Where should loop guard be implemented in a campus network design?
A. ports configured with port fast
B. alternate, backup and root ports
C. alternate ports only
D. ports configured with root guard
Where should loop guard be implemented in a campus network design?
On which ports should the loop guard be enabled? The most obvious answer is on the blocking ports. However, this is not totally correct. Loop guard must be enabled on the non-designated ports (more precisely, on root and alternate ports) for all possible combinations of active topologies. As long as the loop guard is not a per-VLAN feature, the same (trunk) port might be designated for one VLAN and non-designated for the other. The possible failover scenarios should also be taken into account.
https://www.cisco.com/c/en/us/support/docs/lan-switching/spanning-tree-protocol/10596-84.html