The rapid development of the Internet has greatly promoted the modernization of information technology. Digital technology is replacing the original analog technology, and digitalization makes the interconnection and intercommunication of the network possible. Because of its unique network advantages, the cable TV network will become the best mode for multimedia communication, comprehensive business development, and finally the transmission of voice, data, analog/digital video and other information on the same network. China's cable TV network is developing towards network and digitalization. The key to building a broadcasting network into a broadband comprehensive service information network is to establish a fixed-band data network.
At present, data services of cable television broadband include:
(1) Broadcasting of digital TV programs.
(2) Transmission of high-speed data broadcasting.
(3) High-speed Internet access: provide users with Internet services, online securities, online games, IP telephones, large-capacity data information services, VOD services, weather forecasts, traffic data broadcasting, recruitment, recruitment, and real estate transactions. Rental, sale and other commodity transactions and other information.
(4) Private network and private line rental: establish a government agency office automation data network to realize e-government; provide private line access, virtual private line, circuit simulation, Local area network interconnection and other access services; establish interactive telemedicine, distance teaching, conference TV, e-commerce, etc., to provide services for all walks of life.
(5) The intelligent community system has been realized: through the HFC network, functions such as automatic meter reading, monitoring system, and community property management have been realized.
(6) GIS network management function: realize network equipment and channel management system, encryption and billing system, network self-inspection and self-diagnosis system under the GIS platform.
A planning and design principle of broadband data network system
1. general principles of design
The general principles of metropolitan broadband data network design are: safe and reliable, advanced technology, and easy network upgrade; give full play to the broadband advantages of cable television networks and develop multi-functional applications.
Security: includes 4 levels, namely network security (physical layer security, network structure security), operating system security, data security, and application security. In terms of network security, it is divided into wide area network and local area network system, and the security is guaranteed by adopting technologies such as firewall, VPN, VLAN, data encryption, and digital signature.
Reliability: The reliability of broadband data network should consider redundant backup of network lines, load sharing, dynamic connection of routing protocols, dynamic connection of IP addresses, backup configuration of domain name system, and high reliability configuration of equipment.
Scalability: The expansion of network capacity should be considered. Expansion of network technology, expansion of network bandwidth, expansion of network users, expansion of network database, etc.
Openness: Adopt protocols and interfaces that conform to international and domestic industry standards, such as ITU-T, IETF, ANSI, etc., to realize interconnection with other networks and information resources.
Manageability: Through the unified management of the network layer and the application layer, comprehensive control can be realized. The network management protocol is based on the SNMP and TCP/IP protocols that meet international standards, and controls equipment, performance, configuration, resources, and users. Billing settlement, application management.
Advanced technology: adopts the latest and mature international DPT technology, POS technology, Gigabit Ethernet switching technology, IPQoS technology, VPN technology, Layer 3/4 switching technology, HA technology, digital signature technology, VOD technology, Multimedia application technology, etc. meet the needs of business and users.
2. broadband data network structure
Based on the overall design of the radio and television broadband IP network, the architecture of the entire system can be divided into four levels:
Broadband data network system: includes various technologies of wide area network, local area network and access network, unifies all technologies through IP, and unifies data, voice, and video services into one network. In terms of network system design, it will provide a multimedia communication platform that is safe, reliable, advanced in technology, open, based on standards, flexible in configuration, manageable, scalable, cost-effective, and oriented to next-generation network technology.
Broadband data network operating system: Through automatic management of network resources, intelligent optimization control ensures reliable operation of network equipment, combined with network management system, further strengthens network control.
Broadband data network application system: the network application system provides standard Internet services, such as Web, E-mail, FTP, broadband video/audio services such as VOIP, data broadcasting, etc., and can also provide a variety of IP value-added services and cross services such as E-mail -mail forwarding BP machine, E-mail forwarding mobile phone, electronic reminder, stock trading, online shopping, property consulting, e-commerce, etc.
Business operation planning: how to organically unify scattered user groups and businesses, and synthesize new businesses to develop markets and serve customers is a perfect business idea.
The integrated system management and security control run through the broadband data network system, network operating system and network application system. Through the integrated management platform, system resource management, performance management, configuration management, user management, billing management, security Management and user-defined management functions. The entire management system can be either centralized or distributed. Our platform can meet the scalability and scalability requirements of users. Security and reliability can be achieved through layered control, active and passive control to achieve the most stringent requirements.
3. Network IP address allocation and domain name system planning
Unified planning of network addresses and city names, here mainly proposes the principles of IP allocation and city name planning. City name planning should pay attention to hierarchy and consistency. Internal city names and external city names should be set separately to reflect the organizational structure and be easy to manage. Address allocation should follow the following principles:
● Simplicity: The allocation of addresses should be simple, avoiding complex masking methods in the backbone L.
●Continuity: Allocate consecutive network addresses for the same network area, which facilitates the use of reduced routing table entries and improves the processing efficiency of routers.
●Scalability: The network address allocated for a network area should have certain redundancy, so that the continuity of addresses can be maintained when the number of hosts increases.
●Flexibility: Address allocation should not be based on an optimization scheme of a certain network routing policy, and it should be convenient for most routing policies to realize modernization on this address allocation scheme.
●Manageability: The allocation of addresses should be layered, and a local change should not affect the upper layer and the overall situation.
●Security: The network should be divided into different sections according to the work content for management.
As a broadband IP network design, the IP address planning, routing planning, and city name planning of the entire network are very important. Each district city node uses intra-domain routing protocol OSPF. OSPF has two main features: one is its openness. Its protocol specification is defined by RFC1247; second, it is based on the SPF algorithm, which is a routing resolution based on link state (linkstate).
Therefore, it requires each router to send link state advertisements (LSAs) to all other routers in its same management domain (Area). OSPF is responsible for distributing routing information between different areas, and it is accomplished through so-called domain border routers.
