Information Technology Reference
In-Depth Information
show module —To display which modules are installed in the switch
show port capabilities —To determine whether the ports that we want to use have the capability to
do EtherChannel
show port —To determine the status of the port (notconnect, connected) and the speed and duplex
settings
ping —To test connectivity to the other switch
show port channel —To see the current status of the EtherChannel bundle
show port channel mod/port —To give a more detailed view of the channel status of a single port
show spantree —To verify that the Spanning-Tree Protocol looked at the channel as one link
show trunk —To see the trunking status of ports
Commands to use for troubleshooting the configuration include these:
show port channel —To see the current status of the EtherChannel bundle
show port —To determine the status of the port (notconnect, connected) and the speed and duplex
settings
clear counters —To reset the switch packet counters to zero. The counters are visible with the show
mac command
show mac —To view packets received and sent by the switch
ping —To test connectivity to the other switch and generate traffic that shows up with the show mac
command
Using PortFast and Other Commands to Fix End-Station Startup
Connectivity Problems
If you have workstations connected to switches that either are incapable of logging into your network
domain (NT or Novell) or are incapable of getting a DHCP address, then you may want to try the
suggestions listed in this document before exploring other avenues. The suggestions are relatively easy
to implement and are very often the cause of workstation connectivity problems encountered during the
workstation's initialization/startup phase.
With more customers deploying switching to the desktop and replacing their shared hubs with switches,
we often see problems introduced in client/server environments because of this initial delay. The biggest
problem that we see is that Windows 95/98/NT, Novell, VINES, IBM NetworkStation/IBM Thin Clients,
and AppleTalk clients cannot connect to their servers. If the software on these devices is not persistent
during the startup procedure, they will give up trying to connect to their server before the switch has even
allowed traffic to pass through .
This initial connectivity delay often manifests itself as errors that appear when you first
boot up a workstation. The following are several examples of error messages and errors that
you might see:
Note
A Microsoft networking client displays “No Domain Controllers Available.”
DHCP reports, “No DHCP Servers Available.”
A Novell IPX networking workstation does not have the “Novell Login Screen” upon
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