JN0-351 Exam Dumps : Enterprise Routing and Switching Specialist (JNCIS-ENT)

A tunnel is a connection between two computer networks, in which data is sent from one network to another through an encrypted link. Tunnels are commonly used to secure data communications between two networks or to connect two networks that use different protocols.

Option B is correct, because tunnel endpoints must have a valid route to the remote tunnel endpoint. A tunnel endpoint is the device that initiates or terminates a tunnel connection. For a tunnel to be established, both endpoints must be able to reach each other over the underlying network.  This means that they must have a valid route to the IP address of the remote endpoint 1 .

Option D is correct, because tunnels add additional overhead to packet size. Tunnels work by encapsulating packets: wrapping packets inside of other packets. This means that the original packet becomes the payload of the surrounding packet, and the surrounding packet has its own header and trailer. The header and trailer of the surrounding packet add extra bytes to the packet size, which is called overhead.  Overhead can reduce the efficiency and performance of a network, as it consumes more bandwidth and processing power 2 .

Option A is incorrect, because BFD can be used to monitor tunnels. BFD is a protocol that can be used to quickly detect failures in the forwarding path between two adjacent routers or switches. BFD can be integrated with various routing protocols and link aggregation protocols to provide faster convergence and fault recovery. BFD can also be used to monitor the connectivity of tunnels, such as GRE, IPsec, or MPLS.

Option C is incorrect, because IP-IP tunnels are stateless. IP-IP tunnels are a type of tunnels that use IP as both the encapsulating and encapsulated protocol. IP-IP tunnels are simple and easy to configure, but they do not provide any security or authentication features. IP-IP tunnels are stateless, which means that they do not keep track of the state or status of the tunnel connection. Stateless tunnels do not require any signaling or negotiation between the endpoints, but they also do not provide any error detection or recovery mechanisms.

The output of the show bgp neighbor command shows the following information:

The local AS number of R1 is 65400, as indicated by the line “Local: 10.32.1.1+179 AS 65400”.

The peer AS number of 10.32.1.2 is 63645, as indicated by the line “Peer: 10.32.1.2+179 AS 63645”.

The BGP session is established, as indicated by the line “State: Established”.

The routers are exchanging IPv4 routes, as indicated by the line “Type: External State: Established Flags: < Sync > ” and the table showing the number of prefixes received and sent for inet.0 routing table. References:  Enterprise Routing and Switching, Specialist (JNCIS-ENT) - Juniper Networks , [show bgp neighbor - Technical Documentation - Support - Juniper Networks]