Refer to the exhibit. You are developing a migration plan to enable IPv6 in your IPv4 network. Starting at R3 and assuming default IS-IS operations, what is likely to happen when you enable IPv6 routi

Single-topology IS-IS does not isolate reachability to only the two routers on the new IPv6 link - the topology-wide adjacency reset affects all routers, not just R3 and R2.

IS-IS does not automatically generate or advertise an IPv6 default route to R2 when IPv6 is enabled on an interface - default route origination requires explicit configuration.

IS-IS default single-topology mode requires all interfaces and routers in the domain to consistently support the same address families within a shared SPF calculation. Enabling IPv6 only on the R3-R2 link creates an inconsistency that causes IS-IS to reset adjacencies across the topology. This adjacency reset disrupts the IS-IS database, resulting in loopback reachability loss for IPv4 across all routers in the domain.

The adjacency reset caused by the single-topology inconsistency affects all routers in the IS-IS domain, not just R2, so this answer incorrectly scopes the impact.

IS-IS is a link-state protocol that floods LSPs to all routers in the domain - it does not selectively advertise the R3-R2 link only to specific neighbors like R1, R4, and R5.