Switch (English: Switch, meaning "switch") is a network device used for the transmission of electrical signals. It can provide exclusive access to electrical signals for any two network nodes in the access switch. The most common switch is an Ethernet switch. Other common ones are telephone voice switches and fiber switches. Recently, VIKOR Huatai has released a new network of coaxial switch access hosts.
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In HD network video surveillance systems, there are often phenomena such as delays in user feedback screens, and stalls. There are many reasons for this phenomenon. However, in most cases, the configuration of the switch is not reasonable enough, resulting in insufficient bandwidth.
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From the perspective of network topology, a medium- and large-scale high-definition network video surveillance system must adopt a three-tier network architecture: access layer, convergence layer, and core layer.
1, the access layer switch selection:
The access layer switch is mainly used for down-linking front-end network HD cameras and uplink aggregation switches. Calculate the 720P network camera 4M code stream, a 100M port access switch can access a few 720P network cameras?
The actual bandwidth of our commonly used switches is 50%-70% of the theoretical value, so the actual bandwidth of a 100Mbit is 50M-70M. 4M*12=48M, so it is recommended that a 100M access switch should have access to a maximum of 12 720P network cameras. At the same time consider that the current network monitoring using dynamic encoding, the camera code stream peak value may exceed 4M bandwidth, while taking into account the bandwidth of redundant design, so a 100M access switch to control the best within 8 units, more than 8 units recommended Gigabit mouth.
2, the choice of aggregation layer switches:
The aggregation layer switch is mainly connected to the access layer switch and the core switch of the monitoring center. In general, aggregation switches need to select Layer 2 switches with Gigabit uplinks.
Or 720P network camera 4M code stream calculation, the front of each access layer switch has six 720P network cameras, the convergence of switches connected to the next five access layer switches. The total bandwidth under the aggregation layer switch is 4M*6*5=120M. Therefore, the gigabit interface should be selected for the cascade port of the aggregation switch and the core switch.
3, the choice of core switch:
The core layer switches are mainly connected to aggregation layer switches, video surveillance platforms of uplink monitoring centers, storage servers, and digital matrix devices, which are the core of the entire HD network monitoring system. When selecting a core switch, you must consider the bandwidth capacity of the entire system and how to configure the core switch incorrectly, which will inevitably lead to the video screen cannot be displayed smoothly. Therefore, the monitoring center needs to select the full gigabit core switch. If there are many points, VLANs should be divided, and three full-Gigabit core switches should also be selected.
Attachment: Several parameters that determine the performance of the switch backplane bandwidth:
Backplane bandwidth calculation method: port number * port speed * 2 = backplane bandwidth. Take the Huawei S2700-26TP-SI as an example. The switch has 24 100Mbit ports and two Gigabit uplink ports. Backplane bandwidth = 24*100*2/1000+2*1000*2/1000=8.8Gbps.
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Packet forwarding rate:
The calculation method of packet forwarding rate: the number of fully configured GE ports × 1.488 Mpps + full-configured Fast ports × 0.1488 Mpps = packet forwarding rate (the theoretical throughput of a Gigabit port with a packet length of 64 bytes is 1.488 Mpps, The theoretical throughput of a Fast Ethernet port at a packet length of 64 bytes is 0.1488 Mpps). Take the Huawei S2700-26TP-SI as an example. The switch has 24 100Mbit ports and two Gigabit ports. Packet forwarding rate = 24 * 0.1488 Mpps + 2 * 1.488 Mpps = 6.5472 Mpps.
Product features â—† Powerful signal access method Supports 8 channels/16 channels of network-connected coaxial signal input options, single-channel maximum expansion of 128 channels of front-end video signal access;
◆ Take full advantage of existing cable resources The use of coaxial products based on the G.hn standard can provide “quasi-Gigabit†broadband access channels without changing the transmission media of the original analog system coaxial cable. Networked high-definition system, while fully protecting the original investment, drastically reduces the infrastructure construction cost and construction period;
â—† Supports single-point, link, star and ring networking modes to support simultaneous access to millions of high-definition video from different cable nodes via a "quasi-Gigabit" broadband access path over a single coaxial cable The network signals (including audio, alarm, and control signals) greatly improve the reuse level of existing coaxial cables, providing sufficient flexibility and convenience for system networking.
â—† Realize the transmission distance of multi-mode optical fiber to realize the transmission of high-definition video data over a distance of 2000 meters without relay. While fully embodying the convenience of copper cabling, the transmission distance of multi-mode optical fiber is realized. When using the economical SYV-75-5 coaxial cable to transmit 2000 meters, the data traffic can still be maintained at about 50Mbps, ensuring the normal transmission of multi-channel high-definition video data;
â—† "Quasi-Gigabit" transmission rate to ensure smooth HD video quality based on SYWV (Y)-75-5 cable, field measurement can achieve Gigabit data throughput;
◆ Out-of-the-box support Plug-and-play mode without setting or debugging is required. Gigabit cascaded coaxial converters can transmit “quasi-Gigabit†Ethernet data immediately after connecting the coaxial cable. Immediately receive HD network video data on the termination. Greatly simplifies the installation of the project, saves construction costs, and is truly ready to use;
â—† Remote centralized management can be managed remotely and discover abnormal links in a timely manner. When the performance is degraded, active alarms are generated.
In HD network video surveillance systems, there are often phenomena such as delays in user feedback screens, and stalls. There are many reasons for this phenomenon. However, in most cases, the configuration of the switch is not reasonable enough, resulting in insufficient bandwidth.
From the perspective of network topology, a medium- and large-scale high-definition network video surveillance system must adopt a three-tier network architecture: access layer, convergence layer, and core layer.
1, the access layer switch selection:
The access layer switch is mainly used for down-linking front-end network HD cameras and uplink aggregation switches. Calculate the 720P network camera 4M code stream, a 100M port access switch can access a few 720P network cameras?
The actual bandwidth of our commonly used switches is 50%-70% of the theoretical value, so the actual bandwidth of a 100Mbit is 50M-70M. 4M*12=48M, so it is recommended that a 100M access switch should have access to a maximum of 12 720P network cameras. At the same time consider that the current network monitoring using dynamic encoding, the camera code stream peak value may exceed 4M bandwidth, while taking into account the bandwidth of redundant design, so a 100M access switch to control the best within 8 units, more than 8 units recommended Gigabit mouth.
2, the choice of aggregation layer switches:
The aggregation layer switch is mainly connected to the access layer switch and the core switch of the monitoring center. In general, aggregation switches need to select Layer 2 switches with Gigabit uplinks.
Or 720P network camera 4M code stream calculation, the front of each access layer switch has six 720P network cameras, the convergence of switches connected to the next five access layer switches. The total bandwidth under the aggregation layer switch is 4M*6*5=120M. Therefore, the gigabit interface should be selected for the cascade port of the aggregation switch and the core switch.
3, the choice of core switch:
The core layer switches are mainly connected to aggregation layer switches, video surveillance platforms of uplink monitoring centers, storage servers, and digital matrix devices, which are the core of the entire HD network monitoring system. When selecting a core switch, you must consider the bandwidth capacity of the entire system and how to configure the core switch incorrectly, which will inevitably lead to the video screen cannot be displayed smoothly. Therefore, the monitoring center needs to select the full gigabit core switch. If there are many points, VLANs should be divided, and three full-Gigabit core switches should also be selected.
Attachment: Several parameters that determine the performance of the switch backplane bandwidth:
Backplane bandwidth calculation method: port number * port speed * 2 = backplane bandwidth. Take the Huawei S2700-26TP-SI as an example. The switch has 24 100Mbit ports and two Gigabit uplink ports. Backplane bandwidth = 24*100*2/1000+2*1000*2/1000=8.8Gbps.
Packet forwarding rate:
The calculation method of packet forwarding rate: the number of fully configured GE ports × 1.488 Mpps + full-configured Fast ports × 0.1488 Mpps = packet forwarding rate (the theoretical throughput of a Gigabit port with a packet length of 64 bytes is 1.488 Mpps, The theoretical throughput of a Fast Ethernet port at a packet length of 64 bytes is 0.1488 Mpps). Take the Huawei S2700-26TP-SI as an example. The switch has 24 100Mbit ports and two Gigabit ports. Packet forwarding rate = 24 * 0.1488 Mpps + 2 * 1.488 Mpps = 6.5472 Mpps.
Product features â—† Powerful signal access method Supports 8 channels/16 channels of network-connected coaxial signal input options, single-channel maximum expansion of 128 channels of front-end video signal access;
◆ Take full advantage of existing cable resources The use of coaxial products based on the G.hn standard can provide “quasi-Gigabit†broadband access channels without changing the transmission media of the original analog system coaxial cable. Networked high-definition system, while fully protecting the original investment, drastically reduces the infrastructure construction cost and construction period;
â—† Supports single-point, link, star and ring networking modes to support simultaneous access to millions of high-definition video from different cable nodes via a "quasi-Gigabit" broadband access path over a single coaxial cable The network signals (including audio, alarm, and control signals) greatly improve the reuse level of existing coaxial cables, providing sufficient flexibility and convenience for system networking.
â—† Realize the transmission distance of multi-mode optical fiber to realize the transmission of high-definition video data over a distance of 2000 meters without relay. While fully embodying the convenience of copper cabling, the transmission distance of multi-mode optical fiber is realized. When using the economical SYV-75-5 coaxial cable to transmit 2000 meters, the data traffic can still be maintained at about 50Mbps, ensuring the normal transmission of multi-channel high-definition video data;
â—† "Quasi-Gigabit" transmission rate to ensure smooth HD video quality based on SYWV (Y)-75-5 cable, field measurement can achieve Gigabit data throughput;
◆ Out-of-the-box support Plug-and-play mode without setting or debugging is required. Gigabit cascaded coaxial converters can transmit “quasi-Gigabit†Ethernet data immediately after connecting the coaxial cable. Immediately receive HD network video data on the termination. Greatly simplifies the installation of the project, saves construction costs, and is truly ready to use;
â—† Remote centralized management can be managed remotely and discover abnormal links in a timely manner. When the performance is degraded, active alarms are generated.
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