JNCIS-ENT Quick Quiz — 10 Questions

Question 1

An administrator wants to modify the Local Preference attribute for all routes received from a specific external BGP peer. Where must this policy be applied in Junos?

Accepted Answer

Import policy applied to the eBGP neighbor or group. Inbound routing policies on Junos affect attributes like Local Preference before path selection occurs.

Answer

Export policy applied to the eBGP group

Answer

Forwarding plane firewall filter

Answer

Global system-level static route policy

Question 2

Which TWO characteristics describe eBGP compared to iBGP? (Choose two)

Accepted Answer

Peers reside in different Autonomous Systems. eBGP peers are typically in different Autonomous Systems and have a default TTL of 1, whereas iBGP peers are in the same AS and have a default TTL of 255.

Answer

Automatic route reflection enabled by default

Answer

Must reside within the same Autonomous System

Answer

Default Local Preference of 200

Question 3

Which TWO actions can be performed using Junos routing policies applied to BGP? (Choose two)

Accepted Answer

Accepting or rejecting routes based on AS_PATH regular expressions.. Routing policies can modify path attributes such as local preference and MED, as well as accept or reject routes.

Answer

Changing the TCP port used for BGP session establishment from 179 to another port.

Answer

Directly modifying the physical interface speed when BGP flaps.

Answer

Encrypting BGP payload data using policy-based IPsec keys.

Question 4

An administrator wants to gracefully restart a BGP routing daemon without dropping the underlying TCP session or causing traffic loss. Which Junos feature should be enabled?

Accepted Answer

BGP Graceful Restart. Graceful Restart allows a BGP speaker to express its ability to preserve forwarding state while restarting the control plane.

Answer

Nonstop Active Routing (NAR)

Answer

TCP MD5 Signature bypass

Answer

BGP Bidirectional Forwarding Detection (BFD)

Question 5

Which TWO statements correctly differentiate eBGP from iBGP? (Choose two.)

Accepted Answer

eBGP routers prepend their own AS number to the AS_PATH attribute when advertising routes.. eBGP sessions are typically established between routers in different autonomous systems and have a default TTL of 1, whereas iBGP sessions are between routers in the same AS and have a default TTL of 255.

Answer

iBGP routes have a default administrative distance (preference in Junos) of 20.

Answer

The default TTL for iBGP packets is 1, requiring explicit multihop configurations for non-directly connected peers.

Answer

iBGP routers modify the next-hop attribute to their own interface address by default when advertising routes to iBGP peers.

Question 6

An MX Series router is configured with BGP Multipath. Two paths have identical Local Preference, AS path length, origin, and MED. Which additional configuration statement is required under protocols bgp to enable multipath load balancing across these iBGP paths?

Accepted Answer

set protocols bgp multipath relaxation. By default, multipath is only for eBGP. To enable iBGP multipath, the 'as-path-multipath relaxation' or 'ibgp multipath' statement must be used.

Answer

set protocols bgp group internal type external

Answer

set routing-options forwarding-table export load-balance

Answer

set protocols bgp group internal multihop

Question 7

You are configuring a Link Aggregation Group (LAG) on an EX series switch. Which statement is correct regarding LACP active mode?

Accepted Answer

The interface will actively transmit LACP packets to initiate and negotiate the aggregation with the peer device.. In LACP active mode, the interface actively transmits LACP packets to the remote peer to negotiate the link aggregation.

Answer

The interface will only respond to LACP packets and never transmit them.

Answer

Active mode can only be used when connecting Juniper switches to non-Juniper servers.

Answer

LACP active mode requires static pinning of member links and disables dynamic hash selection.

Question 8

An engineer wants to configure Nonstop Active Routing (NSR) alongside GRES on an MX204 router running OSPF. What is the primary operational benefit of enabling NSR compared to running GRES alone?

Accepted Answer

NSR synchronizes protocol daemon states between Routing Engines, preventing neighbors from detecting a control plane switchover.. GRES preserves forwarding state during a switchover, but routing protocols must restart and re-converge unless NSR is running, which synchronizes routing protocol states between REs.

Answer

NSR automatically configures VRRP tracking on all local VLAN interfaces.

Answer

NSR allows software upgrades to be performed without ever rebooting either Routing Engine.

Answer

NSR replaces LACP negotiation with static member pinning during link failures.

Question 9

An operator troubleshooting BGP path selection notices two routes have identical Local Preference, AS path length, origin, MED, and both are eBGP routes. Which attribute does the BGP path selection algorithm evaluate next?

Accepted Answer

Lowest IGP cost to the BGP next hop. According to the BGP best path selection algorithm, after comparing local pref, AS path, origin, MED, and iBGP vs eBGP, the router prefers the path with the lowest IGP metric to the BGP next hop.

Answer

Lowest Router ID

Answer

Oldest route

Answer

Lowest peer IP address

Question 10

An engineer needs to verify which BGP routes are currently installed in the forwarding table (FIB). Which command should be used?

Accepted Answer

show route forwarding-table protocol bgp. The forwarding table is viewed using 'show route forwarding-table'.

Answer

show bgp forwarding

Answer

show route table inet.0

Answer

show route summary