Cisco 350-501 Implementing and Operating Cisco Service Provider Network Core Technologies (350-501 SPCOR) Exam Practice Test

Configure an IP domain name: An IP domain name is essential for generating RSA keys needed for SSH. The RSA keys are part of the crypto key configuration, which is necessary to enable SSH on the router. This step ensures that users are authenticated via the SSH protocol when accessing the network remotely.

Configure crypto keys: The crypto keys are crucial for secure communication. The engineer should generate RSA keys using the configured IP domain name. These keys will be used for encryption and authentication during SSH sessions.

The other options (B, D, and E) are not directly related to completing the SSH configuration for secure remote access. Therefore, the correct answers are A and C.

 To establish MPLS LDP sessions between two routers, both routers must be configured to support MPLS on the interfaces that connect them. The configuration shown for R2 includes enabling MPLS label protocol LDP and configuring interfaces Ethernet1/0 and Ethernet1/1. However, to complete the MPLS LDP session setup, R2 also needs to have MPLS enabled on the interface toward R1. This is done by entering the interface configuration mode for the relevant interface and using the mpls ip command. This command enables MPLS forwarding for IP packets on the interface, which is necessary for LDP to advertise and map labels to the IP routes.

References := The answer is based on the concepts covered in the Implementing and Operating Cisco Service Provider Network Core Technologies (SPCOR) course,

When there is an LSP breakage during the testing of MPLS OAM ping capabilities, the ingress MPLS router does not receive any reply because MPLS OAM ping is used to verify connectivity over Label Switched Paths (LSPs), and if an LSP is broken, the echo request will not reach the egress router, resulting in no echo reply being sent back.

The issue with establishing an IS-IS adjacency between the two routers stems from a mismatch in the configuration of their interfaces. Router R2’s interface is set to point-to-point, while the peer router interface is set to multipoint. For IS-IS adjacencies to form, both interfaces must be configured with the same network type. The discrepancy in the network types is preventing the adjacency from being established. To resolve this, the network operator must ensure that both interfaces are either configured as point-to-point or as multipoint. References := Implementing and Operating Cisco Service Provider Network Core Technologies (SPCOR)

: In the context of telemetry for data analytics, a destination (such as a collector or monitoring system) initiates a session to a router. This session allows the router to send telemetry data to the destination for analysis.

 A Virtual Network Function (VNF) role refers to a network function that is executed in software and can be deployed on a Network Functions Virtualization Infrastructure (NFVI). A firewall serves as a VNF role because it performs network functions, such as filtering traffic and security management, in software form rather than as a physical device.

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.

Option A corresponds to the desired configuration. It uses an access-list to permit IGMP joins for the specific multicast group 239.10.10.10 from the source 172.20.20.3.

Options B, C, and D do not match the desired configuration. They either allow all IGMP traffic or do not specify the correct source and group addresses.

The difference between SNMP (Simple Network Management Protocol) and model-driven telemetry lies in their data delivery mechanisms. Telemetry allows for modeled network data to be pushed to network administrators on an as-needed basis, providing real-time insights into network performance and health. On the other hand, SNMP typically relies on polling mechanisms where network administrators request data at specific intervals. References: Implementing and Operating Cisco Service Provider Network Core Technologies source documents or study guide

The script is designed to leverage REST API calls for network configuration tasks. It uses the requests library in Python to send a PATCH request to the device with IP address 172.168.211.65. The script includes RFC 2617-based authentication, which is used for HTTP, indicating that it’s not using SSH for login. The payload of the REST API call specifies the configuration for the interface GigabitEthernet0/1 with the IP address 10.1.131.112/30. Therefore, the script is performing option B, configuring the interface via REST API calls.

 The number 2 in the configuration “snmp-server community ciscotest ro 2” is significant because it 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, meaning that SNMP managers listed in ACL 2 can only read data from the SNMP agent but cannot modify it. The ACL defines which IP addresses are allowed to access SNMP data. References: Implementing and Operating Cisco Service Provider Network Core Technologies source documents or study guide

 To prevent an MPLS TE Label Switched Path (LSP) from using any overseas links, an operator would use the explicit path feature. This feature allows the operator to define a specific route for the LSP to follow, which can be configured to exclude paths that traverse overseas links.

 The issue described involves packets being dropped when sent from the application server to the access site. Since OSPF and BGP peerings are confirmed to be operational, the problem likely lies within the route advertisement. Allowing 172.16.20.1 in the BGP advertisement on R3 by adjusting the route-map will likely resolve the issue, ensuring that traffic destined for 172.16.20.1 is not being inadvertently filtered or blocked.

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.

The configuration creates a class map named WEB which is used to match HTTP traffic. This class map can then be referenced in a policy map to define specific actions for traffic that matches the criteria, such as applying QoS policies or traffic shaping.

Network Services Orchestrator (NSO) uses the YANG (Yet Another Next Generation) modeling language to provide a standardized way to automate network devices. YANG provides a powerful schema to model configuration and state data for network elements, which NSO leverages for service automation and orchestration.

The requirement is to redistribute routes with a tag of 80 and IP prefixes other than 192.168.10.20/24 from Level 1 into Level 2, and also to configure route leaking from Level 2 into the Level 1 domain for routes that are tagged with only 50 or 40. Option B, “Add match ip address 152 in route-map redist1-2”, meets the first requirement as it allows all IP prefixes except for the specified one (192.168.10.20/24) to be redistributed from Level-1 to Level-2 when they have a tag of 80.

The configuration shown indicates that R1 has been configured to support Label Distribution Protocol (LDP) graceful restart. This means that R1 will maintain the forwarding state during an LDP restart, allowing it to continue forwarding packets along known routes while it re-establishes LDP neighbors/peers. This ensures minimal disruption to traffic flow during such events. References: Implementing and Operating Cisco Service Provider Network Core Technologies source documents or study guide

To complete the launch of the new internet service, ISP_A needs to ensure that routes are shared between different VRFs for Customer_A and Customer_B. Importing route-target 62:101 into the customer VRFs on R1 and R3 allows for the exchange of routes between these VRFs, facilitating the necessary connectivity for the new service. References := Cisco SPCOR

 To meet the scalability and service recovery requirements, the network engineer should implement BGP PIC core functionality on routers R2 and R3 (Option A). This will enhance the convergence time during a failure. Additionally, establishing BGP connectivity between routers R1 and R4 with VPNv4 address family enabled (Option C) will facilitate MPLS services across multiple IGP domains.

References :=

Implementing and Operating Cisco Service Provider Network Core Technologies

On-Demand E-Learning for Implementing and Operating Cisco Service Provider Network Core Technologies

 The iosxr_command module in Ansible is used to issue commands on remote devices running Cisco IOS XR. This module allows network administrators to execute operational commands on Cisco routers and switches, which is essential for tasks such as retrieving information or applying configuration changes. It is a part of network automation using Ansible, which simplifies the management of network devices by automating repetitive tasks.

 IP over ATM (IPoATM) and MPLS offer significant benefits over traditional ATM backbone networks, primarily due to their support for variable-length packets. Unlike ATM, which uses fixed-length cells, IPoATM and MPLS can handle packets of varying sizes, making them more efficient for carrying IP traffic. This efficiency comes from reduced overhead and better bandwidth utilization, as IP packets don’t need to be segmented and reassembled, avoiding the cell-padding issues inherent in ATM’s fixed-size cells1.

 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.

IS-IS uses NET addresses to identify each router in the network, and the NET address of each router must be unique. In order for IS-IS to establish connectivity between R1 and R3, the NET address of R3 must be different from the NET address of R1, but it must also follow the same structure. In this case, the NET address of R1 is 49.0133.532b.ca14.6915.21311.F40F.1B3a.ba10.00, so the NET address of R3 must be 49.0133.532b.ca14.6915.21311.F40F.1B4a.bb87.00.

 QPPB (QoS Policy Propagation via BGP) is a mechanism that allows the application of QoS policies using IP precedence or QoS group settings based on BGP community lists, AS paths, and prefix lists. In the context of the exhibit provided, it’s clear that QPPB is being used to apply a specific QoS policy (qos-group 10) based on AS path attributes. This aligns with option C, as it indicates that QoS policies are utilizing BGP to achieve comprehensive network coverage.

 YAML’s readability and straightforward syntax make it an ideal choice for expressing infrastructure as code, which is a core principle in both Ansible and SaltStack for automating and managing IT infrastructure.

Option D is the correct answer because, in the context of Auto-RP, sparse-dense mode allows the router to forward Auto-RP messages. Auto-RP uses dense mode multicast groups (224.0.1.39 and 224.0.1.40) to advertise RP mapping information, so enabling sparse-dense mode on the interface ensures that it can process both types of multicast traffic. References: Implementing and Operating Cisco Service Provider Network Core Technologies (SPCOR) official course materials, which can be found here.

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. References: Implementing and Operating Cisco Service Provider Network Core Technologies

 To address the issue of BGP session flapping between ISP A and ISP B, the networking team at ISP A should implement BGP route dampening. This feature helps stabilize the network by suppressing the advertisement of flapping routes. The command bgp dampening 15 700 1500 30 will set the parameters for route dampening, where routes that flap will be suppressed for 30 minutes. This action will prevent the constant advertisement and withdrawal of unstable routes, thus improving the stability of the network. References := For further details on BGP route dampening and its configuration, the Implementing and Operating Cisco Service Provider Network Core Technologies (SPCOR) course materials and Cisco’s official documentation provide comprehensive guidance.

In the context of OSPF multiarea implementation, adjacency issues can often be resolved by specifying the type of network on the interface. In this case, option B “ip ospf network point-to-point” is appropriate as it helps in forming OSPF adjacency over point-to-point links by allowing OSPF to use a simpler neighbor discovery process, which can resolve adjacency issues. References := Implementing and Operating Cisco Service Provider Network Core Technologies

YANG (Yet Another Next Generation) is a data modeling language used primarily for the configuration and state data of network elements. It is closely associated with the NETCONF (Network Configuration Protocol) for which it models configuration data. YANG provides schemas that define how data is structured and transported by NETCONF operations. It also shapes the state data of network elements, allowing for a standardized format for representing the operational state of devices. References: YANG is defined in RFCs such as RFC 6020 and RFC 7950, which outline its role in NETCONF operations and its capabilities in modeling both configuration and state data.

The configuration shown in the exhibit indicates that Router 1 is configured with NETCONF-YANG and has enabled the feature candidate-datastore. This means that Router 1 has a temporary data store where a copy of the running configuration can be manipulated and verified before committing the configuration. This allows administrators to test changes before applying them to the running configuration, reducing the risk of errors that could impact network operations.

 In the given scenario, to ensure that area 15 traffic from R5 to R1 prefers the route through R4, a multiarea adjacency should be implemented on the link between R2 and R4. The cost can be manipulated to make this path preferred. Multiarea adjacency allows OSPF routers to form adjacencies with routers in other areas, enabling more direct routing of traffic. By adjusting the cost of this adjacency, traffic can be directed preferentially through specific paths.

 MPLS TE tunnels are designed to optimize the flow of network traffic by mapping it onto specific paths based on resource requirements. Two key characteristics of MPLS TE tunnels are:

RSVP for Bandwidth Reservation: MPLS TE tunnels use the Resource Reservation Protocol (RSVP) to reserve the necessary bandwidth for the tunnel, ensuring that the required resources are available for the data that will flow through it12.

Unidirectional Flow: These tunnels are unidirectional, meaning they are established from a source to a destination and do not inherently support traffic in the reverse direction. This is because each MPLS TE tunnel is associated with a label-switched path (LSP) that is specifically set up for traffic flowing in one direction

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 “show cef interface” command is used to display per-interface statistics about Unicast Reverse Path Forwarding (uRPF) drops and suppressed drops. uRPF is a feature that helps to mitigate problems caused by IP address spoofing, and the “show cef interface” command provides detailed information on the interfaces where uRPF is applied, including drop statistics.

R1

router ospf 10

redistribute static

int et0/0

ip ospf hello-interval 5

ip ospf dead-interval 10

ip ospf cost 15

ip ospf 10 area 0

copy run start

R2

router ospf 10

redistribute static

int et0/0

ip ospf hello-interval 5

ip ospf dead-interval 10

ip ospf cost 15

ip ospf 10 area 0

copy run start

In MPLS Layer 3 VPNs, shared services such as Internet access can be provided through the use of a shared services VRF (Virtual Routing and Forwarding). The customer VRF uses route targets to import routes from the shared services VRF, which contains the routes to the Internet. This allows the customer sites to access the Internet without compromising the isolation of their private networks. References: The concept of shared services VRF and the use of route targets for importing and exporting routes are common practices in MPLS VPN implementations.

In an EVPN operation, the PE (Provider Edge) router determines and advertises Ethernet segment reachability by discovering remote ESIs (Ethernet Segment Identifiers) and determining their redundancy mode (all-active or single-active). This is crucial in multihoming scenarios where the PE needs to auto-discover remote PEs and the corresponding redundancy mode. In case of segment failures, PEs withdraw the routes used at this stage to trigger fast convergence by signaling a MAC mass withdrawal on remote PEs3.

 In the given configuration, “tacacs-server host 192.168.1.2 single-connection” indicates that Router 1 will maintain a single connection to the TACACS+ server at IP address 192.168.1.2 for multiple authorization requests instead of opening a new connection for each request. This can be efficient in scenarios where there are frequent authorization requests as it reduces the overhead associated with establishing a new TCP connection each time.

References := Implementing and Operating Cisco Service Provider Network Core Technologies

To influence inbound path selection when implementing BGP in a multihomed architecture, an engineer must configure a route map with the AS_PATH attribute. The AS_PATH attribute is used to manipulate the path information to make certain routes more or less attractive, thereby influencing the decision-making process for inbound traffic.

When implementing a prefix list, it is a best practice to use nonsequential sequence numbers. This allows for the insertion of additional entries at a later time without the need to renumber the entire list, providing flexibility in managing the prefix list.

 In the context of Cisco IOS XR software, the configuration under Option D is appropriate for adding an interface to a bundle using LACP (Link Aggregation Control Protocol). The configuration specifies two Ten Gigabit Ethernet interfaces (TenGigE0/1/0/5 and TenGigE0/1/0/6) with descriptions indicating they are part of “bundle_1_link”. Both interfaces are assigned to “bundle id 1” with a load interval of 30 seconds, ensuring they are part of the same link aggregation group and share traffic load.

Solution

R3

router bgp 65413

add ipv4

nei 2.2.2.2 allowas-in

nei 4.4.4.4 allowas-in

add ipv6

nei 2001:db8:4:4:4::4 allowas-in

end

copy run start

=======================

R2

router bgp 65413

nei 1.1.1.1 as-override

nei 3.3.3.3 as-override

end

copy run start

=======================

R3

router bgp 65413

nei 10.3.4.2 remot 65412

nei 2001:db8:3:4::2 remot 65412

nei 2001:db8:4:4:4:4::4 remot 65412

nei 2001:db8:4:4:4:4::4 ebgp-multihop 10

add ip4

nei 10.3.4.2 act

ex

add ipv6

nei 2001:db8:4:4:4:4::4 activate

nei 2001:db8:4:4:4:4::4 ebgp-multihop 10

nei 2001:db8:3:4::2 act

end

copy run start

===================

R4

router bgp 65412

nei 10.3.4.1 remot 65413

nei 2001:db8:3:3:3:3::3 remot 65413

nei 2001:db8:3:3:3:3::3 ebgp-multihop 10

nei 2001:db8:3:4::1 remot 65413

add ipv4

nei 10.3.4.1 remot act

nei 10.3.4.1 prefix-limit 10

add ipv6

nei 2001:db8:3:3:3:3::3 activate

nei 2001:db8:3:3:3:3::3 ebgp-multihop 10

nei 2001:db8:3:3:3:3::3 prefix-limit 10

nei 2001:db8:3:4::1 activate

nei 2001:db8:3:4::1 prefix-limit 10

end

copy run start

: In this scenario, E-LINE pseudowires are suitable because they create a point-to-point Ethernet connection between the two sites. E-LINE pseudowires are commonly used for point-to-point Ethernet services.

Here is the solution:

The REST API script in the exhibit is used to configure a VRF (Virtual Routing and Forwarding) instance. In the script,  defines a tenant named “customer”, and  creates a VRF named “customervrf” within that tenant. A VRF allows multiple instances of a routing table to co-exist within the same router at the same time, enabling network paths to be segmented without requiring multiple routers. References: Implementing and Operating Cisco Service Provider Network Core Technologies source documents or study guide.

 Both options provide a default route pointing to CE-1, allowing CE-2 to access the internet. The specific choice would depend on additional context or requirements not provided in the question.

In this scenario, CE1 and CE2 need connectivity to the internet through the ISP connected to PE3. The most straightforward approach is to configure CE1 and CE2 with a static default route pointing to PE3 as the next-hop for internet-bound traffic. This ensures that any traffic destined for the internet will be routed directly to PE3, which is directly connected to the internet. Other options (A, B, and D) involve more complex configurations and are not necessary for this specific task. References: Implementing and Operating Cisco Service Provider Network Core Technologies source documents or study guide

The neighbor relationship is down because R2 is operating as a Level 1 router and the two routers are in different areas. In the IS-IS (Intermediate System to Intermediate System) protocol, Level 1 routers exchange routing information with other Level 1 routers in the same area, while Level 2 routers exchange information between areas. Since R1 is configured as a level-2 router and R2 as a level-1 router, they cannot form a neighbor relationship if they are not in the same area. References: Implementing and Operating Cisco Service Provider Network Core Technologies source documents or study guide

 NSO, or Network Services Orchestrator, provides full lifecycle management of devices and services in a network. It is designed to automate the service lifecycle from design and creation through deployment and decommissioning, without the need for manual intervention. This includes configuration, activation, updating, and ultimately, removal of services.

Packet loops can occur during the configuration of BIDIR-PIM if not all parts of your network support this protocol or are configured correctly for it. If some routers or switches in your network don’t understand or aren’t configured for BIDIR-PIM, they can inadvertently forward packets back into parts of the network they were already in, creating a loop. References: Implementing and Operating Cisco Service Provider Network Core Technologies (SPCOR) - Multicast section.

The configuration snippet in the exhibit shows that BGP summarization is configured with the “aggregate-address” command followed by an IP address and a subnet mask, and then the “summary-only” and “as-set” options. The IP address is 192.168.0.0, and the subnet mask is 255.255.0.0, which corresponds to a /16 prefix length (indicating that the first 16 bits of the IP address are the network portion). However, there seems to be a typo in option B as it’s not a valid IP address format; hence option A is correct with an assumption of typo error.

 MPLS LDP (Label Distribution Protocol) is used for label distribution in MPLS networks. When making changes to the LDP configuration, it’s essential to ensure that the changes do not disrupt existing LDP sessions. In this scenario, the network administrator implemented MPLS LDP changes on the PE-A LSR (Label Switching Router) device, and the goal is to prevent any disruption to LDP peers.

The MPLS LDP Non-Stop Routing (NSR) feature allows LDP sessions to survive control-plane switchover events without interruption. When NSR is enabled, the LDP session state information is synchronized between the active and standby control planes. If the active control plane fails, the standby control plane takes over seamlessly, and LDP sessions continue without interruption.

To configure multi-topology IS-IS for IPv6, the router must be configured with the ipv6 router isis command under the interface configuration mode. This command enables IS-IS for IPv6 on the interface. The ipv6 router isis command is used to enable IS-IS for IPv6 on an interface. The multi-topology keyword specifies that the interface will participate in multiple topologies. The level-1 and level-2 keywords specify the IS-IS levels for which the interface will participate. In this case, we want the interface to participate in both Level 1 and Level 2 topologies, so we use both keywords. 

TI-LFA, or Topology Independent Loop-Free Alternate, is a fast-reroute mechanism that provides protection against link or node failures in a network. It guarantees a loop-free alternate path for all areas configured in OSPF, ensuring traffic can be quickly rerouted in case of a failure. This characteristic is crucial for maintaining network stability and avoiding traffic loops, which can lead to packet loss and network congestion.

The configuration snippet shows that MPLS and LDP are configured globally but not enabled on an interface. The commands include “mpls label protocol ldp,” “mpls ldp router-id loopback 0,” and “mpls ip,” which are necessary for global settings. However, to establish LDP neighbors and exchange labels, LDP must be enabled on the specific interface where it’s needed.

In the context of VPLS (Virtual Private LAN Service) configuration, the engineer should perform additional configurations to enable the virtual switch instance. The correct answer is Option A, which likely involves configuring interface VLAN and associating it with xconnect vfi to establish end-to-end LAN connectivity between customer’s remote offices. This is essential for enabling VPLS, which allows geographically dispersed sites to be connected over a service provider’s network as if they were on the same local area network.

 The configuration shown is for the head-end router of a Cisco MPLS TE tunnel with segment routing. The commands included, such as “mpls traffic-eng tunnels” and “segment-routing mpls,” indicate that this is set up for a head-end router in an MPLS TE tunnel. There is no requirement for an explicit path or OSPF to be running, which eliminates options A and B. Option C is also incorrect as there’s no indication of a dynamic path configuration present.

Router 4 must be in the same area as Router 1, so it should have the same area address which is “49.0111”. The system ID can be different to uniquely identify the router in that area, but since there is no option with a different system ID and the same area address, option B is correct as it has both the same area address and system ID as Router 1. References := Cisco

In this scenario, when edge routers at different regional sites are connected over a global carrier backbone, MP-eBGP must be run between routers to exchange customer VPNv4 routes. This is essential for enabling communication between customer sites located in different regions while utilizing a global carrier backbone service. References: Implementing and Operating Cisco Service Provider Network Core Technologies source documents or study guide

R1

Router bgp 65515

No bgp default ipv4-unicast

Neig 2.2.2.2 remote-as 65516

Nei 2.2.2.2 update-soc loopback0

Nei 2.2.2.2 ebgp-multihop 2

Neig 2.2.2.2 pass C1sc0!

Nei 2000:cc13:cc13:2::1 remote-as 65516

Nei 2000:cc13:cc13:2::1 update-so loopback0

Nei 2000:cc13:cc13:2::1 pass C1sc0!

Nei 2000:cc13:cc13:2::1 ebgp-multihop 2

Address-family ipv4

Neig 2.2.2.2 activate

Address-family ipv6

Nei 2000:cc13:cc13:2::1 activate

Ip route 2.2.2.2 255.255.255.255 192.168.1.2

Ipv6 route 2000:cc13:cc13:2::1/128 2000:cc13:cc13:cc13::2

R2

Router bgp 65516

No bgp default ipv4-unicast

Neig 1.1.1.1 remote-as 65515

Nei 1.1.1.1 update-soc loopback0

Nei 1.1.1.1 pass C1sc0!

Nei 1.1.1.1 ebgp-multihop 2

Nei 2000:cc13:cc13:1::1 remote-as 65515

Nei 2000:cc13:cc13:1::1 update-so loopback0

Nei 2000:cc13:cc13:1::1 pass C1sc0!

Nei 2000:cc13:cc13:1::1 ebgp-multihop 2

Address-family ipv4

Neig 1.1.1.1 activate

Address-family ipv6

Nei 2000:cc13:cc13:1::1 activate

Ip route 1.1.1.1 255.255.255.255 192.168.1.1

Ipv6 route 2000:cc13:cc13:1::1/128 2000:cc13:cc13:cc13::1

A SYN flood is a type of denial-of-service (DoS) attack where an attacker sends a large number of SYN requests to a target server, overwhelming its resources and preventing legitimate connections. The attacker does not complete the TCP handshake, leaving the server in a half-open state.

Remember that SSM is an extension of IP multicast where datagram traffic is forwarded only from explicitly joined multicast sources to receivers. It creates source-specific multicast distribution trees without shared trees.

 In a Unified MPLS routing architecture with partitioned IGP domains, it is essential to ensure that the iBGP Labeled Unicast address families are correctly configured to facilitate the exchange of VPNv4 routes directly between PE routers. In this case, ABR R102 should be configured with the address family-level configuration depicted in Option A to support this architecture. This configuration ensures that R101 can peer with both R102 and R103, and similarly, R201 can peer with R202 and R203 using iBGP Labeled Unicast address families. References := Implementing and Operating Cisco Service Provider Network Core Technologies

The script shown in the exhibit is a REST API call that adds a user with the last name ‘CiscoTest’ to the AAA database on the server located at the IP address 192.168.201.10. This is achieved through a POST request, which is typically used to create or update resources on a server. The script specifies the user details in JSON format, which is a common data format used for API calls.

 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.

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

Path Computation Element (Calculates paths through the network, keeps TE topology database information, sends path status updates)

Path computation Client (sends path calculation request, sends path creation request)

Path Computation Element (PCE)

Represents a software module (which can be a component or application) that enables the router to compute paths applying a set of constraints between any pair of nodes within the router’s TE topology database. PCEs are discovered through IGP.

Path Computation Client (PCC)

Represents a software module running on a router that is capable of sending and receiving path computation requests and responses to and from PCEs. The PCC is typically an LSR (Label Switching Router).

re/crs_r5-3/mpls/configuration/guide/b-mpls-cg53x-crs/b-mpls-cg53x-crs_chapter_0110.html#con_1279822

In Cisco’s path selection process, the weight attribute is the first criterion for selecting a path. It is a Cisco-specific parameter, local to the router, and it is not propagated in routing updates. The path with the highest weight is preferred. Therefore, configuring a high weight on the peer to ASN 4567 will make Router R1 prefer this path for all outbound traffic directed towards ASN 4567. References: Implementing and Operating Cisco Service Provider Network Core Technologies (SPCOR) - Cisco SPCOR Training & Certification

 The TTL security mechanism is used to protect a router from receiving BGP sessions that are not originated from the expected peer. It drops incoming TCP segments whose TTL value is not equal to or greater than the expected minimum value, thus helping in preventing DoS attacks that could be initiated from an unauthorized source pretending to be a legitimate BGP peer. References := Implementing and Operating Cisco Service Provider Network Core Technologies

The issue with Router 1 missing the route for Router 2’s loopback 0 is likely due to the routers being configured in different OSPF areas. For OSPF to properly exchange routing information, routers within the same network should be configured in the same area. Therefore, the engineer should change the area numbers on Router 1 and Router 2 to be the same, ensuring they can exchange routes, including the route for Router 2’s loopback 0.

The configuration in Option A is used to implement URPF in loose mode on the GigabitEthernet0/1 interface.

Loose mode allows the router to check for any route back to the source, not necessarily the best route.

By enabling URPF, the router ensures that incoming packets have a valid return path in the routing table.

This helps prevent IP spoofing and limits malicious traffic on the network.

The QoS-group keyword on Cisco IOS XR is used for marking packets on the ingress of the device. This allows for internal handling and is not transmitted across the network. It can be used in fabric QoS policy as a match criteria to apply specific policies based on the QoS group marking.

The configuration shown in the exhibit is used to disable IP directed-broadcasts on a specific interface of a network device. This is typically done to mitigate smurf attacks, which involve sending a large amount of ICMP echo (ping) traffic to IP broadcast addresses, all having a spoofed source address of the victim’s IP. By disabling IP directed-broadcasts, the network device will not forward packets that are sent to broadcast addresses, thus mitigating this type of DDoS attack. References: Implementing and Operating Cisco Service Provider Network Core Technologies (SPCOR) - Module on Security in the Service Provider Network

 When interface Gi0/0/0/2 is shut down for maintenance, the other interfaces’ states are affected based on their current configurations and roles. In this case, Gi0/0/0/0 becomes active because it is next in line to take over the traffic load, ensuring that network service remains uninterrupted. Gi0/0/0/1 remains standby as it was before the shutdown of Gi0/0/0/2.

LDP session protection capability is a feature that maintains LDP bindings when a link fails, using LDP Targeted Hellos to protect LDP sessions. Without the specific exhibit, it’s not possible to determine which router has LDP session protection enabled but session hold up is not active.

OSPF adjacency is established when two OSPF routers have matching interface parameters. This includes the OSPF router ID, network address, area ID, and other OSPF-specific configurations such as MTU size and network type. For example, the configuration commands provided in the image description suggest setting the OSPF router ID, network address with a wildcard mask, and specifying the OSPF area. Additionally, the interface is set to a point-to-point network type with a specific MTU size, which is important for OSPF adjacency as mismatched MTU sizes can prevent OSPF neighbors from forming an adjacency.

The RPL script in the image is used to filter BGP routes based on the AS path. The script includes a condition that checks if the AS path contains ‘7077’ using a regular expression (ios-regex ‘777$’). If this condition is met, the route is passed; otherwise, it would be denied by default. Therefore, this script allows routes from AS 7077 and denies others.

References := For specific references, please consult the Implementing and Operating Cisco Service Provider Network Core Technologies source book or study guide, as I am unable to provide direct links or access content from external websites.

 To complete the implementation of the route map “ciscotest” for filtering routes to a BGP peer, the engineer must attach the route map to the BGP neighbor statement in the inbound direction. This will apply the specified filtering criteria to routes received from the BGP neighbor, thereby limiting access to restricted areas within the network as intended by the client. References := The Implementing and Operating Cisco Service Provider Network Core Technologies (SPCOR) course materials discuss the configuration of route maps and their application to BGP neighbors for route filtering purposes

To view login history for users who activated a session, the network administrator can use the show netconf-yang sessions command. This command provides information about active NETCONF/YANG sessions, including the login times for each user.

The configuration in Option C correctly sets up the interfaces for VLAN tag translation. On interface GigabitEthernet2, the command rewrite ingress tag translate 1-to-1 dot1q 21 changes the incoming VLAN tag from 12 to 21. Conversely, on interface GigabitEthernet3, the command rewrite egress tag translate 1-to-1 dot1q 12 changes the outgoing VLAN tag from 21 to 12. This setup ensures that traffic flowing from R1 to R2 and vice versa has the correct VLAN tags as required.

The weight parameter in BGP (Border Gateway Protocol) is a Cisco-specific attribute that is local to the router on which it is configured. It is used to prefer one path over another when multiple paths to the same destination are available. The weight is not advertised to other routers, making it a local parameter.

 The show command output indicates that the BGP neighbor is in an Idle state, which means the BGP session has not been established. Additionally, it mentions “eBGP neighbor with no inbound or outbound policy; defaults to ‘drop’”. This implies that in the absence of specific policies for route advertisement and acceptance, the default action is to drop all routes. Therefore, no routes are accepted from the neighbor 192.168.2.2, nor are any routes advertised to it, aligning with option C. References: = Implementing and Operating Cisco Service Provider Network Core Technologies course materials.

In Cisco hardware, when a high bandwidth multicast stream is sent over a Multicast VPN (MVPN), a data Multicast Distribution Tree (MDT) is specifically created for that stream. This data MDT is used in addition to the default MDT, which is used for lower-bandwidth or control traffic. The purpose of the data MDT is to optimize the transmission of high-bandwidth streams through the core of the network, ensuring that the multicast traffic is only sent to those PE routers that have local receivers for the multicast group in question. This mechanism helps in efficiently using network resources and provides a scalable solution for transmitting high-bandwidth multicast streams.

The configuration ip verify unicast source reachable-via any under interface gigabitethernet0/1 on Router 1 ensures that incoming packets have a source IP address that matches an entry in the FIB (Forwarding Information Base), indicating it’s reachable via a real interface. This helps mitigate attacks by dropping traffic with unreachable source addresses. References := Cisco

A. Reconnect Timeout field: Specifies the time within which the LDP session should be reestablished after a failure.

C. Graceful restart capability in OPEN message: Indicates that the router supports LDP graceful restart and is capable of maintaining its MPLS forwarding state across a control plane failure.

D. Recovery Time field: Specifies the time that the router will maintain the MPLS forwarding state while it attempts to reestablish LDP sessions.

In an MPLS network, the Label Distribution Protocol (LDP) is used to distribute labels which can include segment prefixes. LDP is a protocol that automatically generates and exchanges labels between routers, allowing for the forwarding of packets along a predetermined path without the need for complex lookups in a routing table at every hop.

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 XML, a self-closing tag such as  indicates that the element does not contain any data, hence the data field is considered blank. This is a common way to represent empty elements in XML documents.

 In this scenario, the network engineer is integrating several recently acquired networks into a more scalable common Unified MPLS architecture. The architecture will support end-to-end VPNv4 and VPNv6 services. The requirements include using IS-IS in Area 0 for the core layer and OSPF in Area 0 for the aggregation layers. LDP is used to distribute label bindings within each IGP domain.

To achieve this, the engineer must configure the ABR (Area Border Router) in each IGP domain to preserve next-hop information on all VPNv4 and VPNv6 prefixes advertised by the PE (Provider Edge) routers. This ensures that the correct next-hop information is maintained throughout the network, allowing end-to-end connectivity for MPLS LSPs (Label Switched Paths).

 To ensure that traffic for the prefix 192.168.1.1/32 travels via the alternate path R6-R5, a route-map with a higher local preference should be applied inbound on R3 for neighbor R6. This will make the path through R6-R5 more preferable, thus meeting the requirement. References := Implementing and Operating Cisco Service Provider Network Core Technologies

To implement Bidirectional Forwarding Detection (BFD) in an IS-IS environment, the first task is to configure BFD in an interface configuration mode. This involves setting up BFD parameters on the interfaces where IS-IS is running to enable quick failure detection.

Router R1 establishes TCP connections that are authenticated with an MD5 password. In the context of BGP (Border Gateway Protocol), TCP is used for establishing connections, and MD5 passwords can be used for authentication to enhance security.