Alternative routing is required by some customers to allow service to continue in the event of a single or multiple failures. Resilience is also required when the traffic concentration is high.

Topologies that offer route protection include point-point or PON systems with two separate fibre paths, dual rings with loop-back protection and mesh networks. All of these networks are used but are not being considered for mass-market fibre to the home systems (FTTH) because of cost.