Enterprise Routing and Switching, Specialist (JNCIS-ENT) JN0-352 Exam Questions with Experts Answers Updated Recently

The diagnostic output explicitly states the root cause: the local router has only the inet6-unicast address family configured for this peer, while the remote router advertised inet-unicast and inet-vpn-unicast in its OPEN message, and BGP requires at least one common negotiated address family (NLRI type) between two peers for a session to remain established; with zero overlap between the two sides' configured families, the session is torn down immediately after the OPEN exchange, which is precisely why the peer state shows Active rather than Established. This confirms the mismatched-address-family statement directly and unambiguously from the exhibit's own Down reason and Detail reason fields. The diagnostic tool's own embedded Suggestion text goes further, explicitly advising the administrator to additionally verify that the local-address configured for the peer matches the remote router's configured neighbor address and vice versa — a secondary, commonly encountered condition in which mismatched or effectively duplicated/incorrect address bindings between the two sides' neighbor statements can independently prevent a session from completing correctly, even once the family mismatch is resolved. This is why address-configuration consistency between the peers is flagged as a second concern worth checking in this scenario. Nothing in the exhibit references NTP or time synchronization at all, nor does anything in the output reference authentication, an MD5 mismatch, or any related failure signature; both of those conditions would present through entirely different diagnostic messages than the one shown here. Reference topics: Junos Enterprise Routing – BGP, Address Family Negotiation and the show bgp diagnostics neighbor Command.

The L column in this output identifies which IS-IS levels are active on each interface, using the standard bitmask where 1 represents Level 1 only and 3 represents both Level 1 and Level 2 combined. Interface ge-0/0/2.0 shows an L value of 1 and its Level 2 DR field explicitly reads Disabled, meaning Level 2 has not been enabled on that circuit at all; consequently no Level 2 adjacency can ever form there, regardless of what the neighboring router advertises, which confirms that statement as correct. The lo0.0 loopback interface shows Passive under both the Level 1 DR and Level 2 DR columns. A passive IS-IS interface is deliberately excluded from adjacency formation — no IIH PDUs are sent or expected on it — but its associated prefix is still injected into the router's own LSP and flooded throughout the area, which is precisely why loopbacks are configured as passive: to guarantee the router ID/loopback prefix is reachable network-wide without wasting adjacency overhead on an interface with no real neighbor. This confirms that R3 advertises its loopback address, while ruling out the claim that the loopback is used to form an adjacency. Regarding designated routers, all circuits shown here report 'Point to Point' rather than an actual DR system ID, because DR election in IS-IS is a construct exclusive to broadcast (LAN) circuits; point-to-point circuits never elect a DR, so the first statement is false. Reference topics: Junos Enterprise Routing – IS-IS, Interface Levels and Passive Interfaces.