3Com 3C16685 User Manual - Isolating A Problem
106
C
HAPTER
5: P
ROBLEM
S
OLVING
Isolating a Problem
A good way of isolating a problem is to see whether it occurs on a
particular port only. This can be done by:
■
Using a different port to see if the problem still exists.
■
Using management to view how a port has been set up. In
particular, see if the port is:
■
Partitioned due to a network loop, receive jabber or false
carrier events (on 100Mbps)
■
Disabled by management
■
Part of a resilient link pair
■
Performing security
■
Operating at the correct speed (10Mbps or 100Mbps)
Solving Problems With the Command Line Interface
The terminal or terminal emulator cannot access the stack
through the console port on one of the units. Check that:
■
Your terminal or terminal emulator is correctly configured to
operate as a standard terminal. If this doesn’t work, try
configuring it to operate as a VT100 terminal.
■
You have performed the wake-up procedure correctly, by pressing
Return twice.
■
Check the settings on your terminal or emulator. The parity must
be set to ‘none’, the stop bit ‘1’ and the data bits (character size)
‘8’. The management facility’s auto-configuration works only with
speeds 1200, 2400, 4800, 9600 and 19,200.
■
You are using the right cable. For examples of the pin wiring for
suitable cables, refer to
“Console Cable”
on
page 113
.
If you still cannot access the stack, reset the stack using the web
interface and retry the wake-up procedure. If this does not work,
initialize the stack.
The Telnet application cannot access the stack over the
network. Check that:
■
The stack’s IP address, subnet mask and default router are
correctly configured. Your Telnet application must point to the
same IP address.