the principles and features of the Dynamic Routing Protocol OSPF. For beginners of dynamic routing, this article gives you a detailed introduction to the composition and classification of the routing protocol.

In recent years, with the rapid development of computer network applications, new network products and network technologies have been further developed, which makes it possible to expand the computer network scale. OSPFOpen Shortest Path First) is a widely used routing protocol. It adopts an OSPF autonomous system. After reasonable planning, it can effectively expand the computer network scale. This section describes the principles and features of OSPF.

Introduction to Dynamic Routing Protocol

Routing and routing protocols

As the name suggests, dynamic routing is a protocol that dynamically generates (or learns) Route information. In the field of computer network interconnection technology, we can define routes as follows. routes are some path information that guides IP packet transmission. Dynamic Routing is one of the ways for network devices, such as routers, to learn route information in networks, these protocols enable the router to dynamically update the saved route table as the network topology changes (such as the failure of some paths or the generation of new routes, in a short period of time, the network administrator is not required to automatically maintain consistent routing information, so that the entire network can converge to maintain fast convergence and high availability of the network.

Routers learn route information and generate and maintain route tables by using Direct, Static, and Dynamic routes ). Direct Connection routing is discovered by the link layer protocol. It generally refers to the path of the network segment where the interface address to the router is located. The path information does not need to be maintained by the network administrator or calculated by the router through an algorithm, as long as this interface is Active, the router will fill in the routing information to this CIDR Block in the routing table. Direct Connection routing cannot allow the router to obtain the routing information that is not directly connected to it. Static Routing is the routing information configured on the router by the network planner using commands based on the network topology. The static routing information guides the packet transmission, and the static routing method does not need to be calculated by the router, however, it relies entirely on network planners. When the network scale is large or the network topology changes frequently, the work that the network administrator needs to do will be very complicated and prone to errors. The dynamic routing method enables the router to automatically calculate new route information according to specific algorithms to adapt to changes in the network topology.

Classification of Dynamic Routing Protocols

According to the region (Autonomous System), the dynamic routing Protocol can be divided into the Internal Gateway Protocol IGP (Interior Gateway Protocol) and the external Gateway Protocol EGP (Exterior Gateway Protocol). According to the algorithm, dynamic Routing Protocols include Distance Vector, Link State, and hybrid routing protocols developed by Cisco,
OSPF features

OSPF is called Open Shortest Path First. "Openness" indicates that it is a public agreement, which is formulated by a standard agreement organization. Each vendor can obtain the details of the agreement. "Shortest Path First" is the algorithm executed by the Protocol during route computing. OSPF is one of the most widely used and optimal performance protocols in the internal gateway protocol. It has the following features:

◆ Suitable for large-scale networks;

◆ Fast convergence of route changes;

◆ No route self-loop;

◆ Variable-length Subnet Mask (VLSM) is supported );

◆ Support equivalent routing;

◆ Supports region division;

◆ Provides Hierarchical Route management;

◆ Verification is supported;

◆ Supports sending protocol packets with multicast addresses.