Administering edge-loop detection, Edge-loop detection overview – Brocade Network OS Administrator’s Guide v4.1.1 User Manual
Page 319
Administering Edge-Loop Detection
Edge-loop detection overview
Edge-loop detection (ELD) detects and disables Layer 2 loops that would cause broadcast storms.
Typically, these loops are caused by misconfigurations.
ELD is configured and enabled on Brocade VCS Fabric clusters. Any topology that includes one or
more Brocade VCS Fabric clusters use ELD to detect Layer 2 loops and prevent broadcast storms.
Standalone switches can be included in such a cluster, but loop detection takes place on the Brocade
VCS Fabric cluster, and not on the standalone switch. You cannot use ELD in a network consisting of
standalone switches only.
Specifically, ELD can be used to prevent broadcast storms caused by Layer 2 loops in the following
topologies:
• A Brocade VCS Fabric cluster connects to a standalone switch.
• A Brocade VCS Fabric cluster connects to a multiple node network.
• A Brocade VCS Fabric cluster connects to other Brocade VCS Fabric clusters.
The following figure shows an example of a misconfiguration between a Brocade VCS Fabric cluster
and a standalone switch that could cause a Layer 2 loop. In this case, a VLAG is configured on the
edge devices of the Brocade VCS Fabric cluster for the two ISLs that connect the Brocade VCS Fabric
cluster to the standalone switch. In this case, a LAG has not been created on the standalone switch at
the other end of the ISLs. ELD detects and breaks this potential Layer 2 loop.
Network OS Administrator’s Guide
319
53-1003225-04