The main business of telecommunication (that is, what you said to do): 1. point of call business 2. Internet business 3. data communication business 4. network element leasing business 3. yellow pages information business 4. international, as well as Hong Kong, Macao and Taiwan communication business 5. emergency communication business
Because you are proficient in the maintenance of computer hardware and software, so it should be the Internet business. (Of course not necessarily)
Internet business and there are many categories: e-lottery business electronic mail business e-commerce certificate business Internet data centers WLAN business LAN business ADSL business Fiber optic access packet switching business ATM business Frame Relay business DDN business
Internet access and applications.
Detailed introduction:A.1 E-lottery business (17987) is established on China Telecom 179 e-commerce platform, telephone/computer as a means of access, relying on China's broadband Internet (CHINANET) to carry out e-commerce business, the business for the majority of the domestic lottery players by dialing the phone (special service number: 17987) to carry out the lottery information query and betting means. The service provides a means for the majority of lottery players in China to inquire about lottery information and place bets by calling the telephone (special service number: 17987). Players can complete customer registration, lottery betting, information inquiry, prize matching and other operations with an ordinary telephone.
B. Electronic mail service is a value-added service based on China Broadband Internet (CHINANET). It is an electronic means of communication that realizes mail transmission through computer technology and modern communication network technology, and it transmits electronic mails that can be text files, data files as well as faxes, voice and image files. The biggest feature of e-mail is that people can receive and send letters at any place and time, solving the limitation of time and space, greatly improving the work efficiency, and providing great convenience for office automation and business activities. At present, China Telecom provides paid e-mail service and free e-mail service.
The free electronic mailbox service provides users with basic e-mail services, including:
1. Sending and receiving mails -- Users can correctly set up the domain name of the sending and receiving server according to the address of the mails, and then input the user name and password of the mailbox to receive mails for local reading or send out mails edited on the client software. edited emails can be sent out. This function should support POP3, IMAP, SMTP and other standard sending and receiving protocols.
2, WEB mail mode--Web Mail refers to the use of standard browser to realize the function of sending and receiving emails through Web mode. Users enter into the Web login page of mailbox to input user name and password, then they can enter into the mailbox.
The chargeable e-mail service has the following functions in addition to providing the basic functions of free electronic mailbox:
1. Secure e-mail
Secure e-mail refers to a series of services provided to the e-mail users to ensure the security of e-mails. Including digital encryption and signature, anti-virus, anti-spam, mail backup and other functions.
2. Video Mail
If you set up a webcam on your computer, users can shoot a video, compress it and send it to the other party as an attachment to an email. After the recipient receives the video e-mail, he or she can download the decoder and watch it.
3, mail arrival to SMS notification
Users will be notified immediately by SMS to their cell phones when they receive emails, and keywords such as the subject, sender and time of the email will be displayed. Users can log in to the mail system's Web page to set up this function, or set the time period for forwarding SMS notification (e.g., restricting nighttime non-forwarding), and also specify which senders need to be notified of their emails, and which do not.
4, corporate mailbox
Email outsourcing is to provide outsourcing mail services to group users. Group users (corporate users or small and medium-sized ASPs) can apply for a certain number of mailbox accounts and storage space from China Telecom, and allocate and manage these mailboxes by themselves.
Business characteristics
1, the sender and the recipient can send or receive mail at any time and any place, and deal with information anytime and anywhere;
2, a letter can be sent to many people at the same time, and can also be repeated many times;
3, no matter where the recipient is far away, the computer can automatically look for the recipient's address, and transmit it quickly;
4, if the recipient is far away, the computer can automatically look for the recipient's address, and transmit it fast;
5, if the recipient is far away, the computer can automatically look for the recipient's address, and transmit it fast;
4, if the letter can not be delivered to the recipient, the electronic mailbox system can be in accordance with the intention of the original sender of the letter back to the letter, and explain the reasons for the return of the letter, or to his friends to receive on behalf of his friends or further forwarding or forwarded to me;
5, with a very strong security and confidentiality measures.
User Use
Web Mode:
Under the Web-based mail system, users can send and receive mails freely by just logging in to the Web page of the mail system and inputting their account numbers and passwords, which is simple, intuitive and convenient.
OP3 mode: Users can send and receive emails through terminal software such as OUTLOOK and FOXMAIL.
C. In order to solve the security problems in e-commerce activities and provide users with a safe and reliable business environment, China Telecom has been carrying out research work on e-commerce security certification since 1996. China Telecom's CA security authentication system (CTCA) passed the joint appraisal of China Cryptography Administration Committee and the Ministry of Information Industry on August 3, 1999, and was certified by the National Center for Information Product Security Authentication (NCIPSAC), obtaining the authentication certificate issued by the NCIPSAC, and becoming the first CA security authentication system that has been granted the right to operate on the public network. The business includes issuance of personal certificates, enterprise certificates and server certificates.
Second, business characteristics
China Telecom's CA security authentication system (CTCA) can issue a CTCA certificate with asymmetric encryption algorithms for individuals, enterprises and websites participating in e-commerce activities, which ensures the security of individuals, enterprises and websites participating in e-commerce in transmitting information on the public network.
The CTCA certificate is equivalent to the "network identity card" of individuals, enterprises and websites. CTCA certificate is equivalent to the "network ID card" of individuals, enterprises and websites, which contains the information of individuals, enterprises and websites. When individuals, enterprises and websites carry out business activities on the network, they can use the security provided by CTCA, and the two parties who do not know each other can use the CA certificate to confirm the authenticity of each other's identities and the reliability of the information transmitted by utilizing the security mechanism provided by CTCA, so that the information transmitted by CTCA can be used to ensure that the information transmitted by CTCA is safe and secure. The information transmitted can utilize the security mechanism provided by CTCA to ensure the integrity and confidentiality of the information.
Third, business positioning:
CTCA business is mainly oriented to individuals, enterprises and websites engaged in online e-commerce activities
Fourth, business realization
China Telecom CA security authentication system (CTCA) adopts equipment and encryption algorithms authenticated by the Office of the State Cryptography Administration Committee, and considering compatibility, the system follows the international PKCS, PKIX series, and PKI series. PKCS and PKIX series standards, and the issued certificates follow ITU-T X.509 V3 standards; according to different applications, the system can issue standard SSL certificates and S/MIME certificates, and interoperate with standard browsers and WEB servers; according to the different needs of actual business systems, the system can expand the certificate attributes on the basis of the X.509 standards to adapt to the needs of different business systems; according to the needs of applications, the system can expand certificate attributes on the basis of the X.509 standards, in order to adapt to the needs of According to the different requirements of different business systems, the system supports the issuance of 512Bit and 1024Bit public key certificates; according to the different requirements of real-time business systems, the system can provide two blacklist querying modes for the application systems, i.e., the OCSP mode and the CRL mode, in which the OCSP mode provides real-time certificate status querying service for the users and the CRL mode regularly provides real-time certificate status querying service for the users, while the CRL mode regularly provides real-time certificate status querying service for the users. CRL method provides users with certificate blacklist list periodically; according to the different application scope of application system, the system can be used to provide users with security certificate service from enterprise intranet to telecommunication network in such a large-scale network.
China Telecom's CA security certification system (CTCA) adopts a hierarchical structure for management, forming a complete system of CA certificate application, issuance and management covering the whole country, which can provide CTCA certificate services for users across the country, so that all kinds of e-commerce users can step into the era of e-commerce with peace of mind, enjoying the rich rewards and great convenience that e-commerce brings to them.
D.I. Business Description
Internet Data Center (IDC) is a new type of Internet service that came into being in the process of Internet development, which is based on the telecom-grade server room and network resources, and provides large-scale, high-quality, safe and secure services for government enterprises, application service providers, content service providers, and system integrators, ISPs provide large-scale, high-quality, safe and reliable server hosting, rental and value-added services such as ASP network platform.
Business Orientation
1, Multinational Enterprises and Institutions
2, National Governmental Institutions
3, Domestic Enterprises and Institutions
4, Internet Service Providers
5, Internet Content Providers
6, E-commerce Service Providers
7, Application Service Providers
7, and other services.
8, system integrators
9, multimedia service providers
10, web site design and hosting providers
Three, the business characteristics
Internet data centers have large-scale site and room facilities, high-speed and reliable internal and external network environment, and systematic monitoring and support means, and a series of conditions such as host hosts of the storage environment. Based on this environment, IDC provides a series of services at different levels from hosting to application outsourcing relying on the Internet. Data centers should not only provide server hardware, fast and safe network, but also provide supervision services for servers, management and service quality assurance of the network, and should have a highly reliable and safe server room network environment. China Telecom currently has four backbone nodes IDC in Beijing, Shanghai, Guangzhou, Xi'an, providing services for the whole country, each province and city have built a telecom-grade IDC room to provide IDC services. IDC has the following business characteristics:
1, lower cost
With the separate construction of the server room and leased leased line compared to the Internet, the overall operating costs have been greatly reduced.
2, high reliability
Telecom-class server room provides 24/7/365 days 7 × 24 hours of operation services, professional and technical personnel responsible for maintenance, network stability, higher security performance. Important network equipment adopts double-point backup, providing 99.99% network connectivity guarantee.
3, high-speed access
Using high-speed lines to achieve non-blocking direct access to the CHINANET backbone, users can choose any 2M-2.5G (exclusive or **** enjoy) access rate.
4, good flexibility
Users to start business quickly, easy to expand the hosting network equipment.
5, service quality assurance
Service Lever Agreement (SLA) is the current international customer service assessment standards, is a kind of service provider and the user signed by the corresponding service. The SLA of China Telecom IDC guarantees to provide users with telecom-grade high-level service assurance, as well as nationally linked 7×24-hour customer service and one-stop solutions.
Four, business types
China Telecom's IDC business includes hosting, resource leasing, value-added services and other businesses.
1, hosting business: the user's host is hosted in the telecommunications department's standard server room environment (including: air conditioning, lighting, humidity, uninterruptible power supply, anti-static flooring, rack space, etc.), using bandwidth exclusive or ****-enjoyed access to the Internet through the high-speed data port. Users can maintain the host computer remotely and entrust the bureau to complete the specified maintenance work according to the maintenance agreement signed with the bureau. Hosting business mainly includes:
(1) Rental of machine space: It refers to the provision of machine space for user's equipment in the public server room as well as the daily basic management services for the equipment.
(2) Rack Rental: Providing racks for user equipment in the public server room as well as daily basic management services for the equipment.
(3) VIP room (cage) rental: refers to provide users with a relatively independent, closed or semi-closed environment for hosting user equipment.
2, resource rental business
(1) virtual hosting business: the telecommunications sector in the data center's standard server room environment (including: air conditioning, lighting, humidity, uninterruptible power supply, anti-static flooring, etc.) to provide Internet-connected servers and bandwidth disk space rental services. Including exclusive hosting (Dedicated Hosting) and *** enjoy hosting (Shared Hosting).
(2) data storage services: refers to the provision of disk space for user information storage.
(3) Data Backup Service: refers to the provision of data backup for users.
3, value-added services
(1) content distribution services: through the content distribution technology will be provided by the data center users of the content pushed to the CHINANET backbone nodes of the traffic servers, and the combination of wide area network load-balancing technology so that users around the world to first access the nearest traffic servers, so that the user's request to get the fastest response.
(2) Multi-access Mirror Acceleration Service: According to the user's request, the content information will be mirrored to the mirror servers of China Telecom's network nodes, so that the user's request can get the fastest response.
(3) Load Sharing: According to user requirements, IDC users' hosts are placed in a number of IDCs distributed by China Telecom in the backbone network nodes, and access requests are directed to the most suitable hosts according to the connectivity status and delay time of the WAN.
(4) Off-site Disaster Tolerance: It refers to storing user data in data centers in different geographical areas, so that when an unpredictable disaster occurs in one of the places, the user's data and functions can be quickly restored to improve the disaster tolerance and security of the user's system.
(5) system security: security management services are divided into two main categories, one is hardware and software firewalls, the other is to provide, security consulting on a regular basis, security scanning and intrusion detection services.
(6) statistical analysis: to provide users with traffic analysis and other services.
V. Application cases
As a well-known professional game site, the legendary game network of data security, reliability and speed and many other aspects of the high demand. At the same time, LegendaryGames.com must also always meet the needs of players with high-speed network response time while the number of users is surging.
Shanghai Telecom's IDC provides a stable guarantee and strong support for LegendaryGames.com's broadband journey.
Shanghai Telecom IDC server room implements full intelligent management. It has four fiber optics up to 1G directly connected to the Shanghai IP city backbone network, and all the internal lines and equipments adopt double backup, which not only guarantees sufficient Internet access bandwidth, but also greatly improves the security and redundancy of network access. It provides a redundant and stable network environment for high-traffic users like LegendaryGames.com.
Legendary Game.com entered the Chinese market in November 2001, rapidly increasing the popularity of its website in a short period of time, with thousands of hosted servers at present. China Telecom's IDC business has made Legend quickly become an online game that players know and care about.
E.I. Business Description
WLAN service utilizes the advanced Wirless LAN wireless LAN technology, which is an extension and supplement to wired broadband access. It includes a wireless network card configured for computer terminals, a base station capable of sending and receiving data wirelessly like a mobile base station, and a number of other access control devices. Users only need to insert a wireless network card in the personal computer, and then install other equipped software, you can realize mobile broadband Internet access in the coverage area.
Second, business characteristics
1, easy to install and maintain: no wiring, just plug the wireless card into the PC, and then install its software.
2, high-speed broadband access: can provide a maximum of 11Mbps bandwidth to fully meet customer demand for broadband services, ideal for high-speed Internet access and video services and other broadband services.
3. Highly Secure and Reliable: Utilizes built-in security monitoring features and sophisticated encryption technology to achieve higher network security.
4. Totally free mobility: continuous connection, mobile office, enjoy a series of value-added broadband information services such as online securities, video-on-demand (VOD), tele-education, telemedicine, videoconferencing, online games, and so on anytime, anywhere.
Third, business positioning
Wireless LAN service is the supplement and extension of fixed broadband service, which can y provide personalized services for hot spots, enterprises and families, so that the convenience and high efficiency of wireless broadband can be truly reflected in the eyes of the world, and people can really feel the freedom and fashion of wireless broadband. It is more suitable for the following applications:
1. Family wireless broadband Internet access, especially for SOHO family.
2. High traffic flow of high-level places: such as airports, exhibition centers, high-level business hotels, large stadiums, recreation centers, coffee bars and so on.
3. High-end community users and modern enterprise users with higher demand for bandwidth, such as import and export trading companies, securities companies, accounting firms, joint ventures and so on.
4. Temporary need for rapid networking occasions.
Fourth, the business brand
WLAN (wireless LAN) national unified business brand includes "WLAN Skywing" and "Wireless Network Express". "WLAN Sky Link" refers to the way users can access the Internet wirelessly in public areas covered by WLAN (such as venues, Internet cafes, etc.), and "WLAN Express" refers to the way users can access the Internet wirelessly in fixed places such as homes and companies.
V. Business Realization
With the high-speed China Broadband Internet (CHINANET) and metropolitan area networks around the world, China Telecom has taken the lead in launching broadband wireless LAN service
F.I. Business Description
LAN (Local Area Network) service mainly adopts the Ethernet technology to provide users with services in the form of informationized community. the form of informationized cell to serve the users. Using high-speed switches in the central node, it provides users with FTTX (fiber to the cell) + LAN (network cable to the home) broadband access. Users only need a computer and a network card for high-speed access to the Internet.
Two, business characteristics
1, high-speed. Basically, it is a gigabit to the neighborhood, a hundred megabytes to the residential building, and ten megabytes to the user.
2, convenient. Low cost and good reliability of access equipment. Users only need a 10Mbps network card can easily access the Internet.
Three, business brand
LAN national unified business brand "LAN Broadband".
Fourth, business positioning
LAN virtual dial-up access business is mainly suitable for users to focus on the new community, LAN leased line access business for commercial buildings, schools, large enterprises and other users of high-speed access to the Internet.
V. Business realization
China Telecom has opened up the LAN access service nationwide, and the business scope covers county-level cities.
G.I. Business Description
ADSL (Asymmetrical Digital Subscribe Line) is to utilize the existing twisted pair of copper wires (i.e., ordinary telephone wires) to access the Internet with asymmetrical transmission rates in upstream and downstream, with the upstream (from the subscriber to the network) being a low-speed transmission up to 1Mbps; the downstream (from the network to the subscriber) being a low-speed transmission up to 1Mbps; and the downstream (from the network to the subscriber) being a low-speed transmission up to 1Mbps. The uplink (from the user to the network) is a low-speed transmission of up to 1Mbps; the downlink (from the network to the user) is a high-speed transmission of up to 10Mbps ( Editor: refers to the theoretical value of using ADSL2+ technology over a transmission distance of 2.5 kilometers).
ADSL currently provides two access methods: virtual dial-up access and leased line access.
Two, business characteristics
1, easy to install
China Telecom ordinary telephone users apply for ADSL service, just install the appropriate ADSL terminal equipment in the ordinary telephone user side to enjoy broadband services, the original telephone line does not need to be transformed, easy to install, easy to use, to avoid users caused by the transformation of the line of the wiring difficulties and damage to the interior decoration and many other problems. The company's products and services are designed to meet the needs of the market and to meet the needs of the customers.
2, high-speed Internet
ADSL is a rate asymmetric access technology, the transmission rate uplink up to 1Mbps, downlink up to 10Mbps, in line with the user's use of the Internet use characteristics: browsing or download more, upload less.
3. Bandwidth exclusivity
ADSL is a point-to-point star network structure, and the user's ADSL line is directly connected to China Telecom's IP metropolitan area network backbone, which ensures that the user has exclusive access to the line and bandwidth.
4, Internet access and phone calls without interference
After installing ADSL service, users can directly utilize the existing telephone line to access the Internet and make phone calls at the same time (the phone remains unchanged from the original number), without interfering with each other.
5, ADSL dedicated line access with a fixed IP address
three, the business brand
ADSL national unified business brand "ADSL Network Express".
Fourth, business positioning
ADSL virtual dial-up access business is for home users, small and medium-sized users of broadband Internet access, both for centralized and decentralized user access, ADSL dedicated line access business is mainly for Internet cafes and other commercial users and small and medium-sized users.
V. Business realization
With the huge and sound copper core cable network resources, China Telecom has opened up the ADSL access business nationwide, the business scope covers the county-level cities and most of the townships, and it can easily provide ADSL access business for individual and enterprise users.
H.I. Description of Business
Fiber optic access refers to the use of fiber optics as a transmission media between the bureau end of the China Broadband Internet (CHINANET) and the customer completely or partially. Fiber optic access network has a variety of ways, the most important are fiber to the curb, fiber to the building and fiber to the home, that is, often referred to as FTTC, FTTB and FTTH.
Second, business characteristics
1, the transmission distance is far away: fiber optic connectivity distance of up to 70 kilometers.
2, fast transmission speed: fiber optic access can provide 10Mbps, 100Mbps, 1000Mbps high-speed bandwidth.
3, low loss: due to the high purity of fiber optic media manufacturing, so the loss of optical fiber is extremely low, so that the number of relay stations in the communication line can be reduced, improving the quality of communication.
4, strong anti-disturbance ability: because the fiber is a non-metallic dielectric material, the use of optical fiber as a conduction medium, free from electromagnetic interference.
Three, business positioning
Because fiber optic access can provide 10Mbps, 100Mbps, 1000Mbps high-speed broadband, and directly converge on the China Broadband Internet (CHINANET) to achieve broadband multimedia applications, mainly for group users and intelligent communities, hotels, business buildings, campus networks and other high-speed access to the
I.I. Business Description
Packet switching is an advanced means of communication developed to adapt to computer communication, which is based on CCITT X.25 recommendation, and can satisfy the communication between terminals and terminals, terminals and computers, computers and computers with different rates and models, so as to realize the database resource **** enjoyment. Different from other switching methods, packet switching is according to certain rules, a whole data message is divided into a number of fixed-length data segments, and each data segment is added with the address of the receiving and transmitting terminals and other control information, and then transmitted in a packet as a unit in the network.
The outstanding advantage of packet switching is that multiple virtual circuits can be opened on a single circuit at the same time, which can be used by multiple users at the same time, and the network has dynamic routing function and BER detection function, which has a better performance.CHINAPAC provides low-rate data switching service below 64K, which is especially suitable for the application of high communication frequency and small amount of communication in a single time.
Two, business characteristics
1, high quality of information transmission: packet switching mode has strong error control function, which not only adopts error checking and retransmission function when transmitting packets between node switches, but also for some terminals with the function of mounting and dismounting packets, error control can be carried out on the subscriber line as well, which makes the packets in the intra-network transmission with a greatly reduced error rate. In the transmission circuit of the BER in the case of 1x10-5, packet network throughout the BER can be guaranteed in the 1x10-10 below, which shows that the packet switching can make the transmission quality greatly improved.
2, high network reliability: in the packet switching network, "packet" in the network transmission routing is to take the dynamic routing algorithm, that is, each packet is free to choose the transmission path, the switch calculates an optimal path. Because the packet switch is connected to at least two other switches, so when a switch or trunk failure within the network, the packet can automatically avoid the fault location, choose another circuitous route to transmit, will not cause communication disruption.
3, convenient for different types of terminals to communicate with each other: packet switching network for the transmission of data can be stored and forwarded, so that terminals with different rates can communicate with each other. As the packet network provides standard interface to the users with X.25 protocol, so wherever the equipment not conforming to this protocol enters the network, the network provides the protocol conversion function, so that the terminals with different code types and different protocols can communicate with each other.
4, good economic performance: the transmission cost of packet switching has nothing to do with the distance, regardless of whether the user is used in the same city or across the provinces, it is calculated according to the same unit price, which provides the users with an affordable means of information transmission.
III. Service Types
1. Basic Services
(1) Switched Virtual Circuit (SVC): It can communicate with different users at the same time, which is convenient and flexible.
(2) Permanent Virtual Circuit (PVC): can establish a fixed connection with one or more users.
2. Optional Services
(1) Closed User Group (CUG): limited to communication between specific users to avoid interference from outsiders.
(2) Network User Identity (NUI): Provides tight security and enables national roaming.
(3) Broadcast service: one-way point-to-multipoint messaging.
(4) Reverse billing: paid by the called party.
(5) Other services: including call forwarding, direct calling, call blocking (inbound/outbound) quick selection, etc.
3. Other Business Functions
(1) Information Card Verification Service (POS): Simultaneous data transmission over telephone lines without mutual interference, 2-3 times faster than traditional POS service.
(2) Virtual Private Network
(3) Asynchronous Polling Interface (APT)
4, value-added services:
EDI business:
Electronic Data Interchange (EDI, Electronic Data Interchange) is an application service carried on packetized networks through computer communication networks. Communication network, from one computer to another computer transmission of electronic data files with a certain standard format. EDI use store and forward the supply chain enterprise trade process order form, invoice, bill of lading, customs declaration, import and export licenses, freight bill and other data in a standardized format, through the computer and communication networks for transmission, exchange, processing, instead of trade, transport, insurance, banking, customs, commodity inspection and other industries manually process information, postal exchange of documents, so that the transaction behavior is faster, safer and more efficient. EDI network organizational structure is built on the packet network star network structure.
Four, business positioning
(1) applicable to banking, insurance, securities, customs, taxation, retail business network interconnection;
(2) group companies, enterprises, institutions of the office system interconnection;
(3) civil aviation, railway stations and other ticketing system interconnection;
Application:
(1) Low transmission rate, high security, high reliability, allowing a certain time delay applications
(2) Users who need to frequently communicate with unspecified objects
(3) Users who need to communicate with different types of terminal equipment at different rates
(4) Users who have a small amount of communication and more dispersed communication time
(5) Users who need to establish a closed user group
V. Business realization
(1) Dialing mode:
Provides SVC service. Customers only need to add terminal equipment and modem to the existing telephone line to access the packet-switched network by telephone dialing (X.28 or X.32).
(ii) Leased line mode:
Provides PVC and SVC services. It can be categorized as accessing the packet-switched network through data leased lines or ordinary leased lines.
VI. Application Examples
Using packet network to carry out real-time business processing of this system.
National economic sectors have their own different computer application systems, such as the financial system of the through deposit and exchange, automated teller machine business (ATM), the securities company's market release; transportation, railroad, civil aviation system of booking services; public security departments of the household registration management; lottery betting point networking, etc., which many applications can be carried out in the packet network. At present, there are many departments to use the packet network to carry out the above business, and received a good benefit. Such as a long-distance bus transportation company to use the group network to establish a ticketing network, so that the outlets around the real-time information transfer, the Spring Festival, to carry out the pre-sale of tickets for 20 days of business, so that the volume of passenger traffic than in previous years rose by 10%. From here we can see: the grouping network in improving efficiency at the same time, will bring great economic benefits.
J.I. Business Description
ATM is the English abbreviation of ASYNCHRONOUS TRANSFER MODE (Asynchronous Transfer Mode), which is a fast packet switching technology developed on packet switching technology. It adopts statistical time-division multiplexing technology and absorbs the advantages of high efficiency of packet switching and high speed of circuit switching comprehensively to address the defects of relatively low packet switching rate and utilize the advantages of high efficiency of packet switching and high speed of circuit switching. It adopts statistical time division multiplexing technology and absorbs the advantages of high efficiency of packet switching and high speed of circuit switching, and in view of the defects of low rate of packet switching and the characteristics of circuit switching which is almost independent of protocol processing, it improves the processing speed through high-performance hardware equipment and realizes the high-speed transmission.ATM carries out the data transmission with the unique ATM signal element, and each ATM signal element is 53 bytes. It can transmit voice, data, image and video services. It can provide high speed data transmission channel between 256K and 622M.
Two, business characteristics
1, flexibility: dynamic allocation of circuit bandwidth as needed, a physical transmission channel can be dynamically divided into a number of sub-channels, each sub-channel is able to provide different rates of service.
2, high speed: ATM simplifies the control of the protocol, less delay, the transmission rate of N * 2MBPS?622MBPS, can meet the LAN and WAN communication of various business requirements.
3, multi-service: ATM network as a multi-service access platform, can meet the data, voice, images and other digital business requirements of different transmission rates.
4, reliability: ATM network provides a good quality assurance mechanism, which can ensure the realization of video on demand and other broadband real-time services.
5, security: users occupy the bandwidth independent of each other, completely eliminating *** enjoy bandwidth brought about by illegal invasion and other insecurity factors.
Three, business positioning
ATM network can be used in finance, aviation, economic and trade, meteorology, government agencies, customs, broadcasting, business, education, construction, medical and other fields, the main applications are:
1, high-speed interconnection of LANs;
2, high-quality videoconferencing;
3, distance learning;
4, remote medical diagnosis;
5, remote collaborative work;
6, multimedia communication;
7, video-on-demand (VOD) and TV-on-demand;
8, timing, selectable bandwidth of various services.
Four, the types of services
The types of data transmission services provided by the network composed of ATM technology include: ATM Permanent Virtual Connection Service (ATM PVC service), ATM Switching Virtual Connection Service (ATM SVC service), Frame Relay Bearer Service (FRBS), and Circuit Emulation Service.
Currently, according to the geographical scope of service provision, it can be subdivided into local ATM service, domestic ATM service, international and Hong Kong, Macao and Taiwan ATM service.
Domestic ATM services are available directly to provincial capitals and some local cities.
International, Hong Kong, Macao and Taiwan ATM services to countries and regions: Hong Kong, Taiwan, Japan, the United States, Singapore and other countries.
V. ATM Service Levels
At present, the ATM network can open the following four service levels for users: Constant Bit Rate (CBR) service, Real-Time Variable Bit Rate (RT-VBR) service, Non-Real-Time Variable Bit Rate (NRT-VBR), and Unlimited Bit Rate (UBR) service.
1. CBR services are characterized by being connection-oriented, having a fixed bit rate, and having a timing relationship between communication endpoints. In the entire connection process can be sustained peak cell rate (PCR) for transmission, the communication terminal can be in any moment, time period to equal or less than (PCR) cell rate for transmission. The main applications require a fixed bandwidth connection, such as voice services, the requirements of strict timing image services and circuit simulation services.
2, RT-VBR service is characterized by connection-oriented, variable bit rate, timing relationship between communication endpoints. The bandwidth occupied by the communication endpoints changes with the change of terminal information sending rate at different times, and the ATM network gives the guarantee of SCR to the communication terminals, and at the same time requires that the communication terminals shall not send information at a rate greater than the peak cell rate (PCR). RT-VBR services are mainly applied to the services with strict time sensitivity requirements (requiring strict delay and delay variation), such as the image services and so on.
3. NRT-VBR service is characterized by connection-oriented, variable bit rate and no timing relationship between communication endpoints. The bandwidth occupied by communication endpoints varies with the rate of terminal information sent at different times, and ATM network gives SCR guarantee to communication terminals, and at the same time requires communication terminals to send information at a rate not greater than the peak cell rate (PCR).NRT-VBR services are mainly applied to sudden services that do not require strict requirements for delay and delay variation, such as data transmission, E-MAIL, FAX and other services. services.
4, UBR service is characterized by connection-oriented
.