Connect Redundant Site to Resilient Ethernet Protocol Ring

D.

The customer wants to connect one site with one box redundant to the Resilient Ethernet Protocol (REP) ring at two different service provider locations, and the requirement is to avoid Layer 2 loops in the network design.

A potential Layer 2 loop can occur when multiple paths exist between two network devices, and frames may loop indefinitely, causing a broadcast storm and network congestion. To avoid loops, a loop prevention mechanism such as Spanning Tree Protocol (STP) or Flex Links can be used.

STP is a protocol that prevents Layer 2 loops by disabling some of the redundant links in the network topology. However, this can cause suboptimal use of network resources and a delay in link convergence. Therefore, it is not recommended to enable STP at both the customer and service provider sides in this scenario.

Flex Links is a feature that provides link redundancy by allowing multiple physical links to appear as a single logical link. If one of the physical links fails, the other links in the group take over the traffic load, providing a fast failover mechanism. Flex Links can be enabled at either the service provider or customer side in this scenario, as long as it is not enabled on both sides to avoid loops.

EtherChannel is a technology that provides link aggregation, allowing multiple physical links to be combined into a single logical link to increase bandwidth and provide redundancy. However, it requires the same configuration at both ends of the link and does not provide any loop prevention mechanism.

Therefore, the best answer for this scenario is G. Flex Links at the service provider side and the customer side must be enabled to provide redundancy and prevent loops. This allows for a fast failover mechanism while maintaining a loop-free network design.