Ericsson SVP 2000, Справочное руководство, Страница: 16 / 196

Introduction
Figure 1.3 Basic SVP 2000 Video Processor Network Concept
t t+8 t+16 t+24 t+32
1
2
SVP2000/BAS/EN
SVP2000/BAS/RX
Encoder
Decoder
Video
+
Audio
Unmanaged IP
Network
Video
+
Audio
1.2.4 When to Use RTP/UDP Mode
In most cases, the SVP 2000 will use the ABR mode. However, there may be cases
where the use of RTP/UDP mode is preferable. These cases are:
1. Where there is guaranteed bandwidth available between the Encoder and
Decoder
2. Where latency between the Encoder and Decoder needs to be reduced
3. If there is suspicion that there is a possibility of data corruption on the network –
enabling FEC would help protect against data corruption.
Note: There is the ability to add FEC to the ABR mode. Adding FEC will increase
latency. Therefore for most applications, ABR mode would be used.
4. ABR uses Transmission Control Protocol (TCP) protocol for transmission and
requires an acknowledgement for every packet transmitted. If
acknowledgements take a long time to be delivered, the protocol assumes
network congestion. For IP over satellite (KA Band), these acknowledgements
could be long and as such may not be usable.
Note: There is the ability to do ABR over UDP instead of TCP. This should then
allow the use of IP networks over satellite bands.
Caution!
In RTP/UDP mode, only a single profile, fixed bit rate is transferred between the
Encoder and the Decoder.
EN/LZT 790 0046/1 R1A 1-8