When looking for the most effective way to manage video in a security system, there are two often-discussed video transmission methods: Multicast and Unicast. Both have their benefits, but which is best for security applications?
Multicast is a method of one-to-many transmission which is often deployed in IP applications of streaming media. Multiple viewers can simultaneously tap into a single transmission from one source.
Television programming is a perfect analogy. When you want to watch HBO you tap into the HBO feed on the cable network, not to a dedicated signal of HBO. If your cable box is authorized, you get access to the existing stream of HBO on the cable network.
To benefit from Multicast, multiple simultaneous views of the same stream are required. For customers who have multiple operators viewing the same live cameras, Multicast may be a benefit.
However, in most security applications, Network Video Management Systems (NVMS) are used to view recorded video much more than live video, like reviewing video from a specific date and time, around an alarm event, or reviewing video as part of an investigation. Since all recorders, including the most advanced multicast-based recorders, are based on Unicast video streaming for playback, there really is no gain on operation performance by utilizing Multicast network.
To realize significant benefits from Multicast transmissions, a multicast-enabled network must be constructed to enable single stream replication on the IP network, making it available for every user looking to view it.
Multicast stream can only be used on the Local Area Network. Operators communicating over a wireless connection or over the corporate WAN will communicate using Unicast stream by default, and will not gain from the Multicast capability. In addition, IT departments are wary about enabling Multicast on their network due to security reasons, not to mention the cost associated with it.
Is Unicast a better option?
With Unicast transmission, every user in the network who would like to view video will receive a dedicated video stream from the Video Management System (VMS). Compared to Multicast transmission, Unicast does utilize more bandwidth; however, these streams are only required between the source and the “viewer”, and do not affect the entire network (as a Multicast transmission would.)
With VMS implementation of advanced video compression technology and the ability to maintain symmetric bandwidth management of video, users can manage multiple high-quality video streams on a Unicast network without the deployment of Multicast transmission.
To summarize, Multicast transmissions do offer the benefit of lower bandwidth consumption, but comes with higher network construction cost. Unicast provide cost-savings on the construction of Multicast-enabled networks while maintaining real-time, low latency, high-quality video with adequate bandwidth management for all users on the network.
Contact MCC’s Security Solutions Division today to help determine which video management option is best for your organizations needs.
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