Getting Started; How The Dme Functions; Plan For Your Dme Deployment - VBrick dme Admin Manual

Getting Started

How the DME Functions

The Vbrick DME is a multi-faceted platform that performs a variety of serving, reflecting,
and transmuxing, and transrating activities and is comprised of the major components shown
in the DME Components topic.
In a typical application, a DME receives a unicast stream over the WAN link (often over
TCP) to effectively traverse the LAN and pass through firewalls. The DME then streams via
unicast and/or multicast to a variety of different clients in the streaming protocol of choice
for each client.
To conserve bandwidth, reflectors can be linked across the WAN to relay video streams from
one remote site to multiple downstream DME reflectors. The net effect is that a single
unicast stream across the WAN can reach tens of thousands of viewers. To improve reliability,
reflectors can either pull or push streams across the WAN using TCP. If a network outage
occurs, the DMEs will automatically reconnect and resume streaming without any user
intervention.
To reach different classes of clients (e.g. PCs, STBs, and mobile devices), a single stream of
H.264-encoded multi-bitrate (MBR) video can work in concert with reflectors to distribute
streams in the most efficient manner. Reflectors can also transmux video streams, converting
from one type of transport stream on the input to another type of transport on the output. In
transmuxing, a digital bit stream is converted from one file format or streaming protocol to
another—without changing the compression method.
An example of transmuxing is when a unicast stream is converted to multicast or when an
RTP stream is converted to RTMP. H.264 offers a variety of transport protocols to ensure
the reliable delivery of video over a variety of networks.
For live broadcasts, the Real-Time Transport Protocol (RTP) is efficient, while the Real-time
Streaming Protocol (RTSP) offers the player controls (fast forward, rewind) needed for VOD
playback. Newer transport protocols like RTMP (for Flash) and HTTP are optimized for
Internet clients and mobile devices.
DME Components

Plan for your DME Deployment

The DME provides a powerful way to redistribute media by allowing you to reach multiple/
remote locations and multiple users with minimal use of streaming bandwidth. Streams can
be converted from unicast to multicast or delivered as Flash HDS and Apple HLS streams
from an RTP source. Since the DME accepts multiple types of input streams and provides
multiple ways to output streams, it may not be entirely clear which use cases apply to you and
what is the simplest way to deploy your solution using the DME. The best way to determine
how to use the DME effectively is to understand three basic factors:
DME Admin Guide
Chapter 3
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