View Full Juniper JN0-364  Exam Dumps and Practice Test Dumps

Question: 121. Which Junos command displays a summary of BGP peer sessions and their states?

1. show bgp summary
   2. show route protocol bgp
   3. show ospf neighbor
   4. show interfaces terse

Correct Answer: 1. show bgp summary

Explanation:

The show bgp summary command provides a concise overview of BGP peer sessions. Its output includes information such as local and peer autonomous system numbers, peer addresses, session state, and the number of prefixes received or advertised. It is commonly used as an initial troubleshooting command when verifying BGP connectivity and session establishment. The show route protocol bgp command instead focuses on BGP-learned routes installed in the routing table rather than providing a summary of peer-session status.

Question: 122. Which OSPF packet type is primarily used to discover and maintain OSPF neighbors?

1. Link-State Update
   2. Database Description
   3. Hello
   4. Link-State Acknowledgment

Correct Answer: 3. Hello

Explanation:

OSPF Hello packets are used to discover neighboring routers and maintain existing neighbor relationships. Hello packets contain information such as the router ID, area, hello and dead intervals, and other parameters that must be compatible for an adjacency to form. Regular Hello exchanges also allow routers to determine whether neighbors remain reachable. Other OSPF packet types serve different purposes: Database Description packets summarize databases, Link-State Updates carry LSAs, and Link-State Acknowledgments confirm receipt of LSAs.

Question: 123. Which BGP attribute is generally preferred when selecting an outbound path within an autonomous system?

1. MED with the highest value
   2. Local Preference with the highest value
   3. AS_PATH with the greatest length
   4. Origin with the least-preferred value

Correct Answer: 2. Local Preference with the highest value

Explanation:

Local Preference is an important BGP path-selection attribute used within an autonomous system to influence outbound traffic. When comparing eligible BGP paths, a higher Local Preference is generally preferred. Because the attribute is propagated through iBGP, administrators can use it to influence exit-point selection throughout the autonomous system. MED has a different purpose and is generally used to communicate a preference for how traffic should enter an autonomous system. AS_PATH length and origin are also considered during BGP path selection but do not replace Local Preference’s role.

Question: 124. What is the primary purpose of the OSPF SPF algorithm?

1. To calculate shortest paths through the OSPF topology
   2. To authenticate BGP peers
   3. To assign IP addresses to interfaces
   4. To negotiate Ethernet link aggregation

Correct Answer: 1. To calculate shortest paths through the OSPF topology

Explanation:

OSPF uses the Shortest Path First algorithm, based on Dijkstra’s algorithm, to calculate the shortest paths through the topology represented by its link-state database. Each router builds a view of the network topology from received LSAs and independently calculates its shortest-path tree. The resulting information is used to install appropriate routes in the routing table. SPF is therefore a core component of OSPF route calculation and is unrelated to address assignment, BGP authentication, or Ethernet aggregation.

Question: 125. Which Junos command displays the currently active configuration?

1. show | compare
   2. show configuration
   3. show route
   4. show system uptime

Correct Answer: 2. show configuration

Explanation:

The show configuration command displays the current committed configuration in Junos configuration mode. It allows an administrator to inspect configured interfaces, routing protocols, policies, system settings, and other configuration hierarchy elements. By contrast, show | compare is used to compare the candidate configuration with the currently committed configuration. show route displays routing information, while show system uptime provides system operational information.

Question: 126. Which protocol is commonly used by RIP to exchange routing updates over IPv4?

1. TCP port 179
   2. UDP port 520
   3. UDP port 161
   4. TCP port 22

Correct Answer: 2. UDP port 520

Explanation:

RIPv1 and RIPv2 use UDP port 520 to exchange routing updates for IPv4. RIP is a distance-vector routing protocol that uses hop count as its primary metric and has a maximum usable hop count of 15. TCP port 179 is used by BGP, UDP port 161 is associated with SNMP, and TCP port 22 is commonly used for SSH. Knowing the transport details of routing protocols can be useful when troubleshooting firewall filters and connectivity problems.

Question: 127. What is the purpose of an OSPF Area Border Router (ABR)?

1. To connect different OSPF areas and exchange inter-area routing information
   2. To replace all OSPF routers with BGP routers
   3. To provide DHCP addresses to hosts in every area
   4. To create Ethernet switching loops

Correct Answer: 1. To connect different OSPF areas and exchange inter-area routing information

Explanation:

An OSPF Area Border Router has interfaces in multiple OSPF areas and participates in exchanging routing information between those areas. ABRs help maintain OSPF’s hierarchical design and can originate Type 3 Summary LSAs to advertise networks from one area into another. Area 0 is the backbone area and normally provides the central connection for inter-area routing. An ABR is a routing function, not a DHCP service or Ethernet switching mechanism.

Question: 128. Which IPv6 mechanism performs address resolution and neighbor discovery instead of traditional IPv4 ARP?

1. ICMPv6 Neighbor Discovery
   2. DHCP relay only
   3. BGP
   4. OSPF Type 5 LSAs

Correct Answer: 1. ICMPv6 Neighbor Discovery

Explanation:

IPv6 uses ICMPv6 Neighbor Discovery to perform functions that include discovering neighboring devices, resolving link-layer addresses, detecting duplicate addresses, and learning router information. Neighbor Solicitation and Neighbor Advertisement messages are central to these operations. Unlike IPv4, IPv6 does not use ARP for address resolution. Neighbor Discovery relies heavily on IPv6 multicast rather than broadcast. This mechanism is fundamental to normal IPv6 operation on an Ethernet or other supported local link.

Question: 129. What is the purpose of the BGP NEXT_HOP attribute?

1. To identify the IP address used as the next forwarding destination toward a BGP route
   2. To specify the BGP authentication password
   3. To identify the originating OSPF area
   4. To define the maximum number of BGP peers

Correct Answer: 1. To identify the IP address used as the next forwarding destination toward a BGP route

Explanation:

The BGP NEXT_HOP attribute identifies the IP address that should be used as the next hop when forwarding traffic toward a BGP-advertised destination. A receiving router must have a valid route to the next-hop address for the BGP route to be usable. In eBGP and iBGP scenarios, next-hop processing can differ depending on the topology and configuration. Troubleshooting an unreachable BGP next hop is therefore an important part of diagnosing routes that are received but not installed as active routes.

Question: 130. Which Junos command is used to compare the candidate configuration with the committed configuration?

1. show route protocol bgp
   2. show | compare
   3. show interfaces extensive
   4. show system alarms

Correct Answer: 2. show | compare

Explanation:

The show | compare command is used in Junos configuration mode to display differences between the candidate configuration and the currently committed configuration. It is particularly useful before committing changes because it lets an administrator review what has been added, removed, or modified. This can help prevent unintended configuration changes from being committed. Operational commands such as show route or show system alarms provide runtime information and do not perform this configuration comparison.

Question: 131. Which OSPF LSA type describes a multi-access network segment and is originated by the DR?

1. Type 5
   2. Type 3
   3. Type 1
   4. Type 2

Correct Answer: 4. Type 2

Explanation:

An OSPF Type 2 Network LSA is originated by the Designated Router on a multi-access network such as Ethernet. It describes the routers attached to that network segment and helps represent the multi-access portion of the topology in the link-state database. Type 1 Router LSAs are originated by individual routers, Type 3 Summary LSAs are generated by ABRs for inter-area information, and Type 5 LSAs describe external routes. The Type 2 LSA therefore has a specific relationship with the DR.

Question: 132. Which BGP community attribute prevents a route from being advertised to external BGP peers?

1. no-export
   2. no-advertise
   3. internet
   4. local-AS

Correct Answer: 1. no-export

Explanation:

The BGP no-export community tells a BGP speaker that a route carrying the community should not be advertised to eBGP peers outside the local autonomous system. The route can still be propagated within the autonomous system according to the relevant BGP behavior and policy. The no-advertise community is more restrictive because it prevents the route from being advertised to any BGP peer. Understanding these community behaviors is important when controlling the scope of route propagation.

Question: 133. What is the primary purpose of a routing policy in Junos?

1. To control how routes are imported, exported, accepted, or modified
   2. To replace the forwarding plane
   3. To physically connect Ethernet cables
   4. To automatically repair damaged hardware

Correct Answer: 1. To control how routes are imported, exported, accepted, or modified

Explanation:

Junos routing policies provide granular control over routing information. Policies can be used to accept or reject routes, modify attributes, set communities, change metrics, and control which routes are imported into or exported from routing protocols. Policies are commonly applied to protocols such as BGP, OSPF, and IS-IS. They provide an important mechanism for implementing routing decisions beyond the default behavior of the protocol itself.

Question: 134. Which IPv4 address represents the default route?

1. 255.255.255.255/32
   2. 127.0.0.0/8
   3. 0.0.0.0/0
   4. 169.254.0.0/16

Correct Answer: 3. 0.0.0.0/0

Explanation:

The IPv4 default route is represented as 0.0.0.0/0. Because the prefix length is zero, it matches any IPv4 destination that does not have a more specific matching route in the routing table. Default routes are commonly used to forward traffic toward an upstream router or Internet gateway. The 255.255.255.255/32 address is the limited broadcast address, 127.0.0.0/8 is reserved for loopback, and 169.254.0.0/16 is associated with IPv4 link-local addressing.

Question: 135. Which Junos feature allows multiple physical Ethernet interfaces to operate as one logical aggregated interface?

1. VRRP
   2. LACP
   3. GRE
   4. BFD

Correct Answer: 2. LACP

Explanation:

LACP is used to dynamically establish and maintain link aggregation, allowing multiple physical Ethernet links to participate in a single logical aggregated Ethernet interface. Link aggregation can provide increased aggregate bandwidth and redundancy. Although LACP is the control protocol used to negotiate the member links, the aggregated interface itself represents the logical combination of those physical links. VRRP provides first-hop redundancy, GRE provides tunneling, and BFD provides rapid failure detection.

Question: 136. Which Junos command can display active system alarms on a device?

1. show system alarms
   2. show route
   3. show ospf database
   4. show bgp summary

Correct Answer: 1. show system alarms

Explanation:

The show system alarms command displays active alarms reported by the Junos system. These alarms can provide information about hardware, environmental, or other system conditions that require attention. Reviewing system alarms is useful during troubleshooting because an apparently unrelated connectivity problem can sometimes be associated with a hardware or platform issue. Routing commands such as show route, show ospf database, and show bgp summary focus on routing information rather than system-level alarms.

Question: 137. Which BGP attribute identifies the autonomous systems a route advertisement has traversed?

1. Local Preference
   2. MED
   3. Origin
   4. AS_PATH

Correct Answer: 4. AS_PATH

Explanation:

The AS_PATH attribute records the sequence of autonomous systems through which a BGP route advertisement has passed. Each eBGP autonomous system normally adds its own AS number when propagating a route. Routers can use the AS_PATH to detect routing loops and to participate in BGP path selection. A route containing the local AS number is normally considered a loop and rejected. Local Preference, MED, and Origin are separate BGP attributes that influence path selection for different purposes.

Question: 138. Which protocol is a link-state interior gateway protocol that supports a Level 1 and Level 2 hierarchy?

1. RIP
   2. BGP
   3. IS-IS
   4. VRRP

Correct Answer: 3. IS-IS

Explanation:

IS-IS is a link-state interior gateway protocol that uses a hierarchical Level 1 and Level 2 architecture. Level 1 routers generally provide routing within an area, while Level 2 routers provide routing between areas. IS-IS builds a link-state database and uses an SPF calculation to determine routes. RIP is a distance-vector protocol, BGP is an exterior gateway protocol, and VRRP is a first-hop redundancy protocol rather than a routing protocol.

Question: 139. What does GRES provide on a Junos device with redundant Routing Engines?

1. Automatic IP address assignment
   2. Routing Engine redundancy during a switchover
   3. BGP route filtering
   4. Ethernet frame encryption

Correct Answer: 2. Routing Engine redundancy during a switchover

Explanation:

Graceful Routing Engine Switchover, or GRES, helps maintain forwarding operations when control-plane responsibility moves from one Routing Engine to another. During an RE switchover, GRES is designed to reduce the disruption to packet forwarding. GRES is a platform high-availability feature rather than a routing policy or encryption mechanism. Other technologies, such as nonstop routing and nonstop active routing, address additional aspects of maintaining routing protocol state and control-plane continuity during Routing Engine events.

Question: 140. Which BGP community is more restrictive than no-export because it prevents advertisement to BGP peers?

1. no-advertise
   2. internet
   3. no-export
   4. standard

Correct Answer: 1. no-advertise

Explanation:

The no-advertise BGP community instructs a BGP speaker not to advertise the associated route to any BGP peer. This is more restrictive than no-export, which prevents the route from being advertised to eBGP peers outside the local autonomous system while still allowing certain internal propagation. Community attributes provide a flexible way to control route distribution without necessarily filtering individual prefixes through separate policy logic. Administrators can use them together with routing policies to implement precise route-control behavior.