A mobile network operator is designing an NGN backhaul and plans to migrate their legacy SDH and SONET-based transport network to a packet-based transport network. The NGN network must achieve…

BFD (Bidirectional Forwarding Detection) is a fast failure detection protocol that notifies routing protocols of link failures but does not itself implement the transport-level protection switching mechanism required to guarantee 50 ms failover.

E-OAM (Ethernet Operations, Administration, and Maintenance), standardized in ITU-T Y.1731 and IEEE 802.1ag, provides connectivity fault management and performance monitoring for carrier Ethernet transport networks. When combined with Ethernet protection switching standards such as ITU-T G.8031 (linear protection) or G.8032 (ring protection), E-OAM enables sub-50 ms failover and failback times that match the protection switching performance of legacy SDH and SONET networks.

UDLC (Unidirectional Link Detection Control) is not a recognized standard for fast protection switching or failover in NGN packet transport networks.

BPDU (Bridge Protocol Data Unit) is a Spanning Tree Protocol message used for loop prevention in Layer 2 networks and does not provide fast transport-level protection switching comparable to SDH or SONET.