MPLS

An engineer is troubleshooting an MPLS VPN where CE1 (10.1.1.0/24) cannot reach CE2 (10.2.2.0/24). The PE routers are running OSPF with the CE routers. On PE1, the 'show ip route vrf CUSTOMER' output shows 10.2.2.0/24 as an OSPF route, but the prefix is not present in the global BGP table. What is the most likely cause?

Question 3hardmultiple choice

A service provider uses MPLS L3VPN with OSPF as the PE-CE routing protocol. A customer reports that a new subnet added on CE1 is not reachable from CE2, even though the PE1 router has the route in its VRF and BGP table. The 'show ip bgp vpnv4 vrf CUSTOMER' on PE2 shows the prefix with a valid next-hop. What should the engineer check next?

Question 4mediummultiple choice

An engineer is designing an MPLS L3VPN service for a customer that requires overlapping IP addresses between two sites. The customer uses OSPF as the PE-CE protocol. The engineer configures VRFs on the PE routers and assigns unique route distinguishers (RDs) and route targets (RTs). However, the customer reports that routes from one site are not being installed in the other site's VRF. What is the most likely cause?

Question 5hardmultiple choice

A network engineer is configuring MPLS TE (Traffic Engineering) in an MPLS core to optimize bandwidth utilization. After enabling MPLS TE on all core routers and configuring tunnels, the engineer notices that traffic is not being rerouted when a link fails. The 'show mpls traffic-eng tunnels' shows the tunnels are up but not using the backup path. What is the most likely missing configuration?

Question 6mediummultiple choice

An enterprise is implementing MPLS L3VPN to connect multiple branch offices. The PE routers are using eBGP to exchange VPNv4 routes. The engineer notices that some VPN routes are not being advertised to the remote PE. The 'show bgp vpnv4 unicast all' on the local PE shows the routes as valid but not best. What is the most likely reason?

Question 7hardmultiple choice

A network engineer is troubleshooting an MPLS L2VPN (VPWS) where two customer sites are connected via a pseudowire. The engineer has configured the xconnect on both PE routers, but the customer reports that the link is down. The 'show mpls l2transport vc' command on PE1 shows the VC state as 'down'. What is the most likely cause?

Question 8mediummultiple choice

An engineer is configuring MPLS L3VPN with OSPF as the PE-CE protocol. The customer wants to ensure that routes from the MPLS backbone are not redistributed back into the customer's OSPF domain. What configuration should the engineer apply on the PE router?

Question 9hardmultiple choice

A service provider is migrating from a traditional IP core to an MPLS core. The engineer has configured LDP on all core routers and verified that LDP sessions are established. However, some prefixes learned via OSPF are not being assigned labels. The 'show mpls ldp bindings' command shows missing bindings for certain routes. What is the most likely cause?

Question 10easymultiple choice

An engineer is configuring MPLS L3VPN with BGP as the PE-CE protocol. The customer uses eBGP between CE and PE. The engineer notices that the CE router is not receiving any VPN routes from the PE. The 'show bgp vpnv4 unicast all' on the PE shows the routes as valid and best. What is the most likely missing configuration?

Question 11mediummultiple choice

A network engineer runs the following command on Router R1:

R1# show mpls ldp neighbor

Peer LDP Ident: 10.1.1.2:0; Local LDP Ident 10.1.1.1:0 TCP connection: 10.1.1.2.646 - 10.1.1.1.179 State: Oper; Msgs sent/rcvd: 120/115; Downstream Up time: 02:30:15 LDP discovery sources: GigabitEthernet0/0, Src IP addr: 192.168.1.2 Addresses bound to peer LDP Ident:

10.1.1.2         192.168.1.2      10.2.2.2

Based on this output, what can be concluded?

Question 12hardmultiple choice

A network engineer runs the following command on Router R2:

R2# show mpls forwarding-table

Local Outgoing Prefix Bytes Label Outgoing Next Hop Label Label or Tunnel Id Switched interface 16 Pop Label 10.1.1.1/32 0 Gi0/0 192.168.1.1 17 18 10.2.2.0/24 1500 Gi0/1 192.168.2.3 18 Untagged 10.3.3.0/24 0 Gi0/2 192.168.3.4

Based on this output, what is the correct interpretation?

Question 13mediummultiple choice

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?

Question 14easymultiple choice

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?

Question 15hardmultiple choice

A network engineer runs the following command on Router R5:

R5# show mpls ldp discovery

Local LDP Identifier: 10.5.5.5:0 Discovery Sources:

Interfaces:

GigabitEthernet0/0: xmit/recv LDP Id: 10.5.5.4:0, no hello (expired) GigabitEthernet0/1: xmit/recv LDP Id: 10.5.5.6:0

Based on this output, what is the state of the LDP session with neighbor 10.5.5.4?

Question 16mediummultiple choice

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?

Question 17mediummultiple choice

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?

Question 18hardmultiple choice

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?

Question 19easymultiple choice

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?

Question 20mediummultiple choice

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?

Question 21mediummultiple choice

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?

Question 22mediummultiple choice

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?

Question 23mediummultiple choice

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?

Question 24mediummultiple choice

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?

Question 25mediummultiple choice

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?

Question 26easymultiple choice

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

Question 27easymultiple choice

Study the full EIGRP explanation →

Which BGP attribute is preferred when it has the lowest value?

Question 28easymultiple choice

What is the maximum hop count for EIGRP?

Question 29mediumdrag order

Drag and drop the steps of MPLS LDP label distribution and FIB population into the correct order, from first to last.

Question 30mediumdrag order

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

Question 31mediumdrag order

Full Practice Test →All Objectives

Drag and drop the steps of MPLS traffic engineering (MPLS-TE) tunnel setup into the correct order, from first to last.

More MPLS questions available in the full practice test.

Continue Practising →

Objective 308.0

MPLS

350-401 Practice Questions

350-401 MPLS — Practice Questions

30 questions from this objective

Question 2mediummultiple choice

An engineer is troubleshooting an MPLS VPN where CE1 (10.1.1.0/24) cannot reach CE2 (10.2.2.0/24). The PE routers are running OSPF with the CE routers. On PE1, the 'show ip route vrf CUSTOMER' output shows 10.2.2.0/24 as an OSPF route, but the prefix is not present in the global BGP table. What is the most likely cause?

Question 3hardmultiple choice

A service provider uses MPLS L3VPN with OSPF as the PE-CE routing protocol. A customer reports that a new subnet added on CE1 is not reachable from CE2, even though the PE1 router has the route in its VRF and BGP table. The 'show ip bgp vpnv4 vrf CUSTOMER' on PE2 shows the prefix with a valid next-hop. What should the engineer check next?

Question 4mediummultiple choice

An engineer is designing an MPLS L3VPN service for a customer that requires overlapping IP addresses between two sites. The customer uses OSPF as the PE-CE protocol. The engineer configures VRFs on the PE routers and assigns unique route distinguishers (RDs) and route targets (RTs). However, the customer reports that routes from one site are not being installed in the other site's VRF. What is the most likely cause?

Question 5hardmultiple choice

A network engineer is configuring MPLS TE (Traffic Engineering) in an MPLS core to optimize bandwidth utilization. After enabling MPLS TE on all core routers and configuring tunnels, the engineer notices that traffic is not being rerouted when a link fails. The 'show mpls traffic-eng tunnels' shows the tunnels are up but not using the backup path. What is the most likely missing configuration?

Question 6mediummultiple choice

An enterprise is implementing MPLS L3VPN to connect multiple branch offices. The PE routers are using eBGP to exchange VPNv4 routes. The engineer notices that some VPN routes are not being advertised to the remote PE. The 'show bgp vpnv4 unicast all' on the local PE shows the routes as valid but not best. What is the most likely reason?

Question 7hardmultiple choice

A network engineer is troubleshooting an MPLS L2VPN (VPWS) where two customer sites are connected via a pseudowire. The engineer has configured the xconnect on both PE routers, but the customer reports that the link is down. The 'show mpls l2transport vc' command on PE1 shows the VC state as 'down'. What is the most likely cause?

Question 8mediummultiple choice

An engineer is configuring MPLS L3VPN with OSPF as the PE-CE protocol. The customer wants to ensure that routes from the MPLS backbone are not redistributed back into the customer's OSPF domain. What configuration should the engineer apply on the PE router?

Question 9hardmultiple choice

A service provider is migrating from a traditional IP core to an MPLS core. The engineer has configured LDP on all core routers and verified that LDP sessions are established. However, some prefixes learned via OSPF are not being assigned labels. The 'show mpls ldp bindings' command shows missing bindings for certain routes. What is the most likely cause?

Question 10easymultiple choice

An engineer is configuring MPLS L3VPN with BGP as the PE-CE protocol. The customer uses eBGP between CE and PE. The engineer notices that the CE router is not receiving any VPN routes from the PE. The 'show bgp vpnv4 unicast all' on the PE shows the routes as valid and best. What is the most likely missing configuration?

Question 11mediummultiple choice

A network engineer runs the following command on Router R1:

R1# show mpls ldp neighbor

10.1.1.2         192.168.1.2      10.2.2.2

Based on this output, what can be concluded?

Question 12hardmultiple choice

A network engineer runs the following command on Router R2:

R2# show mpls forwarding-table

Based on this output, what is the correct interpretation?

Question 13mediummultiple choice

A network engineer runs the following command on Router R3:

R3# show mpls ldp bindings

Based on this output, what is true?

Question 14easymultiple choice

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?

Question 15hardmultiple choice

A network engineer runs the following command on Router R5:

R5# show mpls ldp discovery

Local LDP Identifier: 10.5.5.5:0 Discovery Sources:

Interfaces:

GigabitEthernet0/0: xmit/recv LDP Id: 10.5.5.4:0, no hello (expired) GigabitEthernet0/1: xmit/recv LDP Id: 10.5.5.6:0

Based on this output, what is the state of the LDP session with neighbor 10.5.5.4?

Question 16mediummultiple choice

A network engineer runs the following command on Router R6:

R6# show mpls ldp neighbor 10.6.6.7 detail

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?

Question 17mediummultiple choice

A network engineer runs the following command on Router R7:

R7# show mpls ldp capabilities

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

Question 18hardmultiple choice

A network engineer runs the following command on Router R8:

R8# show mpls ldp traffic

Based on this output, what is a likely issue?

Question 19easymultiple choice

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?

Question 20mediummultiple choice

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?

Question 21mediummultiple choice

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?

Question 22mediummultiple choice

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?

Question 23mediummultiple choice

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?

Question 24mediummultiple choice

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?

Question 25mediummultiple choice

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?

Question 26easymultiple choice

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

Question 27easymultiple choice

Study the full EIGRP explanation →

Which BGP attribute is preferred when it has the lowest value?

Question 28easymultiple choice

What is the maximum hop count for EIGRP?

Question 29mediumdrag order

Drag and drop the steps of MPLS LDP label distribution and FIB population into the correct order, from first to last.

Question 30mediumdrag order

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

Question 31mediumdrag order