User Manual

Section 2: Advanced Topics
LONWORKS/IP Channel Timing Considerations
When designing a LONWORKS/IP channel over an IP network that might have a large
latency, such as the Internet, it is important to be aware of the relationship between the
three timing parameters that can be set when configuring the channel. Two of the timing
parameters, Channel Timeout and Packet Reorder Timer, are set for the LONWORKS/IP
channel through the Configuration Server. Channel Delay is set through an LNS based
tool such as the LonMaker tool.
On local area networks, Channel Timeout is required only if MD5 Authentication is
used. Packet Reorder Timer should be disabled on a LAN, and the LonMaker Channel
Delay for the channel should be set to twice the aggregation timer.
On networks using the Internet, Channel Timeout and Packet Reorder Timer must
consider the value of the LonMaker Channel Delay parameter. Table 12
specifies how to
approximate the timing values for network implementations using the Internet.
Table 12. Timing Parameter Calculations for Internet L
ONWORKS/IP Channels
Timing Parameter Set to:
Channel Timeout (Average Ping Delay / 2) + 20%. A typical LAN based channel will
require at least a 50 ms delay and a typical WAN based channel will
require at least a 100 ms delay.
Packet Reorder Timer The lesser of:
¼ of Channel Timeout Value, or 64 MS
LonMaker Channel Delay Average Ping Delay + 10%
If using aggregation, and if the aggregation delay is a high percentage of the channel
timeout or channel delay, add twice the aggregation delay to the Channel Delay and one
times the aggregation delay to the Channel Timeout.
Use the ping command from a DOS window to obtain the average ping delay. Do not use
the ping command in the i.LON 600 Console Application.
i.LON 600 User’s Guide 61