350-501 Architecture — All Questions With Answers

A service provider is designing a new MPLS L3VPN service. The customer requires that their VPN traffic be isolated from other customers and that the provider edge routers maintain separate routing tables for each VPN. Which architectural component is essential for this separation?

Question 2hardmultiple choice

An operator notices that a new MPLS-TE tunnel is not being established. The tunnel configuration includes a dynamic path option and a bandwidth of 100 Mbps. The network uses RSVP-TE with CSPF. The link-state database shows sufficient reservable bandwidth on all links along the calculated path. What is the most likely cause of the tunnel establishment failure?

Question 3easymultiple choice

Which network architecture model separates the control plane and data plane in a way that allows for centralized control and distributed forwarding?

Question 4mediummultiple choice

A service provider is troubleshooting a BGP route advertisement issue. Routes from a customer are not being advertised to the upstream provider. The PE router is configured with 'neighbor 10.0.0.1 route-map RMAP out'. The route-map RMAP permits the customer prefix. However, the BGP table on the PE shows the prefix as valid but not advertised. What is a likely cause?

Question 5hardmultiple choice

In a carrier's network, MPLS-TE tunnels are used to steer traffic away from congested links. The operator configures a tunnel with a bandwidth of 200 Mbps and a dynamic path. The CSPF computation shows a path with sufficient bandwidth, but the tunnel fails to come up. The RSVP neighbor is established. What is the most likely cause?

Question 6easymultiple choice

A service provider wants to offer Layer 2 VPN services using MPLS. Which technology should be used to transport Ethernet frames across the MPLS core?

Question 7mediummultiple choice

An engineer is designing an MPLS L3VPN solution and must ensure that the provider edge (PE) routers can handle routing updates for multiple customers without interfering with each other. Which mechanism should be used on the PE routers?

Question 8hardmultiple choice

A network operator is deploying segment routing in an MPLS network. They want to use a centralized controller to compute paths based on traffic demand and network constraints. Which architecture is being used?

Question 9mediummulti select

Which TWO of the following are characteristics of MPLS L3VPN architecture? (Choose two.)

Question 10mediummulti select

Which TWO of the following are advantages of segment routing over traditional LDP-based MPLS? (Choose two.)

Question 11mediummulti select

Which THREE of the following are key components of an MPLS L3VPN architecture? (Choose three.)

Question 12mediummultiple choice

Refer to the exhibit. A network engineer configures a BGP route-map to set communities on routes advertised to a neighbor. After applying the configuration, the engineer checks the BGP table on the neighbor router and does not see the communities. What is the most likely reason?

Exhibit

Refer to the exhibit.

router bgp 65000
 neighbor 10.0.0.1 remote-as 65001
 neighbor 10.0.0.1 route-map SET-COMMUNITY out
!
route-map SET-COMMUNITY permit 10
 match ip address prefix-list CUSTOMER_PREFIXES
 set community 65000:100 65000:200
!
ip prefix-list CUSTOMER_PREFIXES seq 5 permit 192.168.0.0/24

Question 13hardmultiple choice

Refer to the exhibit. An engineer configures MPLS LDP on a router. The router has two interfaces with IP addresses 10.0.0.1/30 and 10.0.0.5/30. The engineer notices that LDP sessions are not established. The OSPF neighbor adjacencies are up. What is the most likely cause?

Exhibit

Refer to the exhibit.

interface GigabitEthernet0/0
 ip address 10.0.0.1 255.255.255.252
 mpls ip
 mpls mtu 1500
!
interface GigabitEthernet0/1
 ip address 10.0.0.5 255.255.255.252
 mpls ip
 mpls mtu 1500
!
router ospf 1
 network 10.0.0.0 0.0.0.3 area 0
 network 10.0.0.4 0.0.0.3 area 0
!
mpls ldp router-id Loopback0 force
!
mpls label range 100 199
!
mpls label protocol ldp

Question 14hardmultiple choice

You are a network architect for a large service provider. The network consists of multiple core routers (P routers) and edge routers (PE routers) supporting both L3VPN and L2VPN services. The network currently uses LDP for label distribution and has a flat IGP (OSPF) design. Recently, there have been scalability issues: the IGP convergence time has increased significantly, and the OSPF link-state database (LSDB) has grown large, causing high CPU utilization on core routers. Additionally, the LDP sessions are taking longer to establish after a router reboot. You are tasked with redesigning the network to improve scalability and convergence. The budget allows for significant changes but cannot replace all hardware. Which approach best addresses the scalability issues while minimizing disruption?

Question 15mediummultiple choice

You are a network engineer at a service provider that offers L3VPN services. A customer complains that their VPN traffic is intermittently dropping. The network uses OSPF as the IGP, LDP for label distribution, and MP-BGP for VPNv4 route exchange. The PE routers are connected to two core routers (P1 and P2) in a redundant design. Upon investigation, you find that the BGP next-hop for some VPN prefixes is set to the loopback interface of the remote PE, but the route to that loopback is sometimes unreachable due to a flapping link between P1 and P2. The IGP converges, but the BGP prefixes take longer to recover. What is the most likely cause of the intermittent drops?

Question 16mediummultiple choice

Study the full IPv6 explanation →

A service provider is redesigning its MPLS core to support both L3VPN and L2VPN services. They want to minimize the number of labels in the forwarding table while maintaining per-VRF label allocation. Which label allocation mode should be used for the L3VPN service?

Question 17hardmultiple choice

A service provider is deploying Segment Routing over IPv6 (SRv6) and needs to ensure that the forwarding plane can support SRv6 encapsulated packets. Which hardware capability is most critical for SRv6 at the line rate?

Question 18easymultiple choice

A network engineer is troubleshooting an OSPF issue in a service provider network. The network uses OSPFv2 with multiple areas. Routers in area 0 are able to ping each other, but routers in area 1 cannot reach routers in area 2. All routers are OSPF-enabled and have correct network type configurations. What is the most likely cause?

Question 19hardmultiple choice

A service provider is implementing MPLS-TE with FRR (Fast Reroute) using one-to-one backup tunnels. After activation, they notice that the number of labels in the forwarding table has increased significantly. What is the most likely reason for this increase?

Question 20mediummultiple choice

A service provider is deploying EVPN-MPLS for L2VPN services. The customer requires that MAC addresses learned from one PE are not advertised to other PEs unless they are active. Which EVPN route type is used for MAC address withdrawal?

Question 21hardmulti select

Which TWO statements about MPLS label operations in a service provider core are correct? (Choose two.)

Question 22mediummulti select

Which THREE of the following are required components for implementing MPLS Layer 3 VPN (L3VPN) in a service provider network? (Choose three.)

Question 23mediummultiple choice

A customer reports that CE routers attached to PE1 and PE2 in the same VRF cannot ping each other. Based on the exhibit, what is the most likely cause?

Exhibit

Refer to the exhibit.

PE1 configuration:
router bgp 65000
 neighbor 10.0.0.2 remote-as 65000
 neighbor 10.0.0.2 update-source Loopback0
 !
 address-family vpnv4
  neighbor 10.0.0.2 activate
  neighbor 10.0.0.2 send-community extended
 exit-address-family
!
ip vrf CUSTOMER_A
 rd 65000:1
 route-target export 65000:100
 route-target import 65000:100
!
interface GigabitEthernet0/0/0/0
 ip vrf forwarding CUSTOMER_A
 ip address 192.168.1.1 255.255.255.0
!

PE2 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
!
ip vrf CUSTOMER_A
 rd 65000:1
 route-target export 65000:100
 route-target import 65000:100
!
interface GigabitEthernet0/0/0/0
 ip vrf forwarding CUSTOMER_A
 ip address 192.168.2.1 255.255.255.0
!

Question 24easymultiple choice

Based on the exhibit, which label operation will occur when a packet destined to 10.2.2.1 enters PE1 with label 17?

Exhibit

Refer to the exhibit.

PE1# show mpls forwarding-table
Local      Outgoing   Prefix           Bytes Label   Outgoing   Next Hop
Label      Label      or Tunnel Id     Switched      interface
16         Pop       10.1.1.0/24      0             Gi0/0/0/0  point2point
17         18         10.2.2.0/24      0             Gi0/0/0/1  192.168.1.2
18         Untagged  10.3.3.0/24      0             Gi0/0/0/2  192.168.2.2

Question 25mediummultiple choice

Refer to the exhibit. The router is configured as a PE router in an MPLS VPN network. Which option correctly identifies a configuration error that would prevent proper operation?

Exhibit

Refer to the exhibit.

interface GigabitEthernet0/0/0/0
 description Link to PE2
 ipv4 address 10.1.1.1 255.255.255.252
 ipv6 address 2001:DB8::1/64
!
router ospf 1
 router-id 1.1.1.1
 network 10.0.0.0 0.255.255.255 area 0
!
router bgp 65001
 bgp router-id 1.1.1.1
 bgp log-neighbor-changes
 neighbor 10.1.1.2 remote-as 65002
 address-family ipv4 unicast
  network 10.1.1.0 mask 255.255.255.252
  neighbor 10.1.1.2 activate
 exit-address-family

Question 26hardmultiple choice

A service provider is deploying an MPLS L3VPN solution for a customer with two sites. The PE routers are running OSPF as the IGP and LDP for label distribution. The provider wants to ensure that customer traffic is load-balanced across two equal-cost paths between the PEs. The network team notices that all traffic is taking only one path despite the IGP showing equal-cost routes. The team has verified that the MPLS forwarding table on the P router shows only one label entry for the BGP next-hop. The team suspects a load-balancing issue. Which action best resolves the problem?

Question 27easymultiple choice

A service provider is designing a new MPLS core network and needs to choose a routing protocol that supports traffic engineering and fast convergence. Which protocol should be used?

Question 28mediummultiple choice

An engineer is troubleshooting a BGP route propagation issue. The customer is receiving a default route from upstream provider, but the route is not being installed in the routing table. The BGP table shows the route is valid but not best. What is the most likely cause?

Question 29hardmultiple choice

A network engineer is designing a Layer 2 VPN using EVPN with MPLS data plane. The customer requires all-hub multipoint connectivity with optimal multicast replication. Which EVPN route type is used to advertise multicast group membership?

Question 30easymultiple choice

An engineer is configuring QoS on a service provider edge router to prioritize real-time traffic. Which queuing mechanism provides the lowest latency and jitter for voice traffic?

Question 31mediummultiple choice

A service provider is implementing MPLS TE to optimize bandwidth utilization. The engineer notices that tunnels are not using the explicitly configured path. What is the most likely reason?

Question 32hardmultiple choice

A network engineer needs to design a multicast solution for IPTV distribution across a service provider network. Which protocol is best suited for building a shared distribution tree where the RP is dynamically elected?

Question 33easymultiple choice

A service provider is deploying Segment Routing in the MPLS core using IS-IS. Which extension is required in IS-IS to advertise the prefix-SID?

Question 34mediumdrag order

Study the full EIGRP explanation →

Drag and drop the steps to configure OSPF on a Cisco IOS router into the correct order.

Drag steps to the numbered slots on the right, or tap a step then tap a slot.

Steps

Order

1Step 1

2Step 2

3Step 3

4Step 4

5Step 5

Question 35mediumdrag order

Drag and drop the steps to configure EIGRP on a Cisco router into the correct order.

Drag steps to the numbered slots on the right, or tap a step then tap a slot.

Steps

Order

1Step 1

2Step 2

3Step 3

4Step 4

5Step 5

Question 36mediummatching

Match each MPLS VPN technology to its description.

Drag a concept onto its matching description — or click a concept then click the description.

Concepts

Matches

Uses BGP to distribute VPN routes between PE routers

Emulates Layer 2 services like Ethernet or ATM over MPLS

Multipoint Layer 2 VPN that simulates an Ethernet LAN

Point-to-point Layer 2 VPN providing pseudowire connectivity

Multicast VPN that supports IP multicast over MPLS

Question 37mediummatching

Match each MPLS protection mechanism to its description.

Drag a concept onto its matching description — or click a concept then click the description.

Concepts

Matches

Fast Reroute to bypass a failed link or node locally

End-to-end path protection for MPLS TE tunnels

Graceful restart for LDP to preserve forwarding during control plane restart

Prefix Independent Convergence for fast BGP failover

Fast Reroute for RSVP-TE tunnels using backup paths

Question 38easymultiple choice

A service provider is deploying MPLS in its core network. The core routers are all configured with LDP. Which label operation does an ingress PE perform on the first packet of a new flow?

Question 39mediummultiple choice

Read the full NAT/PAT explanation →

A network engineer is troubleshooting QoS in a service provider environment. Customer traffic is marked with DSCP AF31 (011010) at the CE. On the PE router, the policy maps trust DSCP and sets the CoS to 4. However, core routers remark the DSCP to 0. What is the most likely cause?

Question 40hardmultiple choice

A service provider is deploying Segment Routing (SR) with TI-LFA for fast convergence. Which mechanism does TI-LFA use to repair a link failure in a node segment path?

Question 41easymultiple choice

In an MPLS VPN environment, which address family is used to exchange VPNv4 routes between PE routers?

Question 42mediummultiple choice

An SP is deploying Inter-AS MPLS VPN option B. Which design characteristic is unique to Option B compared to Option A?

Question 43hardmultiple choice

A service provider is implementing EVPN with MPLS data plane. Which encapsulation type is used in MPLS EVPN to carry Ethernet frames across the MPLS network?

Question 44easymultiple choice

Which protocol is used to discover MPLS peers for LDP session establishment?

Question 45mediummultiple choice

Study the full IPv6 explanation →

A service provider is designing a core network with IS-IS as the IGP. To support MPLS traffic engineering, which IS-IS extensions are required?

Question 46hardmultiple choice

In Segment Routing over IPv6 (SRv6), what is the function of the SRH (Segment Routing Header)?

Question 47mediummulti select

Which TWO statements about EVPN Route Type 2 (MAC/IP advertisement) are correct?

Question 48hardmulti select

Which THREE are requirements for deploying MPLS Traffic Engineering with RSVP-TE?

Question 49easymulti select

Which TWO are functions of the MPLS data plane?

Question 50mediummultiple choice

Refer to the exhibit. The router has an outgoing label of 'Pop' for prefix ***********. What does this imply?

Exhibit

Refer to the exhibit.

Router# show mpls forwarding-table
Local  Outgoing    Prefix            Bytes Label   Outgoing   Next Hop
Label  Label       or Tunnel Id      Switched      Interface
16     Pop         ***********       0             Gi0/0/0    192.168.1.2
17     18          10.1.1.0/24       1500          Gi0/0/1    192.168.2.2
18     20          10.2.2.0/24       3000          Gi0/0/1    192.168.2.2
19     Untagged    10.3.3.0/24       0             Gi0/0/2    192.168.3.2

Question 51hardmultiple choice

Refer to the exhibit. The router is configured as a route reflector for VPNv4. What is the requirement for the route reflector to propagate VPNv4 routes received from a client to other clients?

Exhibit

Refer to the exhibit.

router bgp 65000
 bgp router-id 10.0.0.1
 neighbor 10.0.0.2 remote-as 65000
 neighbor 10.0.0.2 update-source Loopback0
 neighbor 10.0.0.2 route-reflector-client
 address-family vpnv4
  neighbor 10.0.0.2 activate
 neighbor 10.0.0.3 remote-as 65000
 neighbor 10.0.0.3 update-source Loopback0
 neighbor 10.0.0.3 route-reflector-client
 address-family vpnv4
  neighbor 10.0.0.3 activate
 !
 address-family ipv4 vrf CustomerA
  redistribute connected

Question 52easymultiple choice

Refer to the exhibit. This JSON policy is used for Segment Routing Traffic Engineering. What is the purpose of the 'color' attribute?

Exhibit

Refer to the exhibit.

{
  "color": 100,
  "endpoint": {
    "type": "srte",
    "prefix": "10.10.10.1/32"
  },
  "candidate-paths": {
    "preference": 200,
    "constraints": {
      "constraint-type": "affinity",
      "affinity-map": ["BLUE"]
    }
  }
}

Question 53easymultiple choice

A service provider wants to provide Layer 3 VPN services to customers using MPLS. Which technology is used to distribute VPNv4 routes between PE routers?

Question 54easymultiple choice

Which MPLS label is used to identify the egress PE in a Layer 3 MPLS VPN?

Question 55easymultiple choice

What is the purpose of the 'mpls ldp autoconfig' command on an interface?

Question 56mediummultiple choice

A customer is experiencing intermittent packet loss in an MPLS L3VPN network. The PE routers show no errors on interfaces. Which tool can help isolate the issue by showing the complete path a packet takes through the MPLS network?

Question 57mediummultiple choice

In Segment Routing, what is the role of the 'Prefix-SID'?

Question 58mediummultiple choice

Which protocol is used to exchange label binding information in a classic MPLS network without Segment Routing?

Question 59hardmultiple choice

An SP is migrating from an MPLS LDP-based network to Segment Routing. They want to ensure that existing LDP LSPs continue to work alongside SR LSPs during the migration. Which mechanism should be configured?

Question 60hardmultiple choice

In a carrier-supporting carrier (CSC) architecture, the customer carrier runs MPLS in its network. Which technology is used to exchange VPN routes between the provider carrier and the customer carrier?

Question 61hardmultiple choice

A service provider is deploying multicast over MPLS L3VPN. Which mechanism is used to provide multicast in the core between PE routers?

Question 62mediummulti select

Which two are requirements for deploying Segment Routing in a service provider network? (Choose two.)

Question 63hardmulti select

Which three are benefits of using MPLS Layer 3 VPNs over traditional VPNs? (Choose three.)

Question 64easymulti select

Which two protocols are commonly used for label exchange in an MPLS network? (Choose two.)

Question 65mediummultiple choice

Refer to the exhibit. A PE router is showing a VRF route. What does the [200/0] indicate?

Exhibit

PE1#show ip route vrf CUSTOMER_A
      10.1.1.0/24 is directly connected, GigabitEthernet0/0/0
      10.1.2.0/24 is subnetted, 1 subnets
B        10.1.2.0 [200/0] via 10.1.1.2, 00:00:45

Question 66hardmultiple choice

Refer to the exhibit. What is the significance of the entry with 'Pop Label'?

Exhibit

PE1#show mpls forwarding-table 
Local  Outgoing    Prefix            Bytes Label   Outgoing   Next Hop    
Label  Label       or Tunnel Id      Switched      interface              
16     Pop Label   10.0.0.0/8        0             Gi0/0/0    192.168.1.1
17     34          10.0.1.0/24       0             Gi0/0/1    192.168.1.2
18     Untagged    10.0.2.0/24       0             Gi0/0/2    192.168.1.3

Question 67easymultiple choice

Refer to the exhibit. Which statement is true about this configuration?

Exhibit

interface GigabitEthernet0/0/0
 ip address 192.168.1.1 255.255.255.0
 mpls ip
 mpls ldp autocfg

Question 68easymultiple choice

A service provider is designing a Layer 3 MPLS VPN for a customer with two sites. The customer requires fast convergence in case of a PE-CE link failure. Which routing protocol should be used between PE and CE to achieve the fastest convergence?

Question 69mediummultiple choice

Read the full NAT/PAT explanation →

A service provider is troubleshooting BGP route selection for prefixes received from two different peers. The first peer prepends its AS path twice, making it longer than the second peer's path. However, the router still prefers the route with the longer AS path. Which additional attribute could cause this behavior?

Question 70hardmultiple choice

A service provider is deploying Segment Routing Traffic Engineering (SR-TE) with a Path Computation Element (PCE). The PCE fails to compute a path for an SR-TE policy configured with constraint 'avoid nodes in affinity red'. The core network has red affinity assigned to several nodes. Which is the most likely cause?

Question 71easymultiple choice

When deploying IS-IS in a large service provider core, what is the recommended network type on Ethernet interfaces to improve scalability?

Question 72mediummultiple choice

An MPLS Traffic Engineering LSP fails to establish. The RSVP signaling shows 'PathErr: Admission Control Failure'. The link has sufficient bandwidth but the headend reports a lack of resources. What is the most likely cause?

Question 73hardmultiple choice

A service provider uses BGP communities to influence routing policies. An administrator wants to prevent a specific prefix from being advertised to any external AS. Which BGP community should be applied?

Question 74easymultiple choice

In an MPLS VPN, what label operation does the egress PE perform on the VPN packet before forwarding it to the CE?

Question 75mediummultiple choice

In Inter-AS MPLS Option B, which routers exchange labeled VPNv4 prefixes directly?

Question 76hardmultiple choice

A service provider is deploying Segment Routing Traffic Engineering (SR-TE) to optimize traffic flows. Which mechanism is used to steer traffic into an SR-TE policy?

Question 77mediummulti select

A service provider is designing a BGP-based network. Which TWO are characteristics of BGP within a service provider core?

Question 78hardmulti select

An engineer is configuring LDP in an MPLS network. Which THREE are valid label distribution modes for LDP?

Question 79easymulti select

In IS-IS, which TWO are types of Link State PDUs (LSPs)?

Question 80easymultiple choice

A service provider is designing its core network to carry both IPv4 and IPv6 traffic. Which BGP approach best minimizes routing table size on core routers while maintaining full reachability?

Question 81mediummultiple choice

An engineer notices that an MPLS LSP in the core is not establishing. Which troubleshooting step should be performed first?

Question 82hardmultiple choice

A large ISP is designing a multicast architecture to support IPTV, requiring high availability and minimal traffic convergence. Which RP placement design is most appropriate?

Question 83easymultiple choice

Which encapsulation technology is commonly used in service provider networks to separate subscriber traffic in an Ethernet aggregation network?

Question 84mediummultiple choice

A service provider wants to implement Segment Routing in its MPLS core to simplify traffic engineering. What is the primary advantage of Segment Routing over traditional RSVP-TE?

Question 85hardmultiple choice

An ISP is deploying EVPN-VXLAN for its data center interconnect. Which statement about control-plane learning is correct?

Question 86easymultiple choice

Which QoS mechanism is most effective for preventing congestion on a service provider edge link when traffic exceeds the link capacity?

Question 87mediummultiple choice

An engineer needs to ensure that a core router can forward MPLS packets without checking the IP header. Which forwarding mechanism should be enabled?

Question 88hardmultiple choice

A service provider is implementing IPv6 transition in its core. Which transition mechanism is recommended for carrying IPv6 over an existing MPLS/IPv4 backbone without dual-stacking all routers?

Question 89easymulti select

Which TWO are characteristics of Segment Routing?

Question 90mediummulti select

Which THREE are benefits of implementing MPLS-TE in a service provider core?

Question 91hardmulti select

Which TWO are essential components for deploying EVPN in a service provider network?

Question 92easymultiple choice

A service provider is implementing MPLS L3VPN for a customer. The customer requires that routes from two different VPNs be imported into a single VRF. Which feature should be used?

Question 93mediummultiple choice

An SP engineer notices that BGP routes from a CE are not being installed in the VRF routing table, although the BGP session is established. The VRF configuration includes route-target import 100:1. The CE is sending routes with RT 100:1. What is the most likely cause?

Question 94hardmultiple choice

A large SP network uses Segment Routing (SR) with MPLS data plane. They want to enforce a strict path for certain traffic flows across the core while using shortest-path for others. Which technique should be used?

Question 95easymultiple choice

A service provider wants to prioritize voice traffic over data traffic on a PE-CE link. Which QoS mechanism should be applied at the PE ingress to classify packets?

Question 96mediummultiple choice

In a multicast environment, a PE router is not receiving multicast traffic from a source behind a CE. The PIM neighbors are established. The RP is reachable. What is the most likely issue?

Question 97hardmultiple choice

An SP is deploying EVPN with VXLAN encapsulation in a data center interconnect. The design requires that the control plane for MAC/VTEP learning is based on BGP. Which BGP address family must be configured?

Question 98easymultiple choice

An SP network uses NTP for synchronization. To secure NTP, which authentication mode should be used?

Question 99mediummultiple choice

Read the full REST/YANG explanation →

A service provider is experiencing suboptimal routing due to BGP route reflection. To improve path selection while maintaining IBGP scalability, which feature should be implemented?

Question 100hardmultiple choice

An SP is using NETCONF with YANG to automate VRF provisioning. The engineer notices that the NETCONF session is established but configuration changes are not applied. Which issue is most likely?

Question 101mediummulti select

A service provider is troubleshooting an L2VPN where a CE is unable to ping the remote CE. The PE-CE interfaces are up, and the pseudowire status shows 'up'. Which two actions should be taken to further isolate the issue? (Choose two.)

Question 102easymulti select

A network engineer is designing a new MPLS core. Which three of the following are recommended best practices for MPLS LDP configuration? (Choose three.)

Question 103hardmulti select

A service provider is implementing Segment Routing (SR) with MPLS. Which three statements are true regarding SR-MPLS? (Choose three.)

Question 104easymultiple choice

Refer to the exhibit. A PE router configuration for VRF CUST1 is shown. What is the most likely result when a CE sends a route with RT 100:100?

Exhibit

vrf definition CUST1
 rd 100:1
 route-target export 100:1
 route-target import 100:1
 !
 address-family ipv4

Question 105mediummultiple choice

Refer to the exhibit. Based on the exhibit, what is the most likely reason for no label bindings?

Exhibit

show mpls ldp neighbor 10.0.0.1 detail
Peer LDP Ident: 10.0.0.1:0; Local LDP Ident: 10.0.0.2:0
    TCP connection: 10.0.0.1.646 - 10.0.0.2.42653
    State: Oper; Msgs sent/rcvd: 100/105; Downstream
    Up time: 00:10:00
    Label bindings: none

Question 106hardmultiple choice

Refer to the exhibit. An engineer has configured an SR-TE policy. What is required for this policy to be used for traffic steering?

Exhibit

segment-routing
 mpls
  segment-list SID_LIST
   index 10 mpls label 16000
   index 20 mpls label 16001
  !
  adjacency SID
 !
 traffic-engineering
  policy SR_POLICY
   color 100
   candidate-path priority 100
    segment-list SID_LIST
   !
  !
 !

Question 107easymultiple choice

A network engineer is configuring MPLS LDP on a new router. After enabling LDP globally and on the interface, the LDP session does not establish. The IGP (OSPF) is fully operational. What should the engineer verify first?

Question 108mediummultiple choice

A service provider is deploying EVPN-VPWS for point-to-point services. They have set up an EVPN instance with Ethernet Segment Identifier (ESI) and EVI. After configuration, the pseudowire is not coming up. Which misconfiguration is most likely?

Question 109mediummultiple choice

In an IS-IS segment routing network, after the global 'segment-routing mpls' configuration, which IS-IS configuration is mandatory for label allocation?

Question 110hardmultiple choice

In a Carrier Supporting Carrier (CSC) architecture, which condition is necessary for the customer carrier's BGP routes to be carried over the provider carrier's MPLS backbone?

Question 111easymultiple choice

An SP has configured MPLS TE tunnels for traffic engineering. To verify the status of the TE tunnels, which command provides the most relevant information?

Question 112mediummultiple choice

In a carrier network using VRF-lite for customer isolation, which issue arises if route-target values are not correctly configured?

Question 113hardmultiple choice

In an SR network, which configuration is required to activate TI-LFA for link protection?

Question 114easymultiple choice

An SP is managing a large MPLS network and needs to verify the MPLS forwarding entries for a specific VRF. Which command provides the most complete information for the VRF?

Question 115mediummulti select

Which TWO are benefits of using Segment Routing over LDP in a service provider core?

Question 116hardmulti select

When configuring EVPN VPWS, which TWO parameters must match between the two endpoints of the pseudowire?

Question 117easymulti select

Which THREE protocols are used for label distribution in an MPLS network?

Question 118hardmultiple choice

A large service provider operates a national MPLS backbone with over 200 P routers and 500 PE routers. They use IS-IS as the IGP with segment routing and have deployed TI-LFA for link and node protection. Recently, a core router (P1) suffered a complete failure, and during the failure, traffic for some prefixes was dropped for over 200ms. After the failure, the network recovered within seconds. The engineer suspects that TI-LFA did not provide the expected sub-50ms protection for some destinations. Further analysis reveals that the affected prefixes have their BGP next-hop on a router that is multiple hops away, and the P1 failure impacted both the primary path and the backup path computed by TI-LFA. The engineer reviews the TI-LFA configuration and finds that 'fast-reroute per-prefix ti-lfa' is enabled under router isis. The engineer also notes that P1 was not a protecting node for those prefixes. Which action should the engineer take to improve convergence time for these prefixes?

Question 119mediummultiple choice

A service provider offers L3VPN services to multiple enterprise customers. One customer reports that they cannot reach some remote sites intermittently. The network uses MPLS L3VPN with MP-BGP for VPN route exchange. The PE routers are configured with route-target import and export. The customer's CE router is dual-homed to two different PEs in the same point of presence. The engineer checks the BGP table on both PEs and sees the customer routes with the correct route-target. However, pings from the CE to a remote site fail about 50% of the time, and the flapping pattern suggests load balancing issues. The engineer discovers that the remote site's network prefix is being advertised from both PEs with the same route-target but with different next-hops. The CE has equal-cost paths via both PEs. What is the most likely cause of the intermittent connectivity?

Question 120easymultiple choice

A small service provider is deploying MPLS in its core network for the first time. They have a simple topology: three P routers in the core and two PE routers connecting customers. They have configured LDP on all interfaces and OSPF as the IGP. They also configured a basic L3VPN for a customer with a single CE attached to each PE. The customer reports that they can ping between CEs for a few minutes, but then the connectivity drops. After a few seconds, it returns. This pattern repeats every few minutes. The engineer checks the LDP neighbors and sees that all LDP sessions are up. The OSPF adjacencies are stable. The engineer also notices that the pings time out exactly when the LDP graceful restart timer is expiring on one of the P routers. What is the most likely cause?

Question 121mediummultiple choice

A service provider is implementing EVPN for its VPLS replacement. They have configured BGP EVPN on all PEs and have set up an EVPN instance for a customer requiring broadcast, unknown unicast, and multicast (BUM) traffic. The customer reports that broadcast traffic from one site is not being received at another site. The engineer checks the EVPN configuration and finds that the EVI is configured correctly, the route-target matches, and the BGP sessions are established. The engineer also checks the MAC address table on the receiving PE and sees that the source MAC of the broadcast frame is learned on the local interface, but not from the remote VTEP. The engineer suspects an issue with the IMET (Inclusive Multicast Ethernet Tag) route. Which action should the engineer take to verify the IMET route?

Question 122mediummulti select

A service provider is designing an MPLS L3VPN network to provide Layer 3 VPN services to multiple customers. Which two statements correctly describe the roles of the Provider Edge (PE) and Customer Edge (CE) routers in this architecture?

Question 123hardmulti select

An SP is migrating its core network to Segment Routing (SR-MPLS). The network uses IS-IS as the IGP with SR extensions. Which three statements about SR-MPLS architecture are correct?

Question 124easymultiple choice

A large service provider operates an MPLS L3VPN network with multiple Route Reflectors (RRs) in the core. The network uses BGP as the control plane for both IPv4 unicast and VPNv4 routes. Recently, one of the RRs started flapping, causing route withdrawals to many clients. The network architect wants to improve stability. The RRs are fully meshed with each other and clients are configured as route-reflector clients. The RRs have both IPv4 and VPNv4 address families enabled. Which action should be taken to minimize the impact of an RR failure?

Question 125easymultiple choice

An SP is deploying a Quality of Service (QoS) architecture in its core network to support multiple services: voice, video, and data. The core routers use MPLS and implement QoS based on the MPLS EXP bits. The architecture must ensure that voice packets are never dropped, even during congestion, while allowing video to have higher priority than data. The current design marks voice with EXP 4, video with EXP 3, and data with EXP 0. During a traffic burst, voice traffic is being dropped, which should not happen. The core routers have the following queue configuration: (1) a priority queue (PQ) for EXP 4+5, (2) a bandwidth queue for EXP 2-3, (3) a default queue for EXP 0-1. What is most likely the cause of voice drops?

Question 126mediummultiple choice

A service provider is deploying EVPN-VXLAN in its data center to provide Layer 2 and Layer 3 overlay services. The underlay uses an eBGP-based CLOS fabric with spine and leaf switches. The leaf switches act as VTEPs and run EVPN for MAC/VXLAN advertisement. One of the tenants, a financial customer, requires that their traffic between two leaf-connected servers is always forwarded through a firewall for inspection, even when the servers are on the same leaf. The firewall is connected to a service leaf. The architect proposes using EVPN integrated routing and bridging (IRB) with asymmetric IRB. However, traffic between two VMs on the same leaf is bypassing the firewall. Which architectural change ensures that all inter-VM traffic within the same leaf goes through the firewall?

Question 127mediummultiple choice

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A service provider offers Carrier Ethernet services using MPLS-TP in the access and aggregation layers. The network uses MPLS-TP tunnels with static LSPs and protection via 1:1 linear protection with APS. One customer reports intermittent connectivity issues on their E-LINE service. The operations team observes that the protection switchover is occurring frequently due to apparent signal failures on the working path. However, the physical layer shows no errors. The protection switching is configured with revertive mode. The working LSP has an RDI (Remote Defect Indication) configured. Upon further investigation, the team finds that the working LSP's OAM continuity check messages (CCMs) are being lost occasionally, triggering a protection switch. What is the most likely misconfiguration?

Question 128hardmultiple choice

A service provider is building a new network slicing architecture to offer differentiated services to enterprise customers. The architecture uses SRv6 with network slices identified by slice IDs embedded in the SRv6 SID. The underlay is an IP network with ISIS. Each slice will have dedicated resources in the core, including guaranteed bandwidth and low latency. The plan is to use the SRv6 network programming concept to steer traffic into different slices. The provider wants to ensure that slice isolation is maintained end-to-end, including at the egress PE where traffic is handed off to the customer. However, during testing, they observe that traffic from one slice is incorrectly entering another slice's queue on an intermediate node, causing performance interference. The intermediate node is a transit router that does not terminate SRv6 but performs 'SID-based forwarding'. Which mechanism is most likely missing to ensure slice isolation on transit nodes?

Question 129hardmultiple choice

A service provider offers IPTV services using multicast. The network uses Multicast VPN (MVPN) with Rosen GRE encapsulation (Profile 1) in an MPLS L3VPN environment. The Provider Edge (PE) routers participate in both the default MDT and data MDT for high-bandwidth streams. Recently, a new channel was added, and it uses a data MDT. The content server is attached to a PE that is acting as a multicast source. Other PEs are receivers. Upon adding the channel, some receivers report missing packets. The network engineer checks the PEs and notices that the data MDT group address is being advertised via BGP as an MDT SAFI route, but some PEs are not joining the data MDT. The source PE's multicast routing table shows that it believes data MDT is active. Which architecture issue is most likely preventing some PEs from joining the data MDT?

Question 130mediummultiple choice

A service provider is troubleshooting an MPLS L3VPN where customers behind CE-A cannot reach CE-B. The PE routers are Cisco ASR 9000 series. On PE-A, the show cef vrf CUSTOMER prefix 10.1.1.0/24 command displays 'punt' as the forwarding path. What is the most likely cause?

Question 131hardmultiple choice

A network architect is designing a Segment Routing (SR) network for a service provider with a requirement for fast convergence upon node failure. The network uses IS-IS as the IGP with segment routing extensions. Which design choice BEST ensures that the network can achieve sub-50ms convergence without relying on any signaling protocol beyond the IGP?

Question 132easymultiple choice

A service provider needs to offer L3VPN services to multiple customers, each with overlapping IP addresses. The provider plans to use MPLS VPNs with VRFs. Which statement is TRUE regarding the configuration of VRFs on the PE routers?

Question 133mediummultiple choice

A service provider has deployed QoS on its MPLS backbone to offer different classes of service. The provider notices that EF (Expedited Forwarding) traffic sometimes experiences high jitter during congestion. Following recommended practices, which action is MOST likely to reduce jitter for EF traffic?

Question 134hardmulti select

A multicast service provider is designing an IPv4 PIM Sparse Mode (PIM-SM) network with multiple RPs. The network must support Anycast RP using MSDP. Which THREE statements are correct regarding this design?

Question 135hardmultiple choice

Based on the exhibit, why is the route 10.10.10.0/24 from remote PE not installed in the VRF Customer-A on PE1?

Exhibit

Refer to the exhibit.

PE1#show ip bgp vpnv4 vrf Customer-A 10.10.10.0/24
BGP routing table entry for 10.10.10.0/24, version 6
Paths: (2 available, best #2, table Customer-A)
  Advertised to update-groups:
     1
  Refresh Epoch 2
  Local
    65000 65001
      10.1.1.1 (metric 20) from 10.1.1.1 (192.168.1.1)
        Origin IGP, metric 0, localpref 100, valid, internal, best
        Extended Community: RT:100:100
        mpls labels in/out vpn-label:24000
        rx pathid: 0, tx pathid: 0x0
      Path #2: (not installed because of route-target mismatch?)
  Not advertised to any peer

PE1#show run | section vrf Customer-A
vrf Customer-A
 rd 100:1
 route-target export 100:100
 route-target import 200:200
!

Question 136easymultiple choice