350-401 Practice Test 19 — 15 Questions

Question 1

A network engineer runs the following command on Router R6:

R6# show mpls ldp neighbor 10.6.6.7 detail
    Peer LDP Ident: 10.6.6.7:0; Local LDP Ident 10.6.6.6:0
        TCP connection: 10.6.6.7.646 - 10.6.6.6.179
        State: Oper; Msgs sent/rcvd: 200/195; Downstream
        Up time: 1d04h
        LDP discovery sources:
          Targeted Hello 10.6.6.6 -> 10.6.6.7, active, passive
        Addresses bound to peer LDP Ident:
          10.6.6.7         192.168.6.7
        Hold time: 15 seconds; keepalive interval: 5 seconds
        Peer hold time: 15 seconds; keepalive interval: 5 seconds

Based on this output, what type of LDP session is this?

Accepted Answer

This is a targeted LDP session established between two non-directly connected routers.. The output shows 'Targeted Hello' in the discovery sources, indicating this is a targeted LDP session (not link-local). The session is operational and uses targeted hellos.

Answer

This is a link-local LDP session because the discovery source is an interface.

Answer

This is a multicast LDP session because the hold time is 15 seconds.

Answer

This is a BGP session because the TCP connection shows port 179.

Question 2

A network engineer runs the following command on Router R7:

R7# show mpls ldp capabilities
    LDP Capabilities:
      Dynamic Capability: advertised
      Typed Wildcard FEC: advertised
      MTU Signaling: advertised
      P2MP: not advertised
      MPLS OAM: advertised
      LDP Graceful Restart: advertised
        Helper mode: enabled
        Restart mode: enabled
        Reconnect time: 120 sec
        Recovery time: 180 sec

Based on this output, which capability is NOT supported by this router?

Accepted Answer

P2MP (Point-to-Multipoint). The output lists capabilities that are advertised. P2MP (Point-to-Multipoint) is explicitly listed as 'not advertised', meaning it is not supported.

Answer

LDP Graceful Restart

Answer

MTU Signaling

Answer

Dynamic Capability

Question 3

A network engineer runs the following command on Router R3:

R3# show mpls ldp bindings
  lib entry: 10.1.1.1/32, rev 2
        local binding:  label: 16
        remote binding: lsr: 10.1.1.2:0, label: 17
  lib entry: 10.2.2.0/24, rev 4
        local binding:  label: 18
        remote binding: lsr: 10.1.1.2:0, label: 19
  lib entry: 10.3.3.0/24, rev 6
        local binding:  label: 20
        remote binding: lsr: 10.1.1.2:0, label: 21

Based on this output, what is true?

Accepted Answer

For prefix 10.1.1.1/32, the local label is 16 and the remote label from LSR 10.1.1.2 is 17.. The output shows the LIB (Label Information Base). For each prefix, there is a local label assigned by this router and a remote label learned from LSR 10.1.1.2. The rev number indicates the revision of the entry.

Answer

The router has learned label bindings from two different LDP peers.

Answer

The label for prefix 10.2.2.0/24 is 18 locally and 19 remotely, indicating that the remote LSR will use label 18.

Answer

The LIB entry for 10.3.3.0/24 has a revision number of 6, meaning it was the sixth entry added.

Question 4

A network engineer runs the following command on Router R4:

R4# show mpls interfaces
Interface              IP            Tunnel   BGP Static Operational
GigabitEthernet0/0     Yes           No       No  No     Yes
GigabitEthernet0/1     Yes           No       No  No     Yes
GigabitEthernet0/2     No            No       No  No     No

Based on this output, what can be concluded?

Accepted Answer

MPLS is enabled and operational on GigabitEthernet0/0 and GigabitEthernet0/1.. The command shows which interfaces are enabled for MPLS. The 'IP' column indicates if MPLS is enabled for IP forwarding. 'Operational' shows if MPLS is actually up. Gi0/2 has MPLS disabled (IP: No) and is not operational.

Answer

MPLS is enabled on all three interfaces, but only Gi0/0 and Gi0/1 are operational.

Answer

BGP and Static label switching are enabled on Gi0/0 and Gi0/1.

Answer

Tunnel interfaces are configured on Gi0/0 and Gi0/1.

Question 5

A network engineer runs the following command on Router R8:

R8# show mpls ldp traffic
    LDP Traffic Statistics:
      Hellos sent: 5000, Hellos received: 4998
      Initialization messages sent: 2, received: 2
      Keepalive messages sent: 15000, received: 14995
      Label mapping messages sent: 100, received: 95
      Label withdraw messages sent: 5, received: 3
      Label release messages sent: 2, received: 1
      Label abort messages sent: 0, received: 0
      Notification messages sent: 1, received: 2
      Address messages sent: 10, received: 9
      Address withdraw messages sent: 1, received: 0

Based on this output, what is a likely issue?

Accepted Answer

There is a problem with label distribution because label withdraw messages are significantly higher than label release messages.. The statistics show a mismatch between sent and received messages for several types, especially label withdraw (5 sent, 3 received) and label release (2 sent, 1 received). This may indicate packet loss or a problem with the LDP session. However, the most notable discrepancy is in label mapping messages (100 sent, 95 received), suggesting some mapping messages were lost. But the question asks for a likely issue; the high number of label withdraws relative to releases could indicate instability.

Answer

The LDP session is experiencing packet loss because the number of hellos sent and received are not equal.

Answer

The router has sent 100 label mapping messages but received 95, indicating that 5 mapping messages were lost.

Answer

The router has sent 1 notification message and received 2, indicating errors in the LDP session.

Question 6

A network engineer runs the following command on Router R9:

R9# show mpls ldp bindings 10.9.9.0 255.255.255.0
  lib entry: 10.9.9.0/24, rev 10
        local binding:  label: 22
        remote binding: lsr: 10.9.9.1:0, label: 23
        remote binding: lsr: 10.9.9.2:0, label: 24
        remote binding: lsr: 10.9.9.3:0, label: 25

Based on this output, how many remote LDP peers have advertised a label for the prefix 10.9.9.0/24?

Accepted Answer

3. The output shows three remote bindings from different LSRs (10.9.9.1, 10.9.9.2, 10.9.9.3), each with a different label. So three remote peers have advertised labels.

Answer

1

Answer

2

Answer

4

Question 7

interface GigabitEthernet0/1
 ip address 10.1.1.1 255.255.255.0
 mpls ip
 mpls label protocol ldp
!
router ospf 1
 network 10.1.1.0 0.0.0.255 area 0
!
router ldp
 interface GigabitEthernet0/1
!
What is the effect of this configuration?

Accepted Answer

MPLS forwarding is enabled on GigabitEthernet0/1, and LDP will distribute labels for all routes in the routing table.. The configuration enables MPLS forwarding and LDP on the interface, with OSPF providing IGP reachability. LDP will distribute labels for prefixes learned via OSPF.

Answer

Only OSPF routes are labeled; static routes are excluded from LDP label distribution.

Answer

The 'mpls label protocol ldp' command is redundant because LDP is the default.

Answer

The configuration will fail because 'router ldp' requires an LDP router-id to be set.

Question 8

ip vrf RED
 rd 200:1
 route-target export 200:1
 route-target import 200:1
!
interface GigabitEthernet0/1
 ip vrf forwarding RED
 ip address 10.1.1.1 255.255.255.0
!
router bgp 65000
 neighbor 192.168.1.1 remote-as 65000
 neighbor 192.168.1.1 update-source Loopback0
 address-family vpnv4
  neighbor 192.168.1.1 activate
  neighbor 192.168.1.1 send-community extended
!
Which statement about this configuration is true?

Accepted Answer

The configuration is correct for MPLS L3VPN, but the VRF RED must also be configured under BGP with 'address-family ipv4 vrf RED'.. The BGP configuration includes 'send-community extended' under the VPNv4 address-family, which is required for MPLS L3VPN route exchange. However, the VRF RED is defined but not used in BGP.

Answer

The 'send-community extended' command is unnecessary because it is enabled by default.

Answer

The interface GigabitEthernet0/1 requires 'mpls ip' to forward MPLS packets.

Answer

The VRF RED will automatically import routes from the VPNv4 address-family without additional configuration.

Question 9

What is the maximum hop count for EIGRP?

Accepted Answer

100. EIGRP has a default maximum hop count of 100, which can be changed up to 255.

Answer

15

Answer

255

Answer

16

Question 10

interface GigabitEthernet0/1
 ip address 10.1.1.1 255.255.255.0
 mpls ip
 mpls label protocol tdp
!
router ospf 1
 network 10.1.1.0 0.0.0.255 area 0
!
router ldp
 interface GigabitEthernet0/1
!
Which statement about this configuration is true?

Accepted Answer

The interface will use TDP for label distribution, ignoring the LDP configuration under router ldp.. The interface is configured with TDP (Cisco proprietary) while the router is configured for LDP (standard). This mismatch will prevent label exchange.

Answer

The router will use LDP because the global configuration overrides the interface command.

Answer

Both TDP and LDP will be used simultaneously on the interface.

Answer

The configuration will fail because TDP is not supported on this platform.

Question 11

interface GigabitEthernet0/1
 ip address 10.1.1.1 255.255.255.0
 mpls ip
!
interface GigabitEthernet0/2
 ip address 10.2.2.1 255.255.255.0
 mpls ip
!
router ospf 1
 network 10.0.0.0 0.255.255.255 area 0
!
router ldp
 interface GigabitEthernet0/1
!
What is the effect of this configuration?

Accepted Answer

LDP will only form an adjacency over GigabitEthernet0/1; no label exchange occurs on GigabitEthernet0/2.. LDP is only enabled on GigabitEthernet0/1, not on GigabitEthernet0/2. This means LDP will not form an adjacency over GigabitEthernet0/2, and MPLS forwarding may be incomplete.

Answer

LDP will automatically enable on GigabitEthernet0/2 because MPLS is enabled there.

Answer

The configuration will fail because LDP must be enabled on all MPLS interfaces.

Answer

OSPF will automatically enable LDP on all interfaces in area 0.

Question 12

ip vrf BLUE
 rd 100:1
 route-target export 100:1
 route-target import 100:1
!
interface GigabitEthernet0/1
 ip vrf forwarding BLUE
 ip address 10.1.1.1 255.255.255.0
!
router bgp 65000
 neighbor 192.168.1.1 remote-as 65000
 neighbor 192.168.1.1 update-source Loopback0
 address-family ipv4 vrf BLUE
  neighbor 192.168.1.1 activate
  network 10.1.1.0 mask 255.255.255.0
!
What is missing from this MPLS L3VPN configuration?

Accepted Answer

The BGP neighbor needs 'send-community extended' under the address-family to exchange VPN routes.. The configuration lacks the 'neighbor 192.168.1.1 send-community extended' command under the BGP address-family, which is required to exchange VPNv4 routes with extended communities.

Answer

The VRF definition is missing the 'mdt' command for multicast VPN.

Answer

The interface needs 'mpls ip' enabled for MPLS forwarding.

Answer

The BGP neighbor needs 'remote-as 65000' under the VRF address-family.

Question 13

What is the default OSPF hello interval on an Ethernet link in Cisco IOS?

Accepted Answer

10 seconds. OSPF hello interval defaults to 10 seconds on broadcast and point-to-point networks (e.g., Ethernet).

Answer

30 seconds

Answer

40 seconds

Answer

5 seconds

Question 14

Drag and drop the steps of MPLS VPN (L3VPN) service provisioning into the correct order, from first to last.

Accepted Answer

Configure IGP and LDP on core interfaces. First, the provider edge (PE) router must have IGP and LDP running in the core. Then the VRF is defined with route distinguisher and import/export RTs. The customer edge (CE) interface is placed into the VRF. MP-BGP is configured between PEs to exchange VPNv4 routes. Finally, the CE routes are redistributed into the VRF and advertised via MP-BGP.

Question 15

interface GigabitEthernet0/1
 ip address 10.1.1.1 255.255.255.0
 mpls ip
!
interface GigabitEthernet0/2
 ip address 10.2.2.1 255.255.255.0
 mpls ip
!
router ospf 1
 network 10.0.0.0 0.255.255.255 area 0
!
router ldp
 interface GigabitEthernet0/1
 interface GigabitEthernet0/2
!
What is the effect of this configuration?

Accepted Answer

LDP will form adjacencies over both interfaces and distribute labels for all routes in the routing table.. LDP is enabled on both interfaces, but OSPF is configured with a wildcard that includes both subnets. LDP will form adjacencies and distribute labels for all OSPF routes.

Answer

Only OSPF routes will receive labels; static routes are ignored by LDP.

Answer

LDP will only form an adjacency on GigabitEthernet0/1 because it is the first interface configured.

Answer

The configuration will fail because OSPF and LDP are not compatible on the same interface.