A mobile service provider wants to design and deploy an Ethernet service with similar physical link failover/failback characteristics on the active/backup links as APS/MSP SONET. Which Layer 2 service

Ethernet Pseudowires provide Layer 2 transport over MPLS/IP networks but have no inherent active/backup physical link protection mechanism comparable to APS/MSP.

FlexLink is a Cisco Layer 2 redundancy feature that operates in a strict active/backup model - one link forwards traffic while the standby link is immediately ready to take over upon failure, directly mirroring APS/MSP behavior. It provides deterministic sub-second failover and failback without depending on Spanning Tree Protocol convergence timers.

MLPPP bundles multiple PPP links into one logical channel to increase aggregate bandwidth, operating in active/active mode rather than providing active/backup failover.

Port-Channel (EtherChannel) aggregates multiple links for combined bandwidth in an active/active load-sharing model, not the active/backup protection switching required.