Comprehensive introduction to the access network system

Source: Internet
Author: User

The access network system has a lot to learn about. Here we mainly introduce the future structure of the access network, including the evolution strategy of the access network. I hope you will have a better understanding of the access network system.

Due to the rapid development of electronic technology, computer technology, and network technology, the market is facing the increasing demand for broadband multimedia smart communication and personal mobile communication. The telecom network is experiencing the greatest change in history. The traditional telecom network structure has a strong dependence on the telecom services provided, and the network structure, service structure, and application structure of the open telecom network in the future are irrelevant to the network nodes and network topology. In this way, it not only provides traditional telecom services, but also dynamically and flexibly provides a variety of smart broadband telecom services and application services. Due to the fundamental changes in the network architecture, the telecom service will be provided through the access network system on the server and the network edge. This means that the access network will be the most complex access network system in the future. It has become an important topic to smoothly evolve from the current network to the future communication network to meet the increasing needs of users and protect the investment of the Telecom Department in the past.

At present, transmission technology, packet exchange technology, network technology, telecommunications service delivery technology, traditional telecommunications service simulation technology that supports the future network architecture have been extensively studied and made significant progress. The Network Layer functions of open networks are supported by the IP protocol system. An important breakthrough has been made in the transmission and Packet Exchange technology that provides high-speed, large-capacity, and quality assurance in the transmission and exchange layer. You can use wavelength division multiplexing and SDH technology to implement the transmission layer function. You can use a-bit or higher line speed Classification Service Router to Achieve Packet Exchange with quality assurance for the core network, and use ATM technology to provide access network switching. Server systems that provide telecommunication services and gateways that act as telecom service interfaces, such as IP telephone gateways, have also been greatly developed. International multi-service exchange forum MSF) conducts in-depth research and establishes standards on the architecture of the transport exchange layer. ISC is committed to standardizing the architecture and protocols of telecom service gateways and service servers. These tasks are carried out in cooperation with ITU and IETF. UTStarcom is one of the initiator members of ISC. It has made an in-depth study on the evolution of telecom networks and predicted the evolution and development of access networks.

I. Future Structure of Access Networks
As the core network in the future is high-speed broadband with multiple services, the telecom access network should also support broadband with multiple business functions. However, as there are already a large number of business-oriented telecommunication access network systems, especially wireless access network systems, the end access functions of the access network should be diversified. Generally, an access network refers to a network from the edge of a core network to a network terminal device. The traditional access network ranges from the business core network to the terminal device. Therefore, the traditional access network is related to the telecom business. In the future, the access network will be broadband, multimedia, and multi-service, and will be an extension of core network functions. Therefore, the access network has the same functional hierarchy as the core network and has nothing to do with the telecom business carried.

Different from the core network, the edge and end access systems of the terminals of the broadband access network should be polymorphism, that is, a variety of access methods coexist. The reason is that a large number of traditional business-related access methods and access technologies still exist, such as POTS fixed terminals, wireless access terminals, analog and GSM mobile terminals, and narrowband CDMA mobile terminals. New access technologies will emerge in the future, such as 3G broadband CDMA mobile terminals. It should be noted that, even if 3G Access is popularized, traditional terminals can still be used from the perspective of protecting investment and adapting to market needs at different levels. Regardless of the access method, the end access system and the network terminal must match on the physical layer and data link layer.

Broadband Access Networks and traditional access networks will coexist. That is to say, the traditional network endpoint access can enter the core network through the future access network, or through the traditional access network to enter the core network.
The interfaces of the broadband access network and the core network are connected to the router. Multiple Access Networks enter the core network here. Because a consortium router is usually installed in a telecom Bureau, gateways of various traditional telecom networks are often integrated with the consortium router. The interfaces of the broadband access network and the end access system are designed according to different end access standards to match the physical layer and data link layer functions of the network and terminal, provides resource control and access control for shared media. For example, coverage control, frequency control, channel control, and Power Control for wireless access. For the traditional end-of-service access system of Telecom, the access network end is equivalent to the original service switch.

Compared with the core network, the access network is not stable due to low access traffic. Therefore, the dynamic distribution of channels and their bandwidth and the assurance of communication quality must be ensured by special technologies. The switch layer and network layer of the Network part of the broadband access network can be achieved by using the ATM technology or the IP over ATM technology. The physical layer and transmission layer can be transmitted directly by optical fiber or through SDH loop. The Network Layer Protocol of the broadband access network should be supported by the IP class. From the perspective of information transmission, the access network and the core network are transparent. If smart terminals are used, the terminals are transparent, regardless of the number of different access networks and core networks in the middle.

In addition to the end systems that support traditional wired and wireless access, broadband access networks include voice systems and data systems such as copper wires, V5, GSM, and narrowband CDMA, the end system with a broadband and open 3G wireless interface is also an important part of the future access network, such as a broadband CDMA system supporting the UMTN architecture. High-speed LAN access is also one of the end systems for broadband access in the future. Smart terminals and local area networks are directly connected through smart terminal gateways. Traditional service terminal gateways are connected to traditional telecom service terminals and local area networks. Smart terminal gateway is used for signal transformation and authentication, authorization, and accounting AAA). Traditional service terminal gateway is used to provide traditional POTS services. Another access method is to access the system through the end of the TV cable. Digital voice and data on telecom networks can coexist with analog and digital TV signals. Traditional TV devices can continue to use traditional TV services. The traditional business terminal gateway can provide traditional telecommunication services through television cables. The Smart terminal gateway supports signal transformation and AAA functions. Smart terminal gateway can provide multimedia services on traditional TV networks and broadband networks in the future.

The management of broadband access networks is hierarchical: Access gateways of traditional telecom service networks such as PSTN, DDN, Internet, and paging systems are managed according to the corresponding business categories; the management of transmission and exchange devices in the access network belongs to the management of the transmission and exchange layer. Traditional service gateways and traditional gateway services are managed by traditional telecom service servers; the end access system is managed by the management system of the corresponding access method. All management systems are built on OSS.

2. Access Network evolution strategy
In the future, the core network of the network is a multi-service broadband network, and telecom services are provided by network servers and edge gateways. In fact, the current core transmission network has been broadband, digitalized, and separated from the bearer service. Its evolution is mainly to further expand capacity, increase bandwidth, multi-service, and quality assurance of the packet exchange router. Therefore, the evolution of the telecom business to the future network is mainly the evolution of the access network.

The goal of telecom network evolution is to gradually migrate traditional telecom services to the broadband network in the future, and use the platform of the future network to expand traditional telecom services, at the same time, new telecom services supported by the future network are developed to meet the new needs of future communication. The evolution process should be smooth, compatible with the past telecom services, and open to new telecom services. Therefore, there must be a reasonable evolution strategy to achieve this goal of evolution. This strategy should have the lowest cost while meeting the evolution goal. The access network evolution strategy proposed by UTStarcom is: first introduce the business architecture of the future network to the existing telecom network, and then gradually expand and transform the existing access network according to the business expansion requirements, it conforms to the future network architecture and develops new telecom services on the new business platform. Key Technologies in evolution are: traditional service gateways and telecom service platforms, traditional telephone network gateways, signaling network gateways and data network gateways, broadband air interfaces, and new service access gateways, open smart mobile terminals and broadband access transmission and exchange networks.

Gateway is a key role in evolution. The traditional service gateway evolution method is to introduce the next-generation network service architecture technology in the traditional network to provide interfaces for traditional telecom services in the future. It is an intersection between a traditional network and a future network and a starting point for a smooth transition to the next generation network. The traditional service gateway will have an IP address for multi-service broadband core network transmission interface, through E1 PSTN business interface, SS7 business interface and data network access to the Internet business interface. On the access side, it has an interface to POTS through V5 and an interface to the ISDN access network through UNI, the interface of the Base Station Controller to the PAS access network system, the interface of the GSM base station and the base station controller, the interface of the paging base station, and the interface of the narrowband CDMA base station controller and the base station. These interfaces are interconnected through IP SoftSwitch. They can be installed on the same rack through high-speed LAN interconnection, and different interfaces can be scattered on the edge of the broadband access network. Each interface is a gateway, which can be configured as needed. All the interface gateways complete the conversion of transmission signals and control signals. Telecommunications services are provided by business servers on the business platform. Business servers are responsible for authentication, access control, call processing, roaming management, user management, network management, business management, and billing.

When the traditional service gateway is configured with the PSTN relay interface, SS7 signaling interface, V5 interface, and PAS interface, it is a system with a future network service architecture, a Softswitch function, and can replace existing fixed telephone circuit switching equipment. The access network system still relies on traditional relay networks and access networks to provide switching, wired access, and wireless access functions. Because of its client server architecture, many smart services that are difficult to support by traditional service networks can be easily implemented.

When the traditional service gateway is configured with the PSTN relay interface, the gsm msc interconnection interface, the SS7 signaling interface, the GSM base station and the Base Station Controller Interface, it is a system with a future network service architecture, a Softswitch function, and can replace existing mobile phone exchange devices. The access network system still relies on the traditional mobile network access air interface to provide exchange and mobile access functions. In addition to authentication, call processing, VLR, and HLR functions, network mobile service servers can also provide a variety of new smart services.

When a telecom network has multiple traditional service gateways, the telecom service platform is shared. When multiple traditional service gateways are connected through a high-speed core network, they are logically equivalent to a system with multiple service interfaces on a Softswitch Network. The telecom business platform has the business creation function. Relying on XML-based open gateway control protocols between servers and gateways, such as MEGACO, new businesses can be continuously increased. For example, it provides services for broadband CDMA Universal Mobile Communication Terminal Access Systems and TV cable access systems.

UTStarcom has released the first generation of gateway and server product WACOS. On one side, it supports access to the PSTN, SS7, IP core network, and Internet. On the other side, it supports access through the V5 fixed phone and PHS, supports access through lan pots and PC phones. The server provides call processing for telephone services, supports new and intelligent telephone services, and supports OSS functions such as network management, online billing, user management, and Internet service processing. PHS air interface provides ISDN access function, can provide wireless voice service and medium speed 32 K to 384 K data service at the same time, can be easily expanded to IP-PHS is PHS-GPRS, the performance will be higher than that of gsm gprs. If GPRS provides a transitional means to support data access on the GSM voice network, IP-PHS is seen as a means to meet the wireless data business needs before the broadband CDMA standardization and practical use, at the same time, it is regarded as a low-cost integrated service access solution after the emergence of broadband CDMA. UTStarcom will provide the terminal access function of GSM, CDMA, and cable TV.

In terms of broadband access, UTStarcom believes that IP over ATM supports traditional telecom services while providing support for the future network service control architecture, it is an important access network transmission technology for realizing future full IP services. The reason is: The end of the access network is multi-state, the statistical characteristics of its traffic are unstable, and the transmission indicators allocated to the access network are very strict. The Wired end access network system supports LAN access and television cable access, and WACOS Gateway provides corresponding interfaces on the network side. Gateway devices on LAN and television cables will be the main means for wired households to access the network in the future. Many new business gateways and application services can be established, such as the gateway of household appliances.

In the future, access networks are used to connect various core gateways, media gateways, and servers. They can also provide connection-based and non-connection IP services. UTStarcom's access network product line has always been based on ISDN and has IP-based signaling and access network switching control functions. Soon, the access network devices for TDM switching will be launched, and the access network devices with the ATM switching function will be under development to meet the needs of network evolution. According to the plan of network evolution, the WACOS access network system that supports both fixed and PAS wireless access will first be used as a fixed and mobile switch on the traditional telephone exchange network. Then, the multi-service PAS terminal Supporting wireless ISDN access can provide both voice and high-speed wireless Web services. The AN series of ISDN access network products will develop towards broadband ATM exchange, And the WACOS access network systems that have run to support different telecom services will be connected through the broadband transmission network through point-to-point connection. The Telecommunications Service server platform provides traditional services, new services, and management of users, services, and networks. Once the new end access technology, such as broadband CDMA, is mature, as long as the supporting Access Gateway provides access services, the telecom business platform has corresponding services, and the new telecom business can be launched. In the future, new terminal access services only need to expand the gateway, and new telecom services only need to expand the software on the telecom business service platform, all traditional services, traditional access networks, and traditional end access networks can still be supported. In this way, all networks and business systems will become open access networks.

Iii. Summary
In the future, the telecom network architecture will develop into an open network structure, function structure, control structure, and management structure. From the perspective of transmission, the basic devices of the future network are high-speed routers and packet switching servers used for access and packet switching. A high-speed router is the application end of the switching server. All classification exchange processes are controlled and managed by the server.

From the perspective of providing telecom services, the basic devices of the Future Telecom Network are Service Access Gateway and telecom service servers. All information exchange is actually performed between access gateways. All services are provided by the Service server. A dedicated signaling protocol is required between the gateway and server of the telecom business, between the telecom business and the server, between the network router and the switch controller. These signals are used for both business and Exchange Control and Management of devices, networks, and services. The signaling gateway also provides interfaces for Future Telecom Network Signaling and signaling 7. In order to meet the multi-level access needs and protect the investment of telecom networks and users, the transfer of access networks is the key to the future development of networks.

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