CCNP Practice Exam 51 — 20 Questions

Question 1

Which three statements about the Multiple Spanning Tree Protocol (MSTP) are true? (Choose three.)

Accepted Answer

MSTP allows multiple VLANs to be mapped to a single spanning-tree instance.. MSTP (802.1s) allows mapping multiple VLANs to a single spanning-tree instance, reducing the number of STP instances needed. It uses an internal spanning tree (IST) to interconnect MST regions. MSTP is backward compatible with 802.1D and RSTP through the use of common spanning tree (CST) at the region boundary. MSTP does not require a separate instance for every VLAN like PVST+; it groups VLANs into instances. MSTP uses the same BPDU format as RSTP with additional MST-specific information.

Answer

MSTP requires a separate spanning-tree instance for every VLAN.

Answer

MSTP uses a different BPDU format than RSTP.

Question 2

Which three statements about trunking and VLAN pruning are true? (Choose three.)

Accepted Answer

VTP pruning dynamically removes VLANs from a trunk if the VLAN is not present on the remote switch.. Correct: A is true because VTP pruning reduces unnecessary broadcast traffic on trunk links by dynamically removing VLANs that are not needed on a switch. B is true because pruning can be manually configured on a trunk using the 'switchport trunk allowed vlan' command to restrict which VLANs traverse the link. C is true because VTP pruning requires VTP to be configured and operating in the domain; it is not available without VTP. D is incorrect because VTP pruning works with VTP versions 1 and 2, not just version 3. E is incorrect because the 'switchport trunk native vlan' command sets the native VLAN, not pruning; pruning is controlled by allowed VLAN lists or VTP pruning.

Answer

VTP pruning is only supported in VTP version 3.

Answer

The 'switchport trunk native vlan' command is used to prune VLANs from a trunk.

Question 3

Drag and drop each MPLS label operation on the left to its matching action on the right.

Accepted Answer

Push: Adds a new label to the top of the label stack. Push adds a new label to the stack, pop removes the top label, and swap replaces the top label with a new one.

Question 4

Drag and drop each DHCP option on the left to its matching purpose on the right.

Accepted Answer

Option 43: Provides vendor-specific information such as TFTP server address. Option 43 provides vendor-specific info; Option 60 identifies vendor class; Option 82 is relay agent information.

Question 5

Drag and drop the steps of MPLS L2VPN (AToM) pseudowire setup into the correct order, from first to last.

Accepted Answer

Configure attachment circuit (AC) on PE. AToM pseudowire setup starts with configuring the attachment circuit on both PE routers. Then a pseudowire class is defined, specifying encapsulation and control word. The VC label is signaled via LDP, and the pseudowire is bound to the attachment circuit. Finally, the pseudowire becomes operational and forwards L2 frames.

Question 6

Drag and drop the steps of Metro Ethernet E-Line service provisioning into the correct order, from first to last.

Accepted Answer

Define service parameters and endpoints. E-Line provisioning starts with defining the service attributes and customer endpoints. The provider then configures the UNI on each customer edge device. Next, the EVC is created across the provider network to connect the two UNIs. Finally, the service is tested and activated for the customer.

Question 7

Drag and drop the steps of PHP (Penultimate Hop Popping) operation into the correct order, from first to last.

Accepted Answer

Egress LSR assigns label to FEC. PHP operation begins with the egress LSR assigning a label to a FEC and advertising it. The penultimate hop receives this label and recognizes implicit-null. The penultimate hop then pops the label before forwarding the packet. The egress receives an unlabeled packet and performs a standard IP lookup.

Question 8

Which three statements about RRM (Radio Resource Management) in a Cisco wireless LAN are true? (Choose three.)

Accepted Answer

RRM automatically selects the best channel for each AP based on interference measurements.. RRM dynamically adjusts channel and power settings based on RF measurements, uses a leader AP to coordinate, and can be configured to run at a scheduled interval. It does not require a dedicated hardware controller (it runs on the WLC) and does not automatically enable client load balancing (that is a separate feature).

Answer

RRM requires a dedicated hardware controller to perform RF calculations.

Answer

RRM automatically enables client load balancing across APs in the same coverage area.

Question 9

Which three statements about Cisco Wireless LAN Controller (WLC) mobility groups are true? (Choose three.)

Accepted Answer

A mobility group can contain up to 24 controllers.. Mobility groups allow seamless client roaming across controllers, support up to 24 controllers per group, require symmetric mobility tunnels, and use a backup controller list for redundancy. They do not require all controllers to be in the same subnet or same hardware model.

Answer

Controllers in the same mobility group must be in the same IP subnet.

Answer

All controllers in a mobility group must be the same hardware model.

Question 10

Drag and drop each EtherChannel load-balance method on the left to its matching hashing input on the right.

Accepted Answer

src-mac: Source MAC address. Methods use different combinations of source/destination MAC, IP, or port to compute hash for link selection.

Question 11

Drag and drop each LACP port mode on the left to its matching negotiation behavior on the right.

Accepted Answer

active: Sends LACP packets to negotiate. Active initiates negotiation, passive waits for partner.

Question 12

Drag and drop the steps of MSDP peering for inter-domain multicast into the correct order, from first to last.

Accepted Answer

MSDP peers establish TCP connection between RPs. MSDP peers first establish a TCP connection, then exchange SA messages to advertise active sources; the remote RP receives the SA, creates (S,G) state, and forwards join toward the source.

Question 13

Drag and drop each broadband type on the left to its matching technology on the right.

Accepted Answer

DSL: Uses telephone copper pairs. DSL uses telephone lines, Cable uses coaxial, Fiber uses optical, 4G LTE uses cellular, Satellite uses RF to orbit.

Question 14

Which two statements about MPLS label distribution protocol (LDP) are true? (Choose two.)

Accepted Answer

LDP uses TCP port 646 for session establishment.. LDP uses TCP port 646 for session establishment and UDP for discovery (hello messages). LDP sessions are established between directly connected LSRs by default, but can also be established between non-adjacent LSRs using targeted hellos. LDP assigns labels to every prefix in the routing table by default. Option C is incorrect because LDP uses TCP, not UDP, for session establishment. Option D is incorrect because LDP does not use RSVP; that is for traffic engineering. Option E is incorrect because LDP assigns labels to all prefixes, not just BGP routes.

Answer

LDP uses UDP for session establishment.

Answer

LDP uses RSVP to distribute labels.

Answer

LDP assigns labels only to BGP routes.

Question 15

Drag and drop each WAN encapsulation on the left to its matching use case on the right.

Accepted Answer

HDLC: Cisco proprietary point-to-point serial encapsulation. HDLC is Cisco proprietary and used for point-to-point serial links. PPP supports authentication and multilink. PPPoE is used for DSL broadband connections. Frame Relay is a legacy packet-switched WAN technology. MLPPP bundles multiple PPP links.

Question 16

Which two statements about SPAN and RSPAN configuration limits are true? (Choose two.)

Accepted Answer

A single port can be a SPAN source for multiple SPAN sessions simultaneously.. Cisco switches have limits on the number of SPAN/RSPAN sessions, typically up to 2 local SPAN sessions and 1 RSPAN source session. A single port can be a source for multiple sessions, but a destination port can only be used in one session at a time. The source and destination ports must be on the same switch for local SPAN.

Answer

A SPAN destination port can be used in multiple SPAN sessions at the same time.

Answer

The maximum number of SPAN sessions on a switch is always 4.

Answer

A SPAN source VLAN can be used in both a local SPAN and an RSPAN session at the same time.

Question 17

Drag and drop each STP port state on the left to its matching function on the right.

Accepted Answer

Blocking: Discards frames, does not learn MAC addresses. Blocking discards frames and does not learn MACs; Listening discards frames but does not learn MACs (receives BPDUs); Learning discards frames but learns MACs; Forwarding forwards frames and learns MACs; Disabled administratively down and discards frames.

Question 18

Drag and drop each LDP message type on the left to its matching function on the right.

Accepted Answer

Hello: Discovers LDP neighbors on a link. Discovery uses Hello messages, Session uses Initialization/Keepalive, Advertisement uses Label Mapping, and Notification signals errors.

Question 19

Drag and drop the steps of PHP (Penultimate Hop Popping) operation into the correct order, from first to last.

Accepted Answer

Egress LSR assigns implicit-null label (3) to FEC. PHP begins with egress LSR assigning implicit-null label (3) to FEC, advertising it upstream, penultimate LSR popping the label, forwarding the IP packet without label, and egress LSR performing IP lookup.

Question 20

Drag and drop each STP protection feature on the left to its matching purpose on the right.

Accepted Answer

PortFast: Immediately transitions a port to forwarding state (access ports). PortFast moves a port to forwarding immediately; BPDU Guard disables a port if a BPDU is received; Root Guard prevents a port from becoming a root port; Loop Guard prevents alternate/backup ports from becoming designated if BPDUs stop.