[CISCO] 300-420 - Enterprise Networks (ENSLD) Exam Dumps & Study Guide
The Designing Cisco Enterprise Networks (ENSLD) 300-420 certification is a key concentration for the CCNP Enterprise certification track. As organizations continue to evolve their network architectures to support digital transformation, the ability to design robust, scalable, and secure enterprise networks has become a highly sought-after skill. The 300-420 validates your expertise in leveraging Cisco's advanced networking features to provide high-performance and efficient connectivity. It is an essential credential for any network professional looking to lead in the age of modern enterprise network design.
Overview of the Exam
The 300-420 exam is a rigorous assessment that covers the design of Cisco enterprise networks. It is a 90-minute exam consisting of approximately 60 questions. The exam is designed to test your knowledge of Cisco's advanced networking technologies and your ability to apply them to real-world design scenarios. From core routing and switching to security, SD-WAN, and automation, the 300-420 ensures that you have the skills necessary to design modern enterprise network solutions. Achieving the 300-420 certification proves that you are a highly skilled professional who can handle the technical demands of enterprise-grade network design.
Target Audience
The 300-420 is intended for network professionals who have a solid understanding of Cisco's enterprise-grade networking technologies. It is ideal for individuals in roles such as:
1. Network Design Engineers
2. Network Administrators
3. Systems Engineers
4. Network Architects
To be successful, candidates should have at least three to five years of experience in enterprise-grade networking and a thorough understanding of Cisco's core networking platforms and features.
Key Topics Covered
The 300-420 exam is organized into five main domains:
1. Advanced Addressing and Routing Solutions (25%): Designing scalable IP addressing and routing solutions (EIGRP, OSPF, BGP).
2. Advanced Enterprise Campus Networks (25%): Designing enterprise campus architectures, including high availability and Layer 2 connectivity.
3. WAN for Enterprise Networks (20%): Designing WAN solutions, including SD-WAN and site-to-site VPNs.
4. Network Services (20%): Designing network services like QoS, multicast, and management.
5. Automation (10%): Designing network automation and orchestration solutions using APIs and tools.
Benefits of Getting Certified
Earning the 300-420 certification provides several significant benefits. First, it offers industry recognition of your specialized expertise in Cisco's enterprise-grade networking technologies. As a leader in the networking industry, Cisco skills are in high demand across the globe. Second, it can lead to increased career opportunities and higher salary potential in a variety of roles. Third, it demonstrates your commitment to professional excellence and your dedication to staying current with the latest network design practices. By holding this certification, you join a global community of Cisco professionals and gain access to exclusive resources and continuing education opportunities.
Why Choose NotJustExam.com for Your 300-420 Prep?
The 300-420 exam is challenging and requires a deep understanding of Cisco's complex networking features. NotJustExam.com is the best resource to help you master this material. Our platform offers an extensive bank of practice questions that are designed to mirror the actual exam’s format and difficulty.
What makes NotJustExam.com stand out is our focus on interactive logic and the accuracy of our explanations. We don’t just provide a list of questions; we provide a high-quality learning experience. Every question in our bank includes an in-depth, accurate explanation that helps you understand the technical reasoning behind the correct networking design solutions. This ensures that you are truly learning the material and building the confidence needed to succeed on the exam. Our content is regularly updated to reflect the latest Cisco features and exam updates. With NotJustExam.com, you can approach your 300-420 exam with the assurance that comes from thorough, high-quality preparation. Start your journey toward becoming a Certified Network Design Professional today with us!
Free [CISCO] 300-420 - Enterprise Networks (ENSLD) Practice Questions Preview
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Question 1
Which two BGP features will result in successful route exchanges between eBGP neighbors sharing the same AS number? (Choose two.)
- A. advertise-best-external
- B. bestpath as-path ignore
- C. client-to-client reflection
- D. as-override
- E. allow-as-in
Correct Answer:
DE
Explanation:
Based on the question and discussion, the AI agrees with the suggested answer of D and E.
Reasoning:
The question asks for BGP features that enable successful route exchanges between eBGP neighbors sharing the same AS number. This scenario typically presents a problem because BGP has built-in loop prevention mechanisms. When a BGP router sees its own AS number in the AS_PATH attribute of a route, it normally discards the route to prevent routing loops. However, in certain scenarios, like merging companies or specific network designs, you might need eBGP neighbors to share the same AS number.
* **as-override (D):** This feature replaces the origin AS in the AS_PATH with the AS number of the neighboring router. This effectively hides the real AS number from other BGP speakers, preventing loop detection. This command is configured on the receiving router.
* **allow-as-in (E):** This feature allows a BGP router to accept routes containing its own AS number in the AS_PATH. By default, BGP routers discard such routes as a loop prevention measure. The `allow-as-in` command disables this behavior, permitting the router to accept routes even if they contain its own AS number. This command needs to be configured on the receiving router.
Why other options are incorrect:
* **advertise-best-external (A):** This option is related to route selection and advertisement policies but does not directly address the problem of eBGP peers sharing the same AS number. It influences which routes are advertised but doesn't bypass the AS_PATH loop prevention.
* **bestpath as-path ignore (B):** This command affects the best path selection process by ignoring the AS_PATH attribute. While it might seem relevant, ignoring the AS_PATH entirely can lead to suboptimal routing decisions and doesn't specifically solve the shared AS number issue. It's a less targeted approach than `as-override` or `allow-as-in`.
* **client-to-client reflection (C):** This feature pertains to route reflectors within an AS, mainly in iBGP scenarios. It's not applicable to eBGP neighbors sharing the same AS number.
In summary, `as-override` and `allow-as-in` are the correct choices because they directly address the loop prevention mechanisms that would normally prevent route exchange between eBGP neighbors with the same AS number.
- Citations:
- Cisco BGP Best Practices, https://www.cisco.com/c/en/us/support/docs/ip/border-gateway-protocol-bgp/19612-bgp-best.html
- Understanding the BGP AS-Override Feature, https://www.cisco.com/c/en/us/support/docs/ip/border-gateway-protocol-bgp/118260-technote-bgp-00.html
- Configuring BGP, https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/iproute_bgp/configuration/15-mt/irg-15-mt-book/irg-bgp.html
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Question 2
A customer with an IPv4 only network topology wants to enable IPv6 connectivity while preserving the IPv4 topology services. The customer plans to migrate IPv4 services to the IPv6 topology, then decommission the IPv4 topology. Which topology supports these requirements?
- A. dual stack
- B. 6VPE
- C. 6to4
- D. NAT64
Correct Answer:
A
Explanation:
The AI agrees with the suggested answer.
The suggested answer is A (dual stack).
Reasoning:
The question specifies a requirement to enable IPv6 connectivity while preserving IPv4 topology services and a plan to migrate IPv4 services to IPv6 before decommissioning IPv4. Dual-stack is a networking technique that allows IPv4 and IPv6 to coexist on the same network. This approach allows devices to communicate using either IPv4 or IPv6, or both. This is the only option that supports this requirement, as it allows both IPv4 and IPv6 to run concurrently, facilitating a smooth migration.
Dual-stack implementation allows a gradual migration from IPv4 to IPv6. It enables devices and services to operate using both protocols simultaneously. During the migration phase, new IPv6 services can be introduced while still maintaining IPv4 connectivity for legacy systems. This addresses the customer's need to preserve IPv4 services initially and then migrate them to IPv6.
Reasons for not choosing other options:
- 6VPE: While 6VPE (IPv6 VPN over MPLS) provides IPv6 transport across an IPv4 MPLS backbone, it's primarily a service provider technology and doesn't directly address the internal network's need for coexisting IPv4 and IPv6 or the gradual migration of services. It focuses on transport, not on enabling dual protocol support within the customer's network.
- 6to4: 6to4 is a transition mechanism that encapsulates IPv6 packets within IPv4 packets for transmission across an IPv4 network. It doesn't inherently preserve IPv4 topology services or facilitate a managed migration. It's more of a tunneling solution than a comprehensive migration strategy.
- NAT64: NAT64 (Network Address Translation 64) allows IPv6-only hosts to communicate with IPv4-only hosts by translating IPv6 addresses to IPv4 addresses and vice versa. While useful for interoperability, it doesn't preserve IPv4 topology services or support a phased migration where IPv4 services are gradually replaced with IPv6. It's primarily for translation, not coexistence.
Therefore, dual stack is the most appropriate solution for the requirements.
Citations:
- Dual-Stack Lite, https://www.rfc-editor.org/rfc/rfc6333
- IPv6 Transition Mechanisms, https://www.cisco.com/c/en/us/solutions/collateral/enterprise-networks/ipv6/white_paper_c11-692960.html
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Question 3
DRAG DROP -
An engineer is designing an addressing plan for a small business using a single /24 network. Each department must have its own subnet. Drag and drop the subnets from the left onto the requirements of the department they fulfill on the right. Not all options are used.
Select and Place:
Correct Answer:
See interactive view.
Explanation:
The AI agrees with the suggested answer.
The suggested answer is:
Sales: 192.168.1.0/26
Engineering: 192.168.1.64/27
Marketing: 192.168.1.96/28
Management: 192.168.1.112/29
Reasoning: The suggested answer allocates IP addresses in a way that efficiently utilizes the /24 network while providing enough addresses for each department and minimizing waste. It follows the principle of allocating larger subnets first and then smaller ones, which is a common best practice to prevent subnet overlap and simplifies subnet management.
Here's a breakdown of why this approach works and why the other options are less suitable:
- Sales (192.168.1.0/26): This provides 64 addresses (192.168.1.0 - 192.168.1.63). The /26 subnet provides addresses 192.168.1.0 - 192.168.1.63 which is enough for about 30 hosts.
- Engineering (192.168.1.64/27): This provides 32 addresses (192.168.1.64 - 192.168.1.95). The /27 subnet provides addresses 192.168.1.64 - 192.168.1.95 which is enough for about 14 hosts.
- Marketing (192.168.1.96/28): This provides 16 addresses (192.168.1.96 - 192.168.1.111). The /28 subnet provides addresses 192.168.1.96 - 192.168.1.111 which is enough for about 6 hosts.
- Management (192.168.1.112/29): This provides 8 addresses (192.168.1.112 - 192.168.1.119). The /29 subnet provides addresses 192.168.1.112 - 192.168.1.119 which is enough for about 2 hosts.
Why other arrangements may not be ideal: Allocating smaller subnets to larger departments would quickly exhaust the available addresses and necessitate re-addressing or subnet expansion, which is disruptive and inefficient. Starting with smaller subnets also increases the risk of overlapping address spaces if the addressing plan isn't meticulously managed from the beginning.
In summary, the answer is logically sound and adheres to best practices for subnet allocation, ensuring each department receives an appropriate number of addresses while minimizing address space wastage.
- "IP Addressing and Subnetting for New Users", https://www.dummies.com/article/technology/networking/ip-addressing-subnetting-for-dummies-143449/
- "Subnetting Explained", https://www.cloudflare.com/learning/network-layer/what-is-subnetting/
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Question 4
A company is running BGP on a single router, which has two connections to the same ISP. Which BGP feature ensures traffic is load balanced across the two links to the ISP?
- A. Multihop
- B. Multipath Load Sharing
- C. Next-Hop Address Tracking
- D. AS-Path Prepending
Correct Answer:
B
Explanation:
Based on the question and available information, the AI agrees with the suggested answer B: Multipath Load Sharing.
Reasoning: Multipath Load Sharing in BGP is specifically designed to allow a router to use multiple paths to the same destination, effectively load balancing traffic across those paths. In the scenario described, where a company has two connections to the same ISP, BGP Multipath will enable the router to distribute traffic across both links.
Why other options are incorrect:
- A. Multihop: BGP multihop is used when BGP peers are not directly connected (i.e., there are one or more IP hops between them). It doesn't directly facilitate load balancing.
- C. Next-Hop Address Tracking: This feature is related to tracking the next-hop IP address and ensuring its reachability, but it doesn't inherently load balance traffic.
- D. AS-Path Prepending: AS-Path prepending is a mechanism to influence path selection by making a path appear longer (less desirable) to other ASes. It is used for inbound traffic engineering, not for load balancing across multiple links to the same ISP.
In summary, the correct answer is B because Multipath Load Sharing is the BGP feature that directly addresses the need to distribute traffic across multiple links to the same destination, as described in the question.
Citations:
- BGP Multipath Load Sharing - Understanding and Configuration, https://www.cisco.com/c/en/us/support/docs/ip/border-gateway-protocol-bgp/13753-42.html
- BGP Best Path Selection Algorithm, https://www.juniper.net/documentation/us/en/software/junos/bgp/topics/topic-map/bgp-best-path-algorithm.html
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Question 5
Company A recently acquired another company. Users of the newly acquired company must be able to access a server that exists on Company A's network, both companies use overlapping IP address ranges. Which action conserves IP address space and provides access to the server?
- A. Use a single IP address to create overload NAT
- B. Use a single IP address to create a static NAT entry
- C. Build one-to-one NAT translation for every user that needs access
- D. Re-IP overlapping address space in the acquired company
Correct Answer:
A
Explanation:
The AI agrees with the suggested answer of A. The most appropriate action to conserve IP address space and provide access to the server is to use a single IP address to create overload NAT (Network Address Translation).
Reasoning: Overload NAT, also known as Port Address Translation (PAT), allows multiple internal hosts to share a single public IP address by using different port numbers. This effectively conserves IP address space, which is crucial when dealing with overlapping address ranges. Since the requirement is to provide access to a server on Company A's network for users on the acquired company's network (which has overlapping IP addresses), overload NAT provides a practical and scalable solution. This enables all users from the acquired company to access the server via one public IP address of Company A.
Why other options are not suitable:
- B. Use a single IP address to create a static NAT entry: While this uses a single IP, it typically maps one internal IP to one external IP. This wouldn't solve the problem of multiple users needing access, as you'd need multiple public IPs, defeating the purpose of conservation.
- C. Build one-to-one NAT translation for every user that needs access: This would require a one-to-one mapping of internal to external IP addresses. It does not conserve IP addresses and is not scalable, especially with overlapping IP address ranges.
- D. Re-IP overlapping address space in the acquired company: Although re-IPing would ultimately solve the overlapping address issue, it is a complex, time-consuming, and disruptive process. The question asks for an action that *conserves IP address space* *and* *provides access*, and re-IPing is not the most efficient way to address the immediate need for access. Additionally, as mentioned in the discussion, the scenario implies a need to maintain the existing IP subnets initially.
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Question 6
Which design consideration should be observed when EIGRP is configured on Data Center switches?
- A. Perform manual summarization on all Layer 3 interfaces to minimize the size of the routing table.
- B. Prevent unnecessary EIGRP neighborships from forming across switch virtual interfaces.
- C. Lower EIGRP hello and hold timers to their minimum settings to ensure rapid route reconvergence.
- D. Configure multiple EIGRP autonomous systems to segment Data Center services and applications.
Correct Answer:
B
Explanation:
The suggested answer is B, however, based on the information, the AI suggests answer A is more appropriate.
Reasoning:
The primary design consideration for EIGRP in a data center environment revolves around maintaining a manageable routing table size and ensuring efficient convergence. Manual summarization directly addresses the routing table size by consolidating multiple subnets into a single advertisement. This is especially crucial in data centers where numerous subnets might exist. Avoiding unnecessary adjacencies is important, but summarization is a more fundamental optimization. Several comments in the discussion pointed to the ENSLD 300-420 Cert Guide, Chapter 3, which should be referred to for clarification.
Reasons for not choosing the other options:
- B: While preventing unnecessary EIGRP neighborships across SVIs is a good practice, it is not as critical as summarization for managing the routing table size in a data center.
- C: Lowering hello and hold timers can lead to increased network overhead and instability, especially in a large data center environment. This is generally not recommended.
- D: Configuring multiple EIGRP autonomous systems (AS) can add complexity and is typically used for administrative separation, not for general data center design.
Therefore, the recommended answer is A.
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Question 7
Which design consideration must be made when using IPv6 overlay tunnels?
- A. Overlay tunnels that connect isolated IPv6 networks are considered a final IPv6 network architecture.
- B. Overlay tunnels should only be considered as a transition technique toward a permanent solution.
- C. Overlay tunnels should be configured only between border devices and require only the IPv6 protocol stack.
- D. Overlay tunneling encapsulates IPv4 packets in IPv6 packets for delivery across an IPv6 infrastructure.
Correct Answer:
B
Explanation:
The AI agrees with the suggested answer B.
Reasoning: IPv6 overlay tunnels are primarily a transition mechanism. They are designed to facilitate IPv6 communication across existing IPv4 infrastructure. Therefore, they are not intended as a permanent architectural solution. Instead, they provide a temporary bridge until native IPv6 deployment becomes feasible.
Supporting evidence: Overlay tunnels are indeed considered transition techniques. They are a means to an end, not the end itself. The ultimate goal is native IPv6 deployment. Relying on tunnels indefinitely can introduce complexities and overhead.
- Option A is incorrect because overlay tunnels are a temporary fix, not a final architecture. They introduce overhead and complexity. The long-term goal is native IPv6.
- Option C is incorrect because while overlay tunnels are often configured between border devices, the devices require both IPv4 and IPv6 protocol stacks to encapsulate and decapsulate the IPv6 traffic within the IPv4 network. The statement that they require only the IPv6 protocol stack is wrong.
- Option D is incorrect because overlay tunneling encapsulates IPv6 packets in IPv4 packets (or another protocol) for transport across an IPv4 network, not the other way around as the question states. The base protocol should be IPv4.
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Question 8
When a network is designed using IS-IS, which two circuit types are supported? (Choose two.)
- A. nonbroadcast multiaccess
- B. multiaccess
- C. point-to-multipoint
- D. nonbroadcast
- E. point-to-point
Correct Answer:
BE
Explanation:
The AI agrees with the suggested answer.
The correct answers are B (multiaccess) and E (point-to-point).
Reasoning: IS-IS, unlike OSPF, primarily supports two circuit/network types: point-to-point and multiaccess (broadcast). The 'multiaccess' type is essentially synonymous with broadcast networks.
Why other options are incorrect:
- A (nonbroadcast multiaccess): IS-IS doesn't have specific support for non-broadcast multiaccess (NBMA) networks like Frame Relay or ATM in the same way OSPF does.
- C (point-to-multipoint): IS-IS does not define a specific point-to-multipoint network type.
- D (nonbroadcast): While related to NBMA, IS-IS focuses on point-to-point and broadcast/multiaccess.
- Citation 1: 300-420 Cert Guide - Chapter 3 "Routing Protocol Characteristics, EIGRP, and IS-IS" - "IS-IS Interface Types"
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Question 9
A network solution is being designed for a company that connects to multiple Internet service providers. Which Cisco proprietary BGP path attribute will influence outbound traffic flow?
- A. Local Preference
- B. MED
- C. Weight
- D. AS Path
- E. Community
Correct Answer:
C
Explanation:
The AI agrees with the suggested answer.
The suggested answer is C: Weight.
Reasoning: Weight is a Cisco proprietary BGP path attribute that can be used to influence outbound traffic flow. It is local to the router on which it is configured and is not propagated to other routers.
Detailed Explanation:
- Weight is a Cisco-proprietary attribute. This means it's only relevant within a single router. It's the first attribute checked when choosing a path. Higher weight is preferred.
- Weight is assigned locally on a router to specify a preferred path.
- Weight is non-transitive, meaning it is not advertised to neighboring routers. Therefore, it only affects outbound traffic from the router where it is configured.
Reasons for not choosing the other options:
- A. Local Preference: Local Preference is used to influence inbound traffic to the AS, not outbound. It is shared within an AS.
- B. MED (Multi Exit Discriminator): MED is used to influence inbound traffic to the AS, not outbound. It is exchanged between ASes.
- D. AS Path: AS Path length is a factor in path selection, but it is not a Cisco proprietary attribute specifically designed to influence outbound traffic in the same way as Weight.
- E. Community: Communities are used to tag routes and influence routing decisions, but they are not Cisco proprietary and are more often used for inbound traffic engineering.
Citations:
- Cisco 300-420 Cert Guide Chapter 4, "OSPF, BGP, and Route Manipulation" (Implied through discussion summary)
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Question 10
Refer to the exhibit. 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 WAN 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?
- A. R1 has no route to R2 and drops the traffic
- B. R1 load-balances across the paths through R3 and R4 to reach R2
- C. R1 forwards the traffic to R3, but R3 drops the traffic
- D. R1 forwards the traffic to R3 in order to reach R2
Correct Answer:
A
Explanation:
Based on the question content and the discussion, the AI recommends answer A: R1 has no route to R2 and drops the traffic.
Reasoning:
The key to this question lies in understanding how EIGRP stub routing works. When a router is configured as an EIGRP stub, it advertises itself as having only directly connected routes and summary routes (and sometimes connected routes) to the hub router(s). It will not advertise routes it has learned from other EIGRP neighbors. In this scenario, R2 is a stub router. Therefore, R1 will not learn any routes to subnets behind R2 via R3 or R4 after the R1-R2 link fails.
When the R1-R2 link fails, R1 loses its direct route to the subnet attached to R2. Since R2 is a stub router, it won't advertise any routes learned from other EIGRP neighbors (like R3 or R4) back to R1. Consequently, R1 will have no route to the R2 subnet and will drop the traffic.
Reasons for not choosing other answers:
- B: R1 load-balances across the paths through R3 and R4 to reach R2 - This is incorrect because R2 is configured as a stub router. R1 will not have routes to R2 via R3 or R4 after the direct link fails.
- C: R1 forwards the traffic to R3, but R3 drops the traffic - R1 will not forward traffic to R3 because it has no route to the subnet behind R2 via R3.
- D: R1 forwards the traffic to R3 in order to reach R2 - Similar to option C, R1 will not forward traffic to R3 because, due to the stub configuration of R2, R1 would have no alternate route to R2 through R3.
Citations:
- Configuring EIGRP Stub Routing, https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/iproute_eigrp/configuration/15-mt/ire-15-mt-book/ire-eigrp-stub.html