Building a video surveillance system only at first glance looks simple
challenge.
Its implementation requires solving a fairly wide range of issues. Apart from
organizing data transmission channels, collecting, storing and searching for the necessary information
it is necessary to provide power for video cameras, as well as control and diagnostics.
Benefits of IP Camera Solutions
There are quite a lot of technical means: from traditional analog
camcorders to small USB webcams and miniature DVRs.
A fairly convenient and affordable solution is the use of IP cameras for
receiving an image.
Cameras of this type transmit the image in digitized form over an IP network. This
gives a number of advantages: the picture from the camera comes immediately in digital form,
that is, it does not require special converters, the collected information is easier
process, systematize, search through the archive, and so on.
If it is possible to run a network cable, and the distance between the switch and
cameras does not exceed the allowable values, then usually use an Ethernet network on
based on twisted pair and cameras working through a cable connection. Such a decision
provides a stable connection and practically does not depend on third-party factors,
such as the choice of frequency range, the presence of radio interference and other nuances.
Using a wired connection also allows you to use the same
cable (twisted pair) and for powering video cameras - Power Over Ethernet, PoE.
Note. Other types of network connections are less commonly used,
for example, via Wi-Fi or GSM. Despite all the advantages of wireless communication,
the issue of powering such cameras must be addressed for each case separately.
For example, power from a lighting network, from a solar battery, and so on. IN
in general, this is not quite the direction that can be recommended as
simple and versatile solution for most tasks.
Features of video surveillance systems in comparison with other distributed IP systems
In the case of video surveillance, it is impossible to directly broadcast the experience of building other
networks. Take for comparison voice communication based on IP-telephony. Despite
completely different areas of application, both there and there an IP network is used, in both
In some cases, PoE power may be used.
But if we consider the features of operation, with a similar general approach
some things are handled differently. Here are a few features:
-
The IP camera needs to be constantly monitored. People, animals or material
objects that are monitored by video surveillance are unlikely to communicate themselves
with the technical support department to report a non-working camera.But next to a corporate IP phone, a user usually sits with
computer. If he has problems with telephone communication, he can report
this, having created a task in the application system, send a request by mail by calling with
personal mobile phone (if corporate policy allows) and so on. -
IP cameras are usually located in hard-to-reach places: under the ceiling, on
pole and the like. Something quickly "take and do" is very
problematic. If the twisted-pair connection is hidden in a wall to
check the condition of the cable - first you need to somehow try to get it.
The operation to replace the camera also looks a little more complicated than just
disconnect and pick up a non-working phone from the table and give it to the user
instead of it a working device.
Important note. IP cameras are often located at a considerable distance from
switch, for example, video surveillance in squares, recreation areas and so on. If
PoE is used, it is necessary to maintain a sufficiently high level
power, which decreases with increasing distance from the source.
The requirement for the stability of the entire video surveillance system is very high. From
quite a lot can depend on the quality and completeness of the picture: from the reduction
waiting time for issuing a pass until the criminal is identified in the system
face recognition. Therefore, stable work is very important. Respectively,
to the switch, as to the central link, high
requirements. Due to the frequent failures of the PoE switch, video surveillance will work
unstable (if it works at all). Therefore, buying a PoE switch is
certainly not the case when it is worth trying to save money and take the first one that comes across
the cheapest option.
Similar questions arise not only when using IP cameras, but also other
video surveillance solutions. Of course, all these problems are solvable, otherwise
IP cameras, and the video surveillance system in general, would be difficult to apply on
practice. But is it possible to somehow simplify your life and not spend extra
resources: time, money, human effort for simple operations?
Specialized switches for connecting IP cameras
Summing up all of the above, it can be argued that working with systems based on
IP cameras are easier if you use equipment specifically designed for
work with them. And since IP cameras are connected to the switch, the following speech
will talk about specialized devices of this type.
For such a switch, the following tasks emerge:
- ensuring stable communication;
- PoE power supply;
- monitoring and control of IP cameras;
- surge and electrostatic discharge protection.
One of the fundamental factors is the allowable cable length along which
the device is powered. The second extremely useful condition is
the ability to manage, for example, using the LLDP protocol. Especially
the function of remote reboot of an IP camera that receives power looks useful
by PoE.
Note. Link Layer Discovery Protocol (LLDP) is a data link protocol
layer that defines a standard method for devices on an Ethernet network to
in our case, for switches and IP cameras. Through the use of LLDP devices
can distribute information about themselves to other nodes on the network and store
received data.
Zyxel has recently introduced new PoE switches with
unique design and software.
In order to better understand the essence of useful innovations, we will consider the line
unmanaged GS1300 switches, and a line of new managed GS1350 models
Extended Range Essentials.
All switches from these lines are specially designed for systems
video surveillance. In total, 7 modern models are at the service of users
switches, of which 3 are unmanaged and 4 are managed
Zyxel G1300 Series Unmanaged Switches
In this line, the following hardware features that are useful can be noted
specifically for video surveillance systems:
- high PoE budget - allows you to maintain the required power even at
considerable distance; - PoE maximum LED;
- connection of cameras at a distance of up to 250 m;
- extended temperature range from -20 to +50β (especially it can be
useful when working in the "field", for example, when the switch
placed in a temporary facility).
ESD/Surge Protection value:
- ESD - 8 kV / 6 kV (Air/Contact);
- Surge - 4 kV (Ethernet Port).
Note. ESD β protection against electrostatic voltage, Arises -
surge protection. If there is a static discharge in the air up to 8
kilovolt, or 6 kV electrostatics at close contact, or temporary surge
voltage up to 4 kilovolts - the switch has a good chance to survive such
trouble.
Figure 1. Indication for PoE control.
Important note. Using DIP switches, you can set the ports for
which will increase the range - up to 250m. The rest of the ports will work in
regular mode.
Zyxel has prepared several switch models with different number of
ports from 8 to 24. This approach allows you to flexibly adapt to the needs
consumers.
Differences in the characteristics of managed models are indicated in Table 1.
Table 1 Zyxel GS1300 Series Unmanaged Switch Models
β
Number of PoE ports
Up-link ports
PoE power budget
Source of power
GS1300-10HP
GE 8
1SFP, 1GE
130 W
Internal
GS1300-18HP
GE 16
1SFP,1GE
170 W
Internal
GS1300-26HP
GE 24
2 SFP
250 W
Internal
Zyxel G1350 Series Managed Switches
Switches of this line have more options for management and
maintaining the CCTV system. Built-in security features and
operability will come in handy in a variety of situations.
Some interesting hardware features:
- advanced 4 kV surge protection and
electrostatic discharge 8 kV (GS1350 series); - LEDs for PoE control;
- Last good button (FW recovery);
- connection of cameras at a distance of up to 250m with a bandwidth of 10
Mbps, which complies with the standard; - extended temperature range (-20 to +50β).
The ESD/Surge Protection values ββthemselves remain the same as for unmanaged
models:
- ESD - 8 kV / 6 kV (Air/Contact);
- Surge - 4 kV (Ethernet Port).
Figure 2. PoE Usage LED Bar and Restore Button.
Speaking of the new line, it is impossible not to note the new features of the firmware,
for example:
- advanced PoE control for video surveillance;
- IEEE 802.3bt support - 60W per port (GS1350-6HP);
- Basic L2, Web support, CLI control.
As for Nebula Flex support, it is expected for GS1350 series models
at 2020.
Speaking about the G1350 equipment line, it is worth noting the appearance of the younger model on
4 PoE ports. Such a "baby" is especially useful in organizing systems
video surveillance for small objects and enterprises of the SMB sector.
Table 2 Managed Models of Zyxel GS1350 Series Switches.
β
Number of PoE ports
Up-link ports
PoE power budget
Source of power
GS1350-6HP
4GE
1SFP, 1GE(802.3bt)
60Vt
External
GS1350-12HP
8GE
2SFP, 2GE
130Vt
Internal
GS1350-18HP
16GE
2 Combo
250Vt
Internal
GS1350-26HP
24GE
2Combo
375Vt
Internal
Advanced control for video surveillance
To achieve the most complete, uninterrupted surveillance, and to
Ease of use Zyxel has added new useful features:
- information about IP cameras on the Neighbors page;
- checking the status of the camera;
- uninterrupted power supply of the camera (when updating or rebooting the switch);
- remote reboot of IP cameras;
- granular PoE parameters to support non-compliant IP cameras
PoE standard; - turn on PoE according to the schedule;
- priorities for PoE ports.
Below we will focus on the three most popular features that appeared in the new
models.
Neighbors web interface page - "Neighbors"
On this page, you can see the status of the camera, the IP through which
interaction (assuming the camera is connected and working), as well as "buttons"
to reboot and reset to factory settings.
Figure 3. Fragment of the page of the Neighbors web interface - "Neighbors".
Auto PD Recovery
This function automatically detects a frozen IP camera and reboots it.
This luxury is now available for any camera from any manufacturer. That is
bought a Zyxel switch and can work with existing cameras or those
required to be installed by the Security Service.
It is possible to determine the status of the camera through the LLDP protocol, as well as through
sending ICMP packets, in other words, through the usual Ping.
It is possible to prevent a permanent reboot of a faulty camera, on
which is powered by PoE.
Figure 4. Fragment of the Neighbors interface page - "Neighbors".
Continuous PoE
This function guarantees continuous power supply to cameras and other sensors.
during switch maintenance.
In addition to normal operation, there are times when it is necessary to
certain actions with the switch, for example:
- perform a firmware update.
- load a new configuration file, or vice versa, return the current ones
settings to the previous ones from the backup; - reset to factory settings.
Also, sometimes there is a need for an additional reboot of the switch,
for example, to check the correctness of the settings made.
Of course, the power supply of the cameras all this time should not disappear properly.
Why is there such a need? It would seem that if the switch
reboots, why do you need continuous power for the cameras?
The fact is that rebooting the cameras themselves and entering the operating mode takes
for a while. In addition, video surveillance software must
have time to "pick up" the newly loaded cameras. In practice, this also
some time is required. As a result, from the moment the switch is restored,
and until the complete restoration of the data recording by the surveillance system, there may be
a pause unacceptable from the point of view of safety regulations.
That is why it is necessary to minimize any chance of downtime, including
including and through the fault of regular maintenance.
Conclusion
The G1300 line of unmanaged switches has already implemented several very
useful features. However, the capabilities of the G1350 are much higher in terms of control
network (managed vs unmanaged switch), and to provide
specific video surveillance needs.
Particularly pleased with the ability to control cameras from other manufacturers, as well as
a balanced approach while ensuring the continuity of the surveillance system.
We answer questions and support system administrators in our . Welcome!
Sources of
By the way, Zyxel turned 30 the other day!
In honor of this event, we announced a generous promotion:
Source: habr.com