Pass the Cisco CCNP Service Provider 350-501 Questions and answers with CertsForce

To achieve this, router 2 should use a route map to filter the routes being redistributed from BGP into OSPF. Specifically, the route map should match the internal route from Lo 2 (which is the loopback interface on router 2) and allow only that route to be redistributed. The other options do not achieve this specific requirement. References: Implementing and Operating Cisco Service Provider Network Core Technologies (SPCOR) source book.

R1

router bgp 100

address-family ipv4

nei 172.16.0.2 route-map R1-TO-R2 in

network 10.1.1.1 mask 255.255.255.255

copy run start

R2

router bgp 200

address-family ipv4

network 10.2.2.2 mask 255.255.255.255

nei 172.16.0.1 route-map R2-TO-R1 in

copy run start

The REST API command shown in the exhibit is a POST request to a specific URL, indicating that it is used to submit data to be processed to a specified resource. In this case, the resource is an XML file named “Descriptions.xml”. POST requests are used when submitting data to be processed by the resource identified by the URI. The nature of the process conducted on the submitted data depends on that particular URI. References: Implementing and Operating Cisco Service Provider Network Core Technologies (SPCOR) - REST API section.

After a router reload, BGP sessions may fail to re-establish due to incorrect source interface configurations for BGP sessions. Since EBGP multihop has been configured, it’s essential that the BGP session uses the correct source interface for establishing the connection. By configuring the neighbor update-source command with the loopback interface on R2, the BGP session will use the stable loopback address rather than the physical interface, which can change state. This ensures that the BGP session remains stable and is not affected by interface states. References: BGP Troubleshooting Cheat Sheet With Examples - Catchpoint2, BGP session stuck in Idle state after NSRP failover - Juniper Networks3, BGP Session is Disconnected - Network Playbook

https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/prog/configuration/166/b_166_programmability_cg/netconf_programmability_configuration_guide.html

https://tools.ietf.org/html/rfc6241

 The Time to Live (TTL) security mechanism is a lightweight security feature that can protect against CPU and memory resource exhaustion due to a denial-of-service (DoS) attack. It works by setting a limit on the number of hops (TTL value) that BGP packets can traverse. By configuring neighbor 10.163.83.55 ttl-security hops 2, ISP A ensures that BGP packets received from ISP C must have a TTL value of at least 254 when they reach R1, as BGP packets decrement the TTL by 1 with each hop. This effectively prevents spoofing attacks from outside the directly connected network because any packets spoofed from further away would have a TTL that drops below the threshold before reaching R1.

The configuration command xconnect 192.168.0.1 12 encapsulation mpls pw-class cisco is used to set up a pseudowire connection to a remote peer at IP address 192.168.0.1 using MPLS encapsulation. The pw-class cisco refers to a pseudowire class named ‘cisco’ that defines the parameters for the MPLS pseudowire. This configuration is part of setting up Layer 2 VPNs, which are often used in service provider networks to extend services such as Ethernet, ATM, or Frame Relay over an MPLS network.

 In OSPF, the election of the designated router (DR) and backup designated router (BDR) is based on the OSPF network type. The network types include:

Broadcast: This is the default network type for Ethernet interfaces. In a broadcast network, OSPF elects a DR and BDR. All other routers become DROTHERs. To prevent the election of a DR/BDR, you can configure the interface as non-broadcast (NBMA) using the ip ospf network non-broadcast command.

Point-to-Point: This network type is used for point-to-point links (e.g., serial links). There is no DR/BDR election in point-to-point networks.

Point-to-Multipoint: This network type is used for point-to-multipoint links (e.g., Frame Relay). There is no DR/BDR election in point-to-multipoint networks.

Point-to-Multipoint Non-Broadcast: Similar to point-to-multipoint, but explicitly configured as non-broadcast. There is no DR/BDR election in point-to-multipoint non-broadcast networks.

Loopback: Loopback interfaces are always treated as point-to-point.

Virtual-Link: Used for OSPF virtual links.

Sham-Link: Used for OSPF sham links.

Demand Circuit: Used for demand circuits (e.g., ISDN).

Non-Broadcast: Explicitly configured as non-broadcast. There is no DR/BDR election in non-broadcast networks.

Cisco MPLS Traffic Engineering (TE) tunnels necessitate a link-state routing protocol like OSPF or IS-IS because these protocols use Shortest Path First (SPF) calculations. The tunnel endpoints leverage these SPF calculations to implement the tunnel, ensuring an efficient and optimized path through the network. This is essential for MPLS TE, which aims to optimize network resource utilization and improve traffic distribution across the network.

 The number “2” in the SNMP server configuration “snmp-server community ciscotest ro 2” refers to the numeric name of the Access Control List (ACL) that contains the list of SNMP managers with access to the agent. In this context, “ro” stands for read-only access, meaning that SNMP managers can only read but not modify data on the device. The ACL identified by number “2” specifies which SNMP managers are authorized to access SNMP data on this device using the community string “ciscotest”.

The failure to implement IS-IS multitopology can be attributed to the routing process not supporting extended metrics. Extended metrics are necessary for multitopology routing because they allow for the definition of multiple topologies within the same routing protocol, each with its own set of metrics and paths1.