Echelon LonWorks Router - Manual (Page 25)

outgoing buffer queue. Thus, priority processing of these outgoing messages is
assured because the transmitting side will send messages from the priority output
buffer queue before sending messages from the non-priority output buffer queue.
Figure 8 shows the message flow through the input and output buffer queues. This
message flow is duplicated for messages moving in the opposite direction, that is,
another set of input and output buffer queues exist for messages flowing in the
opposite direction.
1 2
1 2
1 2 3 N - 1 N
Message Receiving Side Message Sending Side
Input Buffer Queue
Priority Output Buffer Queue
Normal Output Buffer Queue
Direction of Message Flow
Figure 8. Buffering Scheme for a L ON W ORKS Router
The size and count of the message buffers is limited by the amount of RAM on
the router.
RTR-10 Message Buffers and Transaction Records
There are three different versions of the router firmware for the RTR-10 router.
To determine the router firmware version of your router, see Appendix B,
Determining RTR-10 Firmware Version.
Some versions of the RTR-10 routers were shipped with a reduced buffer and
transaction record capacity. This does not impact system performance. However, a
catastrophic failure of the router can occur if the buffers or transaction records on a
router with reduced buffer and transaction record capacity are reconfigured and
assume that a larger buffer and transaction record space is available. This could
occur if you are using a manufacturing test station to reconfigure routers based on
the higher router buffer and transaction record capacity. It can also occur if you
use a network installation tool that reconfigures router buffers or transaction
records when replacing a router using a non-standard configuration. The failure
condition that occurs is that the router will go into the application-less state and
will no longer function as a router. This failure mode cannot be recovered in the
field. If you are making the change with a tool based on the OpenLNS Server or
the OpenLNS Commissioning Tool (or LNS and the LonMaker Turbo Integration
Tool), in some cases, the tool will prevent an invalid configuration; however, in
other cases the tool may allow an invalid configuration and the router will fail. Use
the tables, below, to understand the correct buffer and transaction record
configurations for your RTR-10 router.
Depending on your firmware, buffers and transaction records are allocated
according to the following tables. For versions A and C, Table 3 shows the
transaction record configurations for receive and transmit transactions, and the
L ON W ORKS Router User’s Guide 15