The exhibit shows an OSPF network where Area 1 is configured as a Not-So-Stubby Area (NSSA). R5 is an Autonomous System Boundary Router (ASBR) injecting an External Route (203.0.113.0/24) into this area.

NSSA ASBR Behavior (Option D): Within an OSPF NSSA, external routes cannot be advertised as standard Type 5 LSAs because stubby areas do not support them. Instead, the ASBR (R5) advertises the external prefix using a Type 7 LSA (NSSA External LSA). This LSA is flooded throughout Area 1.

ABR Translation Behavior (Option C): When the Type 7 LSA reaches the Area Border Router (R1), the ABR is responsible for translating it into a Type 5 LSA (AS External LSA). This allows the external route to be propagated into the backbone (Area 0) and subsequently to the rest of the OSPF domain.

Incorrect Statements (A & B): Option A is incorrect because Type 7 LSAs are local to the NSSA and are never advertised into Area 0. Option B is incorrect because Type 5 LSAs are strictly prohibited within an NSSA.

In BGP path selection, the Local Preference attribute is one of the most common ways to influence outbound traffic from an Autonomous System (AS). It is a well-known discretionary attribute that is propagated throughout the AS to tell internal routers which path is preferred for a specific destination.

Priority Rule: In the BGP selection algorithm, a higher local preference value is always preferred over a lower one. The default value in Junos OS is 100.

Influencing Outbound Traffic (Option A): To ensure that Provider A is always preferred, you would apply an import policy on R1 (the router connected to Provider A) to set the local preference of all received routes to a value higher than the default (e.g., 200). Since 200 > 100, R3 and R4 will prefer the path via R1.

Alternative Method (Option C): Conversely, you can achieve the same result by applying an import policy on R2 (the router connected to Provider B) to set the local preference to a value lower than the default (e.g., 50). Since the routes from R1 remain at the default of 100, and 100 > 50, the path via R1 (Provider A) is preferred.

Why B and D are incorrect: Setting a higher local preference on R2 (Option B) would make Provider B the preferred exit point. Setting a lower local preference on R1 (Option D) would make Provider A the least preferred exit point.

In a standard campus deployment on Juniper EX Series switches involving VoIP phones and 802.1X authentication, understanding the default behavior of Junos OS 24.4 is critical:

Voice VLAN (Option A): By default, an access port belongs to a single VLAN (the native or data VLAN). For an IP phone to operate correctly on the same physical port as a PC, a Voice VLAN must be explicitly configured and associated with the interface. This allows the switch to segregate voice traffic (usually tagged) from data traffic (untagged).

802.1X Configuration (Option D): Access ports do not have 802.1X authentication enabled by default. To enforce network access control for the client PCs, you must manually enable and configure the dot1x protocol on all relevant interfaces.

PoE Default (Option B): On EX Series switches that support PoE (like P or MP models), PoE is enabled by default on all PoE-capable ports. Therefore, additional configuration is generally not required unless you need to change power priorities or management modes.

LLDP Default (Option C): Standard LLDP is typically enabled by default in the factory configuration of most EX Series switches to facilitate neighbor discovery. While LLDP-MED is used for VoIP, the core requirement for " deploying " the described environment highlights the manual steps of VLAN and security setup rather than protocol discovery which often runs out-of-the-box.

OSPF determines the best path to a destination by calculating the metric (cost) of each link. By default, Junos OS uses a reference bandwidth of 100 Mbps to calculate this cost using the formula:

When the reference bandwidth is left at the default 100 Mbps, any interface with a speed of 100 Mbps or higher (including 1 GbE and 10 GbE) is assigned a cost of 1 because the minimum OSPF cost is 1. This results in equal-cost paths, preventing the router from preferring the faster 10 GbE link.

To ensure 10 GbE interfaces are preferred, you must create a cost differential:

Option A (Reference Bandwidth): By increasing the reference bandwidth to 10G (or higher), the calculation changes. For a 10 GbE link, the cost becomes $10,000 / 10,000 = 1$. For a 1 GbE link, the cost becomes $10,000 / 1,000 = 10$. Since OSPF prefers the path with the lowest cumulative cost, the 10 GbE link is now preferred.

Option D (Manual Metric): You can manually override the automatic cost calculation by assigning a higher metric specifically to the 1 GbE interfaces. If a 1 GbE interface is manually set to a cost of 50 and the 10 GbE interface remains at 1 (or is set to a lower value), the router will prioritize the 10 GbE path.

Option B is incorrect because a higher metric makes a path less preferred. Option C is incorrect because a 1G reference bandwidth would still result in both 1 GbE and 10 GbE interfaces having a cost of 1.

In an EVPN-VXLAN environment, different BGP route types serve distinct purposes in building the control plane. The Ethernet Segment Identifier (ESI) is a unique 10-byte identifier used to represent a multi-homed segment.

Type 1: Ethernet Auto-Discovery (A-D) Route (Option A): This route type is essential for multi-homing scenarios. It carries the ESI to support features like fast convergence and aliasing. By advertising an A-D route per Ethernet Segment, a PE tells other routers that it is connected to that specific ESI. It does not carry individual host MAC addresses; instead, it provides a " mass withdraw " mechanism to quickly update paths if the entire segment goes down.

Type 4: Ethernet Segment Route (Option D): This route is used exclusively for Designated Forwarder (DF) election. It advertises the existence of an ESI and the ES-Import Route Target to all other PE routers. This allows PE routers connected to the same multi-homed segment to discover each other automatically and elect a DF to handle BUM traffic. Like Type 1, it focuses on the segment identity and does not include MAC addresses.

Type 2: MAC/IP Advertisement Route (Option B): This is the primary route used for host reachability. It must include a MAC address (and optionally an IP). While it also includes the ESI to indicate which segment the host is behind, its primary function is MAC advertisement.

Type 3: Inclusive Multicast Ethernet Tag Route (Option C): This route is used for VTEP discovery and building the replication list for BUM traffic. It identifies the VTEP ' s IP and the VNI, but it does not carry the ESI or MAC addresses.

The exhibit shows the Class of Service (CoS) transmit queue information for interface ge-0/0/11. To determine the correct behavior, we must analyze the bandwidth allocations and the queue limit settings:

Bandwidth Calculation (Option A): In Junos OS, when multiple queues are assigned specific percentages of bandwidth, the " remainder " (represented by ' r ' ) is the total interface bandwidth minus the sum of the explicitly configured percentages.

Bandwidth assigned to Queue 1 (EF) = 10%.

Bandwidth assigned to Queue 2 (AF) = 10%.

Bandwidth assigned to Queue 3 (NC) = 4%.

Total explicitly assigned = $10\% + 10\% + 4\% = 24\%$.

Remainder for Queue 0 (Best Effort) = $100\% - 24\% = 76\%$.

" Limit: exact " Behavior (Option B): The exhibit shows that Queue 2 (assured-forwarding) has a Limit set to exact.

By default, a queue in Junos can consume more than its allocated bandwidth if other queues are idle.

However, when the exact keyword is applied to the transmit-rate (transmission rate), the queue is strictly rate-limited to its configured percentage.

This means that traffic in Queue 2 will be capped at 10% of the interface bandwidth regardless of whether the network is congested or not. If the traffic exceeds 10%, the excess will be dropped or buffered to match the exact rate.

Option C is incorrect because 100% of the bandwidth is not reserved for a single queue; it is distributed across four queues.

Option D is less accurate than B because it implies the drop behavior only occurs during congestion. The exact parameter enforces the limit even when the rest of the interface is completely idle.

When integrating a QFX Series switch into an EVPN-VXLAN IP fabric, specific BGP and EVPN hierarchy configurations are required to establish the control and data planes:

EVPN Encapsulation (Option A): In Junos OS, the encapsulation vxlan statement must be explicitly configured under the protocols evpn hierarchy. This defines that the EVPN control plane will use VXLAN as the data plane encapsulation method rather than MPLS.

BGP Address Family (Option C): EVPN uses Multiprotocol BGP (MP-BGP) to distribute reachability information. For the control plane to function, you must enable the EVPN signaling address family under the BGP protocol using the command set protocols bgp group < name > family evpn signaling.

Incorrect Options: Option B is incorrect because family vpls is used for traditional VPLS signaled by BGP, not for EVPN-VXLAN. Option D is incorrect because while the loopback interface must be reachable, it is typically advertised via an IGP (like OSPF or IS-IS) to provide the underlay connectivity that BGP then rides upon; BGP itself does not " advertise " the loopback to establish the initial peerings.

The exhibit shows the MSTP configuration for two switches, switch1 and switch2. MSTP allows you to group multiple VLANs into a single Multiple Spanning Tree Instance (MSTI), enabling different root bridges and topologies for different sets of VLANs.

Root Bridge Election (Option B): For any Spanning Tree instance, the switch with the lowest bridge priority is elected as the root bridge.

For msti 2, switch1 has a priority of 4k (4096), while switch2 has a priority of 8k (8192).

Since 4096 < 8192, switch1 is elected the root bridge for msti 2.

Failover Behavior (Option D): Spanning Tree is designed for redundancy. If a primary root bridge fails, the remaining switches in the network re-elect a new root based on the next lowest priority.

If switch2 goes down, switch1 becomes the only switch in the region.

Regardless of its original priority (4k or 8k), switch1 will take over as the root bridge for both msti 1 and msti 2 because there are no other contenders with a better (lower) priority.

Incorrect Statements: Option A is incorrect because for msti 1, switch2 has the lower priority (4k vs. 8k), making switch2 the root bridge. Option C is incorrect because it contradicts the fundamental high-availability nature of Spanning Tree.

In a three-stage EVPN-VXLAN fabric (Spine-Leaf architecture) where leaf devices perform the gateway services (Edge-Routed Bridging or ERB):

VTEP Functionality (Option B): Leaf devices act as VXLAN Tunnel End Points (VTEPs). They are responsible for encapsulating Ethernet frames from locally connected hosts into VXLAN packets for transport across the IP fabric and de-encapsulating incoming VXLAN packets.

Fabric Support (Option C): In a standard Juniper IP fabric design, both the leaf and spine devices are typically expected to support VXLAN and EVPN capabilities. While spines in an ERB design might only perform IP forwarding in the underlay, they often participate in the BGP control plane (as Route Reflectors) or provide the ability to transition to Centrally-Routed Bridging (CRB) where spines would act as gateways.

Incorrect Options: Option A is incorrect because the entire fabric infrastructure must be " VXLAN aware " in terms of MTU settings and routing capability to support the overlay. Option D is incorrect because in an ERB design, the spine devices are high-speed transit nodes and do not terminate VXLAN tunnels; only the edge (leaf) devices act as VTEPs.