Difference between Hub and Switch

Difference between Hub and Switch 

Network devices, or networking hardware, are physical devices that are required for communication and interaction between hardware on a TCP/IP network.

Here is the common network device list:

·        Hub

·        Switch

·        Router

·        Bridge

·        Gateway

·        Modem

·        Repeater

·        Access Point

In 2006 The Network Hub is invented at Vancouver, British Columbia, Canada. A hub is a device that connects multiple Ethernet devices on one network and makes them act together as a single network. A hub does not gather information and input in one port results as an output in all ports on the network. A switch is a networking device that performs the same job as the hub but are considered as a more intelligent hub as it gathers information about the data packets it receives and forwards it to only the network that it was intended for. A Hub is a layer-1 device and operates only in the physical network of the OSI Model.

Hubs and switches are devices that are used in data networking on the internet. These devices are used in order to connect two or more networking ports in order to transfer data along the connection. Though the primary job of hubs and switches are the same, to forward data to different networks, they work in different ways.

A hub, also known as Ethernet hub, active hub, network hub, repeater hub or multiport repeater, is a device that connects multiple Ethernet devices on one network and makes them act together as a single network. A hub has multiple input/output (I/O) ports, in which an input in one port results in it being an output in all the other ports, except the port where it was input. In layman’s terms, a hub connects many networks into one, where a data packet that is sent by one networks, is copied and pasted to all network ports, making it so that every port can see that data packet. A hub works on the physical layer or layer 1 of the Open Systems Interconnection (OSI) model. It also works as a data collision detector, sending a jamming signal to all ports if it detects collisions at one port.

It is a simple device that does not examine the data it receives or sends, while just duplicating the data and making it visible for all. The receiving port that has to decide if the data packet is actually intended for it by checking the address on the packet, before passing it on further. Since hubs only have one collision domain, constant collisions occur. Unnecessary traffic is sent to all devices on the network. Originally hubs were popular due to the high price of switches, but switches are not so expensive these days. Hubs are slowly becoming obsolete in many practices, but are still used in special circumstances.

A switch is a networking device that performs the same job as the hub; it connects network segments or devices making them act as a single network. Switches are commonly referred to as a multi-port network bridge that process and routes data on a data link layer or layer of the OSI model. Switches can also process data at the network layer (layer 3) or higher layers and are known as multilayer switches.

Switches are considered as a more intelligent hub as it gathers information about the data packets it receives and forwards it to only the network that it was intended for. When a switch receives a data packet, it examines the data address, the sender and the receiver and stores the memory, after which it then sends the data to the device that the data is meant for.

Most modern Ethernet Local Area Networks (LANs) operate on switches. Small offices and residential devices commonly use single layer switch, while bigger applications require multilayer switches. The switches use a bridge or a router in order to split a larger collision domain to smaller collision domains, resulting in lesser collisions.  Each port has an individual collision domain, allowing computers to maintain dedicated bandwidth.

	Hub	Switch
Definition	A hub is a connection point for different segments of a LAN. It contains multiple ports and when it receives a packet of information at one port, it copies this packet to all segments of the LAN so that it can be viewed by all ports.	A switch is multi-port networking device that connects network devices together. A switch operates at the data link layer (layer 2) of the OSI model. A switch filters and then forwards data packets between networks.
Layer	Physical Layer (Layer 1)	Data Link Layer (Layer 2)
Spanning-Tree	No Spanning-Tree	It allows many Spanning-Trees to take place.
Type of Transmission	Broadcast	Broadcast, Uni-cast & Multicast.
Table	No MAC table. Hubs cannot learn MAC address.	Stores MAC address and maintains address.
Used in	LAN (Local Area Networks)	LAN (Local Area Networks)
No of Ports	4	24-48 depending on type of switch.
Collision	Occurs	No collision occurs
Collision Domain	One collision domain	Every port has its own collision domain.
Transmission Mode	Half duplex	Full duplex

Types of Hub

There are three types of the hub that are given below:

1.  Passive Hub

2.  Active Hub

3.  Intelligent Hub

Passive Hub: The passive hubs are the connection point for wires that helps to make the physical network. It is capable of determining the bugs and faulty hardware. Simply, it accepts the packet over a port and circulates it to all ports. It includes connectors (10base-2 port and RJ-45) that can be applied as a standard in your network. This connector is connected to all local area network (LAN) devices. Additionally, the advanced passive hubs have AUI ports, which are connected as the transceiver according to the network design.

Active Hub: As compared to a passive hub, it includes some additional features. It is able to monitor the data sent to the connected devices. It plays an important role between the connected devices with the help of store technology, where it checks the data to be sent and decides which packet to send first.

It has the ability to fix the damaged packets when packets are sending, and also able to hold the direction of the rest of the packets and distribute them. If a port receives a weak signal, but still it is readable, then the active hub reconstructs the weak signal into a stronger signal before its sending to other ports. It can boost the signal if any connecting device is not working in the network. Therefore, it helps to make the continuity of services in LAN.

Intelligent Hub: It is a little smarter than passive and active hubs. These hubs have some kinds of management software that help to analyze the problem in the network and resolve them. It is beneficial to expend the business in networking; the management can assign users that help to work more quickly and share a common pool efficiently by using intelligent hubs. However, it offers better performance for the local area network. Furthermore, with any physical device, if any problem is detected, it is able to detect this problem easily.

The important applications of a hub are given below:

·        Hub is used to create small home networks.

·        It is used for network monitoring.

·        They are also used in organizations to provide connectivity.

·        It can be used to create a device that is available thought out of the network.

Advantages of Hub

1. It provides support for different types of Network Media.

2.  It can be used by anyone as it is very cheap.

3.  It can easily connect many different media types.

4.  The use of a hub does not impact on the network performance.

5.  Additionally, it can expand the total distance of the network.

Disadvantages of Hub

1. It has no ability to choose the best path of the network.

2.  It does not include mechanisms such as collision detection.

3.  It does not operate in full-duplex mode and cannot be divided into the Segment.

4.  It cannot reduce the network traffic as it has no mechanism.

5.  It is not able to filter the information as it transmits packets to all the connected segments.

6.  Furthermore, it is not capable of connecting various network architectures like a ring, token, and ethernet, and more.

Security Camera Input Setup

 Security Camera Input Setup

Artificial Intelligence (AI) security cameras are specialized network IP cameras that perform advanced analytical functions such as vehicle detection, person detection, face detection, traffic counting, people counting, and license plate recognition (LPR). These artificial intelligence functions are achieved using highly advanced video analytics software that is built-in to the camera and recorder they are connected to. AI cameras can be used as a stand-alone device by recording to an SD card, or they can be connected to a network video recorder (NVR) to create a multi-camera AI system that records to a central hard drive. Please note that only certain models are capable of license plate recognition / automated number plate recognition (ANPR).

A special characteristic some network video devices possess is an integrated input & output ports. This incorporation allows for the communication and interaction of external devices, such as but not limited to:

1.   Doorbells

2.   Switches

3.   Alarm System Relay

4.   Pressure strips

5.   Detectors (frequency, smoke, movement, sound, temperature, and humidity sensors)

All these functions can be achieved via:
1.   NVR/DVR (remote or local)
2.   Application through a smart device (Tablet or Phone)
3.   Computer (local or remote / software or browser)

 

Camera / DVR / NVR Alarm Input

Motion sensors / motion detectors can be integrated with video surveillance systems to provide additional security for buildings and also outdoor areas. For example, a PIR sensor (passive infrared) can be connected to the alarm input of a security camera DVR or IP camera NVR to trigger video recording and send an alert to the property owner that motion has been detected in a certain area.

When motion is detected by the motion sensor, it triggers the following alarm actions.
1.   Trigger video recording on the camera associated with the alarm.
2.   Enable the alarm output on channel one, where I have an alarm light attached (turn the strobe light on).
3.   Pop-up live video of the camera associated with the alarm on the DVR’s display monitor.

Here are some additional actions that can be triggered from an alarm input.
1.   Capture a still image snapshot.
2.   Send a push notification to the mobile app for iPhone & Android.
3.   Enable the alarm buzzer on the DVR / NVR.
4.   Send an email notification.

The inputs and outputs can be used to eliminate unnecessary recording of video or coincide with your alarm system to systematically create a reliable and accountable security source. When input and output mechanisms are triggered, you can (manually or automatically) request through the network video device that certain actions be performed over the network as well as trigger devices attached to the output ports. Example:

This example picture above shows a person interrupting a sensors function. This creates a signal that travels to the camera and the camera computes the message. The camera then functions as programmed and starts recording (snapshots or footage) to the delegated device while simultaneously triggers a relay to close. When the relay closes, it completes the circuit for the siren or strobe to activate. Another configuration (as long as the cameras capable), have the camera record to the desired method based on motion and simultaneously trigger the relay to set off the siren. In this example, a motion sensor is taken out of the equation.

Again, the above picture shows only one of many configurations. You can configure in whatever method you desire. Including or excluding recording methods based off of:

·        Motion (movement takes place)

·        Masking (the camera has been covered or obstructed significantly)

·        Video Loss (picture is no longer materializing, this feature is more prone to function correctly via a recorder or program)

Other devices that can be attached and configured to your I/O ports are as follows:

Device Type	Description	Occurrence of activation
Entry Contacts	Simple magnetic sensors detecting opening of doors, windows, gates and shutters.	When the circuit is broken (door is opened) the camera can record and/or send a snapshot and notifications
Motion Sensors	A sensor that detects motion either based on heat, light, or frequency	When motion is detected, the sensor breaks the circuit and  the camera can record and/or send a snapshot and notifications
Glass Break or Glass Shock Sensor	A sensor capable of distinguishing the sound/vibration of breaking glass and/or splintering wood.	When glass is  disturbed or shattered, the glass sensor breaks the circuit and the camera can record and/or send a snapshot and notifications
Pressure strip or switch	A pressure or switch sensor that are needed to interact with before gaining entry or exiting a premise or structure	When the sensor is triggered it breaks the circuit and the camera can record and/or send a snapshot and notifications

How-to Install Motion Detectors with a Security Camera System

Installing a motion detector and integrating it with a security camera system is fairly simple. CCTV Camera Pros supports professional and DIY installers. Most PIR motion sensors are 12V DC powered which gives installers the choice of using a individual 12V DC power supply or one of the ports on a multi-channel power supply box (the same ones used with security cameras).

In this first diagram, a single 12V DC power transformer is used. This is how it works.

1.   On the right side of the diagram, the alarm input / output panel of the DVR is shown. This is what the alarm panel on the back.

2.   18/2 gauge power cable connects the output of the motion detector to one of the alarm input ports on the DVR.

3.   18/2 gauge power cable is also used to connect the motion detector to an individual DC power supply.

4.   A PT-4 power lead connects the raw cables to the 3.1mm plug on the power supply.

Installation with Power Supply Box

A multi-channel power supply box can be used instead of an individual power supply.

This installation is the same as the one above using the single power supply. The only difference is the use of a multi-channel power supply box to power the motion detector. CCTV Camera Pros supplies many of these power boxes for security camera installations. These power boxes can be shared with cameras and 12V DC powered alarm sensors. Because power supply boxes use screw based wire terminals, there is no need to use a PT-4 power lead (as with the individual power supply installation). Same connection for Camera & NVR.

Most of Camera PIR motion sensor is located on the front of the camera, just below the camera lens. This motion sensor is designed to detect movement of human sized objects when they come into view of the camera’s lens. The camera has a 2.8-12mm varifocal lens which when adjusted to the widest angle (the 2.8mm setting) the camera provides a 109 degree horizontal field of view. The PIR sensor detects motion across a 100 degree field of view. Please note that if you adjust the lens to a more narrow field of view, this does not effect the area where the PIR sensor will detect motion.

In my experience, using a PIR sensor based motion detection is much more reliable than software based video motion detection (especially for outdoor video surveillance). Typically there are a lot of small moving objects outdoors which makes it difficult to get the sensitivity just right. When security cameras turn to night mode, there is typically some video noise because of the lack of light. This noise can cause false alarms when using video motion detection. A PIR sensor uses infrared light to measure the radiation reflected by objects in its view. When a certain amount of this radiation changes, the PIR sensor triggers an alarm, so they are not susceptible to some of the challenges of outdoor video motion detection.

FAQ

Here are some frequently asked questions about integrating PIR motion detectors with security camera systems.

·        How are motion detectors used with security camera systems?
The most common way to integrate a motion detector with a security camera system is to hard wire the motion detector to the same surveillance DVR that your security cameras are connected to. You must make sure that your DVR that has alarm inputs.

·        Can I just use motion detected from my security camera instead of an external motion sensor?
Yes, most DVRs support video motion detection triggered by cameras. Please note that this is different from PIR (passive infrared) motion detection and can be less reliable. Video motion detection tends to produce more false positives than PIR motion detection, especially in outdoor and infrared camera applications. This is because the video tends to be more noisy and outdoor environments tend to always have some motion from wind and other natural elements.

·        What type of cable is used to wire motion detectors to DVRs?
The following types of cable can be used to wire motion detectors: CAT-5 cable (one pair), 18/2 conductor power cable.

·        Do motion detectors require power?
Yes. Most PIR motion detectors use 12V DC power. All of ours include the proper power supply with them.

·        Can I use multiple motion detectors with my surveillance system?
Yes, as long as your DVR has multiple alarm input ports, you can use multiple motion detectors. Different model DVRs support different numbers of alarm inputs so consult the specification or contact us if you need help.

Not every camera or NVR/DVR possesses this unique features or can be operated through the above mentioned methods. Be sure you research everything you will need to make this type of setup successfully work for you. This includes the correct relays, power supplies, capable camera and recording devices. Most our IP mega pixel cameras and recorders have the capability of all previous mention features above.

If you are not understand, you can touch with us for further support. We deal Infinova, Hanwha, Milestone, Mirasys & Luxriot brand.

AI Based Camera Output Triggers Strobe Light

AI Based Camera Output Triggers Strobe Light 

Artificial Intelligence (AI) security cameras are specialized network IP cameras that perform advanced analytical functions such as vehicle detection, person detection, face detection, traffic counting, people counting, and license plate recognition (LPR). These artificial intelligence functions are achieved using highly advanced video analytics software that is built-in to the camera and recorder they are connected to. AI cameras can be used as a stand-alone device by recording to an SD card, or they can be connected to a network video recorder (NVR) to create a multi-camera AI system that records to a central hard drive. Please note that only certain models are capable of license plate recognition / automated number plate recognition (ANPR).

 

DVR / NVR Alarm Relay Output

Please note that the the alarm strobe light is self-powered. The alarm outputs on the DVR / NVR are simple relays (they are either open or closed). They DO NOT provide any power output. Also, please note that you can ONLY connect low voltage devices alarm devices to these alarm relay ports. Connecting high powered devices can fry your motherboard and ruin your DVR / NVR.

Important WARNING! The maximum current rating of these alarm relays is 1A, the voltage is 30VDC/ 250VAC, so the maximum power rating is 30W for DC alarm device, 250W for AC alarm device.

You can see above how I wired the strobe light to the output port. Notice how the strobe light’s 12V DC power supply is connected in-line. I used 18 gauge 2 conductor PVC Insulation Jacket Unsheilded / Stranded Copper wire to connect the strobe light to the recorder.

Here is a close-up of the alarm output ports on the back of the DVR / NVR. I am using the COM1 and NO1 ports. NO stands for normally open, which means that power does not flow thorough the relay until the alarm is triggered.

AI Software Setup

Please follow these steps to configure the AI software on the NVR.

From the DVR/ NVR main menu, select AI / Event.

On the AI / Event screen, do the following.

1.   Select More from the AI Event menu.

2.   Select the camera that you are applying the AI rule to from the camera dropdown.

3.   Select Line Crossing as the event type.

Next, do the following.

1.   Check the Enable Detection by IPC (IP Camera) checkbox.

2.   Check the Draw Line checkbox and draw your tripwire on the screen.

3.   Choose the direction of the traffic flow used to trigger the alarm. You can choose a single direction or both directions.

Next.

1.   Click on the Detection Target tab.

2.   Check Human for the detection target type. Uncheck Motor Vehicle and Non-motor Vehicle as they are not applicable in this case.

1.   Click on the Trigger Mode tab.

2.   Click on the Alarm Out Configure button. Please note that you may setup additional alarm triggers on this screen such as image snapshot, mobile app push notification, alarm buzzer, pop-up video, and email alerts.

On the DVR alarm output screen, select the alarm output that your light (or other device) is connected to from the window on the left and click on the arrows (>>) to put the alarm output on the right window. Then, check the checkbox next to it.

Click OK. Then, click Apply in the lower right.

You may then close all of the DVR / NVR configurations screens and return to the live view of your security cameras.

AI Software / Object Detection Visualization

On the live security camera view of your recorder, double click on the camera that you are using for this alarm project to show that camera’s live view full screen. You can enable the AI / Object Visualizations by clicking on the above icon.

 

When you enable the AI software visualizations on the live camera view, a few things happen.

1.   The alarm event window opens on the right. When your security camera detects the event that you configured, a snapshot image will appear in that screen to document the event.

2.   All objects that the system is able to detect will be outlined. Please note above that I am outlined with that yellow box because the AI software is detecting me as a human. The cars in the background are outlined in purple. Even though we are only using people detection for our alarm, the NVR software still outlines the other object types that it recognizes.

3.   The line crossing / virtual trip wire is shows in red. And the A->B traffic flow that I setup it also shown

4.   NVR / DVR Alarm Output Turns Light On

Last, here is a screenshot of the strobe light turned on as a result of the human detection / line crossing event.

Trigger Alarm Output from iPhone App

This is how you can manually trigger (turn on) the alarm relay output on the DVR from the iPhone app. Please note that the Android mobile app is identical to the iPhone all in looks and functionality. They are exactly the same app.

1.   Tap the menu icon in the lower right (the icon with the 3 dots…).

2.   Tap Manual Alarm.

3.   Tap the Alarm Output that you want to trigger / enable.

If you are not understand, you can touch with us for further support. We deal Infinova, Hanwha, Milestone, Mirasys & Luxriot brand.