Topologies Not Recommended; Unsupported Topologies - Alcatel-Lucent OmniSwitch AOS Release 7 Manual

Configuring Multi-chassis Link Aggregation

Topologies Not Recommended

In the topology shown below, edge devices are not attached to both MC-LAG peers at the core. As a
result, some traffic may need to constantly flow across the Virtual Fabric Link. Still, Spanning Tree is not
required as there are no logical loops in this network.
MC-LAG

Unsupported Topologies

In the topology shown below, MC-LAG is not supported since Spanning Tree cannot run with a "back-
door" connection and will result in a loop.
MC-LAG
OmniSwitch AOS Release 7 Network Configuration Guide
MC-LAG
LAG
MC-LAG MC-LAG
Edge Switches Without MC-LAG
LAG
MC-LAG
MC-LAG
Back-door Connection Causing Physical Loop
Ordinary
aggregate, i.e.
non-MC-LAG
L2 Bridging
Spanning tree cannot
run on the dual-
homed aggregates.
March 2011
MC-LAG Topologies
page 8-15