Cisco Model D-PCG1000 PowerKEY CAS Gateway Installation Guide

 

4012215 Rev B 

3 

 

In addition to Network-Attached mode, the NOBE also supports the use of 
unidirectional GbE interconnects without a switch. When operating without a 
switch, the clear copy and encrypted copy of the program streams arrive on separate 
GbE links, and the partially encrypted output stream leaves the NOBE on a third 
GbE link, as shown in the following diagram.  

 

 

The partially encrypted stream allows Cisco and third-party DHCTs to receive a 
digital broadcast that is compatible with their compliant CA system. To generate a 
partially encrypted stream, requires that the NOBE receive a clear copy and an 
encrypted copy of the same program stream. From the clear stream, the NOBE 
selects and encrypts critical packets of the elementary streams and picks the 
corresponding critical packets of the third-party-encrypted stream. Then, the NOBE 
multiplexes the PowerKEY-encrypted portion, the equivalent third-party encrypted 
packets, and the rest of the stream still in the clear to form the partially encrypted RF 
output stream, or Overlay stream.