Verilink Red Zone Encryption (REMS) (880-502423-001) Product Manual - Manual (Page 31)

System operation
Red Zone Encryption Management System (REMS) User Manual 3-5
System operation
The Red Zone Encryption Management System (REMS) consists of two
of each of the following components:
■
DTE equipment, operating at 1.544 Mbps (such as IDN
multiplexers)
■
Frame Bit Repositioners (FBR)
■
Encryptors (such as the KG81 or KG94), and
■
Black-to-Red Communicators (BRC)
When the system starts up, each piece of equipment tries to “get into
sync” with its counterpart at the other end of the network. To accomplish
this, the entire system goes through an ordered procedure to align itself.
How the REMS
aligns itself The system alignment process involves four sequential steps:
1. BRC-to-BRC framing
2. Encryptor-to-encryptor synchronization
3. FBR-to-FBR alignment and framing, and
4. DTE-to-DTE framing
In this example, we consider the near-end REMS termination to be the
transmitting side.
BRC frame
synchronization The BRCs frame to each other, using ESF framing across the public
network.
Each BRC arbitrarily assigns a bit position in the cipher text signal and
overwrites the original cipher text bit with standard ESF frame bits and
CRC-6 bits. Although this would appear to create errors within the cipher
text data, the following sequences eliminate any errors.