Which Switch?
When deploying a network video system, everything from frames per second to field of view is typically specified; everything except one of the most critical pieces of equipment - the switch.
In most installations, IP video devices transmit video via Unicast. Due to the number of Unicast streams that a device can transmit, as well as the sheer volume of traffic that video can generate, it is always recommended you install a managed layer 2 switch. Managed layer 2 switches will offer such features as Internet Group Management Protocol (IGMP), Quality of Service (QOS), and configurable switch features, such as "cut-through" switching for low-latency environments.
All Bosch IP devices can supply up to five Unicast sessions per stream. When designing your video system, if any video stream will be viewed by more than five clients simultaneously, consider configuring the system for Multicast. Multicast technology utilizes network equipment to replicate streams for multi-user environments. For example, an IP camera would supply one stream, and the network would replicate that stream and supply video to multiple users.
Since Multicast is a hybrid of Unicast and Broadcast technologies, all layer 2 switches must be at least IGMP-2 capable, and a managed layer 3 switch with a Multicast Query chip must be used. Multicast Queries allow the switch to ask network devices if they want to join, remain, or leave a Multicast Group (MG). Since Multicast is a hybrid of Broadcast, this prevents issues such as network flooding.
