Campbell NL241, Instruction Manual

Page: 50 / 76

Appendix A. Glossary
A-2
PakBus®
Campbell Scientific’s packet-switched communications protocol. Packets
of information transmitted between PakBus devices contain user data and
administrative information (a header) that routing devices use to move the
packets to their ultimate destination. PakBus devices examine the header
information and then either remove the header (at the packet’s final
destination) or forward the packet to another PakBus device.
PakBus® Node
A device in a PakBus network. Each device in a network must have a
unique PakBus address.
Port Number
A port number is a way to identify a specific process to which a network
message is to be forwarded when it arrives at the NL241.
SDC (Synchronous Device Communications)
A Campbell Scientific addressable and synchronous communications
protocol. The protocol allows multiple peripherals to be connected to the
same device as long as each peripheral has a unique SDC address.
Serial Server
A serial server (also referred to as a terminal server) allows serial
communication over an IP communications link.
Proxy (Proxy Server)
A device that acts as an intermediary for IP communications between two
clients. In the context of this manual, the NL241 acts an intermediary
between two or more clients requiring a secure connection (TLS) and one
client requiring an unsecured connection. Communications are encrypted
and decrypted as necessary for the two clients to communicate via the
proxy.
TLS (Transport Layer Security)
An encryption protocol allowing secure client/server communications. A
keyed, message-authentication code is used for message reliability.
Verify Interval
An interval of time that a PakBus device uses to determine when it is time
send a hello message to another device to verify that they can still
communicate.