|
|
 |
 |
 |
| To
understand the QoStream™ product family is to understand
how tomorrow's services can be deployed today in a highly
cost-effective way. Implementing an ESON architecture with
Amedia's QoStream™ products provides the scalability,
reliability, security, and flexibility to meet the needs of
the most demanding customer. |
|
 |
|
|
|
|
| The video head end delivers
Standard Definition Television (SDTV) and High Definition
(HDTV) digital video information to the QoStream™
network directly and via video servers that are networked
to an Ethernet core switch. One type of video head end
is a Digital Turn-Around (DTA) System which receives
video content in one form and turns it around to a digital
MPEG form, receiving, descrambling, demultiplexing,
streaming, and adapting the video channels for the network.
Broadcast TV channels are normally delivered to network
operators by satellite, processed by the DTA system,
and delivered to the Ethernet network as individual single program |
 |
 |
streams. Each
single program stream is encapsulated into an IP frame and
into an Ethernet packet with source and destination MAC addresses.
Ethernet networks utilize multicasting techniques, with a
single copy of the program sent to the network and multicasting
copies sent to the destination addresses by multicasting at
the various Ethernet switching locations in the network, so
that network bandwidth is consumed only where it is viewed
by the end consumers. Streaming is the process of addressing
the video channels for the appropriate multicast group and
traffic shaping the video channels for real time receipt.
Subscribers tune to these multicast groups using Digital Set
Top Boxes (STBs), which deliver TV signals to the video monitor
in response to the channel selection made by means of the
hand-held remote control. Channel surfing with the hand-held
remote control stimulate a fast leave and joining process
in the network by which a subscriber associates his real time
reception to different multicast groups and tunes to the program
stream of interest.
Such a broadcast head end can receive video content from a multiplicity
of satellite transponders supplied by many different content
providers. Some of the resulting single program streams can
be SDTV, and some of them can be HDTV, streaming content to
the QoStream network in accordance with subscriber content requirements.
Likewise, PPV events are available as single program streams,
usually first stored in a video server, and then multicast through
the Ethernet network at the appropriate event viewing time,
selectable by those consumers who have ordered the PPV event
and who therefore can join that particular multicast group (authentication
process). For VOD, streams are not multicast, but instead are
unicast through the network from a video server to specific
destination addresses corresponding to the subscriber who has
ordered the VOD program. In this way, each subscriber can start
the program at an arbitrary time, stop, restart, and end the
program whenever the subscriber wishes. The VOD video server
should be visualized as a large digital database, partitioned
into program sectors, and with each subscriber having a pointer
into a desired program sector. Such a video server can also
be the basis of a network-level personal DVD player, with all
the control functionality of a local DVD player in the home.
A Ethernet core switch networks to video content services functionality
that provides direct broadcast video, PPV video through a video
server, and on-demand programming through a VOD server. Single
copies of the broadcast and PPV content is delivered to the
core switch as Ethernet packets, and the multicast groups are formed
in the core switch, AS5000, and PG1000 to deliver video content to
the QoStream subscriber STBs via the GbE and 100 Base FX paths
through the network. QoStream intelligent multicasting is performed
closest to the subscriber in the core switch, AS5000, or PG1000,
thereby avoiding multiple copies of programs and reducing traffic
upstream in the network.
Subscribers are arguably most sensitive to impairments on video
services, especially dropped packets and jitter, due to the
impact they have on the video image. Accordingly, separate VLANs
with Guaranteed Bandwidth or Bursty Bandwidth service guarantees
are normally used for video services. In addition, separate
VLANs are often used for subscribed events such as PPV and VOD
for purposes of viewer authentication.
Back to top >
|
|
|
|