Which three statements about the Cisco MPLS TE Fast Reroute (FRR) process are true? (Choose
three.)

A.
TE tunnels that are configured with the FRR option cannot be used as backup tunnels.

B.
TE tunnels that are configured with the FRR option can be used as backup tunnels.

C.
The backup tunnel that is used to protect a physical interface must have a valid IP address
configured.

D.
Interfaces must use MPLS global label allocation.

E.
The source IP address of use backup tunnel and the merge point (MP) should not be
reachable.

Explanation:
Restrictions for MPLS Traffic Engineering—Fast Reroute Link and Node Protection
•Interfaces must use MPLS Global Label Allocation.
•Backup tunnel headend and tailend routers must implement FRR as described in draft-pan-rsvpfastreroute-00.txt.
•Backup tunnels are not protected. If an LSP is actively using a backup tunnel and the backup
tunnel fails, the LSP is torn down.
•LSPs that are actively using backup tunnels are not considered for promotion. If an LSP is
actively using a backup tunnel and a better backup tunnel becomes available, the active LSP is
not switched to the better backup tunnel.
•You cannot enable FRR Hellos on a router that also has Resource Reservation Protocol (RSVP)
Graceful Restart enabled.
•(Applicable only to Release 12.2.) You cannot enable primary one-hop autotunnels, backup
autotunnels, or autotunnel mesh groups on a router that is also configured with stateful switchover
(SSO) redundancy. This restriction does not prevent an MPLS TE tunnel that is automatically
configured by TE autotunnel from being successfully recovered by any midpoint router along the
LSP’s path if the router experiences an SSO switchover.
•MPLS TE LSPs that are fast reroutable cannot be successfully recovered if the LSPs are FRR
active and the Point of Local Repair (PLR) router experiences an SSO.
•When SSO (stateful switchover) occurs on a router, the switchover process must complete before
FRR (fast reroute) can complete successfully. In a testing environment, allow approximately 2
minutes for TE SSO recovery to complete before manually triggering FRR. To check the TE SSO
status, use the show ip rsvp high availability summary command. Note the status of the HA state
field.
–When SSO is in the process of completing, this field will display ‘Recovering’.
–When the SSO process has completed, this field will display ‘Active’.