VBrick currently supports a variety of shelf and rack-mount models. See the latest DME Release Notes for a detailed description of DME models and specifications. There are no absolute rules for sizing a multipurpose device like the DME but there are some basic guidelines that can help you select the right model.

The smaller Model 7530 does not offer redundant power supplies or redundant VOD storage so if these attributes are important, you should consider the larger models. The Model 7530 is shelf‑mount only while the larger models are rack mount 1U and 2U servers. Users seeking significant VOD content playback should consider one of the two larger models.

The RAID arrays built into the Models 7550 and 7570 (seen below) are much more powerful and better suited for frequent requests than for concurrent VOD playback. The single drive on the Model 7530 is well suited for small to medium offices that have occasional VOD demands.

All of the models have excellent throughput performance and are designed to manage occasional traffic bursts exceed recommended performance characteristics. The throughput recommendations are based on a combination of input and output. For example, a Model 7530 (with 250 Mbps throughput) can support four 1 Mbps streams in, and reflect out 96 1 Mbps unicast streams of RTP or Flash (any combination that equals 250 Mbps).

Also keep in mind that one multicast stream out counts as a single stream from a bandwidth perspective, regardless of how many users are watching. Please refer to the latest DME Release notes for complete hardware specifications.