332 questions total · 5pages · All types, answers revealed
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Page 2Which TWO types of OSPF areas allow the generation of Type-7 LSAs? (Choose two)
NSSAs allow ASBRs to inject external routes using Type-7 LSAs.
Why this answer
Type-7 LSAs are exclusively generated within Not-So-Stubby Areas (NSSA) and NSSA totally stubby areas by ASBRs connecting external routes.
You are troubleshooting MAC address learning on an EX Series switch and want to display dynamic MAC entries learned specifically on interface ge-0/0/5. Which operational command should you use?
This command filters the bridging table by the specified interface.
Why this answer
The command 'show bridge mac-table interface ge-0/0/5' displays MAC addresses learned on that interface.
Isolated VLAN ports can only communicate with the promiscuous port.
Why this answer
Isolated VLAN ports can only communicate with promiscuous ports.
Which TWO factors can cause an EVPN instance on a Junos device to fail in importing incoming Type-2 MAC/IP routes? (Choose two)
Without a properly configured EVPN routing instance, the routing table cannot accept EVPN route imports.
Why this answer
Route import failures in EVPN are typically caused by mismatched Route Targets between the advertising and receiving PE, or missing/incorrect EVPN routing instance configurations.
Which standard Junos forwarding class is reserved for control plane traffic such as routing protocols and management traffic?
network-control is the default class for high-priority control plane traffic.
Why this answer
In Junos, the network-control forwarding class is reserved for control plane traffic to ensure it receives priority handling.
Which TWO BGP attributes are classified as well-known mandatory attributes that must be recognized by all BGP implementations? (Choose TWO)
AS_PATH is a well-known mandatory attribute.
Why this answer
The well-known mandatory BGP attributes are AS_Path, NEXT_HOP, and ORIGIN. Among the choices, AS_PATH and NEXT_HOP are well-known mandatory attributes.
You are troubleshooting a scenario where multi-field classifiers and behavior aggregate classifiers are both configured on the same ingress interface. In what order does Junos process classification?
BA classifies based on CoS bits; MF filters can subsequently override the class.
Why this answer
Junos processes Behavior Aggregate (BA) classification first, followed by Multi-Field (MF) classification which can override the BA result.
An engineer needs to ensure that a Junos router balances BGP traffic across multiple paths with unequal IGP costs. Which feature must be configured to achieve this?
Relaxing strict AS path or IGP cost checks allows multipath load balancing across paths with different metrics.
Why this answer
By default, BGP multipath requires equal cost. To allow paths with different costs, 'as-path-multipath' or variance-based multipath configurations are required depending on specific Junos platform support, but generally standard multipath requires equal IGP cost unless specific multipath relaxation options are set.
Which THREE statements are true regarding voice VLAN technologies and implementation on Junos EX Series switches? (Choose three.)
LLDP-MED network policies distribute voice VLAN info to endpoints.
Why this answer
Voice VLAN features allow separation of voice and data traffic, support both tagged and untagged configurations, and integrate with discovery protocols.
You want to filter OSPF Type-3 Summary LSAs leaving Area 1 on an ABR running Junos OS. Where must this export policy be applied?
Type-3 LSA generation for aggregated prefixes can be controlled and filtered using the area-range export policy on the ABR.
Why this answer
To filter Type-3 summary LSAs generated by an ABR as they leave an area, you apply the export policy using the 'set protocols ospf area <area-id> area-range <prefix> export <policy-name>' hierarchy.
An engineer is troubleshooting a newly configured EVPN-VXLAN multi-homed setup where the Designated Forwarder (DF) is constantly toggling between two PE routers. What is the most likely cause of this DF churn?
If ESIs match but BGP session stability or Type-4 route advertisements fluctuate, the DF election re-runs continuously, causing churn.
Why this answer
DF churn typically occurs when BGP sessions or reachability between the PE routers flapping, or when the timers (such as wait-for-timer) are misconfigured, causing conflicting DF election states.
Which command allows an administrator to view the active BGP routes along with their associated communities on a Junos device?
The 'extensive' output includes detailed route attributes such as communities, AS path, and origin.
Why this answer
The 'show route protocol bgp' command with the 'extensive' modifier displays detailed path attributes including BGP communities.
During an audit of a multiregion enterprise network using PIM Sparse-Mode, an engineer needs to ensure that only designated Bootstrap Routers (BSRs) can inject candidate-RP information into the domain. Which Junos configuration feature should be applied on the core routers to secure the BSR domain?
The bsr-edge statement prevents BSR messages from crossing into or out of specific interfaces, establishing a security boundary for the PIM domain.
Why this answer
To protect the PIM domain from rogue BSR messages or unauthorized candidate-RP announcements, Junos allows configuring BSR edge boundaries or using a bsr-candidate policy to filter incoming bootstrap messages.
Which command displays the global status, TLV counters, and operational state of LLDP on an EX Series switch?
show lldp is the primary command to check global LLDP status and statistics.
Why this answer
show lldp provides system-wide operational data for LLDP.
Which TWO commands are used to troubleshoot OSPF issues on Junos devices? (Choose two)
Displays OSPF neighbor states and adjacency progress.
Why this answer
Operational commands like 'show ospf neighbor' and 'show ospf database' are standard for troubleshooting OSPF adjacencies and LSDB status.
Which THREE statements describe the behavior of critical authentication (fallback) when a RADIUS server becomes unreachable on an EX Series switch? (Choose three)
Correct. Critical fallback assigns clients to predefined critical parameters.
You are troubleshooting a Q-in-Q tunneling implementation on an MX Series router where customer VLAN tags are being stripped instead of preserved across the service provider core. Under which configuration hierarchy should the 'vlan-tagging' and 'pop-pop' or 'push' actions be applied on the interface?
flexible-vlan-tagging is required on the physical interface to process multiple VLAN tags.
Why this answer
For Q-in-Q tunneling on Juniper routing and switching platforms, flexible VLAN tagging is configured under 'interfaces <interface> flexible-vlan-tagging'.
What is the default number of forwarding classes available on Juniper MX Series routers equipped with Modular Port Concentrators (MPCs)?
Junos supports a maximum of 64 forwarding classes on MPC hardware.
Why this answer
Junos supports up to 64 forwarding classes on modern MPC-based hardware platforms, though default configurations typically use a subset.
You are troubleshooting a BGP route selection issue on a Junos device. Two otherwise identical paths are received from external peers. According to the standard BGP route selection algorithm implemented by Junos, which tie-breaking attribute is evaluated immediately AFTER comparing the Router ID (RID) of the advertising routers?
The Junos BGP decision process evaluates the lowest neighbor IP address immediately after comparing the router ID.
Which operational command is used to verify the operational status and peer state of MSDP sessions on a Junos device?
This command displays MSDP peer addresses, connection states, and uptime.
Why this answer
The 'show msdp summary' command provides an overview of MSDP peers, state, and connection status.
An administrator wants to configure a static Rendezvous Point (RP) with IP address 192.168.100.1 for all multicast groups on a Junos router. Which configuration accomplishes this?
This configures a static RP address for all groups under PIM.
Why this answer
Static RPs are defined under protocols pim rp static address. Group ranges can also be specified.
When configuring OSPFv3 authentication, which mechanism is natively utilized in modern Junos implementations since OSPFv3 relies on IPv6 AH/ESP or OSPFv3 Authentication Trailer (RFC 7166)?
Authentication trailers are configured using the authentication-trailers option in OSPFv3.
Why this answer
Junos supports the OSPFv3 Authentication Trailer defined in RFC 7166, configured via the authentication-trailers command under protocols ospf3.
Which OSPFv3 LSA type is responsible for carrying IPv6 prefix information within the same area, replacing the role of Router and Network LSAs carrying IP addresses in OSPFv2?
Type 9 LSAs are used in OSPFv3 to advertise IPv6 prefixes associated with a router or transit network within the same area.
Why this answer
OSPFv3 separates topology information from IP prefix information. Type-9 (Intra-Area-Prefix-LSA) carries IPv6 prefixes associated with routers or transit networks within the area.
An administrator implements LLDP-MED on an EX Series switch network. To prevent unauthorized devices from masquerading as IP phones and requesting voice VLAN access, which feature should be combined with LLDP-MED?
Combining 802.1X or MAC Authentication Bypass (MAB) ensures endpoints are authenticated before receiving secure network policies.
Which TWO of the following characteristics apply to EVPN Route Type 3 (Inclusive Multicast Ethernet Tag Route)? (Choose two)
Type 3 route payloads include the originating router's IP and the Ethernet tag or VNI.
Why this answer
Route Type 3 routes are used to construct the multicast/broadcast distribution tree using ingress replication (head-end replication) by advertising the PE's IP address and Ethernet tag/VNI.
Which Junos command displays the link-state database for OSPFv2, showing router LSAs and network LSAs?
This command outputs the complete OSPF LSDB.
Why this answer
The command 'show ospf database' displays the OSPF link-state database on a Junos device.
Which TWO statements describe the function and operation of a PIM Bootstrap Router (BSR)? (Choose two)
The BSR gathers C-RP info and floods bootstrap messages domain-wide.
Why this answer
The BSR collects Candidate-RP advertisements and distributes the RP-set to all routers in the domain via bootstrap messages.
Which statement is true regarding the behavior of the supplicant mode 'single' on an EX Series switch port?
Correct. Single mode restricts the port to one authenticated client.
Why this answer
Single-supplicant mode allows only a single authenticated client on the port. If a hub or IP phone with a PC is connected, only one device passes authentication.
When configuring voice VLANs and PoE on an EX Series switch, which THREE benefits are achieved by implementing LLDP-MED alongside standard PoE? (Choose three.)
LLDP-MED power management allows precise wattage negotiation.
Why this answer
LLDP-MED combined with PoE provides dynamic power negotiation, automated voice VLAN provisioning, and enhanced inventory tracking.
You are reviewing syslog messages on an EX Series switch and see frequent entries indicating PoE power budgeting warnings. You want to configure a custom trap/syslog threshold so that warnings trigger when the total power consumption exceeds 85% of the total available PoE budget. How is this configured?
The budget-threshold statement under the system poe hierarchy sets the percentage threshold for syslog generation.
Why this answer
PoE threshold settings allow operators to set a percentage limit that triggers traps when power consumption nears capacity.
An enterprise network uses a BGP route reflector (RR) architecture where client routers reflect routes to each other. A non-client router sends a route with an Originator ID and Cluster List to the RR. How does the route reflector handle these attributes when reflecting the route to other clients?
The RR preserves the Originator ID and adds its local cluster ID to the front of the Cluster List.
Why this answer
A route reflector leaves the Originator ID untouched and prepends its own Cluster ID to the existing Cluster List to prevent routing loops.
An administrator wants to configure Candidate-RP (C-RP) advertisements using the Bootstrap Router (BSR) mechanism in PIM sparse-mode. Which hierarchy level in Junos is used to configure the local router as a Candidate-RP?
Candidate RP settings, including local address and group ranges, are configured under protocols pim candidate-rp.
Why this answer
Candidate RPs in Junos are configured under protocols pim candidate-rp.
You need to configure a classifier that inspects the Multiprotocol Label Switching (MPLS) experimental (EXP) bits. Which classifier type must you specify?
exp specifies the MPLS experimental bits classifier.
Why this answer
The MPLS EXP bits are classified using the exp classifier type in Junos CoS configurations.
An engineer wants to restrict IGMP membership reports to only accept version 2 on a specific VLAN interface configured on an MX Series router. Which configuration statement achieves this requirement?
This explicitly forces the IGMP version on the specified interface to version 2.
Why this answer
Junos allows configuring specific IGMP versions per interface under protocols igmp interface.
In Junos CoS architecture, what role does a forwarding class play?
Forwarding classes group packets for queue scheduling and drop profiles.
Why this answer
Forwarding classes act as internal labels used by the router to group traffic into specific queues for scheduling and drop treatment.
An administrator is troubleshooting BGP route reflector operations in a Junos environment. Which TWO statements regarding route reflection behavior and loop prevention are correct? (Choose two)
Cluster Lists prevent routing loops between clustered route reflectors by rejecting paths containing the local cluster ID.
Why this answer
Route reflectors use Originator ID to prevent loops from clients and Cluster Lists to prevent loops between cluster route reflectors.
An administrator notices that an EX4300 switch is supplying power using LLDP-MED power negotiation, but the IP phone is drawing more power than the initial hardware class allows. Where would you check the advertised LLDP-MED TLV power value received from the phone?
The detail modifier displays all received TLVs, including LLDP-MED power management details.
Why this answer
The show lldp neighbor interface command displays detailed TLVs received from connected LLDP-MED endpoints, including power requirements.
An administrator configures a BGP routing policy to match routes with community members using regex matching in Junos. Which statement accurately describes how Junos represents standard BGP communities in policy matching?
Junos uses named community lists with AS:number syntax to match BGP communities.
Why this answer
In Junos, standard BGP communities are represented as target communities or community sets in the form of autonomous_system:identifier or named community lists.
When applying a rewrite rule on an interface, you notice that packets are being remarked incorrectly. You realize that both a DSCP rewrite rule and an IEEE 802.1p rewrite rule are configured on the same physical interface. What is the rule regarding multiple rewrite rules on a single interface in Junos?
Multiple distinct header rewrite rules can coexist on an interface.
How do you examine the specific OSPF routing table entries learned via OSPF on a Junos device?
This command filters the routing table to show only OSPF routes.
Why this answer
The 'show route protocol ospf' command displays routes learned specifically through the OSPF routing protocol.
Which THREE optional BGP attributes are supported and processed by Junos routing devices? (Choose three)
Community attributes are fully supported and widely used in Junos policies.
Why this answer
Junos supports standard optional attributes such as MED, Communities, and Atomic Aggregate.
An engineer is configuring PIM sparse-mode in an enterprise network. Which TWO characteristics are true regarding PIM sparse-mode operation? (Choose two)
PIM-SM uses explicit joins to build distribution trees rather than flooding and pruning.
Why this answer
PIM sparse-mode assumes that multicast traffic is not wanted across all segments by default, requiring explicit join messages. It relies heavily on a Rendezvous Point (RP) to connect sources and receivers initially.
A network engineer troubleshoots an issue where multicast data packets are being dropped due to an RPF (Reverse Path Forwarding) check failure. The unicast routing table uses OSPF, but MBGP is deployed for multicast routing. Which operational command should the engineer use to verify the multicast RPF path for a specific source IP?
The 'show route rpf' command displays the RPF lookup results and path used by multicast routing.
Why this answer
When MBGP is used for multicast RPF separate from unicast routing, the command 'show route rpf <source-ip>' helps check which routing table and next-hop is used for the multicast RPF check.
Which TWO well-known BGP communities are recognized universally to control route propagation? (Choose two)
no-export prevents advertising outside the local AS or confederation.
Why this answer
NO_EXPORT and NO_ADVERTISE are standard well-known communities.
You are configuring MACsec (Media Access Control Security) on an EX Series switch interface to secure Layer 2 links between two enterprise buildings. Which requirement is mandatory for MACsec to establish a secure session successfully between the two switches?
MACsec encryption relies on matching security keys (CAK/CKN) and negotiated cipher suites.
Why this answer
MACsec requires pre-shared keys (PSK) or MKA (MACsec Key Agreement) with matching connectivity association keys (CAK) and cipher suites.
An administrator needs to implement a traffic conditioning profile on a Juniper MX Series router to limit traffic to a specific burst size and drop packets exceeding the rate. Which policing action parameter is required to ensure that exceeding traffic is dropped immediately without coloring?
The discard action drops the packet immediately.
Why this answer
A policer in Junos uses policer action statements like loss-priority or discard. To drop non-compliant traffic immediately, the action discard is configured.
Which Junos configuration command enables MD5 cryptographic authentication on an OSPFv2 interface?
This is the correct Junos syntax for OSPFv2 MD5 authentication.
Why this answer
MD5 authentication for OSPFv2 in Junos is configured under the interface hierarchy with the 'authentication md5' statement followed by a key ID and password.
Junos assigns a default metric of 5 for routes redistributed into OSPF when not specified.
An administrator needs to filter Type-3 LSAs entering an OSPF stub area on a Junos routing device. Which statement under the area hierarchy is required?
The 'restrict' option prevents the summary LSA from being injected into the area.
Why this answer
In Junos OS, you can filter inbound Type-3 LSAs into a stub or NSSA area using the 'area-range' command with the 'restrict' or 'hidden' parameter, or using an import policy at the area level, but specifically for summarization and blocking, the area-range statement with 'restrict' prevents the LSA from being advertised.
You want to configure voice VLAN functionality on a Juniper EX switch so that IP phones automatically place voice traffic into VLAN 50 while passing PC data through unchanged. Which feature should you configure?
LLDP-MED provides network policy advertisement, allowing IP phones to discover the voice VLAN.
Why this answer
Voice VLAN feature on EX switches automatically assigns voice traffic from known MAC OUIs to the designated voice VLAN.
You are configuring Ethernet switching on an EX4300 switch and need to implement storm control to prevent broadcast, multicast, and unknown unicast traffic from overwhelming access links. Where is storm-control applied in the Junos configuration hierarchy?
Storm control is configured directly under the ethernet-switching family on the interface.
Why this answer
Storm control is applied under 'interfaces <interface-name> unit 0 family ethernet-switching storm-control'.
Which statement describes the function of a drop-profile in Junos CoS?
Drop-profiles implement Random Early Detection (RED) based on queue fill levels.
Why this answer
A drop-profile defines the packet drop probability as a function of buffer occupancy to implement RED or WRED congestion avoidance.
An enterprise architect is designing an IP multicast solution using PIM Sparse-Mode and needs to configure a Rendezvous Point (RP) redundantly using Auto-RP. However, Junos OS does not natively support listening to Cisco Auto-RP discovery and announcement messages without specific helper configurations. Which TWO configuration steps are required on Junos to interoperate with or process Auto-RP messages? (Choose two)
Auto-RP messages use dense-mode flooding over well-known addresses 224.0.1.39 and 224.0.1.40, requiring those groups to operate in dense mode or be statically handled.
Why this answer
Junos does not natively run Auto-RP (Cisco proprietary). To support Auto-RP environments, Junos routers can be configured to map Auto-RP groups using static RP or by using RPM/helper statements, or by mapping Auto-RP group addresses (224.0.1.39 and 224.0.1.40) into PIM dense-mode or static mappings if supported. Specifically, standard deployments map the Auto-RP well-known group addresses or use static RP configurations since Junos natively relies on standard BSR.
During BGP route resolution on Junos, an indirect next hop is encountered. What mechanism does Junos use to resolve this indirect next hop to a direct forwarding next hop?
Junos performs recursive lookups in the routing table to resolve BGP next hops via the resolving protocol (IGP).
You are configuring a BGP Route Reflector (RR) in a Junos environment. To prevent routing loops within the iBGP cluster, what mechanism does the route reflector use to track the path of reflected routes?
Cluster List and Originator ID are the standard BGP path attributes designed specifically for route reflection loop prevention.
Which THREE of the following statements describe the behavior and purpose of EVPN Route Type 5 (IP Prefix Route)? (Choose three)
Type 5 routes bridge EVPN data centers with external IP-VRF / L3VPN networks.
Why this answer
Route Type 5 carries IP prefixes independently of MAC addresses, supports inter-subnet forwarding in IP-VRF or EVPN-VXLAN integrations, and can carry gateway IP information.
Which command allows you to verify the real-time PoE power consumption, allocated wattage, and operational status of all interfaces on an EX Series switch?
show poe interface is the correct operational command to view PoE statistics on Junos switches.
Why this answer
The show poe interface operational command displays detailed power metrics per port.
An enterprise is designing a BGP confederation to reduce iBGP mesh complexity across multiple data centers. Which statement is correct regarding how confederation members interact with BGP attributes?
Confederation member AS numbers are encapsulated in confederation-specific path segments internally and hidden from external peers.
Why this answer
Within a BGP confederation, sub-AS numbers are stripped as routes leave the confederation and are replaced by the confederation identifier. However, within the confederation, sub-AS numbers are kept in the AS_CONFED_SEQUENCE and AS_CONFED_SET path segments to prevent loops, and MED/Local Preference are preserved across member sub-AS boundaries.
An EX3400 switch experiences a total PoE power budget exhaustion after multiple high-power IP phones and security cameras are plugged in. You want to ensure that if a power deficit occurs, the switch immediately cuts power to lower-priority ports while maintaining power to executive phones on specific ports. How should you configure this?
Setting interface priorities ensures the power management daemon sheds low-priority ports first during an overload condition.
Why this answer
Priority-based PoE allocation allows administrators to assign priorities (high, low, medium) to specific interfaces to dictate shedding order.
An administrator needs to ensure that a Junos routing device performs unequal-cost multi-path (UCMP) load balancing across multiple BGP paths with different local preferences or path attributes. Which BGP feature must be enabled to allow multipath load balancing across paths with different AS path lengths?
The as-path-ignore parameter allows Junos to consider paths for BGP multipath even if their AS path lengths do not match exactly.
Why this answer
By default, Junos multipath requires multiple attributes (such as AS path length) to match. To allow BGP multipath even when AS path lengths differ (as long as they have the same length numerically, or using 'as-path-ignore'), the 'as-path-ignore' statement under protocols bgp multipath must be configured.
An EX Series switch is configured with multiple-supplicant mode on an access port connected to an IP phone with a PC daisy-chained behind it. The IP phone authenticates via 802.1X, but the PC uses MAC RADIUS. The phone authenticates successfully and moves to the voice VLAN. However, when the PC boots, it fails authentication because the switch rejects a second supplicant on the same logical port index. Which configuration parameter resolves this issue?
Correct. Enabling multiple supplicants per port allows both the IP phone and the PC to authenticate independently.
Why this answer
In multiple-supplicant mode, you must configure 'supplicant multiple' and ensure the port is configured to support multiple clients using different authentication methods (e.g., multi-supplicant mode rather than single-supplicant).
When designing an EVPN-VXLAN fabric with integrated routing and bridging (IRB), which THREE considerations are critical for proper inter-subnet forwarding across VTEPs? (Choose three)
Anycast gateways require identical virtual MAC and IP settings on every leaf router's IRB interface.
Why this answer
Distributed IRB gateways require consistent anycast gateway MAC and IP configurations across all leaf nodes, correct VNI to bridge domain mappings, and EVPN Type-5 or Type-2 route propagation for host/subnet reachability.
You are troubleshooting an IP phone that is failing to discover its voice VLAN via LLDP-MED on an EX4600 switch. You issue the show lldp interface command and see that LLDP is transmitting properly, but the phone reports no voice VLAN TLV received. What is the most likely cause of this issue?
Without an explicit LLDP-MED network policy defining the voice VLAN ID and DSCP values, the switch will not advertise the voice VLAN TLV.
Why this answer
LLDP-MED network policy must be explicitly configured and tied to the interface or globally mapped so that the switch populates the voice VLAN TLV in its outbound LLDP-MED packets.
Which TWO statements are true regarding Junos OSPF routing policies and policy evaluation? (Choose two)
Junos processes policy terms sequentially until a match and terminal action occur.
Why this answer
Junos routing policies are evaluated top-to-bottom per term, and if no match is found, the default action depends on the context (reject for export policies, accept for import policies in some contexts, but let's review exact Junos behavior: export policies default to reject, import policies default to accept). Also, route filtering can match specific prefixes.
The 'domain-id' command defines the OSPF domain identifier.
Why this answer
The domain-identifier for OSPF (often used in MPLS VPNs or inter-AS scenarios) is configured under protocols ospf using the domain-id statement.
A BGP routing policy on a Junos router uses an 'as-path' regular expression '^[0-9]+$' in a match condition. Which routes will this regular expression match?
The anchors ^ and $, combined with digits and plus sign, match exactly a single AS number in the path.
Why this answer
The regex '^[0-9]+$' matches an AS path that consists of exactly one autonomous system number (from the beginning to the end of the path string).
When configuring a hierarchical scheduler map on an MX Series router, what is the primary purpose of the aggregate level shaping?
Aggregate shaping controls the sum of all traffic belonging to the child schedulers.
Why this answer
Aggregate level shaping controls the total bandwidth allocated to a group of queues or sub-interfaces, ensuring overall traffic limits are respected.
You are troubleshooting a scenario where an MX Series router running an EVPN-VXLAN instance receives Type-2 routes from a remote PE, but the local data plane fails to install the forwarding entries because of a mismatch in encapsulation types. Where is the encapsulation type for VXLAN defined within a Junos EVPN instance?
Encapsulation vxlan is configured directly inside the routing instance or switch options block.
Why this answer
In Junos OS, the encapsulation for the routing instance or switch options is defined using the 'encapsulation vxlan' statement under the routing-instance or switch-options hierarchy.
An enterprise network operates VSTP across 150 VLANs. The network engineering team notices high CPU utilization on the Routing Engine due to VSTP BPDU processing. Which Junos command or feature can mitigate this control-plane load while keeping VSTP operational?
Increasing the hello-time interval reduces the frequency of BPDU transmissions and processing overhead.
Why this answer
BPDU rate-limiting or adjusting VSTP hello timers helps reduce control-plane processing overhead. In Junos, VSTP timer tuning and bpdu processing limits control overhead.
Which command allows you to view the configured drop-profile statistics and monitor packet drop counts on an MX Series router?
This command shows drop-profile states and drop counters.
Why this answer
The show class-of-service drop-profile command displays drop-profile utilization and drop statistics.
Which TWO operational commands are valid for troubleshooting VSTP on Juniper EX switches? (Choose two)
Displays VSTP status per VLAN.
Why this answer
show vstp and show vstp vlan are valid operational commands for VSTP.
An engineer needs to verify which multicast groups have active receivers joined on an interface using IGMP. Which operational command should be used?
This command displays the multicast groups and receiver memberships learned via IGMP.
Why this answer
The 'show igmp group' command lists the multicast groups joined on interfaces via IGMP.
You are configuring a voice VLAN on an EX Series switch access port where an IP phone is connected in series with a PC. Which configuration is required on the switch interface to handle both tagged voice traffic and untagged data traffic?
Using an access port with a voice VLAN allows untagged PC traffic to fall into the native VLAN while tagged phone traffic uses the voice VLAN.
Why this answer
IP phones typically act as a mini-switch, requiring an access port configured with a native VLAN for the PC and a voice VLAN for the phone's tagged traffic.
Which command should an engineer use on a Junos device to verify whether a BGP next hop is successfully resolved via the routing table?
This command is specifically designed to inspect BGP next-hop resolution state in Junos.
Why this answer
The 'show route protocol bgp next-hop' command displays all BGP next hops and indicates whether they are resolved in the routing table.
In an enterprise network running PIM sparse-mode, an engineer notices that multicast traffic is switched from the shared tree (*,G) to the source-specific tree (S,G) prematurely, causing micro-bursts on core links. Which command disables this automatic switchover behavior on a Junos router?
Setting the SPT threshold to infinity prevents the last-hop router from switching to the source-specific tree, keeping it on the shared tree.
Why this answer
By default, last-hop routers switch from (*,G) to (S,G) upon receiving the first packet from source S. To prevent this, the 'spt-threshold infinity' command is configured under [edit protocols pim].
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