JNCIS-ENT Practice Test 6 — 10 Questions

Question 1

An engineer configures a BGP policy to set the MED attribute on routes advertised to an eBGP peer. What is the primary purpose of the MED (Multi-Exit Discriminator) attribute?

Accepted Answer

To indicate to an external AS which entry point is preferred for traffic entering the local AS.. MED is an optional non-transitive attribute used to inform external peers about the preferred entry point into an AS.

Answer

To dictate the preferred path for traffic leaving the local AS.

Answer

To prevent routing loops across multiple autonomous systems.

Answer

To assign a priority score for internal route selection within the same AS.

Question 2

When troubleshooting a BGP routing loop or unexpected route suppression, which THREE Junos operational commands provide visibility into BGP path attributes and decision processes? (Choose three)

Accepted Answer

show route extensive. Detailed route inspection and BGP neighbor debugging commands include 'show route extensive', 'show bgp neighbor', and 'show route protocol bgp'.

Answer

show ldp database

Answer

show ospf interface

Question 3

Which BGP message type is responsible for negotiating session parameters, including autonomous system numbers, hold times, and BGP identifiers during session establishment?

Accepted Answer

Open. The BGP Open message is the first message sent after a TCP connection is established. It contains parameters such as the BGP version, local AS number, hold time, BGP identifier, and optional parameters (capabilities).

Answer

Notification

Answer

Update

Answer

Keepalive

Question 4

During an audit of a Juniper EX4300 Virtual Chassis, you notice that member 1 and member 2 are connected via mixed 1G and 10G uplink ports. How does Junos handle mixed-speed Virtual Chassis port configurations?

Accepted Answer

Virtual Chassis ports (VCPs) must be explicitly configured to match supported transceiver speeds, and mixing unsupported interface types will result in port initialization failure.. Junos EX series virtual chassis ports can be configured for specific speeds, but mismatched or unsupported port combinations will cause initialization failures or link errors depending on the platform.

Answer

Mixed speed links automatically drop to 1G to maintain backward compatibility without administrative intervention.

Answer

Junos automatically load-balances stacking traffic across 1G and 10G links using weighted round-robin.

Answer

Only the 10G ports will carry control plane traffic while 1G ports are restricted to data transit.

Question 5

An administrator is setting up VRRP tracking on an EX4300 switch interface. If the uplink interface monitoring the core network fails, what should happen to the VRRP priority on the gateway interface?

Accepted Answer

The VRRP priority is decremented by a configured value so that the backup router can assume the master role.. VRRP interface tracking automatically decrements the local router's priority when a monitored tracking interface goes down, allowing a backup router with higher priority to take over as master.

Answer

The VRRP priority is increased to maximum to force immediate forwarding.

Answer

The interface shuts down all LACP bundles connected to the switch.

Answer

The switch initiates an immediate In-Service Software Upgrade.

Question 6

An engineer configures a LAG between an EX4300 switch and a server. The server uses static LAG mode (no LACP). How must the Junos switch interface be configured to successfully form the bundle?

Accepted Answer

Omit the LACP protocol configuration under the aggregated-ether-options stanza, operating in static mode.. When connecting to a device that does not support LACP, you must configure the Junos aggregated interface without LACP (manual/static mode).

Answer

Configure VRRP on the ae0 interface to manage the static bundle.

Answer

Configure LACP passive mode on the EX4300 switch.

Answer

Enable Graceful Restart on the physical ports.

Question 7

Which TWO statements accurately describe the behavior of the BGP AS_PATH attribute? (Choose two)

Accepted Answer

It is a well-known mandatory attribute.. AS_PATH is well-known mandatory and gets prepended with the local AS number every time an update leaves an Autonomous System via eBGP.

Answer

It is automatically stripped when crossing a confederation boundary.

Answer

It is modified when an update is sent to an iBGP peer.

Answer

It is an optional non-transitive attribute used for internal metrics.

Question 8

Which TWO options represent valid benefits of configuring Link Aggregation Groups (LAG)? (Choose two)

Accepted Answer

Increased aggregate bandwidth between connected networking devices.. LAGs provide increased aggregate bandwidth and link redundancy/failover.

Answer

Synchronization of BGP routing daemon state between separate routers.

Answer

Automatic upgrade of Junos OS across peer devices.

Answer

Elimination of the need for Spanning Tree Protocol across all VLANs.

Question 9

Which THREE potential issues can arise if LACP is misconfigured between a Juniper switch and a connected peer device? (Choose three)

Accepted Answer

Traffic loops may occur if static LAG mode is mismatched with LACP active mode on opposite ends.. LACP misconfigurations can lead to link suspension, flapping due to timeout mismatches, or bundle failure if minimum links aren't met.

Answer

GRES will be disabled on the routing engine automatically.

Answer

The switch will automatically trigger an In-Service Software Upgrade (ISSU) to fix the mismatch.

Question 10

An administrator configures BGP multipath on a Junos router. Which THREE conditions must be met for BGP paths to be considered equal and installed as multipaths? (Choose three)

Accepted Answer

The paths must have the same Local Preference value.. For BGP multipath, paths must typically have matching AS path lengths (unless relaxation is on), matching local preference, matching MED, and matching origin, and the next-hop router must resolve via the same IGP metric cost.

Answer

The paths must originate from different Autonomous Systems entirely.

Answer

The router IDs of the advertising routers must be identical.