Users Guide

Table Of Contents
Link Aggregation 1079
assigned, but MLAG VLANs cannot be used to route across MLAG or non-
redundant VLANs, as the MLAG feature does not correlate failures in one
VLAN with another VLAN to unblock packets crossing the MLAG peer-link.
Recommended Layer-3 Connectivity
The topology shown in Figure 28-12 uses the MLAG switches as Layer-2
switches. All VLANs traverse the MLAG topology from the top
switches/routers to the bottom switches/routers. The LAGs for each VLAN
host are in a separate VPC. The router sees the port-channel as a single logical
interface with multiple VLANs. This topology is highly recommended as it
utilizes MLAG in the scenario for which it was intended (redundant full-
bandwidth replacement for spanning tree) and allows the MLAG peers to
detect failures and unblock the appropriate VLANs on the peer link so that
traffic flow can continue unimpeded.
Figure 28-12. Recommended Layer-3 Connectivity