350-501 Practice Questions

Egress PE NAT via a single centralized router allows L3VPN customers to access the internet. The NAT operation maintains a table that includes a field to identify the inside VRF of a translation. This is crucial for distinguishing between different customer VPNs that may use overlapping IP address spaces. By having this field, the NAT process can correctly associate each internal IP with its respective VRF and outside global IP address1. Reference: Centralized egress to internet, Egress PE NAT single centralized router.

The control plane protocol used between Cisco SD-WAN routers and vSmart controllers is the

Overlay Management Protocol (OMP). OMP is a proprietary protocol of Cisco SD-WAN that facilitates

the exchange of routing, policy, and management information across the network. It operates within

the secure environment provided by the Datagram Transport Layer Security (DTLS) or Transport Layer

Security (TLS) control connection, ensuring that the communication between the routers and

controllers is encrypted and authenticated1.

Reference := Cisco 300-415: Cisco SD-WAN vSmart-WAN Edge Router Control Plane Protocol

To prevent packet loss when IGP (Interior Gateway Protocol) and LDP (Label Distribution Protocol)

are not synchronized, enabling MPLS LDP IGP synchronization is crucial. This synchronization ensures

that the IGP routing protocol (such as OSPF or IS-IS) waits until LDP convergence is completed before

advertising labels for MPLS traffic. It helps maintain consistency between the IGP and LDP databases.

Reference: Implementing and Operating Cisco Service Provider Network Core Technologies course

materials.

When a prefix list is applied to a BGP neighbor, it filters routes based on the specified conditions. In this scenario, the prefix list is designed to permit prefixes that are equal to or longer than /17 but shorter than or equal to /19. Therefore: A: 192.168.0.0/19 is denied because it falls outside the specified range. D: 192.168.0.0/16 is denied as it is shorter than the minimum length of /17. E: 192.168.0.0/16 is permitted because it is the exact prefix specified in the prefix list, and the ge and le modifiers apply to more specific routes derived from this prefix. Reference: Implementing and Operating Cisco Service Provider Network Core Technologies (SPCOR) - Cisco official courseware.

The IPv4 address family configuration under neighbor configuration-mode must be removed. The exhibit shows the configuration of a BGP neighborship between an ASBR and a directly connected BGP speaker. The ASBR is running Cisco IOS XR. The neighbor is configured with the IPv4 address family, which is not supported on Cisco IOS XR. To establish the BGP neighborship, the IPv4 address family configuration must be removed. https://www.cisco.com/c/en/us/td/docs/routers/xr12000/software/xr12k_r41/routing/configuration /guide/routing_cg41xr12k_chapter1.html

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The network operator needs to provide connectivity between two IPv4 and IPv6 dual-stacked networks using specific assigned IPv6 space. NAT46 (Network Address Translation 46) is the appropriate technology for this scenario. It allows translation between IPv4 and IPv6 addresses, enabling communication between the dual-stack networks. NAT46 maps IPv6 addresses to IPv4 addresses and vice versa, facilitating seamless communication across different address families. Reference: Implementing and Operating Cisco Service Provider Network Core Technologies