Dell Networking N4000 Series Configuration Manual page 948

Alternative Recommended L3 Connectivity
The loop-free topology shown in Figure 28-13 uses the MLAG switches as L2
switches in an EOR role. The single VLAN traverses the MLAG topology
from the top router to the bottom storage and servers. Multiple VLANs in
different VPCs may be used to isolate clusters of storage/servers from each
other. This topology is highly recommended, as it utilizes MLAG in the
scenario for which it was intended (redundant full-bandwidth replacement
for spanning tree in a fully L2 topology) and allows the MLAG peers to detect
failures and unblock the appropriate VLANs on the peer link so that traffic
flow can continue unimpeded.
The lower pair of switches connects clusters of storage and servers in a TOR
role in support of devices that do not support link aggregation. Switching
between the storage and the servers within the rack proceeds in the normal
manner and remains isolated on the lower switch pair that is not part of the
MLAG domain. Traffic entering or exiting the rack proceeds over the EOR
MLAG.
Figure 28-13. Alternative Recommended L3 Connectivity
MLAG Peer Switch
Switch (not part of
Storage
948
Configuring Link Aggregation
MLAG
MLAG domain)
Server
Router
MLAG
MLAG Peer Switch
MLAG
Switch (not part of
MLAG domain)
Server
Storage