Campbell CR850, Operator'S Manual, Page: 337 / 566

Section 8. Operation
337
Table 80. PakBus Leaf-Node and Router Device Configuration
Network
Device
Description
PakBus
Leaf Node
PakBus
Router
PakBus
Aware
Transparent
SC932A Serial interface •
COM220
Telephone
modem
•
COM310
Telephone
modem
•
SRM-5A
Short-haul
modem
•
1
This network link is not compatible with CR800 datalogger.
8.5.3 Linking PakBus Nodes: Neighbor Discovery
New terms (see Nodes: Leaf Nodes and Routers
(p. 335)
):
•
node
•
link
•
neighbor
•
neighbor-filters
•
hello
•
hello-exchange
•
hello-message
•
hello-request
•
CVI
•
beacon
To form a network, nodes must establish links with neighbors (neighbors are
adjacent nodes). Links are established through a process called discovery.
Discovery occurs when nodes exchange hellos. A hello-exchange occurs during a
hello-message between two nodes.
8.5.3.1 Hello-message (two-way exchange)
A hello-message is an interchange between two nodes that negotiates a neighbor
link. A hello-message is sent out in response to one or both of either a beacon or a
hello-request.
8.5.3.2 Beacon (one-way broadcast)
A beacon is a broadcast sent by a node at a specified interval telling all nodes
within hearing that a hello-message can be sent. If a node wishes to establish itself
as a neighbor to the beaconing node, it will then send a hello-message to the
beaconing node. Nodes already established as neighbors will not respond to a
beacon.