Troubleshooting and Technical Support 30
NS-Link Driver Troubleshooting
The device will not
load the NS-Link
device driver and
continually reboots
Analysis:
The normal NS-Link load process is:
• If NS-Link determines that it needs to load an RTS, it
resets the device. It does this to get the RTS into
RedBoot mode. Only RedBoot accepts load binary
commands, which are needed to load the NS-Link
binary into the RTS.
• After a 6 second delay, NS-Link sends an ID query to
the RTS. This query is to verify that the RTS is in
RedBoot and can accept load binary commands.
• The RTS sends an ID query response.
• NS-Link loads the RTS.
If the RTS is not loaded after timeout seconds (default
15), it loads SocketServer.
The problem is caused by an L2 bridging feature called
Spanning Tree Algorithm (STA) in some Ethernet
switches. In some cases, this feature is enabled by
default in the switch. This features causes timeout
problems on certain L2 protocols, such as the Comtrol
MAC mode.
The above process fails when STA is running because the
switch blocks packets for 30 seconds after the RTS is
rebooted. Therefore, the ID query is not received by the
RTS and after 15 seconds the RTS loads SocketServer.
After 30 seconds, NS-Link finally can do an ID query,
which reveals that the RTS is not in RedBoot. NS-Link
therefore reboots the device, and the process repeats.
Solution:
L2 bridging is rarely used in the industry, and is basically
obsolete. There are a number of ways to resolve the
problem. More than one method may be required and these
may be used in combination with each other:
1. Disable STA in the switch.
2. Enable STA fast forwarding on the port.
3. Change the STA Forward Delay and Message Age to
minimum time values.
4. On the RTS, set the timeout value to 0 (to disable
loading of SocketServer) or 120. The command from
the RedBoot prompt is Timeout 120 without the quotes.
The Comtrol device
has a lower
limitation of network
bandwidth
requirement of 64
Kbps.
At this speed the entire available bandwidth is required for
the purpose of uploading the firmware from the driver to
the Comtrol device. At lower speeds, timing issues will
prevent the firmware from being successfully installed to
the Comtrol device, thus preventing the device from
normal operation.
When using the Comtrol device over a WAN link that is
less than the recommended 64 Kbps, a timing modification
may be made that will allow uploading of the firmware.
Load the driver locally to the device for the purpose of
getting the firmware installed. The PC on the other side of
the slow link can then share the port. The sharing may be
exclusive as the firmware loader PC may not need to access
the ports.
NS-Link Condition Explanation/Action
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