Distributed zero-configuration routing stack solution (1)

Looking back at the development process of the local area network, we have roughly gone through the following stages: the first stage is the router + bridge, the second stage is the central router + switch, and the third stage is the route switch + working group switch.

Although the supporters of the exchange technology always insist on pushing the router to the edge of the network, they cannot avoid the problem of subnet routing in the design of medium and large networks. Today's personal computers and workstations are greatly enhanced in processing power, and network applications are increasingly rich. The network bandwidth should be the most effective, and the network traffic should have the fastest path. According to the current popular LAN establishment mode, the routing design still has the following defects.

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The network is composed of a backbone switch with the routing function and a working group switch. Node A and Node B are connected to the same workgroup switch. However, because A and B are in different subnets/VLANs, the communication between them must go through the core backbone switch. After layer-3 forwarding of the backbone switch, the communication between A and B can be completed. This not only loads local data traffic to the backbone network, but also all route information of the entire network must pass through the Central Route switch.

No wonder some network users simply select a network switch with the routing function. However, they encountered other difficulties, as shown in figure 2.

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In this solution, communication between A and B, and between C and D does not need to go through the central switch. The load of the network backbone and the central switch is diverted. However, there are some other problems:

1. There are multiple routing devices on the network. To achieve route load splitting, the network administrator must reschedule the routing splitting of the IP subnet;

2. Route division of the IP subnet requires reconfiguration of the default routes of each node;

3. The emergence of multiple routers brings about a lot of Routing Management Work;

4. data packets are split/packaged twice, which affects the performance;

5. Some exchange routers allow configuring a load balancing mode for one hop, but occupy more IP addresses and increase network management problems;

6. high cost.