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An engineer is preparing to perform an In-Service Software Upgrade (ISSU) on a pair of dual-RE MX240 routers. Which condition must be met to ensure the ISSU succeeds without dropping traffic?
2You are configuring VRRP between two EX4600 switches to provide a default gateway for a VLAN. To ensure that the switch with the higher physical interface capacity assumes the master role, what parameter should you adjust?
3An EX4300 Virtual Chassis experiences a split-brain condition due to a failure of all stacking cables between members 0/1 and members 2/3. How does Junos handle this scenario by default?
4An administrator is configuring Graceful Restart on a pair of Juniper MX series routers running OSPF. What is the primary purpose of Graceful Restart in this scenario?
5You are troubleshooting a Virtual Chassis formed by four EX4300 switches. The primary Routing Engine (RE) unexpectedly rebooted. Upon recovery, you notice that a different member switch has taken over the role of primary. How can you prevent this specific member from becoming the primary RE in the future?
6You are verifying BGP Graceful Restart helper mode on a Juniper router. A peering router restarts its control plane. What output or verification command confirms that your router is acting as a Graceful Restart helper for the peer?
7You are configuring a Link Aggregation Group (LAG) on an EX series switch. Which statement is correct regarding LACP active mode?
8An engineer needs to configure a Link Aggregation Group (LAG) between two Juniper EX4300 switches to provide redundant uplinks to a core router. Which statements regarding the LACP configuration requirements on the EX4300 switch must be met?
9You are configuring a Link Aggregation Group (LAG) with LACP on an EX3400 switch. You want to ensure that the interface bundle drops traffic if fewer than two active member links are operational. Which feature configuration achieves this?
10An administrator wants to verify that GRES is operating correctly on an MX series router with dual Routing Engines. Which operational command should be used?
11When planning an In-Service Software Upgrade (ISSU) on a Juniper routing platform, what is the behavior of the Routing Engines during the execution of the upgrade command?
12You notice frequent mastership transitions in a VRRP group configured between two EX4300 switches. The logs indicate that VRRP advertisements are intermittently missing. Which troubleshooting step addresses the underlying cause without changing the master priority?
13During 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?
14When configuring VRRP on a Juniper router, what IP address must be assigned as the virtual IP address for the group?
15Which command displays the status of Virtual Chassis member switches, their roles, and their serial numbers on an EX series switch?
16An 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?
17Which CLI command displays detailed information about VRRP groups, including master router status, virtual IP addresses, and advertisement intervals on an EX series switch?
18An engineer configures a Virtual Chassis using EX4300 switches. To ensure member IDs are assigned consistently even if physical positions change, how should the administrator provision the member IDs?
19You are troubleshooting a Link Aggregation Group (LAG) between an EX4300 switch and a third-party switch. Member links are flapping intermittently. Examination of system logs reveals LACP timeout errors. What is the most likely cause?
20You are troubleshooting a BGP session failure immediately following a manual Routing Engine switchover on an MX series router configured with GRES and NSR. BGP drops its peering session. What is the most likely reason for the failure?
21When configuring a Link Aggregation Group (LAG) on a Juniper switch, what is the naming convention used for the aggregated interface in the Junos CLI?
22An 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?
23You are performing a pre-check for an ISSU on an MX series router. You execute 'request system software in-service check' and the system reports an error indicating that graceful restart or NSR is not properly configured for active routing protocols. How do you resolve this?
24Which 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?
25You are configuring Multi-Chassis Link Aggregation (MC-LAG) across two Juniper switches acting as separate control plane devices. Which protocol is used between the peer switches to synchronize state and ensure MAC address table consistency across the MC-LAG domain?
26Which CLI command is used to manually initiate a Routing Engine switchover on an MX series router configured with GRES?
27An EX4300 Virtual Chassis has GRES enabled. During a primary Routing Engine failure, what happens to the backup Routing Engine?
28You are troubleshooting a Virtual Chassis where member 0 has failed completely. The replacement switch arrives. Before inserting it into the running Virtual Chassis ring, what critical precaution must be taken regarding Junos OS software versions?
29An 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?
30Which CLI command verifies that OSPF Graceful Restart helper mode is enabled by default on a Juniper routing platform?
31You 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?
32An engineer configures VRRP between two routers. Client traffic destined for the outside network is being dropped intermittently. Investigation reveals that the VRRP master is responding to ARP requests with its physical MAC address instead of the virtual router MAC address. What is the cause of this behavior?
33An engineer wants to configure a Link Aggregation Group (LAG) to load-balance traffic based on Layer 3 and Layer 4 header fields (source/destination IP and source/destination port) rather than just Layer 2 MAC addresses. How is this achieved in Junos?
34You are troubleshooting a split-brain condition in an EX4300 Virtual Chassis where both partitions have elected a primary Routing Engine. Which feature can be configured to detect this condition and shut down downstream ports on the non-designated partition to prevent duplicate packet forwarding?
35An administrator is configuring VRRP on an EX4300 switch and wants to ensure that when the primary router recovers from a failure, it immediately reclaims the master role from the backup router. Which VRRP configuration parameter controls this behavior?
36Which configuration command enables Graceful Routing Engine Switchover (GRES) globally on a Juniper routing platform?
37You are troubleshooting an issue where an EX4300 Virtual Chassis fails to boot after adding a new switch member. The system console displays errors regarding incompatible Junos images and hardware mismatch on the Virtual Chassis ports. What is the correct procedure to recover and integrate the new member?
38Which operational command displays the configured member IDs, priorities, and roles in an EX Series Virtual Chassis?
39Which CLI command displays the packet statistics, errors, and drop counters for a Link Aggregation Group (LAG) named ae0?
40An engineer configures Nonstop Active Routing (NSR) on an MX series router. What is required for NSR to function properly on BGP peering sessions?
41You are troubleshooting a VRRP deployment where two EX4600 switches are acting as redundant gateways for several VLANs. Clients on VLAN 10 report intermittent gateway unreachability. You notice that VRRP mastership frequently flips between Switch A and Switch B. What is the most effective way to stabilize VRRP mastership?
42Which CLI command displays the operational status and roles of all members in a Juniper EX Series Virtual Chassis?
43An administrator configures a Link Aggregation Group (LAG) using LACP between two EX series switches. The link fails to aggregate, and the log shows 'LACP status: Expired'. What does the 'Expired' state indicate?
44Which THREE statements accurately describe the behavior and configuration of VRRP tracking on Junos devices? (Choose three)
45Which TWO commands are used to verify link aggregation and LACP operational status on a Juniper switch? (Choose two)
46Which THREE conditions must be met to successfully execute an In-Service Software Upgrade (ISSU) on a dual-RE Juniper routing platform? (Choose three)
47Which TWO operational commands are used to check the health and status of Routing Engines and GRES on an MX series router? (Choose two)
48Which THREE factors must be considered when configuring a Link Aggregation Group (LAG) with LACP on Junos switches? (Choose three)
49Which TWO options represent valid benefits of configuring Link Aggregation Groups (LAG)? (Choose two)
50Which TWO items are required when configuring VRRP on a Juniper router interface? (Choose two)
51Which THREE statements regarding Juniper Virtual Chassis architecture and master election are correct? (Choose three)
52Which THREE statements are true regarding OSPF Graceful Restart helper mode on Juniper routers? (Choose three)
53Which THREE conditions can cause a Virtual Chassis primary Routing Engine election or switchover to occur unexpectedly? (Choose three)
54Which THREE parameters can be tuned under the VRRP hierarchy in Junos to customize failover timing and behavior? (Choose three)
55Which THREE actions occur when a Junos router with GRES and NSR enabled performs a manual Routing Engine switchover while running OSPF and BGP? (Choose three)
56Which TWO methods are used to connect switches in a Juniper EX Series Virtual Chassis? (Choose two)
57Which THREE criteria are evaluated by Junos when electing the primary Routing Engine in an EX Series Virtual Chassis? (Choose three)
58Which THREE potential issues can arise if LACP is misconfigured between a Juniper switch and a connected peer device? (Choose three)
The High Availability domain covers the key concepts tested in this area of the JNCIS-ENT exam blueprint published by Juniper Networks. Courseiva provides free domain-focused practice, mock exams, missed-question review, and readiness tracking across all JNCIS-ENT domains — no account required.
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