350-501 Exam Dumps - Cisco CCNP Service Provider Questions and Answers

 Unicast Reverse Path Forwarding (uRPF) in strict mode ensures that packets are received on the interface that the router would use to forward the return traffic. If a packet is received on an interface that is not the best reverse path, the packet is dropped. This helps mitigate IP address spoofing and DDoS attacks.

The available PHY modes to implement an IOS XR Gigabit Ethernet interface are MAN (Metropolitan Area Network) and WAN (Wide Area Network). References:

Cisco IOS XR Software Configuration Guide

Cisco ASR 9000 Series Aggregation Services Routers Interface and Hardware Component Configuration Guide

Hr40wan - 10 Gigabit Ethernet WAN PHY Controller Commands on Cisco IOS XR

10-Gigabit Ethernet WAN PHY Controller Commands 

To inject a default route into the MP-BGP address family for a dedicated VRF, you would typically need to:

Configure a static default route in the VRF using the ip route vrf 0.0.0.0 0.0.0.0  command.

Redistribute the static route into BGP using the redistribute static command under the BGP VRF configuration.

The configuration shown is for the head-end router of a Cisco MPLS TE tunnel with segment routing. This setup involves commands related to segment routing and MPLS traffic engineering tunnels, such as “mpls traffic-eng tunnels”, “segment-routing mpls”, and “segment-routing prefix-sid-map advertise-local”. These commands configure the head-end router to effectively create and manage TE tunnels using segment routing. References: Implementing and Operating Cisco Service Provider Network Core Technologies (SPCOR) - Cisco SPCOR Training & Certification.

The OSPF adjacency issue between R1 and R2 is likely due to mismatched OSPF network types or hello/dead interval settings. The command ip ospf network point-to-point is used on point-to-point network types, which do not require matching hello/dead intervals, thus allowing OSPF adjacency to form even if these intervals are mismatched on the two routers. References: = Implementing and Operating Cisco Service Provider Network Core Technologies course materials. (

The term ‘ImpNull’ in the CLI output indicates that Label 0, also known as the “Implicit Null” label, is used for the prefix displayed. This label instructs the penultimate router in an MPLS network to pop the label before forwarding the packet to the ultimate hop, which is the egress router. Therefore, Label 0 will not be part of the MPLS label stack for packets destined for 192.168.10.10 (Option A). This process is known as Penultimate Hop Popping (PHP) and is used to optimize the forwarding process by reducing one level of lookup at the egress router (Option D).

In IS-IS, to advertise only the network prefixes associated with passive interfaces, the command advertise passive-only under the address family configuration mode is used. This ensures that only the prefixes of passive interfaces are advertised to other IS-IS routers in the network. The passive interface command is used to prevent IS-IS from forming adjacencies over that interface, while still allowing the network prefix of the interface to be included in the IS-IS link-state database.

The configuration shown in the exhibit enables IP flow information collection on the interface gigabitethernet0/1. This setup is used for network traffic analysis, and when applied, it provides data that includes the source interface of the traffic for traceback analysis. This is useful for identifying the origin of traffic, which can be critical in situations such as security incidents or network troubleshooting.

Router 1 is the trigger router in a Remote Triggered Black Hole (RTBH) implementation. In the configuration provided, Router 1 has a static route to null0 for network 192.168.1.0/24 with a tag of 1, which is used to drop traffic destined to this network, effectively mitigating DDoS attacks. The route-map “ddos” matches this tag and sets local preference and community accordingly. The BGP process redistributes this static route based on the “ddos” route-map, signaling other routers in the network to drop traffic destined for the attacked network. References: Implementing and Operating Cisco Service Provider Network Core Technologies (SPCOR) - RTBH section1.

 In Segment Routing Traffic Engineering (SR-TE), when defining explicit path hops for devices using IP unnumbered interfaces, the router ID and labels are crucial. The router ID uniquely identifies a router in the network, while labels are used to direct packets along a specific path without relying on IP addresses, which is essential in unnumbered interface scenarios