Specifications

If your nodes are geographically distributed such that they are always more than 1 hop away from their
logical peers, then you can increase this parameter. Consequently, if most of your nodes are within
direct radio range of each other, having this parameter at the default setting of 1 will use less radio
bandwidth.
If you set this parameter to zero, SNAP will make an initial attempt to talk directly to the destination
node, on the assumption it is within direct radio range. (It will not attempt to communicate over any
serial connection.) If the destination node does not acknowledge the message, and your Radio Unicast
Retries and Mesh Routing Maximum Hop Limit are not set to zero, normal mesh discovery attempts
will occur (including attempting routes over the serial connection).
This means you can eliminate the overhead and latency required of mesh routing in environments
where all your nodes are within direct radio range of each other. However it also means that if the
Mesh Routing Initial Hop Limit is set to zero and there are times when mesh routing is necessary,
those messages will suffer an additional latency penalty as the initial broadcast times out
unacknowledged before route requests happen.
This parameter should remain less than or equal to the next parameter, Mesh Routing Maximum
Hop Limit.
Also, although Portal (or SNAPconnect) are “one hop further away” than all other SNAP nodes on
your network (they are on the other side of a “bridge” node), the SNAP code knows this, and will
automatically give a “bonus hop” to this parameter’s value when using it to find nodes with addresses
in the reserved Portal/SNAPconnect address range of 00.00.01 – 00.00.15. So, you can leave this
parameter at its default setting of 1 (one hop) even if you use Portals and/or SNAPconnects.
ID 28 – Mesh Routing Maximum Hop Limit
To cut down on needless broadcast traffic during mesh networking operation (thus saving both power
and bandwidth), you can choose to lower this value to the maximum number of physical hops across
your network. The default value is 5.
ID 29 – Mesh Sequence Number
Reserved for future use.
ID 30 – Mesh Override
This is used to limit a node’s level of participation within the mesh network.
When set to the default value of 0, the node will fully participate in the mesh networking. This means
that not only will it make use of mesh routing, but it will also “volunteer” to route packets for other
nodes.
Setting this value to 1 will cause the node to stop volunteering to route packets for other nodes. It will
still freely use the entire mesh for its own purposes.
Page 100 of 202 SNAP Reference Manual Document Number 600-0007K