IP high-speed backbone network switching standard MPLS

1 Multi-Protocol Label exchange

Multi-protocol label switching MPLS, multi-protocol label switching) is a third-generation network architecture and is the standard for switching the next-generation IP High-Speed Backbone Network. It is proposed by IETF of the Internet Engineering Task Group, led by Cisco, ASCEND, 3Com, and other network equipment vendors.
MPLS is an integrated IP over ATM technology that combines routing functions on frame relay or ATM Switching). Data packets are transmitted through a virtual circuit and only need to be transmitted at the Layer 2 Data Link of OSI) execute a hardware switch to replace the third-tier network layer) software-based routing ). It integrates IP routing and layer-2 tag exchange into a single system. Therefore, it can solve the Internet routing problem, shorten the delay of data packet transmission, accelerate the network transmission speed, and is suitable for multimedia information transmission. The biggest technical feature of MPLS is that it can specify the sequence of data packet transmission, which uses label exchange label switching), the network router only needs to identify the label, you can transfer.
MPLS works by providing a label for each IP packet, and thus determining the packet path and priority. A vrompls compatible with MPLS reads only the packet label before forwarding data packets to its path, and does not need to read the IP address and header network of each data packet ), then, the transmitted data packets are placed on the virtual circuit of frame relay or ATM, and quickly transmitted to the destination router to reduce the packet delay. At the same time, the transmitted data packets are classified based on the Qos provided by the frame relay or ATM switch, which greatly improves the network service quality and provides diversified services.
2 network requirements

Many years ago, people expected that ATM could do anything. With the development of the Internet, people tried to transmit voice and images through ATM. However, due to the limitations of ATM, make it unable to adapt to the rapid development of the Internet. At the same time, due to point-to-point connections, it is difficult for people to bear the high price and a serious waste of Bandwidth Resources. However, due to the openness of the IP network, it is difficult for people to achieve end-to-end connections. At the same time, there are also many problems in the transmission of voice packets. Therefore, integrating the ATM network with the IP network is the original intention of the people.
3. Support of main technologies

The earliest method was IP over ATM, but encountered many problems and difficulties, such as the ing between IP addresses and ATM addresses. The advantage of ATM is that it uses hardware to forward packets with a fixed length. As long as the packet header's forwarding information is displayed, it can be directly forwarded. The two protocols are not successfully bound together and cannot be promoted. Later, some people tried to combine the advantages of the two protocols, that is, to combine the forwarding mechanism of the ATM with the addressing and routing mechanism of the IP network, thus generating the IP exchange technology, and launched the MPLS protocol through the IETF organization.

4. Carrier's needs
Despite the increasing network demand, bandwidth prices have sharply declined, making operators less and less revenue. For emerging operators, it is hard to find an investor, it is also difficult for operators with debt to have new funds to build networks. Even so, users do not need to stop the demand for new services. Operators must seek new services and technologies to provide users with better and more intelligent services. Therefore, despite various difficulties, operators are still investing in network technologies. On the other hand, operators have invested a lot of money to build backbone networks, but these backbone networks have not been fully utilized. The last mile of network restrictions have hindered the speed of information entry and become a bottleneck for network development.
Many carriers say that MPLS will be the first choice when selecting a new backbone network. Therefore, in the future, MPLS will work together with ATM, SDH, and DWDM to drive together in the army of backbone networks. Some surveys show that in the next few years, in the backbone network of the data network, the development prospects of MPLS technology are extremely good, and it will take a central place in the future European network market. This is because MPLS will bring huge benefits to the IP network through hierarchical services and new services. At the same time, MPLS can combine ATM and IP addresses to simplify the network.
5. application fields of MPLS
MPLS networks are mainly used in three aspects: 1) Qos of IP networks; 2) Traffic Engineering of IP networks; 3) service functions of IP networks such as VPN ). Because the regions and operators are different, people have to focus on MPLS.
In the United States, MPLS is widely used in traffic engineering. Because of the long history of the United States Network, the old and new products are also used in the network, and the structure of the entire network is as complex as a spider network. In this case, we need to allocate traffic to different channels reasonably to make full use of the existing resources and routes of the network. MPLS functions in traffic engineering can be used properly.
In Europe, China and other regions and countries, due to the relatively late development of the IP network, but the development speed is very fast, in this case, the network bandwidth is relatively high, for example, China's new network bandwidth is around Gbps, so the application of network traffic engineering is not urgent. Network service providers put the value-added service requirements for MPLS on the agenda, the most urgent of which is the VPN service. They hope to launch Frame Relay and ATM virtual private network services on the IP network.

6. MPLS development prospects
1) move from backbone to edge
MPLS switching from the backbone network to the edge network is an increasingly obvious trend. This process will bring greater bandwidth, higher intelligence, and more services to the edge. In the access network, the Ethernet network carried by MPLS technology makes the network more easily upgraded and elastic. In each backbone network, common Ethernet can only process 4000 VLANs, while MPLS allows each router to support a maximum of 1 million tags. Therefore, edge router manufacturers are also paying attention to MPLS.
2) Alternative ATM
At the beginning, people provided IP services on the ATM network. Currently, from the perspective of development trends, people only want to provide services similar to ATM on the IP network. Because it is still impossible to completely replace ATM, MPLS will be developed on the IP network. In the future, people will gradually limit ATM to a small part with special needs, such as private network users renting specific bandwidth and implementing telephone and television conferences on this line.
3) combined with underlying optical devices
From the perspective of the overall network development direction, in the future core network, all new operators will use optical nodes for backbone Internet networks established in the first time. MPLS is no longer a single existence, and it will complement the underlying optical devices. The previous IP addresses were the first layer, the second layer, and the third layer. Now, based on MPLS, IP addresses are combined with the underlying layer and optical devices so that IP routing cannot be identified, that is, IP is used to drive light. In the future, the core of the network is wavelength routing. The relationship between the existing network and the future network is that the existing network will be the Access Node of the large network in the future. In the future, the network will not abandon existing technologies and products, but integrate them, but all applications will be implemented in the form of IP addresses.