The engineering team at ISP_1 must improve network stability time and minimize the impact of routing instabilities from other domains to unicast transit services in the backbone R1 is part of an…

Configuring 'ip ospf resync-timeout 180' under interface Gi0/1 sets the NSF helper resynchronization timeout to 180 seconds, which equals the required 3-minute suppression window. This controls how long the OSPF helper router waits for the restarting ASBR to resynchronize its LSDB before tearing down the adjacency, preventing transient external routing instability from propagating into the backbone. Because RFC 3623 helper mode is already active on R1, this interface-level timer is the targeted knob to achieve the desired suppression duration.

'ip ospf timer nsf interval' is not a valid Cisco IOS interface-level command for controlling NSF or graceful restart suppression timers.

'nsf ietf restart-interval' is a global OSPF process command that configures the restart interval for the restarting router itself, not the helper-mode resynchronization timeout used to suppress instability propagation to neighbors.

'nsf ospf wait' is not a valid Cisco IOS OSPF configuration command and would not be accepted by the router.