What is IP camera ?

Network IP Cameras have been around for at over a decade now. Only recently have cabling installers began to pay attention to the technology because surveillance cameras have traditionally run on separate coaxial cable. Around 10 years ago, the first digital IP camera connected directly to a data network which changed the future of the surveillance camera industry.

During the early stages, the technology was not as professional as analog cameras. Most cameras were seen as ‘web cameras’, which were used to view objects or events over the internet or a LAN.

Today IP network cameras meet the same requirements and specifications as analog counterparts and in many areas surpass analog camera performance and features . Forecasts show that the network IP camera market share is growing at a much faster rate than its analog competitor and has surpassed the analog camera in market share.

An IP Camera is a networked digital video camera that transmits data over a Fast Ethernet link. IP Cameras (also called “network cameras”) are most often used for IP surveillance, a digitized and networked version of closed-circuit television (CCTV).

Benefits of IP camera over analog technology include:

• Remote administration from any location.
• Digital zoom.
• The ability to easily send images and video anywhere with an Internet connection.
• Progressive scanning, which enables better quality images extracted from the video, especially for moving targets.
• Adjustable frame rates and resolution to meet specific needs.
• Two-way communication.
• The ability to send alerts if suspicious activity is detected.
• Lower cabling requirements.
• Support for intelligent video.

Disadvantages of IP surveillance include greater complexity and bandwidth demands. One alternative for organizations with substantial investment in analog technology is to use a video server to, in effect, turn analog CCTV cameras to IP cameras. A video server is a small standalone server that converts analog signals to a digital format and provides the analog cameras with IP addresses.

Nevertheless, because it offers much more sophisticated capabilities, IP surveillance is increasingly replacing analog CCTV. An industry report from International Data Corporation (IDC) predicts that shipments of IP cameras and related products will increase 75% between 2012 and 2015.

IP CCTV transmission methods

There are essentially three ways of transmitting video streams over the network from the source to the destination: broadcast, unicast and multicast.

Broadcast
Broadcast is defined as a one-to-all communication between the source and the destinations. In IP video surveillance, the source refers usually to the IP camera and the destination refers to the monitoring station or the recording server. In this case, broadcasting would mean that the IP camera would send the video stream to all monitoring stations and recording servers, but also to any IP devices on the network, even though only a few specific destination sources had actually requested the stream. Typically, this method of transmission is not commonly used in IP video surveillance applications, but can be seen more often in the TV broadcasting industry where TV signals are switched at the destination level.

Unicast
Unicast is defined as a one-to-one communication between the source and the destination. Unicast transmissions are usually done in TCP or UDP and require a direct connection between the source and the destination. In this scenario, the IP camera (source) needs to have the capabilities to accept many concurrent connections when many destinations want to view or record that same video at the same time.
In terms of video streaming in unicast transmission, the IP camera will stream as many copies of the video feed requested by the destinations. In figure 1 below, three copies of the same video stream are sent over the network; one copy for each of the three destinations requesting the stream. If each video stream is 4 Mbps, this transmission will produce 12 Mbps (3x4Mbps) of data on multiple network segments.

As a result, many destinations connected in unicast to a video source can result in high network traffic. In other words, if we imagine a large system with 200 destinations requesting the same video stream, we would end up having 800 Mbps (200x4Mbps) of data travelling over the network, which is realistically unmanageable. Although this method of transmission is widely used over the Internet where most routers are not multicast-enabled, within a corporate LAN, unicast transmission is not necessarily the best practice as it can quickly increase the bandwidth needed for viewing and recording camera streams.

Multicast
In multicast transmission, there is no direct connection between the source and the destinations. The connection to the video stream of the IP camera is done by joining a multicast group, which in simple terms means actually connecting to the multicast IP address of the video stream. So the IP camera only sends a single copy of the video stream to its designated IP address and the destination simply connects to the stream available over the network with no additional overhead on the source. In other words, the destinations share the same video stream. In figure 2 below, the same three destinations requesting the video stream have the same impact on the network as a single destination requesting the stream in unicast and there is no more than 4 Mbps of data travelling on each segment of the network. Even with 200 destinations requesting that video stream, the same amount of data would be travelling on the network.

It is evident at this point that using multicast transmissions in an IP video surveillance application can save a lot of bandwidth, especially in large scale deployments where the number of destinations can grow very quickly.

Bandwidth optimisation for IP CCTV
When it comes to IP video surveillance, it is important to efficiently manage the way video streams are transmitted over the network in order not to overload the available bandwidth. Even though IT infrastructures are built to handle any kind of data, the applications generating traffic over the IP network need to be conducive with the efficient utilization of the network resources in place. To this end, different functionalities and mechanisms are offered by IP video surveillance solution providers to allow optimization of bandwidth and network resources such as:
• Multicasting
• Multistreaming
• Video compression

Even though the capacity and speed of the network are constantly increasing and its associated costs are declining, this is still not a good reason for users to ignore the additional investments and efforts needed to optimise bandwidth management. The amount of data travelling on the network is also still on the rise and therefore, investments in bandwidth optimization are ones that can contribute to a reduction in total cost of ownership, specifically in respect to efficiency gains and maximized resources.

For example, in video surveillance, more and more end-users are requesting cameras with higher picture quality and resolution, often opting for high-definition and megapixel cameras. These types of cameras require much more bandwidth than standard definition cameras. Also, more and more people inside as well as outside an organization’s walls are requesting access to video streams over the network. In the case where a large number of users are simultaneously trying to access a specific video stream, efficient use of network resources can be crucial in avoiding overloaded capacity and entire network crashes.
It is equally important to realize that optimizing the bandwidth on the network does not necessarily go hand in hand with large capital investments, but is more a matter of putting the right solutions in place and leveraging the unique and powerful capabilities of these solutions.