Appendix a. glossary – Campbell Scientific NL240 Wireless Network Link Interface User Manual

Page 45

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Appendix A. Glossary

Beacon Interval

Devices in a PakBus® network may broadcast a hello-message to other

devices in order to determine "neighbor" devices. Neighbor devices are

devices that can be communicated with directly by the current device

without being routed through an intermediate device. A beacon in a

PakBus network helps to ensure that all devices in the network are aware

of which other devices are viable in the network.

Bridge (Bridging, Network Bridge)

In the context of this manual, bridging is the act of connecting two

network interfaces at the data link layer. The NL240 acts as a semi-

transparent bridge passing, without alteration, IP packets between the Wi-

Fi and CS I/O ports.

DHCP (Dynamic Host Configuration Protocol)

A TCP/IP application protocol in which IP addresses are assigned

automatically by a DHCP server. Note that an IP address obtained

through DHCP is not static but is leased for a period of time set by the

network administrator. The address may change, if the NL240 is powered

down.

Hello Exchange

A communication exchange that establishes two PakBus® devices as

neighbors. A hello command packet is sent by one PakBus device (A) to

another device (B). Device (B) then sends a hello response (A). The

receipt of that packet establishes the two devices as neighbors. Only a

hello exchange can establish two devices as neighbors.

Neighbor (PakBus® Neighbor)

A device in a PakBus network that can be communicated with directly

(i.e., not via a router). Every PakBus device maintains its own Neighbor

List.

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.

A-1

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