300-410 Infrastructure Services Practice Test 14 — 15 Questions

Question 1

A network administrator is configuring a Cisco IOS XE router for MPLS Traffic Engineering (TE). The administrator wants to ensure that the router can signal an MPLS TE tunnel using RSVP. Which protocol must be enabled on the interfaces along the path to reserve bandwidth and distribute labels?

Choose an answer to begin — your selection is scored in the full session.

Accepted Answer

RSVP. MPLS Traffic Engineering requires RSVP to signal TE tunnels and reserve bandwidth along the path. RSVP-TE is an extension of RSVP that carries additional objects for traffic engineering, such as explicit route objects and label requests. It must be enabled on all interfaces that the tunnel traverses. While OSPF or IS-IS with TE extensions are used to advertise link attributes, and BGP may be used for routing, RSVP is the protocol that performs the actual signaling and resource reservation.

Answer

BGP

Answer

LDP

Answer

OSPF

Question 2

A network engineer is configuring a Cisco IOS router to support IPv6 OSPFv3. The engineer wants to enable OSPFv3 on an interface and ensure that it forms adjacencies with neighbors. Which command must be used to enable OSPFv3 on an interface?

Accepted Answer

ipv6 ospf 1 area 0. To enable OSPFv3 on a specific interface for IPv6, the interface configuration command ipv6 ospf 1 area 0 is used. This command assigns the interface to OSPFv3 process 1 and area 0, allowing it to form adjacencies. Global configuration commands only create the OSPFv3 process; interface activation is required for adjacency formation.

Answer

router ospfv3 1

Answer

ospfv3 1 ipv6 area 0

Answer

ipv6 router ospf 1

Question 3

A network engineer is deploying an MPLS L3VPN using BGP as the PE-CE routing protocol. The customer requires that the PE router accept only routes with a specific BGP community and set a local preference of 200 for those routes. Which configuration on the PE router accomplishes this requirement?

Accepted Answer

Configure a route-map that matches the community and sets local preference, then apply it as an inbound route-map under the BGP neighbor configuration for the CE.. Inbound route-maps on the PE-CE BGP session are the correct tool to match BGP communities and modify attributes such as local preference. They allow granular control over which routes are accepted and how they are treated within the VRF. Outbound route-maps affect advertisements, distribute-lists cannot set attributes, and the network command does not provide community-based filtering.

Answer

Configure a route-map that matches the community and sets local preference, then apply it as an outbound route-map under the BGP neighbor configuration for the CE.

Answer

Configure a distribute-list with an extended ACL that matches the community and sets local preference under the BGP process.

Answer

Use the BGP network command with a backdoor route to inject the routes with the desired local preference.

Question 4

A network engineer is configuring a Cisco IOS XE router as a Dynamic Multipoint VPN (DMVPN) Phase 3 hub. The hub must support spoke-to-spoke direct tunnels while allowing the hub to remain in the data path for initial spoke-to-spoke communication. The engineer has configured the tunnel interface with 'ip nhrp redirect' on the hub. Which additional command must be configured on the spoke routers to enable them to dynamically create direct tunnels to other spokes?

Accepted Answer

ip nhrp shortcut. In DMVPN Phase 3, the hub uses ip nhrp redirect to inform a spoke that a better path exists. The spoke must have ip nhrp shortcut configured to act on that redirect, install a shortcut route, and initiate a direct tunnel to the destination spoke. This combination allows dynamic spoke-to-spoke tunnels while the hub remains involved only for initial resolution.

Answer

ip nhrp map multicast dynamic

Answer

ip nhrp holdtime 300

Answer

ip nhrp network-id 100

Question 5

A network engineer is configuring a Cisco IOS XE router to support First Hop Redundancy Protocol (FHRP) for a group of hosts on VLAN 10. The design requires that the virtual IP address and virtual MAC address remain the same even if the active router changes. The engineer decides to use Virtual Router Redundancy Protocol (VRRP) version 2. Which statement about VRRPv2 is true?

Accepted Answer

VRRPv2 uses a virtual MAC address of 0000.0c07.acXX, where XX is the group ID in hexadecimal.. VRRPv2 uses the virtual MAC address 0000.0c07.acXX, where XX is the VRRP group ID in hexadecimal. This ensures a consistent virtual MAC for hosts, regardless of which physical router is master. The other statements are incorrect: VRRPv2 does not support IPv6 (that requires VRRPv3), it uses multicast 224.0.0.18 (not 224.0.0.2), and preemption can be disabled on any router, not just the master.

Answer

VRRPv2 allows preemption to be disabled only on the master router.

Answer

VRRPv2 supports IPv6 natively without any additional configuration.

Answer

VRRPv2 uses multicast address 224.0.0.2 for hello packets.

Question 6

A service provider is deploying MPLS Traffic Engineering (TE) with RSVP-TE to guarantee bandwidth for critical traffic. The network uses OSPF as the IGP with TE extensions enabled. An engineer notices that a TE tunnel fails to establish because the path computation cannot find a path with sufficient bandwidth, even though the physical links have enough capacity. Which action should the engineer take to ensure that RSVP-TE can reserve bandwidth on the links?

Accepted Answer

Enable MPLS TE on the physical interfaces and configure the ip rsvp bandwidth command with the appropriate reservable bandwidth.. RSVP-TE requires that MPLS TE be enabled on the physical interface and that the interface be configured with the ip rsvp bandwidth command to specify the reservable bandwidth. Without this interface-level configuration, the TE tunnel cannot signal a reservation, and path computation fails due to lack of available bandwidth. OSPF TE extensions are already enabled, so the missing piece is the interface configuration.

Answer

Enable MPLS LDP on all interfaces to ensure label distribution for the TE tunnel.

Answer

Configure the mpls traffic-eng tunnels command under the OSPF process to advertise TE metrics.

Answer

Configure the ip rsvp bandwidth command under the OSPF process to allow RSVP to reserve bandwidth.

Question 7

A network engineer is configuring a Cisco IOS XE router to act as a DHCP server for a subnet. The router must assign IP addresses from the 192.168.100.0/24 pool, but the first 10 addresses and the last address in the range must be excluded from dynamic assignment. Which command accomplishes this requirement?

Accepted Answer

Two separate commands: ip dhcp excluded-address 192.168.100.1 192.168.100.10 and ip dhcp excluded-address 192.168.100.254. The Cisco IOS DHCP server uses the ip dhcp excluded-address command to specify addresses that should not be assigned dynamically. You can configure multiple excluded addresses or ranges by entering the command multiple times. In this scenario, the first 10 addresses and the last address must be excluded, so two separate commands are needed: one for the range and one for the individual address. Combining them into a single command with multiple arguments or using 'and' is not valid syntax.

Answer

ip dhcp excluded-address 192.168.100.1 192.168.100.10 192.168.100.254

Answer

ip dhcp excluded-address 192.168.100.1 192.168.100.10 and ip dhcp excluded-address 192.168.100.254

Answer

ip dhcp excluded-address 192.168.100.1 192.168.100.10

Question 8

A network engineer is configuring a Cisco IOS XE router to support MPLS L3VPN. The router is a PE device with a VRF named CUSTOMER. The engineer wants to ensure that the PE router can forward traffic for the CUSTOMER VRF using MPLS labels. Which command must be configured on the PE router's core-facing interface to enable MPLS forwarding?

Accepted Answer

mpls ip. To enable MPLS forwarding on a Cisco IOS XE router interface, the mpls ip command must be configured. This command instructs the interface to process MPLS labels and forward labeled packets. On a PE router, the core-facing interface must have mpls ip enabled to send and receive MPLS traffic for VPNs. While other MPLS-related commands configure label distribution or router IDs, they do not enable the actual forwarding of MPLS packets on the interface.

Answer

mpls label protocol ldp

Answer

mpls ldp router-id Loopback0

Answer

mpls ldp discovery transport-address interface

Question 9

A network engineer is configuring a Cisco IOS XE router to support MPLS Traffic Engineering (TE) with RSVP-TE. The engineer has enabled MPLS TE globally and on the interfaces. The engineer wants to ensure that the router can signal an LSP with a specific bandwidth requirement of 100 Mbps. Which command is required to enable RSVP-TE signaling on the interface?

Accepted Answer

ip rsvp bandwidth 100000. To enable RSVP-TE signaling on an interface, the 'ip rsvp bandwidth' command must be configured. This command reserves bandwidth for RSVP-TE LSPs and allows the interface to participate in RSVP signaling. The bandwidth value is specified in kilobits per second, so 100 Mbps is 100,000 kbps. Without this command, the router cannot signal an LSP with the required bandwidth, even if MPLS TE is enabled globally and on the interface.

Answer

mpls traffic-eng tunnels

Answer

mpls traffic-eng bandwidth 100000

Answer

mpls rsvp-te bandwidth 100000

Question 10

A network engineer is troubleshooting a Cisco IOS XE router that is configured for IPv6 First Hop Security on a user VLAN. Hosts report intermittent connectivity, and the engineer suspects that IPv6 Router Advertisement (RA) messages from an unauthorized device are being accepted. Which feature should be enabled to ensure that only RAs from the legitimate router are processed by hosts?

Accepted Answer

IPv6 RA Guard. RA Guard is the IPv6 First Hop Security feature that filters Router Advertisement and Redirect messages on a per-port basis. When configured to block RAs on host-facing ports, it ensures hosts only accept RAs from the authorized router, mitigating rogue RA attacks. The other features address different threats such as rogue DHCPv6 servers or spoofed source addresses.

Answer

IPv6 Source Guard

Answer

IPv6 Destination Guard

Answer

IPv6 DHCPv6 Guard

Question 11

A network engineer is configuring a Cisco IOS XE router to act as an IPv6 DHCP server for a LAN segment. The router must provide IPv6 addresses and other configuration parameters to hosts. Which two tasks must the engineer perform to enable stateful DHCPv6 operation on the router? (Choose two.)

Accepted Answer

Configure an IPv6 DHCP pool with the address prefix and other parameters.. To enable stateful DHCPv6 on a Cisco IOS XE router, you must create a DHCPv6 pool that defines the address prefix and options, and then enable the DHCPv6 server on the interface with the ipv6 dhcp server command referencing that pool. These two steps allow the router to assign addresses and parameters to clients. The other options are either unrelated or would not contribute to server functionality.

Answer

Enable IPv6 unicast routing globally with the ipv6 unicast-routing command.

Answer

Configure a DHCPv6 relay destination on the interface pointing to itself.

Answer

Configure a static IPv6 address on the interface using the eui-64 keyword.

Question 12

A service provider is deploying MPLS Traffic Engineering (TE) with RSVP-TE to ensure bandwidth guarantees for critical traffic. The network engineer has configured an MPLS TE tunnel on a Cisco IOS XE router. The tunnel must be able to signal an explicit path that includes a specific link with a reserved bandwidth of 50 Mbps. Which RSVP-TE object is used to carry the explicit route information in the Path message?

Accepted Answer

EXPLICIT_ROUTE object. In RSVP-TE, the EXPLICIT_ROUTE object (ERO) is used to specify the explicit path for a TE tunnel. It is included in the Path message and contains the list of hops that the tunnel must traverse. The SESSION object identifies the session, the RSVP_HOP object provides previous hop information, and the LABEL_REQUEST object requests label bindings. Only the EXPLICIT_ROUTE object carries the explicit route information needed to signal a path that includes a specific link.

Answer

LABEL_REQUEST object

Answer

RSVP_HOP object

Answer

SESSION object

Question 13

A network administrator is configuring a Cisco IOS XE router for MPLS Traffic Engineering (TE). The administrator wants to ensure that the router can signal an MPLS TE tunnel using RSVP. Which protocol must be enabled on the interfaces along the path to reserve bandwidth and distribute labels?

Choose an answer to begin — your selection is scored in the full session.

Accepted Answer

The router will forward DHCP requests from clients to the DHCP server, and the server will reply to the router, which then forwards the reply to the clients.. When a Cisco IOS XE router is configured with 'ip helper-address', it acts as a DHCP relay agent. It forwards DHCP discover messages from clients to the specified DHCP server, inserting its own interface IP address as the giaddr. The DHCP server uses the giaddr to select the correct address pool and sends the DHCP offer back to the relay agent. The relay agent then forwards the offer to the client. This allows DHCP to function across subnets without requiring a DHCP server on every subnet.

Answer

The router will forward DHCP requests from clients to the DHCP server, and the server will reply directly to the clients.

Answer

The router will forward DHCP requests from clients to the DHCP server, but the server will not be able to assign an address because the router does not have a route to the client subnet.

Answer

The router will drop DHCP requests because it is not configured as a DHCP server.

Question 14

A network engineer is configuring a Cisco IOS XE router as a LISP ITR. The router must encapsulate traffic from local EIDs to remote RLOCs. Which command is required to enable LISP functionality and allow the router to act as an ITR?

Accepted Answer

router lisp. On Cisco IOS XE, LISP is enabled by entering the router lisp global configuration command. This mode allows you to configure the router as an ITR, ETR, or both, and to define EID-to-RLOC mappings and map-resolvers. The other commands are either invalid in this context or belong to different platforms, so they would not enable LISP functionality.

Answer

lisp itr enable

Answer

feature lisp

Answer

ipv4 lisp

Question 15

A network engineer is troubleshooting a DMVPN Phase 3 deployment on a Cisco IOS XE hub. Spokes use NHRP to register with the hub and have working mGRE tunnels to the hub. The design requires that spoke-to-spoke traffic be sent directly between spokes without transiting the hub's data path. The engineer observes that all spoke-to-spoke packets still traverse the hub even though spoke registration and routing are correct. Which configuration change on the hub is required to enable direct spoke-to-spoke forwarding?

Accepted Answer

Configure ip nhrp redirect on the hub so the hub can inform the source spoke that a better path exists, triggering an NHRP resolution for the destination spoke.. DMVPN Phase 3 achieves direct spoke-to-spoke forwarding by combining hub-side NHRP redirect with spoke-side NHRP shortcut. When a spoke sends traffic through the hub, the hub issues an NHRP redirect telling the source spoke a better path exists. The spoke then resolves the destination's NBMA address and installs a shortcut route, allowing direct forwarding. Without the hub redirect, spokes continue to hairpin traffic through the hub.

Answer

Configure ip nhrp shortcut on the hub so the hub can cache the destination spoke's NBMA mapping and forward directly.

Answer

Configure ip nhrp map multicast dynamic on the hub so the hub can dynamically learn the NBMA addresses of all registering spokes.

Answer

Configure no ip next-hop-self eigrp under the tunnel interface's routing process so the hub does not rewrite the next hop for EIGRP routes.