In the process of transition from analog TV to digital TV, it is particularly important to realize digital collection and broadcast. The broadcast control network of TV stations has been successfully applied in many TV stations, so that the way of establishing a TV digital broadcast system based on hard disk storage has been recognized by the industry and is gradually being promoted and applied.
The construction of the broadcast control network of a television station is a systematic project, which covers various technologies such as computers, videos, and networks. Here, the author will introduce the construction of the broadcast control network of small and medium-sized TV stations in combination with actual work.
1. Business process
The radio and television industry is characterized by strong timeliness and social responsibility. Therefore, the management system of program acquisition, editing, reviewing and broadcasting is very strict. After the program is compiled, it will be broadcast after being checked by the broadcast department. At the same time, the finance and advertising will be broadcast and checked (Figure 1 is the business flowchart).
The broadcast control network of the TV station takes the video server as the main body, giving full play to the advantages of hard disk storage, avoiding the impact of the failure of the recorder, mechanical arm and other equipment on the broadcast, and can easily realize the serial compilation and broadcast between the programs Control management of various insertion and timing broadcast
2. Features
TV station broadcast control network is different from ordinary local area network, it has the following characteristics:
1. Large data flow
This type of network transmission is basically based on MPEG-2 or MPEG-4 video stream, so the network needs to have sufficient throughput to ensure the high-quality and efficient transmission of information.
2. High safety requirements
Television broadcasting is a highly political and socially responsible job. Therefore, it is necessary to prevent illegal access on the network through security technology and ensure network isolation.
3. Strong stability
In order to ensure the "high quality and uninterrupted" broadcast requirements of TV programs, the stability of the network must be guaranteed.
It can be seen from this that in addition to strictly following the principles of advancement, practicability, openness, manageability, and scalability, we should also emphasize high bandwidth, reliability, and security when setting up broadcast control networks for TV stations.
3. Network construction plan
1. Network topology
The broadcast control network of the TV station adopts a star topology structure (Figure 2). The nodes in the network have a high degree of independence and are suitable for the three-layer Browser / Server / DB architecture.
2. Networking technology
At present, commonly used backbone networking technologies are Fast Ethernet (100Mbps), FDDI, Gigabit Ethernet (1000Mbps) and ATM (155Mbps / 622Mbps).
Fast Ethernet is a very mature networking technology, which has a very low cost and a high performance-to-price ratio; FDDI is also a mature networking technology, but the technology is complex and costly, and it is difficult to upgrade; ATM technology is mature, yes Ideal network platform for multimedia application systems, but its actual utilization rate of network bandwidth is very low; currently Gigabit Ethernet has become a mature networking technology, the cost is lower than the ATM network, its effective bandwidth is more than 622Mbps ATM high.
Therefore, the author recommends the use of Gigabit Ethernet as the backbone, fast Ethernet switching to the desktop to build a computer broadcast control network. For small and medium-sized TV stations that do not have sufficient funds, you can choose Fast Ethernet first. After the time is ripe, you can smoothly upgrade to Gigabit Ethernet.
3. Network switching equipment
(1) Network core layer
A Cisco high-end Layer 3 switch Catalyst 6506 (with routing function) is used as the core of the entire switching system, and the network administrator manages and dispatches in a unified manner, so that the TV station broadcast control network is built on a Gigabit Ethernet backbone and has a third It is based on the integrated network communication platform with layer switching function. At the same time, configure two power supplies to supply power at the same time, share the load with each other and backup each other.
(2) Convergence layer
Use Cisco Catalyst 3524 switch or Catalyst 3548 switch as the network layer aggregation layer device. The aggregation layer device will be connected to the core layer device Catalyst 6506 through multimode optical cable and Gigabit Ethernet backbone, and some users can be connected through ultra-category 5 UTP cable. To this layer of switches, to achieve 100Mbps rate connection.
(3) Access layer
In the network access layer, the author chose multiple Cisco 2924 switches as access switches to provide 100Mbps access rate for desktop applications.
4. Computer equipment
(1) Server
As the domain control server, file server and database server, it should be able to meet the long-term work requirements and ensure the safe and stable operation of the system. The server used in the broadcast control network of the TV station integrates a high-performance RAID controller, and at the same time fully uses hot-swappable / hot-swappable components, including hard drives, power supplies, fans, and hot-swappable PCI slots.
(2) Hard disk storage
This system uses a 480GB RAID-3 fault-tolerant hard disk array, which has a faster data transfer rate and a larger storage capacity. At the same time, it uses error correction technology to improve the reliability of storage. There is one parity check disk for each group in RAID-3. When one of the disks in the array group is damaged, the information of the damaged disk can be recovered by the parity of the parity information and the remaining disk information.
(3) Workstation
Workstations use special computers such as subtitles, collection, and broadcast, and some workstations use ordinary computers.
5. IP address planning
Due to the particularity of the system, the entire network uses the reserved network segment 172.XXX.XXX.XXX to match the division of the virtual local area network (VLAN) and configure different subnet segments for different virtual local area networks. The entire network can be easily divided into several subnets, and the communication between the subnets is realized by the central layer 3 switch (Figure 3 is a schematic diagram of the broadcast control network of the TV station)
The construction of the broadcast control network of a television station is a systematic project, which covers various technologies such as computers, videos, and networks. Here, the author will introduce the construction of the broadcast control network of small and medium-sized TV stations in combination with actual work.
1. Business process
The radio and television industry is characterized by strong timeliness and social responsibility. Therefore, the management system of program acquisition, editing, reviewing and broadcasting is very strict. After the program is compiled, it will be broadcast after being checked by the broadcast department. At the same time, the finance and advertising will be broadcast and checked (Figure 1 is the business flowchart).
The broadcast control network of the TV station takes the video server as the main body, giving full play to the advantages of hard disk storage, avoiding the impact of the failure of the recorder, mechanical arm and other equipment on the broadcast, and can easily realize the serial compilation and broadcast between the programs Control management of various insertion and timing broadcast
2. Features
TV station broadcast control network is different from ordinary local area network, it has the following characteristics:
1. Large data flow
This type of network transmission is basically based on MPEG-2 or MPEG-4 video stream, so the network needs to have sufficient throughput to ensure the high-quality and efficient transmission of information.
2. High safety requirements
Television broadcasting is a highly political and socially responsible job. Therefore, it is necessary to prevent illegal access on the network through security technology and ensure network isolation.
3. Strong stability
In order to ensure the "high quality and uninterrupted" broadcast requirements of TV programs, the stability of the network must be guaranteed.
It can be seen from this that in addition to strictly following the principles of advancement, practicability, openness, manageability, and scalability, we should also emphasize high bandwidth, reliability, and security when setting up broadcast control networks for TV stations.
3. Network construction plan
1. Network topology
The broadcast control network of the TV station adopts a star topology structure (Figure 2). The nodes in the network have a high degree of independence and are suitable for the three-layer Browser / Server / DB architecture.
2. Networking technology
At present, commonly used backbone networking technologies are Fast Ethernet (100Mbps), FDDI, Gigabit Ethernet (1000Mbps) and ATM (155Mbps / 622Mbps).
Fast Ethernet is a very mature networking technology, which has a very low cost and a high performance-to-price ratio; FDDI is also a mature networking technology, but the technology is complex and costly, and it is difficult to upgrade; ATM technology is mature, yes Ideal network platform for multimedia application systems, but its actual utilization rate of network bandwidth is very low; currently Gigabit Ethernet has become a mature networking technology, the cost is lower than the ATM network, its effective bandwidth is more than 622Mbps ATM high.
Therefore, the author recommends the use of Gigabit Ethernet as the backbone, fast Ethernet switching to the desktop to build a computer broadcast control network. For small and medium-sized TV stations that do not have sufficient funds, you can choose Fast Ethernet first. After the time is ripe, you can smoothly upgrade to Gigabit Ethernet.
3. Network switching equipment
(1) Network core layer
A Cisco high-end Layer 3 switch Catalyst 6506 (with routing function) is used as the core of the entire switching system, and the network administrator manages and dispatches in a unified manner, so that the TV station broadcast control network is built on a Gigabit Ethernet backbone and has a third It is based on the integrated network communication platform with layer switching function. At the same time, configure two power supplies to supply power at the same time, share the load with each other and backup each other.
(2) Convergence layer
Use Cisco Catalyst 3524 switch or Catalyst 3548 switch as the network layer aggregation layer device. The aggregation layer device will be connected to the core layer device Catalyst 6506 through multimode optical cable and Gigabit Ethernet backbone, and some users can be connected through ultra-category 5 UTP cable. To this layer of switches, to achieve 100Mbps rate connection.
(3) Access layer
In the network access layer, the author chose multiple Cisco 2924 switches as access switches to provide 100Mbps access rate for desktop applications.
4. Computer equipment
(1) Server
As the domain control server, file server and database server, it should be able to meet the long-term work requirements and ensure the safe and stable operation of the system. The server used in the broadcast control network of the TV station integrates a high-performance RAID controller, and at the same time fully uses hot-swappable / hot-swappable components, including hard drives, power supplies, fans, and hot-swappable PCI slots.
(2) Hard disk storage
This system uses a 480GB RAID-3 fault-tolerant hard disk array, which has a faster data transfer rate and a larger storage capacity. At the same time, it uses error correction technology to improve the reliability of storage. There is one parity check disk for each group in RAID-3. When one of the disks in the array group is damaged, the information of the damaged disk can be recovered by the parity of the parity information and the remaining disk information.
(3) Workstation
Workstations use special computers such as subtitles, collection, and broadcast, and some workstations use ordinary computers.
5. IP address planning
Due to the particularity of the system, the entire network uses the reserved network segment 172.XXX.XXX.XXX to match the division of the virtual local area network (VLAN) and configure different subnet segments for different virtual local area networks. The entire network can be easily divided into several subnets, and the communication between the subnets is realized by the central layer 3 switch (Figure 3 is a schematic diagram of the broadcast control network of the TV station)
Fourth, the realization of security
In view of the particularity of the broadcasting work of TV stations, the security of the network must be technically guaranteed. The main setting work has the following three points:
1. Assign appropriate VLAN
In order to ensure the security of the network, the isolation function of similar circuits must be provided. Generally, VLAN technology is adopted, that is, virtual local area network technology. Set different departments to different VLANs (such as editor room, broadcast department, production department, advertising department, financial department, etc.), and set up a three-tier access list (see table) to control the interconnection of corresponding computers to ensure the network safety.
2. Binding
The MAC address is the only sign of the network card. By binding the switch port and MAC address, you can easily prevent illegal access and prevent the destruction of illegal intruders. At the same time, the remaining unused ports of the switch are prohibited.
The specific settings are as follows (take Cisco 2924 switch as an example)
Log in to the switch, enter the management password, and then enter the command "#config terminal" to enter the configuration mode
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