Cabletron Systems DLE22-MA - Manual (Page 128)

Chapter 5: Local Management
5-64 DLE22-MA,DLE32-MA,DLE23-MA and DLE33-MA User’s Guide
6. You must enable Spanning Tree before enabling SmartTrunk.
Spanning Tree will ‘block’ any ports not used by SmartTrunk that are
looped. This can include NETWORK and USER ports. The reason
for the blocking of a NETWORK port is that the port at the other end
of the link may be configured as a USER port.
Other Considerations
• If a network loop exists and SmartTrunk becomes disabled, and
Spanning Tree is operational, then the Spanning Tree Algorithm will
respond and block the necessary ports.
• If SmartTrunk becomes disabled, and a network loop exists, and
Spanning Tree is not-operational (disabled), then an infinite packet
loop would occur, taking down the network.
• If a port is disabled and as a result SmartTrunk is no longer active, then
all traffic is redirected over the remaining port(s).
• If three or more interface modules, such as the DLE2X-MA and
DLE3X-MA, or standalone devices are connected together in a loop
condition and all the ports that connect the loop are set to
“NETWORK,” the results are unpredictable. In this case all ports are
assigned as “NETWORK” ports and none are configured as “USER”
ports. This is deemed an illegal configuration.
• If a network loop exists when a port is disabled, then SmartTrunk will
reconfigure the remaining ports and continue to distribute traffic.
5.20.2 SmartTrunk Configuration Screen
The SmartTrunk Configuration screen, Figure 5-25, allows the user to
logically group interfaces together between devices to achieve greater
bandwidth between the devices.
Access the SmartTrunk Configuration screen from the Module Specific
Configuration Menu screen by using the arrow keys to highlight the
The SmartTrunk Configuration screen may not be available if
the operational mode of the module has been set to 802.1Q
SWITCHING. Refer to your Release Notes to see if the
SmartTrunking feature is supported.
Section 5.15.9 describes how to set the operational mode.