Which two features must be configured to perform AToM NSF? (Choose two)

A.
FRR

B.
SSO

C.
distribute CEF

D.
switch virtual path

E.
graceful restart

Explanation:
Before you configure AToM NSF, you need to configure MPLS LDP Graceful Restart. MPLS LDP
GR is enabled globally. When you enable LDP GR, it has no effect on existing LDP sessions. LDP
GR is enabled for new sessions that are established after the feature has been globally enabled.
How AToM NSF Works
AToM NSF improves the availability of the network of the service provider that uses AToM to
provide Layer 2 VPN services. HA provides the ability to detect failures and handle them with
minimal disruption to the service being provided. AToM NSF is achieved by SSO and NSF
mechanisms. A standby RP provides control-plane redundancy. The control plane state and data
plane provisioning information for the attachment circuits (ACs) and AToM pseudowires (PWs) are
checkpointed to the standby RP to provide NSF for AToM L2VPNs.