How to use multiple router protocols

It is very important to use the vro protocol when using vrouters. So I studied how to use multiple vro protocols. Here I will share with you, hoping to help you. There are many ways to implement multiple router protocols in a network. Sometimes, these router protocols do not even know the existence of other protocols as "Night ships"), and there is no information exchange between them. This is often the case in complex porting. Another extreme situation is completely dynamic relationships, such as when "mutual redistribution" is configured. Between the two situations, the "Optimal Method" is used ".

In my last introduction, I discussed how to use both the Intranet gateway and the external gateway IGP and EGP). In this article, I will focus on the interaction of these vro protocols, the following describes in detail how to implement these vro protocols.

At the beginning, you must clearly understand what you want to achieve, because the two identical Router Protocol sets have two completely different usage methods. The difference depends on whether your network is an exchange network. That is to say, do you want to allow data packets from both the source and destination addresses that are not your network to pass through your network. If you are an Internet service provider ISP, the answer is probably "yes". If you are a formal enterprise, the answer is usually "no ". The answer to this question will guide you in Designing Principles for ease of management. Specifically, IP subnets released through the exchange network are usually very active, and it is unrealistic to configure each IP router statically. On the other hand, enterprise networks may be greatly changed internally, but their address space does not change frequently.

For enterprise network administrators, this option usually comes down to whether it is easy to configure mutual redistribution between their intranet gateway and external gateway, and to control the network through the access list, or whether it is easy to use network declarations to configure the Intranet gateway and external gateway. Generally, you do not select Network declaration because you think the network declaration is static. This is true, but the access list of the driver routing diagram is also static, therefore, mutual redistribution is no longer dynamic. Mutual redistribution in the enterprise network is usually not a good method.

In the network declaration, although the command itself is static, the network Declaration is very simple and easy to understand, so it can lead to very definite behavior. You don't have to guess what your network will do. However, many network administrators do not realize that network declarations are dynamic to some extent, because even if you have made a declaration, the route will not be published unless it already exists in the routing table. That is to say, the router has an IGP path, static route, or connected interface). Therefore, if the IGP route goes out, the BGP Route goes out.

Even so, another popular option is one-way redistribution. This is useful when you have multiple paths to exit the network, but you need to make a good balance between dynamic and controllability. Finally, remember that using two vro protocols helps you make informed decisions on EGP without having to issue 120,000 routes to your IGP. Filter as many items as possible. The default items are often not perfect.