What is the full name of STP IEEE 802 1d ? What is the main effect?

The role of STP is to prevent redundant links in the bridge network from forming loops.

STP is the abbreviation of Spanning Tree Protocol, which means that spanning tree protocol can be applied to the establishment of tree topology in computer networks, and its main role is to prevent redundant links in bridge networks from forming loops.

However, there are specific factors that can cause STP to fail, and it can be very difficult to troubleshoot, depending on the network design. Spanning Tree Protocol is suitable for network equipment from all vendors, and there are differences in configuration and functional strength, but the principle and application effect are the same.

The role of STP:

The main application of spanning tree protocol is to avoid single point of failure and network loopback in LAN, and solve the "broadcast storm" problem of looped Ethernet network, which is a network protection technology in a sense that can eliminate the cyclic connection caused by mistakes or accidents.

STP also provides the possibility to provide a backup connection to the network, which can be combined with SDH protection to form a dual protection of the Ethernet ring. The new Ethernet board supports the IEEE-compliant Spanning Tree Protocol (STP) and the IEEE-compliant Rapid Spanning Tree Protocol (RSTP), with a convergence speed of up to 1 second.

Prevent broadcast storms from being generated by logically disconnecting loops.

To put it simply, STP (spanning tree protocol) is a data link layer protocol run by switches to solve loop problems in switch networks.

The essence of this protocol is in this "tree", we know that there is a topological environment that will never have a loop, and that is the tree topology! Because the characteristic of this topology is that there is only one path to any destination, just like a tree, from root to leaf, there is only one path, so there will never be a loop, and it is precisely because the tree topology has only one path and no loop, in the current network environment, the tree topology is gradually eliminated! Why?

Because it doesn't always have one feature--- high availability! To put it simply, there is only one path from the source to the destination, and if anything goes wrong in the middle of the path, the data will be inaccessible. Is there a way to ensure that there is no loop, but also to achieve link redundancy?

That's right! It's the STP protocol! Through the selection of the roles of the root bridge, the root port and the specified port, it calculates a loop-free optimal path with the root bridge as the root, and selects a port in each loop for blocking, of course, this blocking refers to logical blocking, so as to prevent loops; In addition, when a normal port (such as the root port or the specified port) fails to perform normal data, the STP protocol changes the original blocked port to a state to ensure data failure.

If your router is smart enough or supports policy routes, you can achieve the results you want, but there are a lot of things you need to do, first of all, you need to know the address segment of the ISP, and then use policy routing according to different access addresses to achieve the purpose of traffic orientation.