S&C Instruction Sheet 1072-530
45
SpeedNet Client Tool
• Hello Interval
—The
Hello Interval
setting determines how frequently the SpeedNet
Radio broadcasts a neighbor beacon message (hello message). Smaller hello interval
values increase the wireless network’s responsiveness to routing changes but do so
at the expense of creating additional network communication overhead. Larger hello
interval values decrease the wireless network’s responsiveness to routing changes but
reduce excessive wireless traffic in the process. This value is measured in seconds and
the recommended value is 30 seconds
• Allowed Hello Loss
—
The
Allowed Hello Loss
value determines the number of
consecutive hello messages that, when missed, constitutes a link failure that will lead
to a new route request for routes incorporating the link that failed. Setting this value
too low can cause unnecessary route generation when a hello message is lost because
of a temporary circumstance (e.g. a burst of interference or a packet collision). Setting
this value too high can cause excessive data loss in a route that is no longer viable
because of the persistent failure of a link in the route. The recommended value is 6
• Net Diameter
—
The
Net Diameter
parameter determines the maximum of number
of wireless hops between the source and destination nodes, specifically, the maximum
number of hops that a route request message can travel. The
Net Diameter
should
be set to at least the maximum number of hops expected for application traffic. If the
Net Diameter
is set too low, then route creation may fail because of route requests
never reaching the desired endpoint. If the
Net Diameter
is set marginally too low,
primary route creation may succeed but creation of a secondary route may not succeed
in the case of a link failure along the primary route. If the
Net Diameter
is set too
high, route requests may propagate needlessly to too many radios, generating excessive
overhead. Setting the
Net Diameter
too high is a more critical issue in high-density
connected mesh deployments than in linear deployments. In mesh deployments, the
overhead incurred by the
Net Diameter
can increase as the square of the diameter.
Do not set this value to the number of radios in the mesh. Set it to the lowest possible
value that allows for redundancy. The recommended value is 10 hops
• Node Traversal Time
—The
Node Traversal Tim
e value provides an estimate of the
time required for a packet to traverse one wireless hop. This value affects how long a
SpeedNet Radio waits before resending a route request packet. This value is measured
in milliseconds and the recommended value is 150 msec
• ARQ Retry Tolerance
—The
ARQ Retry Toleranc
e parameter allows a configurable
number of successive, unique packet delivery retries prior to terminating a route.
When this number of successive retries is reached, a radio node is able to know more
quickly that its next hop radio neighbor is no longer available to route packets, and a
route will be built around that unavailable neighbor if there is another valid neighbor.
This configuration parameter is useful to balance the identification of an unavailable
neighbor with packet delivery success rates so more expedient routing may be
performed around an unavailable node. The recommended value is 3
• Link Threshold
—SpeedNet Radio only considers a neighboring radio node valid,
if its signal strength is above a configured threshold, called the grayzone threshold
A radio neighbor with signal strength above the grayzone threshold is considered
viable to build routes through, and a neighbor below this threshold will not be used
for routing from that specific radio