Advanced Linux Routing and traffic Control: Dynamic routing of OSPF and BGP

When your network becomes really big, or when you start thinking about becoming part of the Internet, you need to be able to dynamically adjust your routing tools. Sites are often interconnected by more and more links.

OSPF and BGP4 have almost become the actual standards of the Internet. All supported by gated and Zebra,linux.

Because these contents are not included in this document for the time being, we only give specific learning directions here:

Overview：

Ciscohttp://www.aliyun.com/zixun/aggregation/9344.html "> system design for large-scale IP network

for OSPF:

Moy, John T. "Ospf,internet Routing protocol Profiling" Addison Wesley. Reading, MA. 1998.

Halabi also wrote a good guide to OSPF routing design, but it seems that this article has been cut off from Cisco's homepage.

For BGP:

Halabi, Bassam "routing system of the Internet" (New Riders publishing house). Indianapolis, 1997.

Other than that

Cisco Systems

Inter-domain routing using Boundary gateway protocols

Although the above example is intended for Cisco, it is clearly similar to the configuration language that Zebra uses ☺.

1. Use Zebra to set up OSPF

If the following information is inaccurate or if you have any suggestions, please let me know as soon as possible. Zebra is a very good dynamic routing software written by Kunihiro Ishiguro, Toshiaki Takada, and Yasuhiro Ohara. Using Zebra, it is fast to set up OSPF, but in practice, you have to adjust a lot of parameters if you have special requirements. OSPF means Open Shortest Path First (Open Shortest path priority), and its main features are:

Hierarchical

The network is divided into regions, each region interconnected by a backbone region designated as Area No. 0, and all routers in the 0 zone know the routing information for each other.

Fast Convergence

The route spreads very quickly relative to rip.

Province bandwidth

Multicast is used instead of broadcasts, so it does not disturb hosts that are not interested in routing information, while reducing network traffic. At the same time, internal routers do not need to know the routing information of other areas. Routers that connect different areas together with different interfaces are called border routers, which store topological information for adjacent areas.

High CPU requirements

OSPF is based on Dijkstra shortest path priority algorithm, which requires more complex computation than other routing algorithms. But fortunately, only in the region to do the shortest path operation, and for small and medium-sized network is not a problem, even you do not feel.

Link state

OSPF considers special information about networks and interfaces, such as bandwidth, link exceptions, and costs.

The protocol is open and the software is GPL.

OSPF is an open protocol, and Zebra is a GPL software that has this obvious advantage over proprietary software and protocols.