Cisco Model D-PCG1000 PowerKEY CAS Gateway Installation Guide
Theory of Operation
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Netcrypt Bulk Encryptor Ports
As shown to the right, the Netcrypt
As shown to the right, the Netcrypt
Bulk Encryptor has four active GbE
ports. There is a MAC address
assigned to each port. Operators
must assign an IP address to any
port they have provisioned on the
DNCS Administrative Console. In
a Layer 3 (routed) network,
operators must provide a gateway
IP address for any port they
provision on the DNCS
Administrative Console.
The first four ports of Netcrypt Bulk Encryptor are active
GbE ports. These ports behave independently. Content
coming in on any one port is processed and leaves
using the same port. Routing between ports is not
supported.
Note: GbE ports 5 to 8 are not active.
GbE Headroom
In designing a content routing and transport network, operators should provide
In designing a content routing and transport network, operators should provide
some amount of headroom at all GbE ports. Bursty traffic can cause the
instantaneous Ethernet frame arrival rate to exceed 1 Gb/s, even when the average
rate is well below this. When this occurs, the switch or router will buffer some of the
frames up to the memory capacity of the dedicated or shared buffer on the
switch/router. When this capacity is exceeded, the switch/router discards the
frames. As a result, it is possible to experience video glitching and macroblocking
even though the switch/router and Netcrypt Bulk Encryptor all can handle the full
GbE rate. The required amount of headroom can vary between 0 to 40 percent of the
port capacity, or even more, depending on the burstiness of the source or VOD
server.
MPEG Transport Layer Rules
The Netcrypt Bulk Encryptor is intended as a network device. Although as a
transport stream encryptor it is necessary to perform some operations at the MPEG
transport layer, the intent is to minimally alter the transport streams. The following
list describes some rules of MPEG transport layer operation to which the Netcrypt
Bulk Encryptor adheres:
By default, the Netcrypt Bulk Encryptor blocks all input streams and programs
from appearing at the output. It passes only streams and programs for which
there exists either a defined session (broadcast or VOD) or one of the new
Transport Stream Route (TSR) structures. The TSR concept has been added to the
DNCS and Netcrypt Bulk Encryptor to enable an operator to instruct a Netcrypt
Bulk Encryptor to pass all programs within a single or multi-program transport
stream from a specified set of input addresses (unicast or multicast) to a specified