Exam 350-401 topic 1 question 606 discussion

Both C and D could be correct answers. But, gun to my head, I'm going with D. SSO is the fundamental technology that allows this. NSF requires SSO.

The correct answer is C that is NSF. SSO works before failover by synching the processors. From CISCO configuration guide : "NSF works with SSO to minimize the amount of time that a Layer 3 network is unavailable following an active switch election by continuing to forward IP packets. Reconvergence of Layer 3 routing protocols (BGP, OSPFv2, and EIGRP) is transparent to the user and happens automatically in the background."

SSO -> Layer2 In the question not mentioned any L3 service only "Cisco Catalyst switch". I would go with 'D'.

So, considering the role of each feature: SSO handles the switchover mechanism. NSF/NSR ensure the forwarding and routing processes continue smoothly during the switchover. If the question asks specifically about the mechanism ensuring the non-disruptive removal of the active supervisor module: D. SSO remains the primary correct answer. If the question considers the broader context of non-disruption during the switchover including forwarding and routing continuity: C. NSF/NSR could be argued as correct too. Given the precise wording of the original question, D. SSO is the best answer.

Correct answer is D The mechanism that ensures the active supervisor removal is not disruptive to the network operation in a Cisco Catalyst switch equipped with two supervisor modules is Stateful Switchover (SSO) https://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst4500/XE35-0XO/configuration/guide/config/RPR_XE.pdf

C. NSF/NSR The RP switchover triggers a routing protocol adjacency flap that clears the route table. When the routing table is cleared, the CEF entries are purged, and traffic is no longer routed until the network topology is relearned and the forwarding table is reprogrammed. Enabling nonstop forwarding (NSF) or nonstop routing (NSR) high availability capabilities informs the router(s) to maintain the CEF entries for a short duration and continue forwarding packets through an RP failure until the control plane recovers.

in order to enable NSF/NSR you must enable SSO first. The answer is SSO.

SSO is the right answer

SSO-enabled routers always checkpoint line card operation and Layer 2 protocol states. During a switchover, the standby RP immediately takes control and prevents basic problems such as interface link flaps. However, Layer 3 packet forwarding is disrupted without additional configuration. The RP switchover triggers a routing protocol adjacency flap that clears the route table. When the routing table is cleared, the CEF entries are purged, and traffic is no longer routed until the network topology is relearned and the forwarding table is reprogrammed. Enabling nonstop forwarding (NSF) or nonstop routing (NSR) high availability capabilities informs the router(s) to maintain the CEF entries for a short duration and continue forwarding packets through an RP failure until the control plane recovers. From the official cert guide. Hence, C is correct

What cisco thinks ...i mean asking half Questions with no reference if you want us say SSO you should mention layer 2 And if you want us to say NSR And NSf so mention in the Question meaning what they are trying to doing i dont know ....confusing at exam who ever make this exhibet need to be fired ...

SSO .....

SSO since you can you it gracefully and you won't need NSF/NSR for that which are required only when RE fails abruptly

Statefull Switch Over is the right answer. SSO

C and D are OK, but the technology which minimizes downtime is NSF.

D is correct

Again, the problem is the wording of the question, IMO. If you need L3 to continue to function without interruption, then you need NSF/NSR. Really its C and D. https://www.routeprotocol.com/stateful-switchover/

C. NSF provides layer 3 redundancy. SSO only synchronization and layer 2 redundancy. https://www.cisco.com/c/dam/en/us/td/docs/switches/lan/catalyst9400/software/release/16-6/configuration_guide/stck_mgr_ha/b_166_nsf_sso_9400_cg.html#concept_gds_jmy_31b