Advantages of BGP multi-line:
1. The server only need to set up an IP address, the best access route is the backbone routers on the network according to the routing hop count and other technical indicators to determine any system resources, does not use server server upstream routing and downward can choose the optimal path routing, so can realize high speed single IP high-speed access,
2. Because the BGP protocol itself has redundancy backup, eliminate the characteristics of the loop, so when IDC service providers have multiple BGP interconnection line can realize mutual backup, routing in a route failure route will automatically switch to the other line,
3. Useful BGP protocol can also make network has strong expansibility IDC network can be connected with other operators, and easily implement single IP line, do all user access Internet operators soon, this is two IP two cannot match,
BGP multi-line technology: [1]
BGP is the routing protocol between autonomous systems, its main function is to exchange with other BGP speakers network accessibility of information, a BGP speakers are the devices that any for BGP configuration, BGP use TCP as its transport protocol (port 179), it provides the reliable data transmission,
Two BGP routers links form a transport protocol, the two routers is known AS neighbors and peers, once the transport connection form, two routers exchange message with an open and confirm the connection parameters, in this step, BGP routers exchange version number, the AS number and duration of BGP logo and other information such AS the optional parameters, if there is any a parameter between peers, there will be error notification, the connection between peers not established,
If peer routers agree on these parameters, the BGP routing tables through the UPDATE message exchange, the UPDATE message contains after each system can reach the destination list (that is, the network layer information accessibility NLRI) and each routing path properties, such as routing path attribute contains the source (ORIGIN), such as information and the priority of high and low,
BGP table for each peers in the process of BGP connection is effective, if there is a routing message changed, neighbor routers use incremental updating (message) to pass this information, BGP does not require a refresh routing information, if there is no routing changes, BGP peers only exchange reserves (keepalive) message, keepalive message is sent periodically to ensure that the connection is to remain effective,