JNCIS-ENT Practice Test 7 — 10 Questions

Question 1

Which Junos configuration command enables Dynamic ARP Inspection (DAI) for a specific VLAN named 'VLAN10'?

Accepted Answer

set ethernet-switching-options secure-access-port vlan VLAN10 arp-inspection. DAI is enabled under ethernet-switching-options secure-access-port vlan for the specific VLAN name.

Answer

set protocols arp-inspection vlan VLAN10

Answer

set vlans VLAN10 dynamic-arp-inspection

Answer

set interfaces vlan unit 10 family inet arp-inspection

Question 2

When configuring VRRP on a Juniper router, what IP address must be assigned as the virtual IP address for the group?

Accepted Answer

An IP address belonging to the same subnet as the physical interface connected to the broadcast domain.. The virtual IP address must belong to the same subnet as the physical interface IP address configured on the participating routers.

Answer

A loopback IP address configured on the master Routing Engine.

Answer

A public IP address provided by your upstream Internet Service Provider.

Answer

A reserved multicast address in the 224.0.0.18 range.

Question 3

When should you consider increasing the 'csnp-interval'?

Accepted Answer

To reduce control traffic overhead on slow links.. Increasing the interval is useful on slow or congested links to reduce the frequency of full database synchronization traffic.

Answer

To improve convergence time.

Answer

To increase the maximum LSP size.

Answer

To fix adjacency flapping.

Question 4

An engineer configures Nonstop Active Routing (NSR) on an MX series router. What is required for NSR to function properly on BGP peering sessions?

Accepted Answer

GRES must be enabled at the chassis level, and NSR must be explicitly enabled under the BGP protocol hierarchy.. NSR requires GRES enabled at the chassis level and NSR configured specifically under the routing-options protocols bfgp hierarchy.

Answer

Graceful Restart must be disabled globally on all routers.

Answer

VRRP must be configured on all BGP peering interfaces.

Answer

LACP fast mode must be enabled on all physical uplinks.

Question 5

Which THREE actions occur when a BGP speaker receives a Notification message from a peer? (Choose three.)

Accepted Answer

The TCP connection associated with the BGP session is closed.. When a BGP Notification message is received, it indicates an error condition. The receiving router moves the session to Idle, closes the TCP connection, and clears all routes learned from that peer.

Answer

A Keepalive message is immediately sent in response to acknowledge the error.

Answer

The peer router automatically re-establishes the connection without applying the connect retry timer.

Question 6

What is the purpose of the 'lsp-lifetime' command?

Accepted Answer

To set the duration for which an LSP is valid.. The 'lsp-lifetime' command sets the duration after which an LSP is considered invalid if not refreshed.

Answer

To define how often the DIS sends Hellos.

Answer

To limit the number of LSPs in the database.

Answer

To set how long the adjacency stays up.

Question 7

Which command displays the status of Virtual Chassis member switches, their roles, and their serial numbers on an EX series switch?

Accepted Answer

show virtual-chassis. The 'show virtual-chassis' command is the primary operational command to view member status, roles (Master/Backup/Linecard), and IDs.

Answer

show lacp statistics

Answer

show vrrp summary

Question 8

Which operational command allows you to view the real-time status of LACP packet exchanges and partner system IDs for an aggregated interface on a Junos switch?

Accepted Answer

show lacp interface. The 'show lacp interface' command displays detailed LACP partner information, partner port numbers, and state flags.

Answer

show interfaces ae0 statistics

Answer

show chassis lacp-status

Answer

show vrrp lacp-summary

Question 9

You are analyzing a core Juniper MX router after an ISSU upgrade procedure completed. You notice that BGP sessions dropped immediately after the final routing engine rebooted. What post-upgrade verification step should have been performed to prevent unexpected protocol drops during ISSU?

Accepted Answer

Verify that all external BGP peers negotiated Graceful Restart capability and that helper mode was active on both ends prior to initiating the upgrade.. Verifying that BGP graceful restart and helper modes were fully operational and peer routers had acknowledged the capability before starting ISSU.

Answer

Confirm that LACP minimum-links is set to zero.

Answer

Check that the Virtual Chassis cable is connected between the MX Routing Engines.

Answer

Ensure VRRP preemption is turned off on all core interfaces.

Question 10

Which CLI command displays the packet statistics, errors, and drop counters for a Link Aggregation Group (LAG) named ae0?

Accepted Answer

show interfaces ae0. The 'show interfaces ae0' command displays general interface statistics, error counts, and drops for the aggregated interface.

Answer

show chassis interface-drops ae0

Answer

show virtual-chassis interface ae0

Answer

show lacp statistics ae0