Free Juniper JN0-351 Practice Exam with Questions & Answers | Set: 3

An ISO NET address is a type of network address used by the IS-IS routing protocol.  It identifies a point of connection to the network, such as a router interface, and is also called a Network Service Access Point (NSAP) 1 .

An ISO NET address consists of three parts: an area ID, a system ID, and a selector 2 . The area ID identifies the IS-IS area to which the device belongs. The system ID uniquely identifies the device within the area.  The selector identifies a specific service or function on the device, such as routing or management 2 .

An ISO NET address must be unique for each device in the network, because it is used by IS-IS to establish adjacencies, exchange routing information, and compute shortest paths 2 . If two devices have the same ISO NET address, they will not be able to communicate with each other or with other devices in the network. Therefore, it is important to assign different ISO NET addresses to each device in the network.

Option A is correct. Creating multiple areas in OSPF can help to reduce the convergence time . This is because changes in one area do not affect other areas, so fewer routers need to run the SPF algorithm in response to a change.

Option D is correct. Creating multiple areas in OSPF can help to reduce Link State Advertisement (LSA) flooding across the network. This is because LSAs are not flooded out of their area of origin.

https://www.juniper.net/documentation/us/en/software/junos/cli-reference/topics/ref/statement/lsa-refresh-interval-edit-protocols-ospf.html

The routers that are directly connected to the Dallas and Denver subnets are not advertising the connected subnets.  This can be resolved by redistributing the connected subnets into OSPF 1 .

Option C suggests to configure and apply a routing policy that redistributes the connected Dallas and Denver subnets.  This is correct because redistribution allows routes from one routing protocol to be communicated to another, and in this case, it allows the connected subnets to be advertised through OSPF 1 .

Option D suggests enabling the passive option on the OSPF interfaces that are connected to the Dallas and Denver subnets.  This is also correct because in OSPF, a passive interface is an interface that belongs to the OSPF router, but does not send OSPF Hello packets 1 .  It’s typically used on an interface that you don’t want to use for OSPF adjacencies, but you still want to advertise its IP address 1 . Therefore, enabling passive interface can help in advertising the Dallas and Denver subnets.

C  is correct because Layer 2 control traffic is permitted on the secondary link of a redundant trunk group (RTG) on EX Series switches.  Layer 2 control traffic includes protocols such as LLDP, LACP, and STP, which are used to exchange information and coordinate actions between switches 1 .  According to the Juniper Networks documentation 2 , Layer 2 control traffic is allowed to pass through both the active and the secondary links of an RTG, but data traffic is only forwarded through the active link. This allows the switches to maintain their Layer 2 adjacencies and monitor the link status on both links.

D  is correct because if the active link fails, then the secondary link automatically takes over in an RTG on EX Series switches.  An RTG consists of two trunk links: an active or primary link, and a secondary or backup link 2 . The active link is used to forward data traffic, while the secondary link is in standby mode.  If the active link fails or becomes unavailable, the secondary link immediately transitions to a forwarding state and takes over the data traffic without waiting for normal STP convergence 2 . This provides fast recovery and redundancy for the network.

The configuration shown in the exhibit is an example of a routing instance of type virtual-router.  A routing instance is a collection of routing tables, interfaces, and routing protocol parameters that create a separate routing domain on a Juniper device 1 .  A virtual-router routing instance allows administrators to divide a device into multiple independent virtual routers, each with its own routing table 2 .

The configuration also includes a rib-group statement, which is used to import routes from one routing table to another. A rib-group consists of an import-rib statement, which specifies the source routing table, and an export-rib statement, which specifies the destination routing table.

In this case, the rib-group name is inet-to-ispi, and the import-rib statement specifies inet.0 as the source routing table. The export-rib statement specifies ispi.inet.0 as the destination routing table. This means that the routes from inet.0 will be imported into ispi.inet.0.

Therefore, the correct answer is B. The inet.0 route table will be imported into the ispi.inet.0 route table.

In a trunk port configuration with multiple VLANs, the native VLAN carries untagged traffic. This means frames sent or received on the port without a VLAN tag are automatically assigned to the native VLAN.

Here ' s why the other options are incorrect:

A. The native VLAN must be the default VLAN on the port.  This is not necessarily true. The native VLAN and the default VLAN can be different. The default VLAN is the VLAN assigned to untagged traffic on access ports, while the native VLAN applies to trunk ports.

B. The native VLAN is automatically configured through DHCP.  This is incorrect. The native VLAN needs to be manually configured on the switch port. DHCP is used for assigning IP addresses, not VLAN IDs.

D. The native VLAN is the highest tagged VLAN ID on the port.  This is also incorrect. The native VLAN and tagged VLANs are independent. The native VLAN is not related to the highest or lowest tagged VLAN ID.

Therefore, the only true statement is that the native VLAN is an untagged VLAN ID on the port.

The exhibit shows the configuration of RSTP on EX-4, which has the command  force-version stp .  This command forces the switch to use the legacy STP protocol instead of RSTP, even though the switch supports RSTP 1 .  This means that EX-4 will not be able to take advantage of the faster convergence and enhanced features of RSTP, such as edge ports, link type, and proposal/agreement sequence 2 .

The other switches in the network are likely to be running RSTP, as it is the default protocol for EX Series switches 3 . Therefore, there will be a compatibility issue between EX-4 and the other switches, which will result in longer convergence times and suboptimal performance.  The switch will also generate a warning message that says “Warning: STP version mismatch with neighbor” when it receives a BPDU from a RSTP neighbor 1 .

To solve this problem, the force-version command must be removed from EX-4, so that it can run RSTP natively and interoperate with the other switches in the network. This will enable faster convergence and better stability for the network topology.  To remove the command, you can use the  delete protocols rstp force-version  command in configuration mode 1 .