Documentation for Axxon PSIM 1.0.0-1.0.1.

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Requirements for TCP/IP Network bandwidth for video signal transferring

Throughput capacity of the network refers to the factors restricting performance of the distributed network. Data exchange flow is primarily made up of image data. For instance, where surveillance cameras are used to monitor remote objects, likes ATMs, the data flow (image flow) is transmitted over communication links.

In order to calculate the required bandwidth of TCP/IP network for video transmission from IP devices and some video capture cards, it is recommended to use the AxxonSoft Platform Calculator, available here (the Summary stream from ip devices (Mbit/s) parameter). For video capture cards that are not supported by the platform calculator, use the calculation data below.

Table below shows the maximum number of remote surveillance cameras as a function of the throughput capacity of various communication links. The frame rate of the image flow (reference format is PAL) for calculation purposes was accepted as equal to 1 frame per second.

Note

In real conditions, the fluctuations of camera streams can be quite significant, depending on the scene illumination, the use of day/night mode, 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

Link capacity

Black and white image

Color image



standard

high

full

standard

high

full

Dial-Up

56 Kb/sec

<1*

<1*

<1*

<1*

<1*

<1*

ADSL, Ethernet

128 Kb/sec

1

<1*

<1*

<1*

<1*

<1*

ADSL, Ethernet

256 Kb/sec

2

1

1

1

1

<1*

ADSL, Ethernet

512 Kb/sec

4

3

2

3

3

2

ADSL, Ethernet

1 Mb/sec

7

5

4

6

5

4

ADSL, Ethernet

1.5 Mb/sec

11

8

6

10

8

6

Ethernet

2 Mb/sec

14

11

8

13

10

8

Ethernet

10 Mb/sec

71

53

39

64

51

38

Ethernet

100 Mb/sec

711

533

388

640

512

376

Ethernet

1 Gb/sec

7282

5461

3972

6554

5243

3855

*max. one surveillance camera, provided that maximum compression and/or additional grooming is applied.

To calculate the maximum number of remote cameras transmitting image flow to the network with a rate over 1 f/sec, the corresponding value shown in the table should be divided by the number of frames.

Example: To transmit live video, a 100 Mb/sec network should be used (25 frame/sec – PAL), video image – color; frame resolution – standard. As the table shows, the Mb/sec link can transmit the image flow at a rate of 1f/sec, specified color grade and resolution from max. 640 surveillance cameras. Consequently, if the image flow rate is 25 frames per second, the maximum number of cameras will decrease by 25 times and will be equal to: 640/25=25 cameras.

Note

More often than not, video signal processing, transfer and recording requirements take up only a small proportion of the digital video surveillance system resources. While calculating performance of the video surveillance system, the proportion of resources, consumed by audio monitoring, may be neglected.

Requirements for TCP/IP network bandwidth for database synchronization functionality

If the Axxon PSIM software operates in the distributed environment where several Servers and/or Remote Admin Workstations are combined the Configuration databases synchronization is performing (see Configuring database synchronization).

The fulfilling of following minimal requirements for network is needed for correct synchronization of Configuration databases:

  1. Minimal speed of data transferring by link channel (capacity) is 64 kbit/sec.
  2. Maximal delay while packet transferring is 500 milliseconds.

With more badly parameters value the correct operation of databases synchronization functionality is not guaranteed.

Requirements to the TCP/IP network quality

The following connection quality requirements are imposed for the Axxon PSIM software 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 will be terminated;
    - for face recognition no more than 1500 milliseconds, if this value is exceeded, many faces will be missed due to the skipping of a large number of frames;
    - for service and smart detection tools no more than 400 milliseconds, if this value is exceeded, the quality of object detection will decrease, smart detection tools may incorrectly generate alarms.


  2. Packet loss:
    - for live video no more than 40%. If this value is exceeded, the connection to the camera will be terminated. With a packet loss of 10% to 40%, frame drops will be observed (the more losses, the more drops);
    - for face recognition, service and smart detection tools no more than 25%. If this value is exceeded, skipping of faces will be missed, and the tracks of smart detection tools will not correspond to objects.

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