Documentation for Axxon PSIM 2.0. Documentation for other versions of Axxon PSIM is available too.

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Requirements for the bandwidth of the TCP/IP network for video transmission

Network bandwidth is a limiting factor in the performance of a distributed system. The transmitted information is primarily made up of video data. For example, when you use cameras to monitor remote objects, such as ATMs, the entire information stream (video stream) is transmitted over communication channels.

To determine the required bandwidth of the TCP/IP network for transmitting video from IP devices and certain video capture cards, we recommend using the AxxonSoft Platform Calculator, available here (the Summary stream from IP cameras (Mbit/s) parameter). For video capture cards that are not supported by the platform calculator, use the calculation data below.

The table below shows the maximum number of remote surveillance cameras depending on the bandwidth of various communication channels. For calculation purposes, the frame rate of the video stream (the original format is PAL) is assumed to be equal to 1 FPS.

Note

In real conditions, the fluctuations of camera streams can be quite significant, depending on the scene illumination, the use of day/night mode, and how much motion there is in the frame. To accurately calculate the required network bandwidth, it is necessary to measure the stream from cameras that are already installed on the protected facility.

Communication mode

Channel bandwidth

Black and white image

Color image



Standard

High

Full

Standard

High

Full

Dial-Up

56 kbit/s

<1*

<1*

<1*

<1*

<1*

<1*

ADSL, Ethernet

128 kbit/s

1

<1*

<1*

<1*

<1*

<1*

ADSL, Ethernet

256 kbit/s

2

1

1

1

1

<1*

ADSL, Ethernet

512 kbit/s

4

3

2

3

3

2

ADSL, Ethernet

1 Mbit/s

7

5

4

6

5

4

ADSL, Ethernet

1.5 Mbit/s

11

8

6

10

8

6

Ethernet

2 Mbit/s

14

11

8

13

10

8

Ethernet

10 Mbit/s

71

53

39

64

51

38

Ethernet

100 Mbit/s

711

533

388

640

512

376

Ethernet

1 Gbit/s

7282

5461

3972

6554

5243

3855

* no more than one camera, provided that maximum compression and/or additional decimation is applied.

To calculate the maximum number of remote cameras that transmit video to the network with a rate over 1 FPS, the corresponding value shown in the table must be divided by the number of frames.

Example. Live video (25 FPS—PAL) must be transmitted over a 100-megabit network. The video image is color, and the frame resolution is standard. According to the table, a 100-Mbps channel can transmit a video stream at 1 FPS and the specified color and resolution parameters from a maximum of 640 cameras. Therefore, with a video stream rate of 25 FPS, the maximum number of cameras is reduced by a factor of 25, to 640/25 = 25 cameras.

Note

In most cases, processing, transmitting, and recording audio signals requires a small amount of resources of the digital video surveillance system. When you calculate the performance of the video surveillance system, the proportion of resources allocated to audio monitoring can be neglected.

Requirements for the bandwidth of the TCP/IP network for database synchronization

If Axxon PSIM operates in a distributed configuration that combines several servers and/or remote administrator workstations, the Configuration database synchronization is performed (see Configuring database synchronization).

For the synchronization of the Configuration database to work correctly, the following minimum network requirements must be met:

  1. The minimum speed of data transmission over the communication channel (bandwidth) is 64 kbit/s.
  2. The maximum packet transmission delay is 500 milliseconds.

With worse parameter values, correct database synchronization is not guaranteed.

Requirements for the TCP/IP network quality

The following connection quality requirements are applied for the Axxon PSIM video subsystem to work correctly when connecting IP devices via WAN:

  1. Latency:

    • For live video, no more than 10 seconds. If this value is exceeded, the connection to the IP device is terminated.

    • For face recognition, no more than 1500 milliseconds. If this value is exceeded, many faces are missed due to the skipping of a large number of frames.

    • For service and smart detectors, no more than 400 milliseconds. If this value is exceeded, the quality of object detection decreases, and smart detectors can generate events incorrectly.

  2. Packet loss:

    • For live video, no more than 40%. If this value is exceeded, the connection to the camera is terminated. With a packet loss of 10% to 40%, frames are skipped (the more losses, the more skips).

    • For face recognition, service and smart detectors, no more than 25%. If this value is exceeded, faces are skipped, and the tracks of smart detectors don't correspond to objects.

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