300-410 MPLS L3VPN — All Questions With Answers

A network engineer is troubleshooting an MPLS L3VPN where CE1 (192.168.1.0/24) cannot reach CE2 (192.168.2.0/24). The PE routers are running OSPF with the CEs. On PE1, the VRF configuration includes route-target import and export 100:100. The show ip vrf detail command on PE1 shows the VRF is active, but the CE1 loopback is not present in the VRF routing table. The show ip route vrf CUSTOMER command on PE1 shows only directly connected interfaces. What is the most likely cause?

Question 2hardmultiple choice

An engineer is troubleshooting an MPLS L3VPN where CE1 (10.1.1.0/24) cannot reach CE2 (10.2.2.0/24). The PE routers have MP-BGP peering and the VRF is configured with route-target import 100:100. On PE1, the show ip bgp vpnv4 vrf CUSTOMER command shows the route for 10.2.2.0/24 with a next-hop of 192.168.1.2 (the PE2 loopback), but the show ip route vrf CUSTOMER command does not have this route. The show mpls forwarding-table on PE1 does not show a label for 192.168.1.2. What is the most likely cause?

Question 3hardmultiple choice

A network engineer is troubleshooting an MPLS L3VPN where CE1 (10.1.1.0/24) cannot reach CE2 (10.2.2.0/24). The PE routers are using OSPF with the CEs and MP-BGP between them. On PE1, the show ip bgp vpnv4 vrf CUSTOMER command shows the route for 10.2.2.0/24 with a next-hop of 192.168.1.2, and the show ip route vrf CUSTOMER command shows the route as well. However, traffic from CE1 to CE2 fails. The show ip cef vrf CUSTOMER 10.2.2.0 command on PE1 shows the next-hop as 192.168.1.2 but the output interface is 'no route'. What is the most likely cause?

Question 4hardmultiple choice

An engineer is troubleshooting an MPLS L3VPN where CE1 (10.1.1.0/24) cannot reach CE2 (10.2.2.0/24). The PE routers have MP-BGP peering and the VRF is configured with route-target import 100:100. On PE1, the show ip bgp vpnv4 vrf CUSTOMER command shows the route for 10.2.2.0/24 with a next-hop of 192.168.1.2, but the show ip route vrf CUSTOMER command does not have this route. The show ip bgp vpnv4 all 10.2.2.0/24 command on PE1 shows the route is received but not best. What is the most likely cause?

Question 5hardmultiple choice

A network engineer is troubleshooting an MPLS L3VPN where CE1 (10.1.1.0/24) cannot reach CE2 (10.2.2.0/24). The PE routers are using eBGP with the CEs. On PE1, the show ip bgp vpnv4 vrf CUSTOMER command shows the route for 10.2.2.0/24 with a next-hop of 192.168.1.2, and the show ip route vrf CUSTOMER command shows the route. However, traffic from CE1 to CE2 fails. The show ip cef vrf CUSTOMER 10.2.2.0 command on PE1 shows the next-hop as 192.168.1.2 and the output interface as GigabitEthernet0/0. The show mpls forwarding-table 192.168.1.2 detail command on PE1 shows a label but the outgoing interface is 'aggregate'. What is the most likely cause?

Question 6mediummultiple choice

An engineer is troubleshooting an MPLS L3VPN where CE1 (10.1.1.0/24) cannot reach CE2 (10.2.2.0/24). The PE routers are using OSPF with the CEs. On PE1, the show ip bgp vpnv4 vrf CUSTOMER command shows the route for 10.2.2.0/24 with a next-hop of 192.168.1.2, and the show ip route vrf CUSTOMER command shows the route. However, traffic from CE1 to CE2 fails. The show ip cef vrf CUSTOMER 10.2.2.0 command on PE1 shows the next-hop as 192.168.1.2 and the output interface as GigabitEthernet0/0. The show ip route 192.168.1.2 command on PE1 shows the route with a next-hop of 10.0.0.2 and output interface GigabitEthernet0/0. The show mpls forwarding-table 192.168.1.2 detail command on PE1 shows a label with outgoing interface GigabitEthernet0/0. What is the most likely cause?

Question 7hardmultiple choice

A network engineer is troubleshooting an MPLS L3VPN where CE1 (10.1.1.0/24) cannot reach CE2 (10.2.2.0/24). The PE routers are using eBGP with the CEs. On PE1, the show ip bgp vpnv4 vrf CUSTOMER command shows the route for 10.2.2.0/24 with a next-hop of 192.168.1.2, and the show ip route vrf CUSTOMER command shows the route. However, traffic from CE1 to CE2 fails. The show ip bgp vpnv4 vrf CUSTOMER 10.2.2.0/24 command on PE1 shows the route is received and best, but the show ip bgp vpnv4 vrf CUSTOMER 10.2.2.0/24 neighbors 192.168.1.2 advertised-routes command on PE2 shows the route is not advertised. What is the most likely cause?

Question 8mediummultiple choice

An engineer is troubleshooting an MPLS L3VPN where CE1 (10.1.1.0/24) cannot reach CE2 (10.2.2.0/24). The PE routers are using OSPF with the CEs. On PE1, the show ip bgp vpnv4 vrf CUSTOMER command shows the route for 10.2.2.0/24 with a next-hop of 192.168.1.2, and the show ip route vrf CUSTOMER command shows the route. However, traffic from CE1 to CE2 fails. The show ip cef vrf CUSTOMER 10.2.2.0 command on PE1 shows the next-hop as 192.168.1.2 and the output interface as GigabitEthernet0/0. The show mpls forwarding-table 192.168.1.2 detail command on PE1 shows a label with outgoing interface GigabitEthernet0/0. The show ip route 192.168.1.2 command on PE1 shows the route with a next-hop of 10.0.0.2 and output interface GigabitEthernet0/0. The show ip cef 192.168.1.2 command on PE1 shows the next-hop as 10.0.0.2 and output interface GigabitEthernet0/0. What is the most likely cause?

Question 9hardmultiple choice

A network engineer is troubleshooting an MPLS L3VPN where CE1 (10.1.1.0/24) cannot reach CE2 (10.2.2.0/24). The PE routers are using eBGP with the CEs. On PE1, the show ip bgp vpnv4 vrf CUSTOMER command shows the route for 10.2.2.0/24 with a next-hop of 192.168.1.2, and the show ip route vrf CUSTOMER command shows the route. However, traffic from CE1 to CE2 fails. The show ip bgp vpnv4 vrf CUSTOMER 10.2.2.0/24 command on PE1 shows the route is received and best, but the show ip bgp vpnv4 vrf CUSTOMER 10.2.2.0/24 command on PE1 also shows the route has the 'r' flag (RIB-failure). What is the most likely cause?

Question 10mediummultiple choice

A network engineer runs the following command on Router PE1:

PE1# show mpls forwarding-table 192.168.1.0 24

Local Outgoing Prefix Bytes Label Outgoing Next Hop Label Label or Tunnel Id Switched interface 16 Pop Label 192.168.1.0/24 0 Gi0/0 10.1.1.2 17 22 192.168.1.0/24 0 Gi0/1 10.2.2.2

Based on this output, which statement is correct?

Question 11mediummultiple choice

A network engineer runs the following command on Router PE2:

PE2# show ip bgp vpnv4 vrf CUSTOMER_A 10.10.10.0 24

BGP routing table entry for 10.10.10.0/24, version 15 Paths: (1 available, best #1, table CUSTOMER_A) Advertised to update-groups: 1 Refresh Epoch 1 Local, imported path from 10.10.10.0/24

10.1.1.1 (metric 20) from 10.1.1.1 (10.1.1.1)

Origin incomplete, metric 0, localpref 100, valid, internal, best Extended Community: RT:100:100 mpls labels in/out 18/19

Based on this output, what is the problem?

Question 12mediummultiple choice

A network engineer runs the following command on Router P1:

P1# show mpls ldp neighbor

Peer LDP Ident: 10.0.0.2:0, Local LDP Ident: 10.0.0.1:0 TCP connection: 10.0.0.2.646 - 10.0.0.1.48632 State: Oper, Msgs sent/rcvd: 120/118, Downstream Up time: 00:12:34 LDP discovery sources: GigabitEthernet0/0, Src IP addr: 10.1.1.2 Addresses bound to peer LDP Ident:

10.0.0.2         192.168.1.1

Based on this output, which statement is correct?

Question 13mediummultiple choice

A network engineer runs the following command on Router CE1:

CE1# show ip route vrf CUSTOMER_B 10.20.20.0 24

Routing Table: CUSTOMER_B Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2 E1 - OSPF external type 1, E2 - OSPF external type 2 i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2 ia - IS-IS inter area, * - candidate default, U - per-user static route o - ODR, P - periodic downloaded static route

Gateway of last resort is not set

10.0.0.0/24 is subnetted, 1 subnets
B       10.20.20.0 [20/0] via 10.1.1.2, 00:02:34

Based on this output, what is the problem?

Question 14easymultiple choice

A network engineer runs the following command on Router PE3:

PE3# show ip vrf interfaces
Interface      IP-Address      VRF                              Protocol

Gi0/0 10.1.1.1 CUSTOMER_C up Gi0/1 10.2.2.1 CUSTOMER_D up

Based on this output, which statement is correct?

Question 15hardmultiple choice

A network engineer runs the following command on Router PE4:

PE4# show bgp vpnv4 unicast all summary

BGP router identifier 10.0.0.4, local AS number 65001 BGP table version is 25, main routing table version 25 5 network prefixes using 640 bytes of memory 5 path entries using 400 bytes of memory 3/3 BGP path/bestpath attribute entries using 360 bytes of memory 1 BGP AS-PATH entries using 24 bytes of memory 0 BGP route-map cache entries using 0 bytes of memory 0 BGP filter-list cache entries using 0 bytes of memory BGP using 1424 total bytes of memory BGP activity 15/10 prefixes, 20/15 paths, scan interval 60 secs

Neighbor        V           AS MsgRcvd MsgSent   TblVer  InQ OutQ Up/Down  State/PfxRcd
10.0.0.5        4        65001    1020    1015       25    0    0 00:12:34        5
10.0.0.6        4        65002     500     495       25    0    0 00:06:20        0

Based on this output, what is the problem?

Question 16easymultiple choice

A network engineer runs the following command on Router PE5:

PE5# show ip ospf neighbor

Neighbor ID     Pri   State           Dead Time   Address         Interface
10.0.0.7          1   FULL/DR        00:00:32    10.1.1.7        GigabitEthernet0/0
10.0.0.8          1   FULL/BDR       00:00:35    10.2.2.8        GigabitEthernet0/1

Based on this output, which statement is correct?

Question 17hardmultiple choice

A network engineer runs the following command on Router PE6:

PE6# show mpls forwarding-table

Local Outgoing Prefix Bytes Label Outgoing Next Hop Label Label or Tunnel Id Switched interface 16 Pop Label 10.0.0.1/32 0 Gi0/0 10.1.1.1 17 20 10.0.0.2/32 0 Gi0/1 10.2.2.2 18 Untagged 10.0.0.3/32 0 Gi0/2 10.3.3.3

Based on this output, what is the problem?

Question 18mediummultiple choice

A network engineer runs the following command on Router PE7:

PE7# show bgp vpnv4 unicast vrf CUSTOMER_E labels

Network Next Hop In Label/Out Label

10.10.10.0/24    10.0.0.8            18/22
   10.20.20.0/24    10.0.0.9            19/23

Based on this output, which statement is correct?

Question 19mediummultiple choice

Examine the following partial configuration on a PE router:

interface GigabitEthernet0/1
 ip vrf forwarding CUSTOMER-A
 ip address 10.1.1.1 255.255.255.252

router bgp 65000
 neighbor 192.168.1.1 remote-as 65000
 neighbor 192.168.1.1 update-source Loopback0

! address-family ipv4 vrf CUSTOMER-A

neighbor 10.1.1.2 remote-as 65001
  neighbor 10.1.1.2 activate

exit-address-family

What is the effect of this configuration?

Question 20mediummultiple choice

Consider the following configuration on a PE router:

ip vrf CUSTOMER-B

rd 100:1 route-target export 100:1 route-target import 100:2 !

interface GigabitEthernet0/2
 ip vrf forwarding CUSTOMER-B
 ip address 192.168.2.1 255.255.255.252

What is the effect of this configuration?

Question 21mediummultiple choice

A PE router has the following configuration:

router bgp 65000
 neighbor 10.0.0.1 remote-as 65000
 neighbor 10.0.0.1 update-source Loopback0

! address-family vpnv4

neighbor 10.0.0.1 activate
  neighbor 10.0.0.1 send-community extended

exit-address-family

What is wrong with this configuration?

Question 22mediummultiple choice

Examine the following configuration on a PE router:

ip vrf CUSTOMER-C

rd 200:1 !

interface GigabitEthernet0/3
 ip vrf forwarding CUSTOMER-C
 ip address 10.2.2.1 255.255.255.252

router ospf 1 vrf CUSTOMER-C
 network 10.2.2.0 0.0.0.3 area 0

router bgp 65000

address-family ipv4 vrf CUSTOMER-C redistribute ospf 1 exit-address-family

What is missing from this configuration?

Question 23mediummultiple choice

A PE router has the following configuration:

ip vrf CUSTOMER-D

rd 300:1 route-target export 300:1 route-target import 300:1 !

interface GigabitEthernet0/4
 ip vrf forwarding CUSTOMER-D
 ip address 10.3.3.1 255.255.255.252

router bgp 65000
 neighbor 10.0.0.1 remote-as 65000
 neighbor 10.0.0.1 update-source Loopback0

! address-family vpnv4

neighbor 10.0.0.1 activate
  neighbor 10.0.0.1 send-community extended

exit-address-family ! address-family ipv4 vrf CUSTOMER-D

neighbor 10.3.3.2 remote-as 65002
  neighbor 10.3.3.2 activate

exit-address-family

What is the effect of this configuration?

Question 24mediummultiple choice

Examine the following configuration on a PE router:

ip vrf CUSTOMER-E

rd 400:1 route-target export 400:1 route-target import 400:2 !

interface GigabitEthernet0/5
 ip vrf forwarding CUSTOMER-E
 ip address 10.4.4.1 255.255.255.252

router bgp 65000
 neighbor 10.0.0.1 remote-as 65000
 neighbor 10.0.0.1 update-source Loopback0

! address-family vpnv4

neighbor 10.0.0.1 activate
  neighbor 10.0.0.1 send-community extended

exit-address-family ! address-family ipv4 vrf CUSTOMER-E

neighbor 10.4.4.2 remote-as 65003
  neighbor 10.4.4.2 activate
  neighbor 10.4.4.2 route-map SET-COMMUNITY in

exit-address-family ! route-map SET-COMMUNITY permit 10 set community 100:100

What is the effect of the route-map on the incoming routes from the CE?

Question 25easymultiple choice

In MPLS L3VPN, what is the purpose of the Route Distinguisher (RD)?

Question 26easymultiple choice

In MPLS L3VPN, what is the default behavior when a PE router receives a VPNv4 route with a Route Target that does not match any import RT on any VRF?

Question 27mediummultiple choice

Which of the following statements about MPLS L3VPN label operations is true?

Question 28mediummulti select

Which TWO commands can be used to verify the MPLS L3VPN label forwarding table on a PE router? (Choose TWO.)

Question 29mediummulti select

Which TWO statements about route targets (RT) in MPLS L3VPN are true? (Choose TWO.)

Question 30hardmulti select

Which THREE symptoms indicate a misconfiguration in the MPLS L3VPN control plane between two PEs? (Choose THREE.)

Question 31mediummulti select

Which TWO configuration steps are required to enable MPLS L3VPN on a new PE router? (Choose TWO.)

Question 32hardmulti select

Which THREE commands would a network engineer use to troubleshoot an MPLS L3VPN issue where a CE router cannot reach a remote CE? (Choose THREE.)

Question 33mediummultiple choice

A network engineer runs the following command to troubleshoot an MPLS L3VPN issue:

R1# debug mpls ldp transport

Output:

*Mar  1 00:01:23.456: mpls_ldp_transport: LDP transport connection from 10.0.0.2:646 to 10.0.0.1:1025
*Mar  1 00:01:23.456: mpls_ldp_transport: LDP transport connection from 10.0.0.2:646 to 10.0.0.1:1025 is accepted
*Mar  1 00:01:23.456: mpls_ldp_transport: LDP transport connection from 10.0.0.2:646 to 10.0.0.1:1025 is established
*Mar  1 00:01:23.456: mpls_ldp_transport: LDP transport connection from 10.0.0.2:646 to 10.0.0.1:1025 is up

What does this output indicate?

Question 34mediummultiple choice

A network engineer runs the following command to verify MPLS L3VPN operation:

R1# show mpls ldp bindings

Output: lib entry: 10.1.1.0/24, rev 2 local binding: label: 101 remote binding: lsr: 10.0.0.2:0, label: 201 lib entry: 10.2.2.0/24, rev 4 local binding: label: 102 remote binding: lsr: 10.0.0.2:0, label: 202 lib entry: 10.3.3.0/24, rev 6 local binding: label: 103 remote binding: lsr: 10.0.0.2:0, label: imp-null

What does this output indicate?

Question 35mediummultiple choice

A network engineer runs the following command to troubleshoot an MPLS L3VPN issue:

R1# show mpls ldp neighbor detail

Output: Peer LDP Ident: 10.0.0.2:0, Local LDP Ident: 10.0.0.1:0 TCP connection: 10.0.0.2.646 - 10.0.0.1.17905 State: Oper, Msg sent: 123, Msg rcvd: 456 Up time: 1w2d LDP discovery sources: GigabitEthernet0/0, Src IP addr: 10.12.0.2 Addresses bound to peer LDP Ident:

10.0.0.2        10.12.0.2

Peer hold time: 15 sec

What does this output indicate?

Question 36mediummultiple choice

A network engineer runs the following command to verify MPLS L3VPN operation:

R1# show ip route vrf CUSTOMER-A summary

Output: Route Source Networks Subnets Overhead Memory (bytes) connected 2 0 48 288 static 1 0 24 144 ospf 100 5 2 168 1008 bgp 65000 10 3 312 1872 External: 10, Internal: 0, Local: 0 Total 18 5 552 3312

What does this output indicate?

Question 37hardmultiple choice

A network engineer runs the following command to troubleshoot an MPLS L3VPN issue:

R1# show bgp vpnv4 vrf CUSTOMER-A 10.1.1.0/24

Output: BGP routing table entry for 10.1.1.0/24, version 10 Paths: (1 available, best #1, table CUSTOMER-A) Advertised to update-groups: 1 Refresh Epoch 1 Local

0.0.0.0 from 0.0.0.0 (10.0.0.1)

Origin incomplete, metric 0, localpref 100, weight 32768, valid, sourced, best Extended Community: RT:100:100 mpls labels in/out nolabel/nolabel

What does this output indicate?

Question 38mediummultiple choice

A network engineer runs the following command to troubleshoot an MPLS L3VPN issue:

R1# debug ip bgp updates

Output:

*Mar  1 00:01:23.456: BGP(0): 10.0.0.2 UPDATE out w/ attr: nexthop 10.0.0.1, origin i, metric 0, path 65000, extended community RT:100:100
*Mar  1 00:01:23.456: BGP(0): 10.0.0.2 UPDATE out for 10.1.1.0/24
*Mar  1 00:01:23.456: BGP(0): 10.0.0.2 UPDATE run, update group 1

What does this output indicate?

Question 39mediummultiple choice

A network engineer runs the following command to verify MPLS L3VPN operation:

R1# show bgp ipv4 unicast 10.1.1.0/24

Output: BGP routing table entry for 10.1.1.0/24, version 10 Paths: (1 available, best #1, table default) Advertised to update-groups: 1 Refresh Epoch 1 Local

0.0.0.0 from 0.0.0.0 (10.0.0.1)

Origin incomplete, metric 0, localpref 100, weight 32768, valid, sourced, best

What does this output indicate?

Question 40mediummultiple choice

A network engineer runs the following command to troubleshoot an MPLS L3VPN issue:

R1# show bgp neighbors 10.0.0.2 advertised-routes

Output: BGP table version is 10, local router ID is 10.0.0.1 Status codes: s suppressed, d damped, h history, * valid, > best, i - internal, r RIB-failure, S stale, m multipath, b backup-path, f RT-Filter, x best-external, a additional-path, c RIB-compressed, Origin codes: i - IGP, e - EGP, ? - incomplete

Network Next Hop Metric LocPrf Weight Path *> 10.1.1.0/24 0.0.0.0 0 32768 i *> 10.2.2.0/24 0.0.0.0 0 32768 i

Total number of prefixes 2

What does this output indicate?

Question 41mediummultiple choice

A network engineer runs the following command to troubleshoot an MPLS L3VPN issue:

R1# show bgp neighbors 10.0.0.2 received-routes

Network Next Hop Metric LocPrf Weight Path *> 10.3.3.0/24 10.0.0.2 0 100 0 65000 i *> 10.4.4.0/24 10.0.0.2 0 100 0 65000 i

Total number of prefixes 2

What does this output indicate?

Question 42easymultiple choice

In an MPLS L3VPN environment using MP-BGP, what is the default value of the BGP keepalive timer on Cisco IOS-XE?

Question 43easymultiple choice

What is the default BGP hold timer value in an MPLS L3VPN deployment on Cisco IOS-XE?

Question 44mediummultiple choice

In MPLS L3VPN, which LSA type is used by OSPF to advertise prefix information from a PE router into a customer VRF instance?

Question 45mediummultiple choice

What is the default administrative distance for OSPF routes in a VRF when OSPF is used as the PE-CE routing protocol in MPLS L3VPN?

Question 46hardmultiple choice

In MPLS L3VPN, what is the default behavior of BGP auto-summary on Cisco IOS-XE?

Question 47mediummultiple choice

Which BGP path attribute is used as the tie-breaker after the local preference and AS-path length in the BGP best path selection algorithm?

Question 48hardmultiple choice

In an MPLS L3VPN environment, what is the default maximum number of routes that can be installed from a single BGP peer?

Question 49mediummultiple choice

What is the default BGP update timer (advertisement interval) for eBGP peers in Cisco IOS-XE?

Question 50hardmultiple choice

In MPLS L3VPN, which OSPF network type is used by default on a Frame Relay point-to-point subinterface when OSPF is enabled?

Question 51mediumdrag order

Drag and drop the steps to set up a PE-CE BGP session in an MPLS L3VPN into the correct order, from first to last.

Question 52harddrag order

Drag and drop the steps to troubleshoot an MPLS L3VPN adjacency or connectivity failure into the correct order, from first to last.

Question 53mediumdrag order

Drag and drop the steps to verify and validate the MPLS L3VPN operational state into the correct order, from first to last.

Question 54hardmulti select

Which TWO statements about the interaction between MP-BGP and the VRF routing table in an MPLS L3VPN PE router are correct? (Choose TWO.)

Question 55hardmulti select

An engineer must prevent a VRF on a PE router from learning routes from a specific remote site in an MPLS L3VPN. Which TWO configuration changes on the local PE can achieve this? (Choose TWO.)

Question 56hardmulti select

Which TWO statements about the 'show ip bgp vpnv4 vrf <vrf-name>' command output are correct? (Choose TWO.)

Question 57hardmulti select

Which TWO statements about the use of 'mpls ldp autoconfig' in an MPLS L3VPN environment are true? (Choose TWO.)

Question 58hardmulti select

Which THREE commands can be used to verify the MPLS label assigned to a specific prefix in a VRF on a PE router? (Choose THREE.)

Question 59hardmultiple choice

Study the full EIGRP explanation →

An engineer configures OSPF between two PE routers in an MPLS L3VPN backbone. Both routers are directly connected via a GigabitEthernet link. The OSPF adjacency forms and then repeatedly flaps between FULL and EXSTART. The engineer verifies that both routers have matching OSPF network types (broadcast), matching area IDs, and no authentication mismatch. What is the most likely cause of the flapping?

Question 60hardmultiple choice

An engineer configures EIGRP named mode on two routers in an MPLS L3VPN. The routers are directly connected and can ping each other. The engineer notices that the EIGRP adjacency forms but then the neighbor relationship goes down and the routers become stuck-in-active (SIA) for certain routes. The engineer checks the logs and sees no errors. What is the most likely explanation?

Question 61hardmultiple choice

An engineer configures iBGP between two PE routers in an MPLS L3VPN. The PE routers are in the same AS and are directly connected. The engineer configures 'neighbor x.x.x.x next-hop-self' on the route reflector (RR) but notices that the RR is not sending the VPNv4 routes to the client PE with the next-hop set to itself. The client PE receives the routes but the next-hop remains the original PE. What is the most likely explanation?

Question 62hardmultiple choice

An engineer configures mutual redistribution between OSPF and EIGRP on a PE router in an MPLS L3VPN. The engineer does not configure any route tagging or filtering. After a few minutes, the OSPF and EIGRP domains become unstable, with routes flapping and high CPU usage. What is the most likely explanation?

Question 63hardmultiple choice

An engineer configures DMVPN Phase 2 on a hub-and-spoke network for an MPLS L3VPN customer. The spokes are configured with a single tunnel interface and use NHRP to register with the hub. The engineer notices that spoke-to-spoke traffic is not being established, even though the spokes have each other's NHRP mappings. The engineer verifies that the tunnel interfaces are up and that the hub can reach all spokes. What is the most likely explanation?

Question 64hardmultiple choice

An engineer configures IPsec between two PE routers in an MPLS L3VPN using a site-to-site VPN. The engineer configures a transform-set with ESP encryption (AES-256) and ESP authentication (SHA-256). The engineer also configures an ACL to define interesting traffic. The VPN tunnel comes up, but no traffic is encrypted. The engineer verifies that the ACL is correct and that the crypto map is applied to the interface. What is the most likely explanation?

Question 65hardmultiple choice

An engineer configures Control Plane Policing (CoPP) on a PE router in an MPLS L3VPN to protect the control plane. The engineer creates a policy-map that matches BGP packets and applies a police rate of 100 pps. The engineer also configures a class-default with a police rate of 10 pps. After applying the policy to the control-plane, the engineer notices that BGP sessions are flapping and the router is dropping BGP packets. The engineer verifies that the ACL for BGP is correct. What is the most likely explanation?

Question 66hardmultiple choice

An engineer configures unicast Reverse Path Forwarding (uRPF) in strict mode on the ingress interface of a PE router in an MPLS L3VPN. The router is receiving VPN traffic from a customer edge (CE) router. The engineer notices that some legitimate traffic is being dropped by uRPF. The engineer verifies that the CE router has a route back to the source address in its routing table. What is the most likely explanation?

Question 67hardmultiple choice