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

According to the Juniper documentation1, a native VLAN is a VLAN that carries untagged traffic on a trunk port. A Wi-Fi access point may need a native VLAN to associate untagged traffic with a specific VLAN, such as the management VLAN. On Juniper EX Series switches, you can enable a native VLAN on a switch port by setting the interface-mode to trunk and specifying a native-vlan-id. For example, the following configuration enables a native VLAN with ID 1 on the switch port ge-0/0/12:

set interfaces ge-0/0/1 unit 0 family ethernet-switching interface-mode trunk

set interfaces ge-0/0/1 unit 0 family ethernet-switching vlan members all

set interfaces ge-0/0/1 unit 0 family ethernet-switching native-vlan-id 1

The other options are not correct because they do not address the requirement of untagged traffic. VLAN tagging is the process of adding a VLAN identifier to a frame, which is not needed for untagged traffic. Flexible VLAN tagging is a feature that allows multiple VLAN tags on a single interface, which is not relevant for this scenario. Voice VLAN is a feature that allows voice traffic to be separated from data traffic on a switch port, which is not related to untagged traffic or Wi-Fi access points. References: Understanding Native VLANs on Trunks | Junos OS, Configuring a Native VLAN on a Trunk Port | Junos OS

 In OSPF, a DR (Designated Router) and a BDR (Backup Designated Router) are elected on each multi-access network, such as Ethernet or Frame Relay. The DR and BDR are responsible for exchanging routing information with other routers on the same network segment. The election is based on two criteria: the OSPF priority and the router ID. The router with the highest priority becomes the DR, and the router with the second-highest priority becomes the BDR. If the priorities are equal, the router with the highest router ID becomes the DR, and the router with the second-highest router ID becomes the BDR. The default priority is 1, and the router ID is either manually configured or derived from the highest IP address on any interface12.

In this scenario, R1 has a priority of 32 and a router ID of 192.168.1.2, and R2 has a priority of 64 and a router ID of 192.168.1.1. Since R2 has a higher priority than R1, it will become the BDR. The router ID does not matter in this case, because the priority is different. Therefore, the correct answer is C.

The other options are not correct because:

A. At least two routers are required for a DR/BDR election, not three2.

B. Router IDs do not have to match for an adjacency to form, they just have to be unique3.

D. R1 will not be the BDR, because it has a lower priority than R212.

The exhibit shows the output of the command  show vlans brief , which displays brief information about VLANs and their associated interfaces 1 .

The output has four columns: Routing instance, VLAN name, Interfaces, and Tagging.

The * symbol indicates that the interface is active, meaning that it is up and forwarding traffic 1 .  This can be verified by the command  show interfaces terse , which displays the status of the interfaces 2 .