IP access network technology is under pressure

The access network technology is still quite common, so I have studied the access network technology for IP addresses. Here I will share it with you and hope it will be useful to you. With the rapid development of the Internet, IP has dominated various terminal applications, and no one will doubt that the mainstream network development in the future is IP, how to transmit IP data more efficiently, quickly, and cheaply is the focus of future research on telecom networks. Up to now, the key to the development of various access network technologies, such as xDSL and Cable Modem, is to adapt to the development of today's network, but these technologies all have the same problem: high cost, not cheap enough. People will naturally think of Ethernet technology when it comes to being cheap, but whether the LAN technology can be applied to a public network environment such as the access network needs to be carefully studied.

1 challenges faced by IP Access Network Technology
Because the access network technology is a public network environment, its requirements are very different from those of a private network environment such as a LAN, it is mainly reflected in user management, security management, business management and billing management. User management refers to the process in which a user needs to register an account with the access network technical operator and authenticate and authorize the user when the user communicates. For all carriers, it is very important to master user information, so as to facilitate user management. Therefore, you need to register an account for each user. During user communication, illegal users must be prevented from accessing the network, occupying network resources, and affecting the use of Valid users. Therefore, users must undergo legality authentication, in addition, users can enjoy their corresponding powers based on user attributes.

The so-called security management refers to the access network technology needs to ensure the security of the frame of the user data Unicast address), isolation of broadcast messages carrying the user's personal information, such as ARP Address Resolution Protocol) DHCP Dynamic Host Configuration Protocol) messages) to prevent attacks on key devices. For each user, we certainly do not want other users to receive the information. Therefore, we need to physically isolate the frames of the user data Unicast address ), ensure that only the user can receive the frame of the unicast address, unlike all the users on the frame bus that share the unicast address in the LAN. In addition, because the user terminal is connected to the access network using a common Ethernet Card, some frames of broadcast addresses such as ARP and DHCP messages are sent during communication ), these messages carry users' personal information, such as users' MAC Media Access Control addresses). If these broadcast messages are not isolated and received by other users, MAC/IP address counterfeiting may easily occur, affecting the normal operation of the device and interrupting the communication process of legal users. In a public network environment such as the access network, it is very important to ensure the security of the devices. Some measures must be taken to prevent the devices from working normally due to illegal access to the management system, and some malicious messages affect users' normal communication.

2 features of existing technical solutions
With the development of Ethernet technology, especially switching Ethernet devices and full-duplex Ethernet technology, people begin to think about applying Ethernet technology to public network environments, there are two main solutions: VLAN and PPPoE.

VLAN-based network structure. Each port of a lan switch is configured as an independent VLAN and has an independent vidvlan id ). Each user port is configured as an independent VLAN. Information is isolated using a lan switch that supports VLAN. the user's IP address is bound to the VLAN Number of the port to ensure correct route selection.

In VLAN mode, VLANs can be used to isolate ARP, DHCP, and other broadcast messages carrying user information, thus further improving the security of user data. In this solution, although the security of user data is solved, the user cannot be authenticated or authorized without the means to manage the user. To identify the user's legitimacy, You can bind the user's IP address to the user's connected port VID so that the device can identify whether the user is legal by verifying the IP address and VID. However, the problem with this solution is that the user IP address is bound with the port where it is located, and only static IP addresses can be configured. On the other hand, because each user is in a logically independent network, each user needs to configure four IP addresses of a subnet: Subnet address, Gateway underground location, subnet broadcast address, and user host address, this will cause extremely low address utilization. VLAN + PPPoE solution can solve the security problem of user data. At the same time, because the PPP protocol provides the user authentication, authorization, and allocation of user IP addresses, it will not cause problems in the above VLAN solution. However, for future network development, PPP cannot support multicast services because it is a point-to-point technology and is not a good solution.

3. Ethernet-based Broadband Access Network Technology
Given that the current solutions and devices cannot fully meet the requirements of a public network environment such as the access network, we need to study the devices and technologies that adapt to the public network environment, this is the Broadband Access Network Based on Ethernet technology. The Ethernet-based broadband access network consists of local devices and user devices. The local equipment is generally located in the residential area, and the user-side equipment is generally located in the residential building; or the local equipment is located in the commercial large area, and the user-side equipment is located in the floor. The local device provides interfaces with the IP backbone network, and the user-side device provides the 10/100 BASE-T interface connected to the user's terminal computer. Local devices can collect the Network Management Information of user-side devices.

In Ethernet-based broadband access networks, user-side devices only have link layer functions and work in the MUX multiplexing mode. Users are isolated from each other at the physical layer and link layer, this ensures the security of user data. In addition, the user-side device can dynamically change its port rate under the control of the local device, so as to ensure the user's lowest access rate, limit the user's highest access rate, and support QoS Assurance for services. For multicast services, the local device controls the status of multicast groups and group members. The user-side device only performs controlled multicast replication and does not need multicast group management. Local devices also support user authentication, authorization, billing, and dynamic allocation of user IP addresses. To ensure device security, the local device and the user-side device adopt a logically independent internal management channel.

Ethernet-based broadband access networks also provide powerful network management functions. Like other access network technologies, it can perform configuration management, performance management, fault management, and security management. It can also provide a wide range of billing information to the billing system, this allows the billing system to charge by Information volume, connection duration, or monthly subscription.

4 Development Prospects of Broadband Access Networks Based on Ethernet Technology
With the explosive growth of IP Services and the increasing openness of China's telecom operation market, both traditional telecom operators and new operators are in an invincible position in the new competitive environment, the construction of an IP-oriented telecom infrastructure network is the focus of their network construction. In the access section of man, many operators choose Ethernet technology. It is worth noting that existing Ethernet Access Technologies all have problems of one or another, which brings great risks to future business development. Some operators even moved the Ethernet technology used for computer LAN to the access network, so the information between different users could not be isolated. It is unimaginable to carry out e-commerce on such platforms. This operation method can only grab a large number of users at a time. When users find that their own interests are not guaranteed, operators will surely eat their own results.

The Ethernet-based broadband access network technology is very different from the traditional Ethernet technology for computer LAN. It only uses the frame structure and interface of Ethernet, and the network structure and working principle are completely different. It has a high degree of information security, telecom-grade network reliability, powerful network management functions, and can ensure the user's access bandwidth, which are not achieved by the existing Ethernet technology. Therefore, the Ethernet-based broadband access network technology can be fully applied in the public network environment to provide users with stable and reliable broadband access services. In addition, because the Broadband Access Network Based on Ethernet technology provides users with standard Ethernet interfaces and is compatible with all terminals with standard Ethernet interfaces, users do not need to configure any new interface cards or protocol software, therefore, it is a very cheap broadband access technology. The Ethernet-based broadband access network technology is much cheaper than ADSL and Cable Modem for network devices and clients. Based on the above considerations, the Ethernet-based broadband access network will play an important role in future broadband IP Access.

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