300-440 Designing and Implementing Cloud Connectivity (ENCC) Questions and Answers

 A fully meshed topology with SD-WAN technology using dynamic routing and prioritized traffic for QoS meets the network architecture requirements of the company. A fully meshed topology provides high availability by eliminating single points of failure and allowing multiple paths between branch offices. SD-WAN technology enables multihoming by supporting multiple transport options, such as MPLS, internet, LTE, etc. SD-WAN also provides QoS by applying policies to prioritize traffic based on application, user, or network conditions. Dynamic routing allows the SD-WAN solution to adapt to changing network conditions and optimize the path selection for each traffic type. A fully meshed topology with SD-WAN technology can also support specific routing needs, such as segment routing, policy-based routing, or application-aware routing. References:

• Designing and Implementing Cloud Connectivity (ENCC) v1.0
• [Cisco SD-WAN Design Guide]
• [Cisco SD-WAN Configuration Guide]

 In the given scenario, an engineer is configuring a site-to-site IPsec VPN connection between an on-premises Cisco IOS XE router and AWS. The correct command to complete the tunnel configuration is “tunnel source 20.20.20.21”. This command specifies the source IP address for the tunnel, which is essential for establishing a secure connection between two endpoints over the internet or another network1. References:

• Configure IOS-XE Site-to-Site VPN Connection to Amazon Web Services - Cisco Community
• [Security for VPNs with IPsec Configuration Guide, Cisco IOS XE Release 3S - Config

The architecture model that establishes internet-based connectivity between on-premises networks and AWS cloud resources is the one that establishes an iPsec VPN tunnel with Internet Key Exchange (IKE) for secure key negotiation and encrypted data transmission. This model is also known as the VPN CloudHub model12. It allows multiple remote sites to connect to the same virtual private gateway in AWS, creating a hub-and-spoke topology1. The VPN CloudHub model provides the following benefits12:

• It enables secure communication between remote sites and AWS over the public internet, using encryption and authentication protocols such as IPsec and IKE.
• It supports dynamic routing protocols such as BGP, which can automatically adjust the routing tables based on the availability and performance of the VPN tunnels.
• It allows for redundancy and load balancing across multiple VPN tunnels, increasing the reliability and throughput of the connectivity.
• It simplifies the management and configuration of the VPN connections, as each remote site only needs to establish one VPN tunnel to the virtual private gateway in AWS, rather than multiple tunnels to different VPCs or regions.

The other options are not correct because they do not establish internet-based connectivity between on-premises networks and AWS cloud resources. Option B relies on AWS Elastic Load Balancing (ELB) for traffic distribution and uses SSL/TLS encryption for secure data transmission. However, ELB is a service that distributes incoming traffic across multiple targets within a VPC, not across different networks3. Option C employs AWS Direct Connect for a dedicated network connection and uses private IP addresses for secure communication. However, AWS Direct Connect is a service that establishes a private connection between on-premises networks and AWS, bypassing the public internet4. Option D uses Amazon CloudFront for caching and distributing content globally and uses HTTPS for secure data transfer. However, Amazon CloudFront is a service that delivers static and dynamic web content to end users, not to on-premises networks5.

References:

• 1: Designing and Implementing Cloud Connectivity (ENCC, Track 1 of 5)
• 2: Cisco ASA Site-to-Site VPN
• 3: What Is Elastic Load Balancing?
• 4: What is AWS Direct Connect?

 Option C is the correct answer because it configures the IKEv2 profile with the correct match identity, authentication, and keyring parameters. It also configures the IPsecprofile with the correct transform set and lifetime parameters. Option A is incorrect because it does not specify the match identity remote address in the IKEv2 profile, which is required to match the AWS virtual private gateway IP address. Option B is incorrect because it does not specify the authentication pre-share in the IKEv2 profile, which is required to authenticate the IKEv2 peers using a pre-shared key. Option C also matches the configuration example provided by AWS1 and Cisco2 for setting up an IKEv2 IPsec site-to-site VPN between a Cisco IOS-XE router and an AWS virtual private gateway. References :=

• 1: AWS VPN Configuration Guide for Cisco IOS-XE
• 2: Configure IOS-XE Site-to-Site VPN Connection to Amazon Web Services

To enable the OMP advertisement of BGP routes for a specific VRF instance on a Cisco IOS XE SD-WAN device, the engineer must first configure the global address-family ipv4 and then enable bgp advertisement under the vrf definition. This will allow the device to advertise the BGP routes learned from the cloud provider to the OMP control plane, which will then distribute them to the other SD-WAN devices in the overlay network1

References := 1: Designing and Implementing Cloud Connectivity (ENCC) v1.0, Module 3: Implementing Cloud Connectivity, Lesson 3: Configuring IPsec VPN from Cisco IOS XE to AWS, Topic: Configuring BGP on the Cisco IOS XE Device, Page 3-24.

 The end-to-end ping between the office user PC and the AWS EC2 instance is not working because either the security group rules for the host VPC are blocking the ICMP traffic or the IPsec SA counters are showing errors or drops. To diagnose the loss of connectivity, the engineer should check both the security group rules and the IPsec SA counters. The network security group rules on the host VNET are not relevant because they apply to Azure, not AWS. The IPsec SA configuration on the Cisco VPN router and the AWS private virtual gateway are not likely to be the cause of the problem because the site-to-site VPN tunnel is already up and the site-to-site routing works correctly. References :=

• Designing and Implementing Cloud Connectivity (ENCC, Track 1 of 5), Module 3: Configuring IPsec VPN from Cisco IOS XE to AWS, Lesson 3: Verify IPsec VPN Connectivity
• Security for VPNs with IPsec Configuration Guide, Cisco IOS XE, Chapter: IPsec VPN Overview, Section: IPsec Security Association
• AWS Documentation, User Guide for AWS VPN, Section: Security Groups for Your VPC

• To configure a custom application with Cisco SD-WAN centralized policy, you need to follow these steps25:

The process of configuring a custom application with a Cisco SD-WAN centralized policy using Cisco vManage involves several steps1.

• Click Configuration, select Policies, and then select Centralized Policy: This is the first step where you navigate to the Policies section in the Configuration menu of Cisco vManage1.
• Click Custom Options, select Centralized Policy, and then select Lists: In this step, you select the Custom Options, then select Centralized Policy, and finally select Lists1.
• Click Custom Applications, and then select New Custom Application: After setting up the Lists, you click on Custom Applications and then select New Custom Application1.
• Enter a name for the application, enter the match criteria, and then click Add: Finally, you enter a name for the application, specify the match criteria, and then click Add to complete the configuration1.

References :=

• Cisco Catalyst SD-WAN Policies Configuration Guide, Cisco IOS XE

Step 1 = Navigate to Configuration, select Templates, and then select Device Templates. Step 2 = Click Create Template, select From Feature Template, and then select the device model. Step 3 = Select Device, select Service Node, and then set Template Name and Description. Step 4 = Attach the device template to the device.

The process of configuring an AppGoE service node for WAN optimization for applications that are hosted in the cloud using Cisco vManage for C8000V or C8500L-8S4X devices involves several steps12.

• Navigate to Configuration, select Templates, and then select Device Templates: This is the first step where you navigate to the Templates section in the Configuration menu of Cisco vManage1.
• Click Create Template, select From Feature Template, and then select the device model: In this step, you create a new template for the device model from the feature template1.
• Select Device, select Service Node, and then set Template Name and Description: After setting up the template, you select the device and the service node, and then set the template name and description1.
• Attach the device template to the device: Finally, you attach the created device template to the device1.

References :=

• AppQoE - Step-by-Step Configuration - Cisco Community
• Cisco Catalyst SD-WAN AppQoE Configuration Guide, Cisco IOS XE Catalyst SD-WAN Release 17.x