Chapter 9      Troubleshooting
Avoiding Configuration Conflicts
9-2
Catalyst 2900 Series XL and Catalyst 3500 Series XL Software Configuration Guide
78-6511-05
Avoiding Configuration Conflicts
Certain combinations of port features conflict with one another. For example, if 
you define a port as the network port for a VLAN, all unknown unicast and 
multicast traffic is flooded to the port. You could not enable port security on the 
network port because a secure port limits the traffic allowed on it.
In Table 9-1, no means that the two features are incompatible and that both should 
not be enabled; yes means that both can be enabled at the same time and will not 
cause an incompatibility conflict.
If you try to enable incompatible features by using CMS, CMS issues a warning 
message that you are configuring a setting that is incompatible with another 
setting, and the switch does not save the change.
Table 9-1 Conflicting Features
ATM 
Port
1
1. Catalyst 2900 XL switches only.
Port 
Group
Port 
Security
SPAN 
Port
Multi-VLAN 
Port
Network 
Port
Connect 
to 
Cluster?
Protected 
Port 
ATM Port
N/ANoNoNoNo NoYesNo
Port Group
No – No No Yes Yes
2
2. Cannot be in a destination-based port group.
Yes Yes
Port Security
No No – No No No Yes Yes
SPAN Port 
No
3
3. An Asynchronous Transfer Mode (ATM) port cannot be a monitor port but can be monitored.
No No – No No Yes Yes
Multi-VLAN Port
No Yes No No – Yes Yes Yes
Network Port
No Yes 
(source-
based 
only)
No No Yes – No
4
4. Cannot connect cluster members to the command switch.
Yes
Connect to 
Cluster
Yes Yes Yes Yes Yes No – Yes
Protected Port 
No Yes Yes Yes
5
5. Switch Port Analyzer (SPAN) can operate only if the monitor port or the port being monitored is not a protected port.
Yes No Yes –