A method of setting up Network Load balancing by boundary router

"How the border routers implement Network Load Balancing," we need to understand several relevant knowledge points about NAT, border routers, and Network Load Balancing.

The primary purpose of network address translation (NAT) is to resolve IP address shortages, and to achieve TCP load balancing, in the design shown in Figure 1, Internet-connected routers adopt network address translation, based on the network structure and IP address given in the router's NAT table and figure-2, Describes the process of "how the border routers implement Network Load Balancing" when Host B makes a request to the internal network for communication. NAT is the internal network in the LAN internal address, internal nodes to communicate with the external network, at the gateway, the internal address to replace the public address, so that in the external public network (Internet) normal use, NAT can enable multiple computers to share the Internet connection, This function is a good solution to the problem of the public IP address shortage. In this way, as long as you apply for a legitimate IP address, you can connect the entire local area network computer to the Internet. At this point, Nat masks the internal network, all intranet computers are not visible to the public network, and intranet computer users usually do not realize the existence of NAT. A global address is a legitimate IP address that is assigned by an ISP (Network service provider) to a public network address that represents one or more internal local addresses and is a globally addressable address.

The boundary router is the edge or the terminal router of the network boundary, which provides the basic security for the outside network, or enters into the private network area from the lack of the network control. In general, most networks have a major access point. This is the "border router" that is typically used with a dedicated firewall. A border router is a critical route that connects the internal and external Internet. As a bridge between the internal and external network, its safe operation is related to the fate of the whole LAN. Because of the direct connection to the Internet, border routers are the focus of hacker attacks. Based on this, the border router should be the object that the network administrator should focus on maintenance.

The initial basic design idea of load balancing is that a common server can handle up to tens of thousands of to hundreds of thousands of requests per second and cannot process millions or even more requests in a second. But if you can make multiple servers such as a system and distribute all requests to all servers through software technology, the system has the ability to handle millions of or more requests per second. Services are not interrupted when one or several servers in Network Load Balancing are not available. Network Load Balancing automatically detects that the server is unavailable and can quickly reassign client traffic to the remaining servers. This protection will help you to provide uninterrupted service for key business processes and increase the number of Network Load Balancing servers according to the increase of network traffic; the concept of "load balancing" is used on the network, in simple terms, the use of multiple network equipment channels to balance the flow of traffic sharing. It is like a temple to pick 10 barrels of water a day, one still has to walk 10 times, but at the same time assign 10 monks but only one trip to complete the work of the same reason. Load Balancing can work at the same time with a number of network devices to speed up the processing of network information, and then optimize the performance of network equipment, replacing equipment must constantly upgrade or eliminate the fate. It is widely used in network devices, such as servers, routers, switches and so on. Because NAT is closer to the lower level of the network, it can be integrated into hardware devices, usually such hardware devices are layer fourth switch and dedicated load balancer, the fourth layer switch is an important function of NAT load balancing.

According to Figure 1,-2 simple elaboration bottom edge router realizes the network load balance process, intuitively feels our understanding to the above related knowledge point. There is no related configuration here, so simply describe the relevant working principle based on this argument.

Figure-1

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