Selected Answer: CD NSF capability is supported for IPv4 routing protocols only. NSF capability is not supported for IPv6 routing protocols. NSF does not support IP Multicast Routing, because it is not SSO-aware. You must configure SSO in order to use NSF with any supported protocol. The Hot Standby Routing Protocol (HSRP) is not supported with NSF SSO. Do not use HSRP with NSF SSO. https://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst9400/software/release/16-6/configuration_guide/stck_mgr_ha/b_166_nsf_sso_9400_cg.html

Restrictions for Cisco Nonstop Forwarding with Stateful Switchover The following are restrictions for configuring NSF with SSO: NSF capability is supported for IPv4 routing protocols only. NSF capability is not supported for IPv6 routing protocols. NSF does not support IP Multicast Routing, since it is not SSO-aware. For NSF operation, you must have SSO configured on the device. All Layer 3 neighboring devices must be an NSF helper or NSF-capable to support graceful restart capability. For IETF, all neighboring devices must be running an NSF-aware software image. The Hot Standby Routing Protocol (HSRP) is not supported with NSF SSO. Do not use HSRP with NSF SSO. An NSF-aware device cannot support two NSF-capable peers performing an NSF restart operation at the same time. However, both neighbors can reestablish peering sessions after the NSF restart operation is complete. For SSO operation, ensure that both active and standby devices run the same version of the Cisco IOS XE image. If the active and standby devices are operating different images, SSO failover might cause an outage.

what about question 160: How does SSO operate with HSRP to reduce network disruptions?

Selected Answer: BC Nowadays HSRP is supported in SSO as also IPV6 https://www.cisco.com/c/en/us/td/docs/routers/ios/config/17-x/ntw-servs/b-network-services/m_fhp-hsrp-sso.html https://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst9300/software/release/16-10/configuration_guide/rtng/b_1610_rtng_9300_cg/b_1610_rtng_9300_cg_chapter_010001.html

Selected Answer: CD NSF does not support ipv6 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

Selected Answer: CE Yes, that is true — improper implementation or configuration of NSF/SSO can cause routing loops, along with other network stability issues. Why This Can Happen NSF (Non-Stop Forwarding) and SSO (Stateful Switchover) are high availability mechanisms that keep data forwarding during a control plane failover.

Selected Answer: AC SSO HSRP changes the behavior of HSRP when a device with redundant Route Processors (RPs) is configured for stateful switchover (SSO) redundancy mode. When an RP is active and the other RP is standby, SSO enables the standby RP to take over if the active RP fails. With this functionality, HSRP SSO information is synchronized to the standby RP, allowing traffic that is sent using the HSRP virtual IP address to be continuously forwarded during a switchover without a loss of data or a path change. Additionally, if both RPs fail on the active HSRP device, then the standby HSRP device takes over as the active HSRP device. The feature is enabled by default when the redundancy mode of operation is set to SSO.

But SSO with "NFS" does not support HSRP. So C D are correct

Selected Answer: CD C. Nonstop Forwarding requires SSO to also be configured D. HSRP is not supported with NSF/SSO Doubled checked the answers , this is 100% correct.

Selected Answer: CD Restrictions for Cisco Nonstop Forwarding with Stateful Switchover The following are restrictions for configuring NSF with SSO: • NSF does not support IP Multicast Routing, as it is not SSO-aware. • For NSF operation, you must have SSO configured on the device. • All Layer 3 neighboring devices must be an NSF helper or NSF-capable to support graceful restart capability. • For IETF, all neighboring devices must be running an NSF-aware software image. • The Hot Standby Routing Protocol (HSRP) is not supported with NSF SSO. Do not use HSRP with NSF SSO. • An NSF-aware device cannot support two NSF-capable peers performing an NSF restart operation at the same time. However, both neighbors can reestablish peering sessions after the NSF restart operation is complete. https://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst9500/software/release/16-6/configuration_guide/b_166_ha_9500/b_166_ha_9500_chapter_00.pdf

it is the NSF/SSO question, not SSO.

Selected Answer: CE C. Nonstop Forwarding requires SSO to also be configured - Correct E. Improper implementation of NSF/SSO can result in routing loops — Correct HSRP can be used with SSO. If you have two supervisor cards in a single L3 Switch, you can still have SVI(s) with HSRP in and active state Then the HSRP standby is a totally separate (likely identical) device. The confusion is if you're thinking that HSRP is active on one SUP and standby on another SUP (in the same chassis)