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JNCIP-DC practice questions

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Question 1Data Center Architecture and Deployment

In an EVPN-VXLAN data center fabric, which EVPN route type advertises the mapping between a tenant MAC address and the VTEP that learned it?

  1. Type 2 route Correct answer.
  2. Type 3 route
  3. Type 5 route
  4. Type 1 route

Explanation

Type 2 (MAC/IP advertisement) routes carry the MAC address and optionally the IP address of a host along with the VTEP next hop, enabling MAC learning across the fabric. Type 3 handles BUM traffic via inclusive multicast, Type 1 handles auto-discovery and split horizon, and Type 5 handles IP prefixes.

Question 2Data Center Architecture and Deployment

Which Junos configuration family must be enabled on the physical interface toward the fabric before an EVPN-VXLAN encapsulation can be used on that interface?

  1. inet
  2. bridge
  3. ethernet-switching Correct answer.
  4. mpls

Explanation

EVPN-VXLAN data center designs use a Layer 2 bridge domain over an Ethernet switching interface, so the physical port must carry the ethernet-switching family. The inet family is for routed ports, mpls is for label switching, and bridge is used on the VLAN/IRB side rather than the access port.

Question 3Data Center Architecture and Deployment

What is the primary purpose of a spine layer in a two-tier IP fabric for a data center?

  1. To act as the Layer 2 access layer for server connections
  2. To provide high-speed any-to-any forwarding between leaf switches Correct answer.
  3. To terminate all tenant VLANs and host the default gateway
  4. To run the EVPN route reflector and MAC learning functions

Explanation

Spines form the backbone of the fabric and are typically unconfigured for tenant services, providing equal-cost multipath forwarding between leaves. Leaf switches, not spines, terminate tenant VLANs and host default gateways, and servers connect to leaves.

Question 4Data Center Architecture and Deployment

Which Junos feature is used to automatically assign a switch to a specific Virtual Chassis or fabric role based on its serial number during zero-touch provisioning?

  1. Autoinstallation with DHCP and a configuration file
  2. Commit scripts triggered by SNMP
  3. Event policies matching syslog patterns
  4. ZTP with a pre-provisioned serial number in the configuration Correct answer.

Explanation

Zero-touch provisioning (ZTP) can map a device's serial number to a pre-provisioned configuration, allowing the switch to receive its fabric role automatically when it boots. Autoinstallation relies on DHCP options and a generic file, not serial-based role assignment, and commit scripts and event policies do not perform initial role assignment.

Question 5Data Center Architecture and Deployment

In an EVPN-VXLAN fabric using a distributed anycast gateway, what property allows a host to retain its default gateway MAC address when it migrates between leaves?

  1. The gateway uses a unique MAC per leaf and relies on ARP suppression
  2. The gateway MAC is derived from the VNI and is identical on every leaf Correct answer.
  3. The gateway uses the physical interface MAC of the local leaf
  4. The gateway MAC is learned dynamically through Type 2 routes

Explanation

A distributed anycast gateway uses the same virtual MAC address on every leaf, so a host that moves to a different leaf keeps the same gateway MAC and does not need to re-ARP. ARP suppression does not change the gateway MAC, and Type 2 routes carry host MACs rather than the gateway MAC.

Question 6Data Center Architecture and Deployment

Which protocol provides loop-free Layer 2 multipathing and replaces STP in a Junos EVPN-VXLAN data center fabric?

  1. VSTP
  2. MSTP
  3. RSTP
  4. EVPN multihoming with ESI Correct answer.

Explanation

EVPN multihoming uses Ethernet Segment Identifiers to allow a host or server to connect to multiple leaves with active-active forwarding and no spanning tree blocking. RSTP, MSTP, and VSTP are spanning tree variants that block redundant links rather than enabling multipathing.

Question 7Data Center Architecture and Deployment

What is the role of the VXLAN Network Identifier (VNI) in an EVPN-VXLAN fabric?

  1. It identifies the BGP autonomous system
  2. It identifies the physical VTEP interface
  3. It identifies the Layer 2 or Layer 3 segment carried in the VXLAN header Correct answer.
  4. It identifies the route reflector cluster

Explanation

The 24-bit VNI in the VXLAN header identifies the tenant Layer 2 or Layer 3 segment so that traffic is scoped to the correct bridge domain or routing instance. It does not identify physical interfaces, autonomous systems, or route reflector clusters.

Question 8Data Center Architecture and Deployment

Which statement correctly describes the function of an IRB interface in a Junos EVPN-VXLAN leaf?

  1. It provides the underlay BGP peering address
  2. It provides the Layer 3 gateway for a VLAN and can be associated with a VNI Correct answer.
  3. It provides the VXLAN tunnel endpoint address
  4. It provides the Ethernet segment identifier for multihoming

Explanation

An integrated routing and bridging (IRB) interface acts as the Layer 3 gateway for a VLAN and, in EVPN-VXLAN, is mapped to a Layer 3 VNI for inter-subnet routing. The VTEP address, BGP peering address, and ESI are separate constructs.

Question 9Data Center Architecture and Deployment

In a Junos EVPN-VXLAN fabric, which configuration statement enables the mapping of a VLAN to a VNI?

  1. set vlans v100 vxlan vni 10100 Correct answer.
  2. set protocols evpn encapsulation vxlan
  3. set switch-options vtep-source-interface lo0.0
  4. set vlans v100 vlan-id 100

Explanation

The vxlan vni statement under the VLAN assigns the VNI that will be used in the VXLAN header for that VLAN's traffic. The vlan-id statement only sets the local VLAN tag, the vtep-source-interface sets the tunnel source, and the evpn encapsulation statement enables the EVPN protocol encapsulation but does not map a VLAN to a VNI.

Question 10Data Center Architecture and Deployment

What is the purpose of ARP suppression in an EVPN-VXLAN fabric?

  1. To encrypt ARP traffic between VTEPs
  2. To reduce BUM traffic by answering ARP requests locally from the EVPN database Correct answer.
  3. To convert ARP requests into Type 5 routes
  4. To load-balance ARP requests across spines

Explanation

ARP suppression lets a leaf answer ARP requests for known remote hosts using MAC/IP bindings learned from Type 2 routes, reducing flooded ARP traffic across the fabric. It does not encrypt traffic, load-balance across spines, or convert ARP into Type 5 routes.

Question 11Data Center Architecture and Deployment

Which BGP address family must be negotiated between VTEPs to carry EVPN routes in a Junos EVPN-VXLAN fabric?

  1. l2vpn
  2. evpn Correct answer.
  3. inet6
  4. inet-vpn

Explanation

EVPN routes such as Type 2 and Type 3 are carried in the BGP EVPN address family, configured under the BGP group. The inet-vpn family carries Layer 3 VPN routes, l2vpn carries VPLS routes, and inet6 carries IPv6 unicast routes.

Question 12Data Center Architecture and Deployment

In a Junos EVPN-VXLAN fabric, which interface is typically used as the source for VXLAN tunnels and the BGP peering address?

  1. The physical uplink toward the spine
  2. The loopback interface lo0 Correct answer.
  3. The IRB interface
  4. The management interface me0

Explanation

The loopback interface provides a stable, always-up address used as the VTEP source and BGP peering endpoint. The management interface is out-of-band, the IRB is the tenant gateway, and physical uplinks can fail, making them unsuitable as stable tunnel sources.

Question 13Data Center Architecture and Deployment

Which statement about the underlay network in a Junos EVPN-VXLAN fabric is correct?

  1. It must run a Layer 2 protocol to extend VLANs between leaves
  2. It must run OSPF or IS-IS or BGP to advertise loopback reachability Correct answer.
  3. It must run STP to prevent loops between spines
  4. It must use MPLS labels to reach remote VTEPs

Explanation

The underlay is a Layer 3 routed fabric that advertises loopback addresses so VTEPs can reach each other; OSPF, IS-IS, or BGP are typical choices. It does not extend VLANs, does not require MPLS, and does not run STP between spines.

Question 14Data Center Architecture and Deployment

What does an Ethernet Segment Identifier (ESI) represent in EVPN multihoming?

  1. A unique identifier for a BGP route reflector cluster
  2. A unique identifier for a set of links connecting a host to multiple leaves Correct answer.
  3. A unique identifier for a leaf's loopback address
  4. A unique identifier for a tenant VNI

Explanation

An ESI identifies an Ethernet segment, which is a set of links from a host or server to multiple leaf switches that are treated as one logical segment. It is not a loopback address, a VNI, or a route reflector cluster identifier.

Question 15Data Center Architecture and Deployment

A design requires inter-subnet routing between two VLANs on different leaves in an EVPN-VXLAN fabric. Which combination is required?

  1. Layer 2 VNI with STP between leaves
  2. Layer 2 VNI only with ARP suppression
  3. Layer 3 VNI with MPLS encapsulation
  4. Layer 3 VNI with a routing instance and an IRB per VLAN Correct answer.

Explanation

Inter-subnet routing needs a Layer 3 VNI associated with a routing instance and IRB interfaces for each VLAN so the leaf can route between subnets and encapsulate the result. A Layer 2 VNI alone only bridges within a subnet, STP does not provide routing, and MPLS is not used in this design.

Question 16Data Center Architecture and Deployment

Which Junos configuration enables a leaf to act as a VTEP and participate in EVPN signaling for VXLAN?

  1. set protocols evpn encapsulation vxlan Correct answer.
  2. set protocols bgp group fabric type internal
  3. set vlans v100 l3-interface irb.100
  4. set switch-options vtep-source-interface lo0.0

Explanation

The protocols evpn encapsulation vxlan statement enables EVPN signaling with VXLAN encapsulation, allowing the device to act as a VTEP. BGP group configuration, VTEP source interface, and IRB assignment are supporting pieces but do not by themselves enable EVPN-VXLAN signaling.

Question 17Data Center Architecture and Deployment

What is the benefit of using a Layer 3 IP fabric underlay compared with a traditional Layer 2 access/aggregation design in the data center?

  1. It allows VLANs to span all switches without configuration
  2. It reduces the number of required loopback addresses
  3. It eliminates the need for any overlay protocol
  4. It provides active-active multipathing with predictable latency and no STP blocking Correct answer.

Explanation

A routed IP fabric uses equal-cost multipath to utilize all links actively, avoids spanning tree blocking, and gives predictable hop count and latency. It does not eliminate the need for an overlay, does not reduce loopback requirements, and does not automatically extend VLANs.

Question 18Data Center Architecture and Deployment

In a Junos EVPN-VXLAN fabric, which route type is used to advertise the inclusive multicast tree for BUM traffic replication?

  1. Type 1
  2. Type 3 Correct answer.
  3. Type 2
  4. Type 4

Explanation

Type 3 inclusive multicast Ethernet tag routes advertise the VTEPs that participate in a VNI so BUM traffic can be replicated to them. Type 1 handles auto-discovery, Type 2 handles MAC/IP advertisement, and Type 4 handles Ethernet segment designation.

Question 19Data Center Architecture and Deployment

Which mechanism elects the designated forwarder for a multihomed Ethernet segment in EVPN?

  1. Type 5 IP prefix routes with the lowest metric
  2. Type 4 Ethernet segment routes exchanged between the multihoming leaves Correct answer.
  3. Type 3 inclusive multicast routes with the highest VTEP address
  4. Type 2 MAC routes with the highest local preference

Explanation

Type 4 Ethernet segment routes are exchanged among the leaves attached to the same segment, and the designated forwarder is elected based on the advertised attributes. Type 2, Type 3, and Type 5 routes serve MAC advertisement, BUM replication, and IP prefix advertisement respectively.

Question 20Data Center Architecture and Deployment

What is the purpose of a route reflector in a large EVPN-VXLAN fabric?

  1. To encapsulate VXLAN traffic between VTEPs
  2. To provide Layer 2 bridging between VLANs
  3. To reduce the number of BGP sessions by reflecting EVPN routes between leaves Correct answer.
  4. To assign VNIs to VLANs automatically

Explanation

A route reflector reduces full-mesh BGP peering requirements by reflecting EVPN routes among leaves, improving scalability. It does not bridge VLANs, encapsulate VXLAN traffic, or assign VNIs.

Question 21Data Center Architecture and Deployment

Which statement about MAC learning in an EVPN-VXLAN fabric with a controller-less design is correct?

  1. MAC learning requires a centralized SDN controller
  2. Leaves learn local MACs and advertise them in Type 2 routes to other leaves Correct answer.
  3. MACs are learned only through STP topology changes
  4. Spines learn all MACs and advertise them to leaves

Explanation

In a controller-less EVPN-VXLAN fabric, each leaf learns MACs on its local interfaces and advertises them via Type 2 routes so remote leaves can program them. Spines do not learn tenant MACs, no central controller is required, and STP is not used for MAC learning.

Question 22Data Center Architecture and Deployment

Which Junos command displays the EVPN database entries learned on a leaf switch?

  1. show ethernet-switching table
  2. show bridge mac-table
  3. show evpn database Correct answer.
  4. show route table bgp.evpn.0

Explanation

The show evpn database command displays the EVPN MAC/IP entries, including local and remote bindings learned through EVPN. The BGP table shows routes rather than the EVPN database, and the Ethernet switching table shows local Layer 2 forwarding entries.

Question 23Data Center Architecture and Deployment

A leaf in an EVPN-VXLAN fabric must route traffic between two VLANs that are both present on the same leaf. Which configuration element provides the local gateway addresses for both VLANs?

  1. A single IRB interface shared by both VLANs
  2. Two IRB interfaces, one per VLAN, each associated with the respective VLAN Correct answer.
  3. A loopback interface with two addresses
  4. A VTEP source interface with two addresses

Explanation

Each VLAN needs its own IRB interface with a gateway address so the leaf can route between the subnets locally. A single shared IRB cannot serve two VLANs, and loopback or VTEP source interfaces are not tenant gateways.

Question 24Data Center Architecture and Deployment

What does the anycast VTEP concept provide in a Junos EVPN-VXLAN fabric?

  1. Each leaf uses a unique VTEP address per VLAN
  2. Spines act as the VTEP for all leaves
  3. The VTEP address changes when a host migrates
  4. Multiple leaves share a common VTEP IP address for a VNI to simplify multihoming Correct answer.

Explanation

Anycast VTEP allows multiple leaves attached to the same Ethernet segment to share a common VTEP IP for a VNI, simplifying multihoming and host mobility. Unique per-VLAN VTEPs, spine-based VTEPs, and changing VTEP addresses on migration are not characteristics of anycast VTEP.

Question 25Data Center Architecture and Deployment

Which factor determines the underlay ECMP path selection between a leaf and a spine in a Junos IP fabric?

  1. The routing protocol's equal-cost multipath calculation over loopback prefixes Correct answer.
  2. The BGP local preference of the EVPN route
  3. The VNI value assigned to the VLAN
  4. The ESI value of the multihomed segment

Explanation

Underlay ECMP is determined by the routing protocol installing multiple equal-cost next hops toward loopback prefixes, and traffic is hashed across them. BGP local preference, VNI values, and ESI values do not determine underlay path selection.

Question 26Data Center Architecture and Deployment

In a Junos EVPN-VXLAN data center fabric, which statement correctly describes the purpose of the route distinguisher (RD) configured under the EVPN routing instance?

  1. It sets the BGP extended community that determines the designated forwarder election for multihomed segments.
  2. It identifies the global VXLAN network identifier that maps the VLAN to the VNI in the forwarding path.
  3. It defines the anycast VTEP loopback address used as the source for VXLAN encapsulation.
  4. It uniquely identifies the EVPN instance within the local PE so that overlapping MAC or IP addresses from different EVPN instances remain distinct in BGP. Correct answer.

Explanation

The route distinguisher is prepended to EVPN routes to create unique VPN-IPv4 or MAC-VRF NLRI entries, allowing the same MAC or IP address to exist in multiple EVPN instances without collision. It does not select a VNI, influence DF election, or define a tunnel source.

Question 27Data Center Architecture and Deployment

A Junos leaf switch is configured with an anycast gateway address shared across all leaves for a given VLAN. What is the primary benefit of this design when a virtual machine migrates between leaves?

  1. The VXLAN tunnel endpoint address changes automatically to the new leaf loopback, which speeds up BUM replication.
  2. The default gateway MAC and IP remain the same on the new leaf, so the VM keeps its ARP cache and does not need to re-ARP after migration. Correct answer.
  3. The underlay routing protocol reconverges faster because the anycast address is advertised into OSPF.
  4. The EVPN route type 2 advertisement is suppressed until the VM sends a gratuitous ARP from the new location.

Explanation

With a distributed anycast gateway, every leaf uses the same virtual MAC and IP for the gateway, so a migrated VM sees no change in its default gateway and can continue using its existing ARP entry. This avoids a re-ARP storm and reduces disruption during live migration.

Question 28Data Center Architecture and Deployment

Which Junos feature allows a leaf to advertise a single virtual VTEP IP address for a multihomed Ethernet segment so that remote VTEPs can send traffic to any participating leaf?

  1. Static VXLAN tunnel with a fixed remote VTEP
  2. PIM-SM anycast rendezvous point
  3. VXLAN-GPE with a shared outer destination port
  4. Anycast VTEP with an ESI-based aliasing model Correct answer.

Explanation

An anycast VTEP address is shared by the leaves attached to the same Ethernet segment, and EVPN aliasing allows remote VTEPs to use that address for active-active forwarding toward the segment. This provides redundancy and load sharing without requiring per-leaf remote VTEP configuration.

Question 29Data Center Architecture and Deployment

In a Junos EVPN-VXLAN fabric, which configuration parameter must match on all leaf switches for a given VLAN to be part of the same EVPN bridge domain?

  1. The OSPF area number used in the underlay
  2. The VXLAN source port range
  3. The VXLAN network identifier (VNI) mapped to that VLAN Correct answer.
  4. The BGP router ID of each leaf

Explanation

The VNI is the global identifier for the EVPN bridge domain; all leaves that participate in the same Layer 2 domain must map the VLAN to the same VNI so that frames are encapsulated with the correct identifier. Router IDs, OSPF areas, and source port ranges are local or underlay parameters and do not define the EVPN bridge domain.

Question 30Data Center Architecture and Deployment

A network designer is choosing an underlay routing protocol for a large Junos EVPN-VXLAN fabric. Which statement best explains why EBGP is often preferred over OSPF for the underlay?

  1. EBGP automatically advertises EVPN routes without needing a separate address family.
  2. EBGP provides explicit policy control and scalable multipath with clear administrative boundaries between leaf and spine. Correct answer.
  3. EBGP guarantees sub-second convergence without any tuning.
  4. EBGP eliminates the need for a loopback address on each leaf.

Explanation

EBGP underlay designs give operators granular policy control, deterministic path selection, and good ECMP scaling while keeping leaf and spine roles distinct. OSPF can also be used, but EBGP is often chosen for its policy and scaling characteristics in large fabrics.

Question 31Data Center Architecture and Deployment

Which Junos command displays the EVPN route type 2 (MAC/IP advertisement) entries learned by a leaf switch?

  1. show ethernet-switching table
  2. show evpn database Correct answer.
  3. show route table bgp.evpn.0
  4. show vxlan tunnel

Explanation

The show evpn database command lists MAC and IP addresses learned through EVPN, including the associated VNI and remote VTEP. It is the primary operational command for verifying Layer 2 EVPN learning on a leaf.

Question 32Data Center Architecture and Deployment

In a Junos EVPN-VXLAN fabric, a leaf is configured with a VLAN that has no local access ports but must still route traffic for that subnet. Which interface type should be configured to provide the default gateway for that VLAN?

  1. An IRB interface with the gateway IP address in the VLAN Correct answer.
  2. A VXLAN tunnel interface without an IP address
  3. A loopback interface with the gateway IP address
  4. A physical access port in the VLAN

Explanation

An IRB (integrated routing and bridging) interface provides Layer 3 termination for a VLAN and acts as the default gateway, even when no local access ports exist. The IRB is associated with the VLAN and the VNI so that routing can occur across the EVPN fabric.

Question 33Data Center Architecture and Deployment

Which statement correctly describes the role of the route target (RT) in a Junos EVPN-VXLAN fabric?

  1. It controls which EVPN routes are imported into which EVPN routing instance on a receiving PE. Correct answer.
  2. It uniquely identifies the local EVPN instance in the BGP NLRI.
  3. It elects the designated forwarder for a multihomed Ethernet segment.
  4. It defines the VXLAN UDP destination port for encapsulated traffic.

Explanation

Route targets are extended communities attached to EVPN routes; the receiving PE imports routes whose RT matches the import target configured for its EVPN instance. This controls the topology of EVPN membership across the fabric.

Question 34Data Center Architecture and Deployment

A Junos leaf is receiving EVPN type 5 (IP prefix) routes from remote leaves. Which configuration is required for the leaf to install those routes into the inet.0 routing table for inter-subnet forwarding?

  1. A VXLAN tunnel interface with a static route to the remote VTEP.
  2. An OSPF area that includes the remote prefix.
  3. A firewall filter that permits BGP port 179.
  4. An EVPN routing instance with a VRF target policy that imports the type 5 routes and a corresponding IRB or VRF interface. Correct answer.

Explanation

Type 5 routes are carried in the EVPN address family and must be imported into a VRF or EVPN routing instance via route targets, then associated with a routing interface so they can be used for forwarding. Without the VRF import policy and interface, the routes remain in the EVPN table and are not used for IP forwarding.

Question 35Data Center Architecture and Deployment

Which Junos statement is used under the EVPN routing instance to enable the exchange of EVPN routes with a BGP peer?

  1. family evpn signaling Correct answer.
  2. family vpls
  3. family bridge
  4. family inet unicast

Explanation

The family evpn signaling statement under the BGP group or neighbor enables the EVPN address family, allowing the router to send and receive EVPN NLRI. This is required for VTEPs to exchange MAC/IP and inclusive multicast routes.

Question 36Data Center Architecture and Deployment

In a Junos EVPN-VXLAN fabric, what is the purpose of the VXLAN tunnel endpoint (VTEP) source interface?

  1. It provides the destination IP address for VXLAN-encapsulated frames.
  2. It provides the multicast group address for BUM replication.
  3. It provides the MAC address used for the anycast gateway.
  4. It provides the source IP address used in the outer VXLAN header and the BGP peering address for EVPN. Correct answer.

Explanation

The VTEP source interface, typically a loopback, supplies the source IP for VXLAN encapsulation and is also used as the BGP peering address for EVPN. Remote VTEPs use this address as the destination when sending traffic back.

Question 37Data Center Architecture and Deployment

A network engineer is troubleshooting an EVPN-VXLAN fabric where a leaf is not learning remote MAC addresses. Which two items should be verified first? (Choose the best single answer.)

  1. The route reflector has a unique cluster ID and the VXLAN source port range is configured.
  2. The OSPF hello timers match and the VXLAN UDP port is set to 4789.
  3. The EVPN BGP session is established and the evpn address family is negotiated, and the VNI is correctly mapped to the VLAN. Correct answer.
  4. The IRB interface has the correct MTU and the anycast gateway MAC is unique per leaf.

Explanation

Remote MAC learning depends on a working EVPN BGP session with the evpn family negotiated and on correct VNI-to-VLAN mapping on both ends. These are the fundamental prerequisites before investigating more advanced issues.

Question 38Data Center Architecture and Deployment

Which statement about the use of a Layer 3 IP fabric underlay in a Junos EVPN-VXLAN data center is correct?

  1. It requires VXLAN to be configured on every spine switch.
  2. It provides equal-cost multipathing at Layer 3 and eliminates the need for Spanning Tree Protocol in the underlay. Correct answer.
  3. It relies on TRILL to provide loop-free forwarding.
  4. It mandates the use of OSPF as the only supported routing protocol.

Explanation

A Layer 3 IP fabric uses routing protocols and ECMP to provide loop-free, multipath forwarding, so STP is not needed in the underlay. VXLAN and EVPN operate at the overlay, and the underlay can use OSPF, IS-IS, or BGP.

Question 39Data Center Architecture and Deployment

A Junos leaf is configured with an ESI for a multihomed Ethernet segment. Which mechanism ensures that only one of the multihomed leaves forwards broadcast traffic for that segment?

  1. Designated forwarder election based on the DF election extended community and ESI. Correct answer.
  2. VXLAN tunnel source port hashing.
  3. Spanning Tree Protocol root election across the segment.
  4. Anycast VTEP election based on the lowest router ID.

Explanation

EVPN uses the designated forwarder election process, signaled by the DF election extended community and the ESI, to choose one leaf to forward BUM traffic for a multihomed segment. This prevents duplicate broadcast, unknown unicast, and multicast frames from reaching the segment.

Question 40Data Center Architecture and Deployment

A designer is planning a Junos EVPN-VXLAN fabric where each leaf must be able to route between locally attached VLANs without sending inter-VLAN traffic to a spine. Which design element accomplishes this requirement?

  1. Static routes on each leaf pointing inter-VLAN traffic toward the spine loopback addresses
  2. A single shared IRB interface bound to all VLANs on each leaf, with one common VNI
  3. Layer 2 stretching of all VLANs to a dedicated services leaf that performs all inter-VLAN routing
  4. An integrated routing and bridging (IRB) interface per VLAN on each leaf, with a VXLAN Layer 3 VNI for each VLAN Correct answer.

Explanation

To route between VLANs locally, a leaf needs an IRB interface for each VLAN so it holds the gateway address, and each VLAN is mapped to its own Layer 3 VNI so routed traffic can cross the fabric when the destination is remote. Because every leaf has the gateway, inter-VLAN traffic for hosts on the same leaf is routed locally and never traverses a spine.

Question 41Data Center Switching and Fabric Technologies

In an EVPN-VXLAN fabric, which route type carries the MAC address and IP address pair that allows a leaf to suppress ARP flooding for known hosts?

  1. Type 3 route
  2. Type 4 route
  3. Type 5 route
  4. Type 2 route Correct answer.

Explanation

EVPN Type 2 (MAC/IP advertisement) routes carry the host MAC and optional IP, which lets remote leaves install ARP and MAC entries proactively. This is the mechanism behind ARP suppression in a VXLAN data center fabric.

Question 42Data Center Switching and Fabric Technologies

What is the primary purpose of a VXLAN Tunnel Endpoint (VTEP) in a data center fabric?

  1. To distribute IP prefixes between fabric underlay routers
  2. To manage spanning tree topology changes across the access layer
  3. To encapsulate and decapsulate tenant frames in VXLAN and map them to a VNI Correct answer.
  4. To elect a designated forwarder for a multihomed Ethernet Segment

Explanation

A VTEP originates and terminates VXLAN tunnels, adding or removing the VXLAN header and associating frames with the correct VNI. On Juniper devices this function is typically performed in the switching hardware of the leaf.

Question 43Data Center Switching and Fabric Technologies

Which Junos configuration element maps a VLAN to a VXLAN VNI on a leaf device?

  1. vni under the bridge-domain vlan stanza Correct answer.
  2. route-target under the routing-instance stanza
  3. esi under the interface stanza
  4. vlan-id under the switch-options vxlan stanza

Explanation

In Junos EVPN-VXLAN configuration, the VNI is bound to the VLAN inside the bridge domain using the vni statement under the vlan stanza. This association determines which VNI encapsulates frames belonging to that VLAN.

Question 44Data Center Switching and Fabric Technologies

A fabric uses EVPN multihoming. Which EVPN route type is used to elect the designated forwarder for an Ethernet Segment?

  1. Type 3 route
  2. Type 2 route
  3. Type 1 route
  4. Type 4 route Correct answer.

Explanation

Type 4 routes (Ethernet Segment routes) are advertised per Ethernet Segment and are used by all multihoming peers to run the designated forwarder election. The elected DF is the only peer that forwards BUM traffic to that segment.

Question 45Data Center Switching and Fabric Technologies

Which underlay routing design is most typical for a large IP fabric where every leaf must reach every other leaf with equal-cost paths?

  1. BGP confederation between leaves with no spine participation
  2. A hub-and-spoke OSPF design with the spines as stub areas
  3. Static routes on each leaf pointing only to its directly connected spine
  4. A single-area OSPF or IS-IS deployment with ECMP enabled on all spine-facing links Correct answer.

Explanation

A single-area IGP such as OSPF or IS-IS across the fabric, combined with ECMP, gives every leaf equal-cost paths through all spines. This provides predictable, loop-free underlay reachability between VTEP loopback addresses.

Question 46Data Center Switching and Fabric Technologies

What is the role of the anycast gateway address in an EVPN-VXLAN fabric?

  1. It provides the underlay loopback used for VXLAN tunnel source addresses
  2. It is the route reflector address used for BGP EVPN peering
  3. Each leaf uses a unique gateway MAC and IP so hosts must be tied to one leaf
  4. All leaves share the same gateway IP and MAC so a host can move between leaves without changing its default gateway Correct answer.

Explanation

An anycast gateway configures the same IP and virtual MAC on every leaf, so a host keeps the same default gateway regardless of which leaf it attaches to. This supports seamless virtual machine mobility across the fabric.

Question 47Data Center Switching and Fabric Technologies

A leaf must advertise tenant MAC addresses learned locally to remote leaves. Which routing instance type is used on Juniper devices to run EVPN for a Layer 2 stretch?

  1. mac-vrf
  2. no-forwarding
  3. evpn Correct answer.
  4. virtual-switch

Explanation

On Juniper devices, an evpn routing instance type carries the EVPN address family and is used with a bridge domain to advertise MAC and IP bindings. It provides the control plane for the Layer 2 stretch.

Question 48Data Center Switching and Fabric Technologies

Which statement correctly describes how a VXLAN-encapsulated frame traverses the underlay?

  1. The original Ethernet frame is rewritten with spine MAC addresses at each hop
  2. The original Ethernet frame is preserved inside the VXLAN payload and carried in a UDP packet over the IP underlay Correct answer.
  3. The original Ethernet frame is fragmented and reassembled by each spine
  4. The original Ethernet frame is carried in an MPLS label stack without IP headers

Explanation

VXLAN encapsulates the original Layer 2 frame in a UDP/IP packet, with the VNI identifying the tenant segment. The underlay only routes the outer IP packet between VTEP loopbacks.

Question 49Data Center Switching and Fabric Technologies

In a centrally routed EVPN-VXLAN design, which device performs inter-VLAN routing for tenant traffic?

  1. The top-of-rack server NIC
  2. A dedicated spine or service node acting as the Layer 3 gateway Correct answer.
  3. The route reflector
  4. The access leaf that first receives the frame

Explanation

In a centrally routed design, Layer 2 traffic is stretched to a central gateway, typically on a spine or dedicated service node, which performs inter-VLAN routing. Leaves act primarily as Layer 2 VTEPs.

Question 50Data Center Switching and Fabric Technologies

Which BGP EVPN route target configuration ensures that a VNI's routes are imported only by leaves that host the same tenant?

  1. A unique route target per VNI that matches on both export and import policies Correct answer.
  2. A route target equal to the underlay loopback address
  3. No route target, relying on the VNI alone
  4. A single route target shared by all VRFs in the fabric

Explanation

Route targets control which EVPN routes a leaf imports into a given routing instance. Assigning a per-VNI route target and matching it on import restricts tenant routes to the leaves that participate in that tenant.