Analysis of Multi-Protocol Label Switching Technology (MPLS)

We break down the Multi-Protocol Label exchange technology into several major elements, hoping to help you understand the working principles of this technology. To facilitate understanding, we will use an interesting analogy to describe how the Multi-Protocol Label Switching Network works.

The package will look like a sandwich candy

Fundamentally speaking, Multi-Protocol Label Exchange is an effective way to forward and transmit data packets, and these two elements are also the basis for data transmission over the Internet. A data packet consists of two main parts: one is the header, which can tell the network to which the data packet is sent and how to send the data packet to the destination; the other is the payload, that is, the data itself. In a network without Multi-Protocol Label Switching, the router must analyze the data header and determine the route to which the data packet should be forwarded before determining the Data Packet Destination.

We can compare a data packet to a sandwich lollipop. the outer part of the candy is the header, and the content in the candy is equivalent to the loaded data. Suppose we have a factory that creates lollipops. The factory needs to produce lollipops of various flavors, then package them into different cartons, and then deliver them to retail stores. Assume that the hacker has already designed a candy classifier. After producing candy of various flavors, the machine can forward it to the corresponding Packing Box Based on the taste. In order to determine the taste of each candy, the machine must analyze the outer elements of the candy and mark it as classification based on different taste characteristics and the color of each candy.

As you can imagine, there are three different types of Candy: Orange, cherry, and strawberry. In the first step of classification machine, the color selector uses color analysis to determine the color characteristics of the candy and then forwards it to the corresponding packing box. For example, the orange color is indeed considered as the orange taste. However, the color selector cannot distinguish between cherry and strawberry colors, so the two flavors of candy must be forwarded to the next selector for deeper analysis of the outer characteristics of the candy. This may reduce the candy selection efficiency, because each selector needs time to analyze the outer part of the candy.

Multi-Protocol Label exchange

In this case, the Multi-Protocol Label exchange technology can be used. Unlike the previous analysis of the outer elements of all sweets at each selector, the Multi-Protocol Label exchange technology is equivalent to a new classifier, it comprehensively analyzes and packs all the elements of a candy at the initial stage of its selection. This packaging clearly identifies the taste of the candy, so it is equivalent to providing a clear sending path for the classifier. Therefore, machines using this new technology no longer need to waste time analyzing the chemical composition of candy. They only need to read the label content and then directly forward it to the appropriate packaging box.

The working principle of the Multi-Protocol Label exchange technology is similar to that described above. When a packet is entered into a network using the Multi-Protocol Label exchange technology, the packet is routed through a tag edge and the packet is attached to a tag stack, the label specifies a Forwarding Equivalence Class (FEC) for the data packet. This Forwarding Equivalence Class tells each route the address to which the data packet is sent, instead of the packet header analysis. Each tag contains four elements: a 20-bit tag value, a 3-bit traffic category domain, an 8-bit Real-Time Domain length, and a 1-bit bottom stack flag. Among them, three bit traffic domains are used to specify the service quality, priority, and explicitly blocking notifications; the real-time duration specifies the maximum number of data packets sent; the bottom stack flag indicates that the last label of the stack is sent.

Using this label technology not only simplifies the packet forwarding process, but also reduces the pressure on the network to process traffic. Because the Multi-Protocol Label exchange technology does not consider the protocol, it can process packets from ATM, frame relay, SONET or Ethernet. In other words, a network using the Multi-Protocol Label exchange technology can extract data packets from multiple networks, tag them, and forward data packets to the correct destination based on the TAG content.

Let's go back to the original candy metaphor. Suppose our candy factory a bought another candy company B, in addition, the multiclass Protocol Label exchange technology will be used in the production of new companies. Then it is necessary to distinguish the name of the candy production company-the classification Machine Based on the Label Edge routing can still pack the candy and then forward it to the final destination.