300-420 ENSLD:Designing Cisco Enterprise Networks (ENSLD)
Update：2026年5月10日
Questions and Answers: 336 Q&A
1.
A customer is planning to onboard three new VPN partner connections in the data center. The new subnets must not overlap with the existing data center network, and the subnet size must not be bigger than necessary. The customer dedicated 10.1.8.0/21 for this design. Ho1// must the subnets be divided to meet these requirements?
2.
An engineer is planning an IPv4 to IPv6 migration solution for a customer. The routers in the network can support IPv4 and IPv6, except for the DWDM routers. The DWDM routers provide a Layer 2 link in which the routers peer directly with each other across a DWDM circuit. The circuit also provides connectivity between the mail servers. Which IPv6 migration technique must the engineer deploy?
3.
Which PIM mode uses a shared tree only?
4.
Which QoS feature responds to network congestion by dropping lower priority packets?
5.
An engineer is working with NETCONF and Cisco NX-OS based devices. The engineer needs a YANG model that supports a specific feature relevant only to Cisco NX-OS. Which model must the engineer choose?
6.
What is an advantage of using model-driven telemetry in the network?
7.
All routers currently reside in OSPF area 0. The network manager recently used R1 and R2 as aggregation routers for remote branch locations and R3 and R4 for aggregation routers for remote office locations. The network has since been suffering from outages, which are causing frequent SPF runs. To enhance stability and introduce areas to the OSPF network with the minimal number of ABRs possible, which two solutions should the network manager recommend? (Choose two.)
8.
In Cisco SD-Access. virtual networks create segmentation that allows for separation of users and resources. How is this type of segmentation described?
9.
Which two LISP components are required in the Cisco SD-Access fabric control plane node? (Choose two.)
10.
An engineer is designing an EIGRP network for a small branch site where there is only one Layer 3 router. The engineer wants the router to advertise the local LAN network to remote EIGRP neighbors without sending any unnecessary multicast messages on the local LAN. Which action should the engineer take?
11.
Which topology within a network underlay eliminates the need for first hop redundancy protocols while improving fault tolerance, increasing resiliency, and simplifying the network?
12.
A customer has several remote sites connected with their headquarters through microwave links. An engineer must propose a backup WAN solution based on these conditions:
- Aphysical WAN solution is not available for most of the sites.
- The customer has a limited budget and a short tmeframe for implementation.
- The backup link will have low bandwidth requirements.
- Users will tolerate a WAN outage of up to 2 hours
Which backup WAN link type the engineer recommend?
13.
Which design consideration must be made when using IPv6 overlay tunnels?
14.
An engineer is creating a design to enable IPv6 to run on an existing IPv4 IS-IS network. The IPv4 and IPv6 topologies will match exactly, and the engineer plans to use the same router levels for each protocol per interface. Which IS-IS design is required?
15.
An engineer must design a routing solution for a company that is single-homed to an ISP. The company's goal is to run BGP between the CE and the PE devices. To support running BGP, the company obtained a public AS number and IP subnet from ARIN. Which solution must the engineer select?
16.
A network engineer must design a BGP solution based on:
- The route reflector must have one or more direct physical connections to the core routers (R3 and R4).
- The route reflector must have full redundancy and avoid a single point of failure.
- R2 to R1 link utilization is 90%. and the remaining links are less than 50% utilized.
Which two solutions must the design Include? (Choose two.)
17.
Which type of rendezvous point deployment is standards-based and support dynamic RP discovery?
18.
Since installing a cisco TelePresence system, the company is experiencing other application having response issues when the system in use. As a result, the company asked an architect to recommend a QoS solution. The customer is currently using a CBWFQ policy to manage traffic on an internet connection with a speed of 100 Mbps. Which link-capacity limit must the architect choose for strict-priority for the real-time traffic?
19.
A branch office has a primary L3VPN MPLS connection back to the main office and an IPSEC VPN tunnel that serves as backup. Which design ensures that data is sent over the backup connection only if the primary MPLS circuit is down?
20.
The connection between SW2 and SW3 is fiber and occasionally experiences unidirectional link failure. An architect must optimize the network to reduce the change of layer2 forwarding loops when the link fails. Which solution should the architect include?
21.
When a first hop redundancy solution is designed, which protocol ensures that load balancing occurs over multiple routers using a single virtual IP address and multiple virtual MAC addresses?
22.
What does the fabric data plane leverage in SD-Access Architecture?
23.
A customer’s environment includes hosts that support IPv6-only. Several of these hosts must communicate with a public web server that has only IPv4 domain name resolution. Which solution should the customer use in this environment?
24.
Drag and drop the elements from the left onto the YANG models where they and used on the right.
25.
Which feature must be incorporated into the campus LAN design to enable Wake on LAN?
26.
An engineer uses Postman and YANG to configure a router with:
- OSPF process ID 400
- network 192.168.128.128/25 enabled for Area 0
Which get-config reply verifies that the model set was designed correctly?
27.
A company wants to switch from static to dynamic routing. The branches use DMVPN back to the hub using two internet connections. One internet connection speed is 10 Mbps, and the other is 100 Mbps. All locations use Cisco routers; however, the branch routers have limited memory and CPU resources. Which routing protocol and design solution must the company choose for optimal traffic forwarding during peak traffic times?
28.
Which queuing structure is used on SD-WAN Edge routers?
29.
An architect must design an IPv6 migration solution for an enterprise customer to support these requirements:
- Clients will transition to the new IPv6 network, which provides NAT64 and IPv6 DNS resolution services, using the same DNS name that points to the IPv4 address.
- The service provider will create a client-facing IPv6 interface with a new IPv6 virtual address that points to the same IPv4 DNS server.
- The service provider will support clients that use global IPv6 addresses and encapsulate IPv4 packets into IPv6 tunnels.
Which two migration solutions must the architect choose? (Choose two.)
30.
An engineer must design a WAN solution so that ISP-1 is always preferred over ISP-2. The path via ISP-2 is considered as a backup and must be used only when the path to ISP-1 is down. Which solution must the engineer choose?
31.
How is sub-second failure of a transport link detected in a Cisco SD-WAN network?
32.
Currently, the network uses a single-homed solution for connecting to the internet. An engineer must design a more resilient WAN using the internet circuits at each site. The design must provide failover connectivity, support load-sharing of traffic, and QoS. Which solution must the engineer choose?
33.
Which consideration must be taken into account when using the DHCP relay feature in a Cisco SD-Access Architecture?
34.
An engineer must design an in-band management solution for a customer with branch sites. The solution must allow remote management of the branch sites using management protocols over an MPLS WAN. Queueing is implemented at the remote sites using these classes:
- Class1 equals voice traffic
- Class2 equals mission-critical traffic
- Class3 equals default traffic
How must the solution prioritize the management traffic over the WAN?
35.
What is the purpose of a Cisco SD-Access underlay network?
36.
What is the purpose of the fabric management plane in a Cisco SD-Access architecture?
37.
A customer needs to apply QoS to the network management traffic passing through the GigabitEthernet0/2 interface. All eight queuing classes are in use, so the new requirement must be integrated into the existing policy. Which solution must the customer choose?
38.
An engineer must design a multicast network for a financial application. Most of the multicast sources also receive multicast traffic (many-to-many deployment model). To better scale routing tables, the design must not use source trees. Which multicast protocol satisfies these requirements?
39.
An architect must ensure a convergence time of 200 ms or less during a link failure within area 0. In addition, the solution must not impact the overall performance of the network. Which solution must the architect select?
40.
An engineer is designing a PIM Anycast RP solution between two data centers. The design must ensure that RP1 in DC1 and RP2 in DC2 inform each other about specific sources that have joined locally. Which solution must the engineer choose?
41.
An engineer is looking for a standards-driven YANG model to manage a multivendor network environment. Which model must the engineer choose?
42.
An engineer is designing an IPv4 addressing plan for an enterprise with 1000 branches. Each branch requires a prefix for data and a prefix for voice. Each prefix must accommodate up to 128 hosts, and prefixes must facilitate summarization at aggregation points in the network. The security team requires a simple method for identifying voce prefixes. Which allocation does the engineer recommend from the RFC1918 address space?
43.
Which feature of Cisco SD-WAN Secure Direct Cloud Access divides user traffic into different zones and VPNs or VRFs?
44.
An engineer must propose a QoS architecture model that allows an application to inform the network of its traffic profile and to request a particular type of service to support its bandwidth and delay requirements. The application requires consistent and dedicated bandwidth end to end. Which QoS architecture model meets these requirements?
45.
A network engineer must improve the current IS-IS environment. The Catalyst switch is equipped with dual supervisors. Each time a stateful switchover occurs, the network experiences unnecessary route recomputation. Which solution addresses this issue if the upstream router does not understand graceful restart messaging?
46.
A network engineer must connect two sites across a public network using a secure tunneling technology that supports multicast traffic. Which technology must be chosen?
47.
A customer plans to adopt distributed QoS in their enterprise WAN. The policy must allow for individual packet marking according to the type of treatment required and for forwarding based on hop-by-hop treatment locally defined on each device. Which technology must the customer select?
48.
An architect is designing a Layer 3 campus network The design must hide network instability, reduce network overhead, and conserve critical device memory Which route summarization solution must the architect select?
49.
In a Cisco SD-Access fabric, which node facilities connectivity between the fabric and networks external to the fabric?
50.
An engineer is designing a Layer 2 campus network. The design must support fast convergence and leverage as much bandwidth as possible between layers. Distribution switches do support VSS; unfortunately, not all routing protocols are available for use due to license limitations. Which solution must the engineer choose?
51.
An engineer is designing a routing solution for a customer. The design must ensure that a failure of network
10.1.0.0/24, 10.1.2.0/24, 10.2.1.0/24, or 10.2.3.0/24 does not impact the core. It also requires fast
convergence
time during any link failover in the core or access networks. Which solution must the engineer
select?
52.
An architect is designing a Layer 2 network for a customer. The network will use the spanning-tree protocol. During a link failure between SW1 and SW2, the fastest possible convergence time is desired. Which solution must the architect select?
53.
An architect must design a solution to connect bank site A with bank site B and support:
- network operation center monitoring end-to-end L3VPN and L2VPN traffic
- company adding thousands of routes in the next two years
Which two BGP solutions must the design include? (Choose two.)
54.
A company wants to enable several third-party video conferencing networks based on multicast services. The video conferencing platform can accommodate numerous and dispersed senders and receivers in third-party networks The interior routing protocol is OSPF and the exterior routing protocol is BGP Which multicast mode must be selected to achieve this goal?
55.
An architect working for a service provider with an employee ID: 4763:44:876 must design a Layer 2 VPN solution that supports:
- transparency of service provider devices
- direct communication between CE routers attached to the same VLAN
Which solution must the design include?
56.
An engineer is designing a networking solution to allow two hosts to communicate—one host located within the company A network and the other within the company B network. The two companies have no other plans for future additional connections. Both companies want to use a single secure and encrypted internet connection, and the configuration must be as simple as possible. Which network solution must the engineer choose?
57.
An engineer is working for a large cable TV provider that requires multiple sources streaming video on different channels using multicast with no rendezvous point. Which multicast protocol meets these requirements?
58.
A company requested that an architect propose a new IPv4 and IPv6 deployment strategy. The company wants a solution that is straightforward, with no information hiding or forwarding overhead. Which solution meets these requirements?
59.
A company wants to deploy IPv6 within its existing network infrastructure. All current infrastructure equipment supports IPv6, and the company wants a migration strategy that must not require purchasing additional equipment The plan must keep operational management costs low. support IPv6 multicast, and allow applications to migrate using DNS. Which strategy must the company choose?
60.
An engineer is upgrading a company’s main site to include a connection to a second ISP. The company will receive full Internet routing tables from both ISPs via BGP. The engineer must ensure that the company does not become a transit autonomous system. Which solution should be included in this design?
61.
An engineer Is designing a redistribution solution for a customer. The customer recently acquired another company and decided to integrate the new network running RlPv1 with the company's existing network. Which redistribution technique must the engineer select to ensure the multipoint two-way redistribution does not cause routing loops?
62.
Which design element should an engineer consider when multicast is included in a Cisco SDAccess architecture?
63.
When expanding an existing Cisco SD-Access network, in addition to the control plane, which two device roles are needed to create an additional fabric site? (Choose two.)
64.
Drag and drop the characteristics from the left onto the correct telemetry mode on the right.
65.
Which two statements describe source trees in a multicast environment? (Choose two.)
66.
Which method will filter routes between EIGRP neighbors within the same autonomous system?
67.
Drag and drop the characteristics from the left onto the configuration protocols they describe on the right.
68.
Which security functionality does gRPC provide?
69.
Drag and drop the characteristics from the left onto the YANG models they describe on the right. Not all options are used
70.
The full EIGRP routing table is advertised throughout the network. Currently, users experience data loss when any one link in the network fails. An architect optimizes the network to reduce the impact when a link fails. Which solution should the architect include in the design?
71.
Drag and drop the Cisco Catalyst SD-WAN components from the left to their definitions on the nght
72.
Which two functions does the control plane node provide in a Cisco SD-Access architecture? (Choose two.)
73.
A company with multiple service providers wants to speed up BGP convergence time in the event a failure occurs with their primary link. Which approach achieves this goal and does not impact router CPU utilization?
74.
A network engineer is designing an OSPF solution to connect a company's remote to a newly provisioned MPLS VPN backbone. Some of the branches have a direct dark fiber connection between each other. The engineer wants to ensure that the dark fibers are used only when the MPLS core is unavailable. Which solution must the engineer choose?
75.
Which control-plane technology allows the same subnet to exist across multiple network locations?
76.
An engineer is designing an OSPF solution with these requirements:
- NMS server will manage R5 and R6.
- Upon failure of R1. all NMS traffic should be routed through R4.
- Upon failure of the link between R5 and R6. all traffic destined for 10.6.6.6 should be routed through R4
Which solution must the engineer choose?
77.
A company’s branch location uses redundant routers and links for connectivity to the headquarters. Also, to use the entire available bandwidth, the branch uses a dynamic routing protocol. An architect must design a multicast streaming solution to avoid RPF check failures because of the current network design. Which deployment model must the architect choose?
78.
How do IETF. OpenConfig and Cisco nativo YANG models differ when used to configuro the same feature on an infrastructure device?
79.
An engineer is designing a Layer 3 campus network running EIGRP between the core,aggregation, and access layers. The access layer switches will be connected to the aggregation layer using Layer 3 copper connections. The engineer wants to improve convergence time for access layer switch failures. Which technique must the design include?
80.
EIGRP has been configured on all links. The spoke nodes have been configured as EIGRP stubs, and the WAN links to R3 have higher bandwidth and lower delay than the links to R4. When a link failure occurs at the R1-R2 link, what happens to traffic on R1 that is destined for a subnet attached to R2?
81.
Area 10 is a regular OSPF area and networks 10.1.1.0/24 and 172.16.1.0/24 are internal. Which design provides optimal routing between both networks when the link between routers C and E fails?
82.
Which protocol is deployed through LAN automation to build node-to-node underlay adjacencies in SDA?
83.
An architect must create a QoS solution for a customer to ensure that a 40 Mbps Internet connection is shared between four subnets based on these requirements:
- Each subnet must receive no less than 10 Mbps of download bandwidth during peak traffic times.
- A subnet can use up to 40 Mbps during nonpeak traffic times if the other subnets are idle.
- Download traffic must never experience a delay.
Which solution must the architect choose?
84.
An architect is designing an ISIS network for a customer migrating from IPv4 to IPv6. The current network uses narrow metrics, and the IPv6 areas will increase to 10 within the next two years. Also, IPv6 traffic must not blackhole in IPv4 network during the migration. Which two solutions must the architect choose? (Choose two.)
85.
An architect is designing a network for an enterprise site. The design must use an active/backup design for the WAN. It must guarantee the SLA for several applications regardless of which connection is used. Which deployment model should the architect choose?
86.
Drag and drop the elements from the left onto the functions they perform in the Cisco SD-WAN architecture on the right.
87.
Which routes does the overlay management protocol advertise in an SD-WAN overlay?
88.
An architect is designing an EIGRP solution based on these requirements:
- Traffic forwarding should use the best two paths while all links are available
- Single path failure must not impact traffic between branch and HQ
Which solution must the architect select?
89.
A company has some offices that are connected via dark fiber in New York. A network architect must optimize the network design based on the EIGRP routing protocol. The network has hierarchical addressing between 10 and 12 routers in each office. Routing convergence time must be at the minimum. What must the network architect do to reduce the query range?
90.
Which two statements about VRRP object tracking are true? (Choose two)
91.
Which AES mode should be used in a Cisco SD-WAN environment that includes multicast applications?
92.
A router running ISIS is showing high CPU and bandwidth utilization. An engineer discovers that the router is configured as L1/L2 and has L1 and L2 neighbors. Which step optimizes the design to address the issue?
93.
Drag and drop the steps WAN Edge performs when on-boarded into the Cisco SD-WAN overlay from the left into the order they are completed on the right.
94.
How is redundancy achieved among Cisco vBond Orchestrators in a Cisco SD-WAN deployment?
95.
A network engineer must design a multicast solution based on these requirements:
- interactive communication
- must not use source trees
- users must register
- 100 multicast sources
Which solution must the company choose?
96.
An engineer must design a VPN solution for a company that has multiple branches connecting to a main office. What are two advantages of using DMVPN instead of IPsec tunnels to accomplish this task? (Choose two.)
97.
When differentiating between IETF. OpenConfig. and Cisco native YANG models, how does the use of containers differ?
98.
A company needs to increase access port capacity on one floor of a building. They want to leverage the existing catalyst access switch. There is no problem with uplink bandwidth capacity. However, no additional uplinks can be added because no ports are available on the distribution switches. Which solution must the company choose to provide additional access ports?
99.
An architect must develop a campus network solution that includes:
logically segmented and isolated networks
ability to communicate between network segments when required
support for overlapping IP addresses
widely available technologies to avoid purchasing specialized equipment
Which solution must the architect select?
100.
Which two functions are provided by the Cisco SD-WAN orchestration plane? (Choose two.)
101.
What are two advantages of the Cisco SD-WAN technology9 (Choose two)
102.
A network engineer must optimize a campus OSPF deployment Currently each time a type 1 or type 2 LSA is generated within an area, the OSPF process must recompute the entire SPT Which solution improves the recomputation process?
