The main business of telecommunications (that is, what you said it does): 1. Click-to-call business 2. Internet business 3. Data communication business 4. Network element leasing business 3. Yellow pages information business 4. International And Hong Kong, Macao and Taiwan communication business 5. Emergency communication business
Because you are proficient in computer software and hardware maintenance, you should go to the Internet business. (Of course not necessarily)
There are many types of Internet business : Electronic lottery business, electronic mailbox business, e-commerce certificate business, Internet data center, WLAN business, LAN business, ADSL business, optical fiber access, packet switching business, ATM business, frame relay business, DDN business
Internet access and applications.
Detailed introduction: A.1 electronic lottery business (17987) is an e-commerce business established on the China Telecom 179 e-commerce platform, using telephone/computer as the access method, and relying on China Broadband Internet (CHINANET). This service provides domestic lottery players with a means to inquire about lottery information and place bets by dialing the phone number (special service number: 17987). Lottery players can use an ordinary phone to complete customer registration, lottery betting, information inquiry, prize matching and other operations.
B. The e-mail service is a value-added service based on China Broadband Internet (CHINANET). It is an electronic communication method that realizes mail transmission through computer technology and modern communication network technology. The electronic letters it transmits can be text files, data files, faxes, voice and image files, etc. The biggest feature of email is that people can receive and send letters at any time, which solves the limitations of time and space, greatly improves work efficiency, and provides great convenience for office automation and commercial activities. Currently, China Telecom provides paid e-mail services and free e-mail services.
The free e-mail service provides users with basic e-mail services, including:
1. Sending and receiving letters - the user correctly sets the domain name of the sending and receiving server according to the email address, and then enters the email address With the user name and password, you can collect emails to read locally, or send emails edited on the client software. This function should support standard sending and receiving protocols such as POP3, IMAP, and SMTP.
2. WEB mail method - Web Mail refers to using a standard browser to realize functions such as sending and receiving emails through the Web. The user enters the mailbox's Web login page and enters the user name and password to enter the mailbox. .
In addition to providing basic free email functions, the paid email service also has the following functions:
1. Secure email
Secure email refers to the A series of services provided by users to ensure email security. Including digital encryption and signature, anti-virus, anti-spam, email backup and other functions.
2. Video email
If a camera is set up on the computer, the user can shoot a video, compress it and send it as an attachment to the email and send it to the other party. After the recipient receives the video email, he or she can download the decoder to watch it.
3. SMS notification of email arrival
After the user receives the email, it will be notified to the mobile phone immediately in the form of text message, and the subject, sender, and Keywords such as time. Users can log in to the web page of the email system to set up this function, and can also set the time period for forwarding SMS notifications (for example, restricting forwarding at night), and specify which senders' emails need to be notified and which do not need to be notified.
4. Corporate mailbox
Email outsourcing is an outsourcing email service provided to group users. Group users (enterprise users or small and medium-sized ASPs) can apply for a certain number of email accounts and storage space from China Telecom, and allocate and manage these mailboxes themselves.
Business Features
1. Both the sender and the recipient can send or receive letters at any time and anywhere, and process information anytime and anywhere;
2 , A letter can be sent to multiple people at the same time, or repeated multiple times;
3. No matter where the recipient is, the computer can automatically find the recipient's address and send it to him very quickly;< /p>
4. If the letter cannot be delivered to the recipient, the e-mail system can return the letter according to the original sender's intention and explain the reason for the return of the letter, or redirect it to his friend to receive it on his behalf or forward it further. Or transfer it to me;
5. Have strong security and confidentiality measures.
User usage
Web method:
Under the Web-based mail system, users only need to log in to the Web page of the mail system and enter their account number and password. You can send and receive emails freely, it is simple, intuitive and convenient.
OP3 method: Users can send and receive emails through terminal software such as OUTLOOK and FOXMAIL.
C. In order to solve security problems in e-commerce activities and provide users with a safe and reliable business environment, China Telecom began research on e-commerce security certification in 1996.
China Telecom CA Security Certification System (CTCA) passed the joint appraisal of China Cryptozoology Management Committee and the Ministry of Information Industry on August 3, 1999, and passed the certification of the National Information Product Security Certification Center, and obtained the certification issued by the National Information Product Security Certification Center. certificate, becoming the first CA security certification system to obtain public network operation rights. The business includes the issuance of personal certificates, enterprise certificates and server certificates.
2. Business Characteristics
China Telecom CA Security Certification System (CTCA) can issue a CTCA certificate using asymmetric encryption algorithm to individuals, enterprises and websites participating in e-commerce activities. , ensuring the security of information transmitted on the public network by individuals, companies and websites participating in e-commerce. The CTCA certificate is equivalent to the "network ID card" of individuals, companies and websites. It contains the information of individuals, companies and websites. When individuals, companies and websites conduct business activities on the Internet, they can use the security provided by CTCA. Guarantee, two parties who do not know each other can use the CA certificate to confirm the authenticity and reliability of the other party's identity. The transmitted information can use the security mechanism provided by CTCA to ensure the integrity and confidentiality of the information.
3. Business positioning:
CTCA business is mainly aimed at individuals, enterprises and websites engaged in online e-commerce activities
4. Business realization
< p>China Telecom CA Security Authentication System (CTCA) uses equipment and encryption algorithms certified by the Office of the National Cryptozoology Management Committee. Considering compatibility, the system follows the international PKCS and PKIX series standards, and the certificates issued comply with ITU-T X.509 V3 Standard; according to different application situations, the system can issue standard SSL certificates and S/MIME certificates to achieve interoperability with standard browsers and WEB servers; according to the different needs of actual business systems, the system can be based on the X.509 standard The extension of certificate attributes to adapt to the needs of different business systems; according to the different requirements of the application system for security strength, the system supports the issuance of 512Bit and 1024Bit public key certificates; according to the different requirements of the business system for real-time performance, the system can provide application systems with There are two blacklist query methods, namely OCSP method and CRL method. The OCSP method provides users with real-time certificate status query services, while the CRL method provides users with a certificate blacklist list on a regular basis; depending on the application scope of the application system, the system can use It is used to provide users with security certificate services on large-scale networks such as corporate intranets and telecommunications networks.China Telecom CA Security Certification System (CTCA) adopts hierarchical structure management to form a complete system of CA certificate application, issuance and management covering the whole country. It can provide CTCA certificate services to users nationwide and enable all types of e-commerce. Users can enter the era of e-commerce with confidence and enjoy the huge returns and great convenience that e-commerce brings to them.
D. 1. Business Description
Internet Data Center (IDC) is a new type of Internet service that emerged during the development of the Internet. It is a carrier-grade Relying on the computer room and network resources, it provides large-scale, high-quality, safe and reliable network platform for server hosting, leasing, ASP and other value-added services for government enterprises, application service providers, content service providers, system integrators, and ISPs.
2. Business positioning
1. Multinational enterprises and institutions
2. National government institutions
3. Domestic enterprises and institutions< /p>
4. Internet service provider
5. Internet content provider
6. E-commerce service provider
7. Application software Service provider
8. System integrator
9. Multimedia service provider
10. Website design and hosting provider
Three , Business characteristics
The Internet data center has a host storage environment with a series of conditions such as large-scale venues and computer room facilities, high-speed and reliable internal and external network environments, and systematic monitoring support methods. Based on this environment, IDC provides a series of services at different levels based on the Internet, from hosting to application outsourcing. The data center must not only provide server hardware and fast and secure networks, but also provide server supervision services, related network management and service quality assurance, and must have a highly reliable and secure computer room network environment. China Telecom currently has four backbone node IDCs in Beijing, Shanghai, Guangzhou, and Xi'an, providing services nationwide. Each province and city has built carrier-grade IDC computer rooms to provide IDC services. IDC has the following business characteristics:
1. Lower cost
Compared with building a separate computer room and renting a dedicated line for Internet access, its overall operating cost is greatly reduced.
2. High reliability
The carrier-grade computer room provides 24/7 operation services, 365 days a year. Professional technicians are responsible for maintenance. The network is stable and the security performance is higher. Important network equipment adopts double-point backup to provide 99.99% network connectivity guarantee.
3. High-speed access
Use high-speed lines to achieve non-blocking direct connection to the CHINANET backbone network. Users can choose 2M-2.5G (exclusive or exclusive) access at will. input rate.
4. Good flexibility
Users can start services quickly, and managed network equipment can be easily expanded.
5. Service Quality Assurance
Service Lever Agreement (SLA) is currently an internationally accepted customer service evaluation standard. It is a contract signed by service providers and users. Corresponding services. China Telecom IDC's SLA guarantees to provide users with carrier-grade high-level service guarantees, as well as nationally linked 7×24-hour customer services and one-stop solutions.
IV. Business types
China Telecom’s IDC business includes hosting, resource leasing, value-added services and other businesses.
1. Hosting business: refers to the user’s hosting business being hosted in the standard computer room environment of the telecommunications department (including: air conditioning, lighting, humidity, uninterruptible power supply, anti-static floor, rack space, etc.) , using bandwidth exclusive or exclusive mode to access the Internet through high-speed data ports. Users can maintain the host remotely and entrust the administrator to complete specified maintenance work according to the maintenance agreement signed with the administrator. Hosting business mainly includes:
(1) Computer space rental: refers to providing computer space for user equipment in a public computer room and providing daily basic management services for the equipment.
(2) Rack rental: refers to providing racks for user equipment in public computer rooms and providing daily basic management services for the equipment.
(3) VIP computer room (cage) rental: refers to providing users with a relatively independent, closed or semi-closed environment to store user equipment.
2. Resource leasing business
(1) Virtual host business: The telecommunications department operates in the standard computer room environment of the data center (including: air conditioning, lighting, humidity, uninterruptible power supply, Anti-static flooring, etc.) provides server disk space and bandwidth rental services connected to the Internet. Including exclusive hosting (Dedicated Hosting) and shared hosting (Shared Hosting).
(2) Data storage service: refers to the disk space that provides user information storage.
(3) Data backup service: refers to providing users with data backup.
3. Value-added services
(1) Content distribution service: push the content provided by data center users to the traffic server of the CHINANET backbone network node through content distribution technology, and Combined with WAN load balancing technology, users from all over the world first access the traffic server closest to them, so that user requests can receive the fastest response.
(2) Multi-site mirror acceleration service: refers to mirroring content information to the mirror server of China Telecom network nodes according to user requests, so that user requests can receive the fastest response.
(3) Load sharing: According to user needs, the hosts of IDC users are placed in several IDCs distributed by China Telecom in the backbone network nodes, and the access requests are directed to the most popular ones based on the connectivity status and delay time of the WAN. Suitable host.
(4) Remote disaster recovery: refers to storing user data in data centers in different regions. When an unpredictable disaster occurs in one of the places, the user's data and functions can be quickly restored and the user system can be improved. Disaster tolerance and security.
(5) System security: Security management services are divided into two categories, one is hardware and software firewalls, and the other is the provision of regular security consulting, security scanning and intrusion detection services.
(6) Statistical analysis: Provide users with traffic analysis and other services.
5. Application Cases
As a well-known professional game website, Legend Game Network has put forward very high requirements for data security, reliability, speed and many other aspects. . At the same time, Legend Game Network must also meet the needs of players with high-speed network response times as the number of users increases.
Shanghai Telecom IDC has provided stable guarantee and strong support for Legend Game Network’s broadband journey.
Shanghai Telecom’s IDC computer room implements fully intelligent management. It has four up to 1G optical fibers directly connected to the Shanghai IP metropolitan backbone network. All internal lines and equipment adopt double backup, which not only ensures 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 Legend Game Network.
Legend Game Network entered the Chinese market in November 2001 and quickly increased the website's popularity in a short period of time. Currently, it hosts thousands of servers. China Telecom's IDC business has made Legend quickly become an online game that players know and pay attention to.
E. 1. Business description
WLAN business uses advanced Wireless LAN wireless local area network technology, which is an extension and supplement to wired broadband access. It includes wireless network cards configured for computer terminals, base stations that can send and receive data wirelessly like mobile base stations, and other access control equipment. Users only need to plug in a wireless network card on their personal computers and install other configuration software to achieve mobile broadband Internet access within the coverage area.
2. Business characteristics
1. Easy installation and maintenance: no wiring is required, just insert the wireless network card into the personal computer and then install the software it comes with.
2. High-speed broadband access: It can provide a maximum bandwidth of 11Mbps, fully meeting customer needs for broadband services, and is very suitable for broadband services such as high-speed Internet access and video services.
3. Highly safe and reliable: Utilize built-in security monitoring features and complex encryption technology to achieve higher network security.
4. Complete freedom of movement: continuous connection, mobile office, and enjoyment of a series of broadband information value-added services such as online securities, video on demand (VOD), distance education, telemedicine, video conferencing, and online games anytime and anywhere.
3. Business positioning
Wireless LAN business is a supplement and extension of fixed broadband business. It can provide personalized services in depth for hot spots, enterprises and families, making wireless broadband more popular. Convenience and efficiency are truly reflected in the eyes of the world, allowing people to truly feel the freedom and fashion of wireless broadband. It is more suitable for the following application ranges:
1. Home wireless broadband Internet access is especially suitable for SOHO people.
2. High-end places with large passenger flow: such as airports, convention and exhibition centers, high-end business hotels, large sports venues, leisure centers, coffee bars, etc.
3． High-end community users and modern enterprise users who have higher demand for bandwidth, such as import and export trading companies, securities companies, accounting firms, joint ventures, etc.
4. Occasions where rapid networking is required temporarily.
4. Business Brands
WLAN (Wireless Local Area Network) national unified business brands include "WLAN Tianyitong" and "Wireless Network Express". "WLAN Tianyitong" refers to the way users use wireless Internet access in public areas covered by WLAN (such as venues, Internet cafes, etc.), and "Wireless Network Express" refers to the way users use wireless Internet access in fixed places such as homes and companies.
5. Business Realization
With the high-speed China Broadband Internet (CHINANET) and metropolitan area networks in various places, China Telecom has taken the lead in launching broadband wireless LAN services
F. 1. Business description
LAN (Local Area Network, LAN) business mainly uses Ethernet technology to serve users in the form of information-based communities. High-speed switches are used at the central node to provide users with broadband access of FTTX (fiber to the community) + LAN (network cable to the home). Users only need a computer and a network card to access the Internet at high speed.
2. Business characteristics
1. High speed. Basically, it can reach Gigabit to communities, 100 Mbit to residential buildings, and 10 Mbit to users.
2. Convenience. Access equipment has low cost and good reliability. Users only need a 10Mbps network card to access the Internet easily.
3. Business brand
LAN’s national unified business brand is “LAN Broadband”.
IV. Business positioning
LAN virtual dial-up access service is mainly suitable for new communities with concentrated users, and LAN dedicated line access service is suitable for high-speed access by users such as commercial buildings, schools, and large enterprises. internet.
5. Business Realization
China Telecom has opened LAN access services nationwide, and its business scope covers county-level cities.
G. 1. Business Description
ADSL (Asymmetrical Digital Subscribe Line) uses existing twisted pair copper wires (ordinary telephone lines). The above, The downlink asymmetric transmission rate is connected to the Internet. The uplink (from the user to the network) is low-speed transmission, up to 1Mbps; the downlink (from the network to the user) is high-speed transmission, up to 10Mbps (Editor: refers to the use of ADSL2+ technology, in 2.5 Theoretical value within kilometer transmission distance).
ADSL currently provides two access methods: virtual dial-up access and dedicated line access.
2. Business features
1. Easy and fast installation
After China Telecom ordinary phone users apply for ADSL services, they only need to install the corresponding software on the ordinary phone client. With ADSL terminal equipment, you can enjoy broadband services. The original telephone lines do not need to be modified. It is easy to install and use, and avoids many problems such as wiring difficulties and damage to indoor decoration caused by line modification.
2. High-speed Internet access
ADSL is an access technology with asymmetric speed. The transmission rate can reach 1Mbps in uplink and 10Mbps in downlink. It is in line with the characteristics of users using the Internet: browsing or More downloads and less uploads.
3. Exclusive bandwidth
ADSL is a point-to-point star network structure. The user's ADSL line is directly connected to China Telecom's IP metropolitan area network backbone, ensuring that the user has exclusive bandwidth. Enjoy line and bandwidth.
4. Internet access and phone calls do not interfere with each other
After installing the ADSL service, users can directly use existing phone lines to access the Internet and make calls at the same time (the phone keeps the original number without change), the two do not interfere with each other.
5. ADSL dedicated line access has a fixed IP address
3. Business brand
The unified national business brand of ADSL is "ADSL Network Express".
IV. Business positioning
ADSL virtual dial-up access service is a broadband Internet access method for home users and small and medium-sized enterprise users. It is suitable for both centralized user access and decentralized user access. user access. ADSL dedicated line access services are mainly targeted at commercial users such as Internet cafes and small and medium-sized enterprise users.
V. Business Realization
With its large and sound copper core cable network resources, China Telecom has opened ADSL access services nationwide, covering the entire county. Level 1 cities and most rural areas can easily provide ADSL access services to individual and enterprise users.
H. 1. Business description
Optical fiber access refers to the use of optical fiber as the transmission medium completely or partially between the China Broadband Internet (CHINANET) central office and customers. There are many ways to access fiber optic networks, the most important ones are fiber to the roadside, fiber to the building and fiber to the home, which are often referred to as FTTC, FTTB and FTTH.
2. Business characteristics
1. Long transmission distance: the optical fiber connection distance can reach 70 kilometers.
2. Fast transmission speed: Fiber optic access can provide high-speed bandwidth of 10Mbps, 100Mbps, and 1000Mbps.
3. Low loss: Since the manufacturing purity of the optical fiber medium is extremely high, the loss of the optical fiber is extremely low. In this way, the number of relay stations can be reduced in the communication line and the communication quality is improved.
4. Strong anti-interference ability: Because optical fiber is a non-metallic dielectric material, optical fiber is used as the transmission medium and is not subject to electromagnetic interference.
3. Business positioning
Because optical fiber access can provide high-speed broadband of 10Mbps, 100Mbps, and 1000Mbps, and is directly connected to China Broadband Internet (CHINANET) to realize broadband multimedia applications, It is mainly suitable for high-speed Internet access for group users and intelligent communities, hotels, business buildings, campus networks, etc.
I. 1. Business description
Packet switching is an advanced communication method developed to adapt to computer communications. It is based on the CCITT X.25 recommendations and can meet different needs. Speed, communication between different types of terminals, terminals and computers, and computers to achieve maximum sharing of database resources. Different from other switching methods, packet switching divides a whole data message into a number of fixed-length data segments according to certain rules, and adds the receiving and sending terminal addresses and other control information to each data segment, and then Groups are transmitted within the network.
The outstanding advantage of packet switching is that multiple virtual circuits can be opened on one circuit at the same time for use by multiple users at the same time. The network has dynamic routing functions and error detection functions, and has better performance. CHINAPAC provides low-rate data exchange services below 64K, which is especially suitable for applications with high communication frequency and small single communication volume.
2. Business characteristics
1. High quality of information transmission: The packet switching method has a strong error control function. It not only adopts error checking when transmitting packets between node switches. With the retransmission function, and for some terminals with the function of installing and splitting groups, error control can also be performed on the user line, thus greatly reducing the error rate during packet transmission within the network. When the bit error rate of the transmission circuit is 1x10-5, the bit error rate throughout the packet network can be guaranteed to be below 1x10-10. This shows that packet switching can greatly improve the transmission quality.
2. High network reliability: In the packet switching network, the routing selection when "packets" are transmitted in the network adopts a dynamic routing algorithm, that is, each packet can freely choose the transmission path, and the routing is calculated by the switch. Find the best path. Since the packet switch is connected to at least two other switches, when a switch or trunk in the network fails, the packet can automatically avoid the fault location and choose another roundabout route for transmission without causing communication interruption.
3. Facilitate mutual communication between different types of terminals: The packet switching network can store and forward the transmitted data, so that terminals with different speeds can communicate with each other. Since the packet network provides users with standard interfaces using the X.25 protocol, whenever devices that do not comply with this protocol enter the network, the network provides protocol conversion functions so that terminals with different code types and protocols can communicate with each other.
4. Good economic performance: The transmission cost of packet switching has nothing to do with distance. Whether the user uses it in the same city or across provinces, it is calculated at the same unit price, providing users with economical and affordable information. means of transmission.
3. Business types
1. Basic services
(1) Switched virtual circuit (SVC): It can communicate with different users at the same time, which is convenient flexible.
(2) Permanent virtual circuit (PVC): A fixed connection can be established with one or more users.
2. Optional services
(1) Closed User Group (CUG): Communication is limited to specific users to avoid interference from outsiders.
(2) Network User Identity (NUI): Provides strict security and enables nationwide roaming.
(3) Broadcast service: One-way point-to-multipoint information transmission.
(4) Reverse billing: The called party pays.
(5) Other services: including call transfer, direct calling, call blocking (in/out) quick selection, etc.
3. Other business functions
(1) Information card verification service (POS): transmit data simultaneously on the telephone line without interfering with each other, 2-3 times faster than traditional POS service times.
(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 a packet network. It transmits from one computer to another through a computer communication network with certain standards. Format electronic data files. EDI uses the storage and forwarding method to store order orders, invoices, bills of lading, customs declarations, import and export licenses, freight bills and other data in the supply chain enterprise trade process in standardized formats through computers and communication networks. Transmission, exchange, and processing replace the manual processing of information and postal exchange of documents between trade, transportation, insurance, banking, customs, commodity inspection and other industries, making transactions faster, safer and more efficient. The EDI network organizational structure is a star network structure built on a packet network.
IV. Business positioning
(1) Suitable for business network interconnection in banking, insurance, securities, customs, taxation, and retail industries;
(2) Group Interconnection of office systems of companies, enterprises, and institutions;
(3) Interconnection of ticketing systems such as civil aviation and railway stations;
Application occasions:
(1) Applications with low transmission rate, high security, high reliability, and allowing a certain delay
(2) Users who need to frequently communicate with unspecific objects
(3) Needs different from Type, users who communicate with terminal devices at different speeds
(4) Users with less communication volume and scattered communication time
(5) Users who need to establish a closed user group
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5. Business implementation
(1) Dial-up method:
Provide SVC services. Customers only need to add terminal equipment and modems to existing telephone lines and access the packet switching network through telephone dialing (X.28 or X.32).
(2) Dedicated line mode:
Provide PVC and SVC services. It can be divided into accessing the packet switching network through data dedicated lines or ordinary dedicated lines.
6. Application examples
Use the packet network for real-time business processing of this system.
Each department of the national economy has its own different computer application systems, such as deposits and withdrawals in the financial system, automatic teller machine business (ATM), and market releases from securities companies; ticket booking in the transportation, railway, and civil aviation systems services; household registration management of the public security department; networking of lottery betting points, etc. Many of these applications can be carried out on the group network. At present, many departments have used packet networks to carry out the above services and have received good benefits. For example, a long-distance bus transportation company established a ticketing network using a group network to enable real-time information transmission at outlets all over the country. During the Spring Festival travel period, it launched a 20-day pre-sale ticket business, which increased passenger volume by 10% compared with previous years. It can be seen from here that the packet network will bring great economic benefits while improving work efficiency.
J. 1. Business description
ATM is the English abbreviation of ASYNCHRONOUS TRANSFER MODE (asynchronous transfer mode). It is a fast packet switching technology developed on packet switching technology. It adopts Statistical time division multiplexing technology, and comprehensively absorbs the advantages of high efficiency of packet switching and high speed of circuit switching, aiming at the shortcomings of relatively low packet switching rate, using the characteristics of circuit switching that is almost independent of protocol processing, and improving performance through high-performance hardware equipment. processing speed to achieve high-speed transmission. ATM uses unique ATM cells for data transmission, and each ATM cell is 53 bytes. , can transmit voice, data, image and video services. It can provide high-speed data transmission channels between 256K and 622M.
2. Business characteristics
1. Flexibility: Dynamically allocate circuit bandwidth as needed. A physical transmission channel can be dynamically divided into several sub-channels. Each sub-channel can provide different speed business.
2. High rate: ATM simplifies the control of the protocol, has low delay, and the transmission rate reaches N*2MBPS~622MBPS, which can meet various business requirements for LAN and WAN communications.
3. Multi-service: As a multi-service access platform, the ATM network can meet the requirements of digital services with different transmission rates such as data, voice, and image.
4. Reliability: The ATM network provides a good quality assurance mechanism, which can ensure the realization of broadband real-time services such as video on demand.
5. Security: The bandwidth occupied by users is independent of each other, completely eliminating unsafe factors such as illegal intrusion caused by shared bandwidth.
3. Business positioning
ATM networks can be used in finance, aviation, economics and trade, meteorology, government agencies, customs, broadcasting, commerce, education, construction, medical and other fields. The main applications are There are:
1. High-speed LAN interconnection;
2. High-quality video conferencing;
3. Remote teaching;
4. Telemedicine diagnosis;
5. Remote collaborative work;
6. Multimedia communication;
7. Video on demand (VOD) and TV on demand;
8. Various services with timing and optional bandwidth.
IV. Business types
The types of data transmission services provided by networks composed of ATM technology include: ATM permanent virtual connection service (ATM PVC service), ATM switching virtual connection service ( ATM SVC service), frame-in-frame bearer service (FRBS), circuit emulation service.
Currently, according to the geographical scope of business provision, it can be subdivided into local ATM business, domestic ATM business, international and Hong Kong, Macao and Taiwan ATM business.
Domestic ATM services can directly reach provincial capital cities and some prefecture-level cities.
Countries and regions where international and Hong Kong, Macao and Taiwan ATM services are accessible: Hong Kong, Taiwan, Japan, the United States, Singapore and other countries.
5. ATM service levels
At present, the ATM network can open the following four service levels to users: constant bit rate (CBR) service, real-time variable bit rate (RT-VBR) ) services, non-real-time variable bit rate (NRT-VBR), and unlimited bit rate (UBR) services.
1. The characteristics of CBR business are connection-oriented, fixed bit rate, and timing relationship between communication endpoints. Transmission can be continued at a peak cell rate (PCR) throughout the entire connection process, and the communication terminal can transmit at a cell rate equal to or less than (PCR) at any time and period. The main applications require fixed-bandwidth connections, such as voice services, image services that require strict timing, and circuit simulation services.
2. The characteristics of RT-VBR service are connection-oriented, variable bit rate, and timing relationship between communication endpoints. The bandwidth occupied by communication endpoints changes with the terminal information sending rate at different times. The ATM network guarantees SCR for communication terminals and requires communication terminals not to send information at a rate greater than the peak cell rate (PCR). RT-VBR services are mainly used for services that require strict time sensitivity (requiring strict delay and delay changes), such as image services.
3. The characteristics of NRT-VBR service are connection-oriented, variable bit rate, and no timing relationship between communication endpoints. The bandwidth occupied by the communication endpoint changes with the rate at which the terminal information is sent at different times. The ATM network guarantees SCR to the communication terminal and requires the communication terminal to send information at a rate not greater than the peak cell rate (PCR). NRT-VBR services mainly apply sudden services that do not have strict requirements on delay and delay changes, such as data transmission, E-MAIL, FAX and other services.
4. UBR business characteristics are connection-oriented