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Remote CCTV cameras and the networks and systems supporting them are a familiar tool in the armoury of any organization involved in transport and logistics. They are essential in providing security around parking lots and other facilities in an attempt to address the thousands of cargo losses reported every year.
However, there is a hidden challenge for those organizations in recognizing how to best manage the networks and storage requirements underpinning any IP video surveillance system.
While organizations continue to benefit from greater network speeds and capacity, the use of IP-based video systems can generate a significant increase in the amount of data traveling on their network. This is as a result of:
• deploying high-definition and megapixel cameras,
• additional cameras to address a need for coverage across larger areas,
• increases to the number of users accessing video,
• recording and maintaining redundant video recordings,
• transferring video from one site to another to maintain long-term or centralized recordings.
When planning and designing an IP video surveillance system, an organization must
take into account the unique aspects of its security environment and its business
operations in order to ensure the reliable transmission of video and avoid overloading
available network resources. For example, certain deployments, such as a largescale cargo transit hub, will require greater flexibility to manage video streams and bandwidth due to their complex nature, further driving the need for advanced video management capabilities.
These scenarios can include:
• Distributed sites requiring operators to connect to remote cameras,
• Cameras connected to networks with limited bandwidth, such as DSL, wireless, or cellular,
• Sharing bandwidth with other operation-critical applications because video is not the top priority for the business.
It is equally important for organizations to realize that optimizing the use of network resources does not necessarily require large capital investments but is more a matter of putting the right solutions in place. With bandwidth and storage representing important ongoing costs of operating an IP system, organizations can significantly reduce the Total Cost of Ownership (TCO) of their video surveillance system by investing in solutions that allow them to optimize their use of bandwidth and storage based on the requirements of their application.
Although system administrators will intuitively manage video quality settings and define recording settings and schedules, addressing the needs of a specific security department can require manual intervention and adjustment. While most Video Management Systems (VMS) applications support these features, Genetec Omnicast™ also supports powerful functionalities and technologies that serve to further reduce the total cost of operating an IP video system.
• end-to-end multicast transmission,
• stream redirection and multicast-to-unicast conversion,
• video caching,
• archive transfer.
By leveraging some or all of these capabilities, organizations can significantly reduce the number of servers required to manage and store video, reduce their network bandwidth requirements, and reliably scale their system while minimizing their investment in new infrastructure.
In IP video surveillance, unicast and multicast are the two most commonly used methods to transmit video from cameras to client workstations. While all VMS platforms can configure unicast, only a few also offer multicast transmission, and, among these, even fewer support end-to-end multicast that provides communication from the edge device (IP cameras and encoders) to the workstation.
Though many VMS platforms may claim multicast support, the majority will only provide limited support for multicast transmission between the recording server and the client station, and require multicast to be set for all cameras on the server, or even implemented system wide. It is important
for organizations to consider that certain VMS systems provide far greater flexibility with regards to transmission, in order to implement the best design for their application. This includes the ability to set up cameras per select network branch or per viewer and the ability to automatically detect the ideal transmission method for different segments of the network, thereby allowing organizations to optimize the performance of their video surveillance system and minimize the network resources that are required.
Unicast requires a direct connection between the source and the destination. Unicast only works if the source has the capability to accept concurrent connections when multiple destinations want to view or record the same video at the same time. In IP video surveillance, unicast involves a camera streaming as many copies of the video feed as are requested by the destinations, so a 6 Mbps video stream that is requested by three operators will produce a transmission of 18 Mbps of data across multiple network segments (6Mbps per stream x 3 requests = a total of 18 Mbps). This method of transmission usually results in higher network traffic.
Moreover, it is not considered best practice for corporate LANs because it can cause a rapid increase in bandwidth requirements for viewing and recording video streams. In the event of an emergency in which several operators require access to the same camera streams, the request for concurrent streams can overtax the processing capabilities of a camera or the bandwidth constraints of the
network. This excess demand can result in a reduction in video quality or, even worse, the inability for operators to access and view the streams that they require to respond to an incident.
In multicast transmission, because connecting to a video stream is accomplished
by simply joining a multicast group, there is no direct connection between the source and the destination. Instead, the source simply sends a single copy of the video stream to its designated multicast address, and then the destination connects over the network to the multicast address of that stream. This means that all destinations share the same video stream. Although multiple operators may request the same video stream, an IP camera in multicast transmission only needs to send one stream over the network without crossing any branch of the network more
than once, thereby realizing a significant gain in network efficiency as compared to a unicast deployment. Therefore, organizations using IP video surveillance, especially those with large-scale deployments with remote locations and cameras or those that could experience a rapid increase in the number of clients, can greatly reduce bandwidth requirements by using multicast transmission.
Advantages of multi-streaming
Multi-streaming refers to the capability of an IP camera to transmit multiple video streams from the same camera device with different video quality settings. Two components are essential for multi-streaming support in an IP video surveillance system:
• an IP camera or encoder capable of producing multiple streams.
• a VMS that is able to manage those streams,
Multi-streaming allows the system administrator to easily assign different purposes to video streams, including live viewing, remote viewing (with reduced bandwidth), recording, and long-term recording. The following are examples of how different multi-stream configurations can help reduce network load, and ensure appropriate video feeds are streamed to all destinations.
When monitoring video, an operator will often need to replay the same sequence to review a scene. Since the video has already been transmitted once from the recording server to the client workstation, a VMS should not need to retrieve the same footage over the network each time the sequence is viewed. To ensure greater fluidity when reviewing video and to minimize the use of bandwidth, organizations should ensure that their VMS has the ability to maintain a live and recorded video cache.
A VMS’ ability to transfer video archives from their initial recording location to another physical storage device provides organizations with greater flexibility to select the storage hardware most suited for their requirements, whether they want to reduce the cost of storage at distributed sites, or maintain long-term recordings. The capability allows organizations to record video locally, either on edge devices or on a Network Video Recorder, and transfer archives to a central server on-demand, or on a schedule, in order to minimize the impact of the video surveillance system will have on their network. For example, when it is not possible to continuously stream video to the central system for recording (due to limited bandwidth or unstable connectivity), archive transfer can be used to schedule the video transfer during periods when network demand is low or after regular business hours in order to avoid impacting business operations. During the transfer, the video is copied from the edge device or server at a rate determined by the capacity of the network connection.
Using Archives Transfer, an organization can configure its video surveillance system in such a way that, instead of continuously streaming video over the WAN, only archives tagged with events, such as motion, or alarms, will be transferred from the remote site to a central server for long-term storage. This provides an effective technique to reduce the use of network resources because it decreases both the load on the WAN and the amount of video that will be stored
in the central system.
Archive transfers can also be used to add a greater layer of reliability to an organization’s IP video surveillance system. In the event where connection to a camera is lost, a VMS can transfer only the video that was recorded on the cameras affected by the connection failure, once connection to servers has been re-established.
There is a lot to think about when it comes to using video as part of your transport and logistics security solution. The right VMS can add greatly to your overall security performance and help to address many of the concerns that security professionals are constantly dealing with in trying to maintain resilience in the supply chain. But time spent understanding your requirements, what functionality you are looking for as well as appreciating what infrastructure is going to be required, will ensure that you are deploying the best possible solution.
About the author
Nick D’hoedt is the business development director, Transport & Logistics at Genetec. He has a strong track record in the IT and security industry and a history as a developer and analyst. He joined Genetec, the global technology company that encompasses security, intelligence and operations, in 2011.
The company's flagship product, Security Center, is an open-architecture platform that unifies IP-based video surveillance, access control, automatic license plate recognition (ALPR), communications, and analytics. Genetec also develops cloud-based solutions and services designed to improve security, and contribute new levels of operational intelligence for governments, enterprises, transport, and the communities in which we live.
Founded in 1997, and headquartered in Montréal, Canada, Genetec serves its global customers via an extensive network of resellers, integrators, certified channel partners, and consultants in over 80 countries.