VBrick dme, Руководство администратора

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90 © Vbrick Systems, Inc.
HLS CDN Reflection
Beginning with DME v.3.12, the DME is able to retrieve, cache and distribute (to viewers)
HLS streams from external sources. This allows customers to utilize their DMEs for caching
and distribution of HLS streams from CDNs. This feature currently only supports retrieval,
caching, and distribution of Akamai HLS streams. Further, this feature is only for VEMS
customers, as Rev utilizes these settings for distribution of live Conference.
As an example, in this scenario, the DME receives an HLS request (m3u8/manifest or video
chunk) from a viewer/player. The DME identifies the stream as an Akamai stream. The
DME will pull the requested content from Akamai, cache it, and deliver the content to the
player. Other subsequent requests are pulled from the local DME cache, Mesh, directly from
Akamai (in this order) and delivered to those players. Manifest files are only minimally locally
cached (< 2 seconds), while video chunks are kept longer. This feature allows customers to
better leverage their Akamai investment jointly with their on premise DME investment
The configuration of this feature requires knowledge of the Akamai publishing
hostnames
,
and the ability to identify a unique string,
identificationString
, within the URL. While a simple
string will work, the
identificationString
will also take a Regular Expression.
For example, your Akamai playback URL may be:
Example Akamai HLS Playback URL: http://myCompany.akamaihd.net/i/
streamName@streamID/master.m3u8
The URL provided to the DME (from a player) would be:
Example DME HLS Playback URL: http://dmeIP/i/streamName@streamID/
master.m3u8
Note the parallelism/similarity highlighted in the two URLs – this is necessary for the feature
to work. In this example, the
hostname
would be myCompany.akamaihd.net. The
identificationString
(regular expression) must be supplied which will uniquely identify (to the
Smooth Streaming Microsoft-specific HTTP adaptive streaming typically used by the
Microsoft Silverlight player or Windows mobile video display.
Adobe HDS HTTP Dynamic Streaming used by Flash players for HTTP
adaptive display of video.
MPEG DASH An emerging video distribution standard for display of video via
HTTP adaptive streaming. Players are not yet widely available.
WM Session Files WM Session Files (asx or nsc) are often used to display WM video
and are required for display of Windows Media multicast. They are
generated by a Vbrick Appliance (not DME)
MPEG Multicast
Session Files MPEG multicast Session Files (.sdp) are required for display of
RTP multicast video. They are generated by Vbrick VB6000,
VB7000, and VB9000 appliances.
Alternate Sources
(siblings) If the DME does not already contain the requested content it will
look sequentially through the alternate sources before it checks the
parents. The syntax is:
<ip_address>:port
Note: The specified port numbers override the displayed port
numbers. See Ports for more information.
Field Description