Cisco 350-501 Dumps

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

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.

 When implementing Nonstop Routing (NSR) High Availability on an MPLS Provider Edge (PE) router, it’s important to consider that NSR generally consumes more memory and CPU resources than Nonstop Forwarding (NSF) because it needs to maintain a stateful switchover capability. Additionally, NSR requires routing protocol extensions to ensure that the state information is correctly synchronized between the active and standby routers, allowing for seamless failover without session loss. This ensures continuous packet forwarding even during a switchover event.

RSVP tear messages are used to clear the PATH or RESERVATION states on a router instantaneously, which enables the reuse of resources on the router for other requests. This is essential in MPLS Traffic Engineering where efficient resource management is crucial for maintaining network performance and stability.

 The configuration sets up a telemetry subscription to collect and send data every 60 seconds, which is indicated by the sample-interval 60000 setting in the configuration. References: For more detailed information, please refer to the official Cisco documentation on Implementing and Operating Cisco Service Provider Network Core Technologies (SPCOR) and the specific section on Telemetry Configuration.

 The ttl-security hops  command sets the maximum number of hops that a BGP message can traverse. In this case, setting ttl-security hops 2 means that the router will accept BGP packets from a neighbor (2.2.2.2) only if the TTL is 253 or more. This is because the default TTL value is 255, and for each hop, the TTL is decremented by 1. Therefore, a packet from a directly connected neighbor would have a TTL of 254 when it reaches the PE router. If the packet has traversed one more router (making it two hops away), the TTL would be 253 upon arrival.

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

The mpls ldp graceful-restart command is applied in the global configuration mode in IOS XE Software. This command enables MPLS LDP Graceful Restart, which assists a neighboring router with MPLS LDP Stateful Switchover/Nonstop Forwarding (SSO/NSF) Support and Graceful Restart to recover gracefully from an interruption in service without losing its MPLS forwarding state1.

The configuration shown indicates that Router 1 is set up with a route-map named “ddos” that matches traffic tagged with “tag 1”. The traffic matching this tag is then set to have a next-hop IP of 192.0.2.1 and a local preference of 150. The community is also set to “no export”, which means this route will not be advertised to external BGP peers. Since there’s no explicit deny statement in the configuration, only traffic with tag 1 and local preference of 150 will be dropped by Router 1 as per the BGP routing policy. References: Implementing and Operating Cisco Service Provider Network Core Technologies course materials. 

Option B: Internet routing through global routing on a PE router means that the PE router performs global routing for internet traffic. This allows the PE router to handle both L3VPN traffic and internet traffic.

Option D: Leaking internet routes from the global table into the L3VPN VRF allows the L3VPN customers to access the internet via the same MPLS backbone. The PE router imports internet routes into the L3VPN VRF, enabling internet access for VPN customers.

The correct configuration for MPLS LDP synchronization with OSPF process 1 on router R1 is to use the command mpls ldp igp sync holddown 60 under the OSPF process configuration. This ensures that the MPLS LDP synchronization is enabled and held for 60 seconds with OSPF process 1, which helps prevent black holes in MPLS networks during the convergence process by ensuring that routes are not advertised until LDP is fully operational and labels have been exchanged between adjacent routers.

YANG (Yet Another Next Generation) is a data modeling language used to model configuration and state data of a network. It is used to define the data structure of configuration files and is widely used for network configuration and management. YANG uses containers to categorize related nodes, allowing for a hierarchical organization of the data. Types can be associated with each leaf, but they are not required. Spines are not used in YANG, and it is not a distributed model of nodes.

NetFlow provides traceback information by analyzing network traffic. To configure NetFlow for traceback, you need to set up a classification ACL (Access Control List) to identify which type of traffic will be analyzed. This allows NetFlow to focus on specific traffic flows and report relevant information. The classification ACL can be based on various criteria such as source/destination IP addresses, port numbers, or protocols. By defining the classification ACL, you ensure that only the relevant traffic is considered for NetFlow analysis.

The issue is occurring in OSPF stub area 100 where the Ethernet link is down between routers RX and RY due to a cut fiber, leading to dropped traffic from CE site A to the hub site. Changing the OSPF area 100 type to stub on RZ can resolve these issues. In a stub area, OSPF routers use a default route to forward traffic to destinations outside the area, reducing the size of their routing tables. This would allow traffic from CE site A to be routed through RZ when the direct link between RX and RY is down.

 In BGP, the weight attribute is the first criterion used to determine the best path. It is a Cisco-specific attribute and is not propagated in BGP updates. Weight is a numeric value, and the path with the highest weight is preferred. If weights are the same, BGP will then consider the local preference, AS path length, origin type, and other attributes in sequence.

The correct configuration for deploying VRF on ASBR router R1 to have connectivity over an MPLS VPN inter-AS Option AB network is found in option C. This involves configuring the interface with the commands shown, including setting the interface ethernet, applying IP VRF forwarding, and enabling MPLS BGP forwarding. These steps ensure that the interface is properly configured for VRF and can support MPLS VPN inter-AS communications effectively. References := Implementing and Operating Cisco Service Provider Network Core Technologies

Cisco MPLS TE uses OSPF extensions to allow for optimized transit between a headend router and a destination router by utilizing Opaque LSAs. Opaque LSAs allow for the calculation and establishment of unidirectional tunnels that are set according to the network constraint. The tunnels are built bidirectionally by utilizing Router LSAs, which share router link advertisements to each router within the MPLS environment. ASBR Summary LSAs are also used to share OSPF domain information so that the two routers know how to reach each other during tunnel setup. Furthermore, Network LSAs are used to share RSVP information which is necessary for setting up the tunnel between the two routers.

 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.

The primary role of a BR (Border Relay) router in a 6rd (IPv6 Rapid Deployment) environment is to connect the CE (Customer Equipment) routers with the IPv6 network. The BR router de-encapsulates IPv6 packets that are encapsulated in IPv4 packets from the CE routers and forwards them to the IPv6 internet. This process is stateless and allows for high availability and load balancing by potentially having more than one BR router configured with the same IPv4 address (anycast), so CE routers are routed to the closest BR router12.

 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.

 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.

The exhibit shows a snippet of configuration for a router using OSPF (Open Shortest Path First) protocol along with segment-routing MPLS (Multiprotocol Label Switching) and segment-routing forwarding MPLS.

In the context of Cisco Service Provider Network Core Technologies, segment routing is designed to be highly scalable, flexible, and allows for simplified traffic engineering and management across network domains.

Once the initial setup is done (as shown in the exhibit), segment routing can operate without any additional configuration. The segment-routing MPLS and segment-routing forwarding MPLS commands are sufficient for the operation of segment routing.

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.

 Both Chef and Puppet are configuration management platforms that aim to configure and manage servers and other IT infrastructure. They operate in the same infrastructure management space and share several similarities:

Use a master-client architecture: Chef functions with a master-client architecture, where the server runs on the master machine, and the client runs as an agent on every client machine. Similarly, Puppet follows a similar setup.

Manage devices or nodes to be configured: Both Chef and Puppet manage the configuration of devices or nodes within an infrastructure.

Leverage a pull model: Both tools use a pull model, where the configuration is pulled from a central server to the managed nodes.

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.

 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

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.

 In Cisco IOS XR, to send BGP IPv4 labels to build inter-domain Label Switched Paths (LSPs), the configuration command used is router bgp 65515 neighbor 172.16.70.23 address-family ipv4 labeled-unicast. This command specifies that the router should use the BGP labeled unicast address family for the specified neighbor, which enables the exchange of label information along with the IPv4 routing information, facilitating MPLS LSP creation for inter-domain traffic.

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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.

OSPFv3 is used for routing IPv6 prefixes and requires that each interface intended to participate in OSPFv3 has the protocol enabled. This involves specifying the OSPF process ID and the area ID that the interface belongs to. The process ID links the interface to a specific OSPFv3 process running on the router, and the area ID determines the area within the OSPF topology that the interface is part of. Without this configuration, the interfaces will not actively participate in OSPFv3 route advertisement or neighbor relationships12.

References :=

Implementing and Operating Cisco Service Provider Network Core Technologies (SPCOR) course materials3.

Cisco OSPFv3 configuration guides and examples

The full separation model for Internet access and MPLS L3VPN services is chosen to enable EGP (Exterior Gateway Protocol) and IGP (Interior Gateway Protocol) to operate independently. In this model, the internet access and MPLS L3VPN services are fully separated, ensuring that the two networks do not interfere with each other’s operation. This separation enhances network security, performance, and manageability. References: Implementing and Operating Cisco Service Provider Network Core Technologies source documents or study guide

To establish LDP sessions between the PE and P routers, you need to enable communication over TCP port 646 for T-LDP hello messages.

T-LDP (Targeted LDP) uses TCP port 646 for session establishment.

Example configuration:

interface GigabitEthernet0/0

mpls ldp discovery targeted-hello accept

The correct configuration for PE1 to connect AS 200 of the service provider with AS 100 of enterprise ABC using BGP, considering the VRF RT 100:10 is already configured, would involve setting up BGP with the correct neighbor and route distinguisher settings. Option C is likely the correct choice as it specifies the BGP neighbor to be within the enterprise ABC’s AS 100 and includes the address family configuration necessary for VRF-aware BGP sessions. References := The Implementing and Operating Cisco Service Provider Network Core Technologies (SPCOR) course materials provide detailed instructions on configuring BGP in a service provider environment, including the use of VRFs and route distinguishers. For more information, please refer to the official Cisco documentation and course materials related to SPCOR1.

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.

Here is the solution:

 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

 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

 The command “show mpls traffic-engineering tunnels” is used to quickly check the path of a TE (Traffic Engineering) tunnel in a Cisco MPLS core network. This command provides detailed information about each TE tunnel, including its current operational status, configuration details, and the specific path it is taking through the network. 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

 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. References: Centralized egress to internet, Egress PE NAT single centralized router.

 The multicast implementation shown in the exhibit indicates that R2 is elected as the RP (Rendezvous Point) for the domain. This is inferred from the configuration commands which show R2 set up as a Bootstrap Router (BSR) candidate. In PIM-SM (Protocol Independent Multicast Sparse Mode), the BSR is responsible for announcing the RP-set to all routers in the PIM domain, and since R2 is the only BSR candidate, it effectively becomes the RP by default unless there are other configurations not shown in the exhibit.

 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 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.

 OSPFv3 is designed to support both IPv4 and IPv6. The message “IPv6 routing not enabled” indicates that IPv6 has not been configured on the router, but this does not prevent OSPFv3 from running for IPv4. The OSPFv3 configuration for IPv4 will still function on the interface FastEthernet0/0 as intended.

In the Pipe model of MPLS QoS, the MPLS EXP bits are set by the Customer Edge (CE) device. This model allows the CE to mark the packets, and these markings are retained throughout the MPLS network until they reach the egress Provider Edge (PE) router. The PE router does not alter the MPLS EXP value, ensuring that the QoS policy applied by the customer is preserved end-to-end.

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

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.

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.

1: graceful restart 2: IGP synchronization 3: session protection 4: targeted-hello accept

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. (

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.

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 achieve the origination of a default route based on the condition of the application server being up, a route map policy needs to be applied. This policy should match the condition of the server’s status and then use the default-information originate command to originate the default route with the specified metric type and value on router RL.

The SPT threshold set to infinity causes multicast traffic to permanently stay on the shared tree and not switch to the source tree. In multicast routing, the Shortest Path Tree (SPT) threshold determines when a router should switch from receiving multicast traffic on the shared tree to receiving it on a source tree. Setting the SPT threshold to infinity means that the router will always receive multicast traffic on the shared tree

To filter routes when redistributing OSPF into BGP, you should configure a route map and reference it with the redistribute command.

The route map allows you to apply filtering criteria to the routes being redistributed.

Example configuration:

router bgp 65000

redistribute ospf 1 route-map OSPF-TO-BGP

!

route-map OSPF-TO-BGP permit 10

match ip address prefix-list OSPF-TO-BGP-FILTER

!

ip prefix-list OSPF-TO-BGP-FILTER seq 10 deny 192.168.0.0/24

ip prefix-list OSPF-TO-BGP-FILTER seq 20 permit any

 In BGP, the Local Preference attribute is used to influence the exit point from an AS (Autonomous System). A higher local preference value is preferred, and all routes received inherit the local preference value of the route that is installed in the IP routing table. So, configuring a higher local preference outbound will make specific BGP speakers as preferred exit points for customer AS. References := Cisco

The configuration in Option C uses a route policy that checks if the MED is equal to 30 and then sets the local-preference to 70. This aligns with the requirement to prioritize routes with a MED of 30 by assigning them a higher local-preference value, which influences the BGP path selection process in favor of these routes.

References := The Implementing and Operating Cisco Service Provider Network Core Technologies (SPCOR) course provides insights into configuring route policies for BGP, which includes setting local-preference based on MED values

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

 The PCE (Path Computation Element) communicates with the PCC (Path Computation Client) using the PCEP. PCEP is responsible for path computation and signaling in MPLS networks.

 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

In the context of OSPF multiarea implementation, adjacency issues can arise due to network type mismatches or area boundary discrepancies. The command “ip ospf network point-to-point” is used on interface G0/1 to specify the OSPF network type as point-to-point. This configuration facilitates OSPF neighbor establishment over a direct connection between two routers, eliminating the need for a designated router (DR) or backup designated router (BDR), and resolving adjacency issues in the new area. References: Implementing and Operating Cisco Service Provider Network Core Technologies source documents or study guide

iproute_ospf/configuration/xe-16/iro-xe-16-book/iro-multi-area-adj-xe.html

 In Cisco IOS XR software, the keychain management for BGP is done in the routing configuration mode. This mode allows you to configure keychain parameters such as the key identifier, cryptographic algorithm, and other related settings. The keychain is essential for authentication and secure communication between BGP peers. By configuring the keychain in the routing context, you ensure that BGP sessions use the specified keys for authentication and integrity protection1.

The issue of no LDP neighbor existing for 1.1.1.1 between two directly connected routers could be due to R2 not receiving any hellos from R1. In the context of LDP (Label Distribution Protocol), hellos are used for the discovery of LDP peers. They are sent periodically on each interface that LDP is enabled on to discover and maintain LDP sessions with neighbors. If R2 is not seeing any hellos from R1, it means there’s a failure in the initial step of establishing an LDP session, hence no neighbor relationship is formed.

The command nsf ietf helper strict-lsa-checking is used to configure the router to terminate the OSPF graceful restart process if it detects any changes in the LSA during the restart. This ensures that the network remains stable and consistent by preventing the use of outdated or incorrect routing information.

 The Network Services Orchestrator (NSO) is designed to allow service providers to automate network operations efficiently. It provides a single, well-defined API that enables integration across various network environments. NSO’s capabilities include zero-touch telemetry, machine learning intuition, open APIs, and automated actions, which facilitate a simpler and more efficient network operation experience. This makes it an ideal choice for service providers looking to plan, optimize, and achieve closed-loop operations within their networks.

References := The information is based on the Implementing and Operating Cisco Service Provider Network Core Technologies (SPCOR) training and certification resources, which offer a deep dive into service provider technologies, including core architecture, services, networking, automation, quality of services, security, and network assurance123.

mt/mp-l3-vpns-15-mt-book/mp-bgp-mpls-vpns.html

The Forward Error Correction (FEC) field within the OTN (Optical Transport Network) signal structure is responsible for error correction. When data arrives at the receiver, the FEC field helps correct any errors that may have occurred during transmission. It enhances the reliability of optical communication by detecting and rectifying errors.

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 should ensure that VRF ABC and XYZ have route targets that allow them to import routes from VRF CENTRAL, but not from each other. This can be achieved by careful manipulation of route targets and import/export policies within the VRF configurations456.

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.

In the given scenario, the goal is to restrict users on the network between R1 and R2 from accessing the external network through R5, while still allowing them access to all resources within the administrative domain. The correct approach is to configure an Access Control List (ACL) that permits traffic to all internal networks and denies traffic to any external address. This ACL should be applied to the R2 interface that connects to R1 in the ingress direction. By doing so, traffic originating from users between R1 and R2 destined for external networks will be blocked, while internal traffic will be allowed.

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.

The correct command to authenticate the OSPF neighbor between PE-A and PE-B using MD5 is found in Option A. In this option, the command ip ospf message-digest-key 1 md5 44578611 is used to configure OSPF MD5 authentication on an interface with the key ID as 1 and key string as 44578611. The second command ip ospf authentication key-chain 44578611 is used to enable OSPF authentication on an interface and associate it with a specific key chain. References := Cisco - Implementing and Operating Cisco Service Provider Network Core Technologies

The script in the exhibit is for configuring a static VLAN (Option D). The XML configuration specifies a static VLAN range with “allocMode=‘static’”, indicating that VLAN IDs are assigned manually, not dynamically.

References := These explanations are derived from the concepts outlined in the Cisco Service Provider source book, specifically the “Implementing and Operating Cisco Service Provider Network Core Technologies” course materials,

 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.

 The show isis neighbors command is used to display the Intermediate System to Intermediate System (IS-IS) neighbors that the router has discovered. This command is essential for troubleshooting and verifying the IS-IS network’s topology and ensuring that the router has formed the correct adjacencies with its neighbors.

References := For more detailed information and study materials, you can refer to the official Cisco course page for “Implementing and Operating Cisco Service Provider Network Core Technologies” here and the on-demand e-learning resources here.

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 correct configuration for the BGP route policy named SUBNET, as per the second set of text in the image details, is to drop traffic if the destination is in BGP. Otherwise, the MED value should be set to 400 and community (4:400) should be added. This matches Option B, which specifies these exact actions. References := The information is based on the image details provided and aligns with common BGP route policy configurations typically found in Cisco’s service provider network core technologies documentation.

 In the context of Implementing and Operating Cisco Service Provider Network Core Technologies, LDP-IGP Synchronization is configured to ensure that the IGP and LDP convergences are synchronized. Option C is correct because it shows the configuration where router ISIS 1 is being configured with MPLS LDP sync, but not on a specific interface, ensuring that LDP is operational on all interfaces where IS-IS is enabled before routes are advertised. References := Cisco

The PSID plays a crucial role in segment routing, allowing efficient forwarding of packets along predefined paths.

For more detailed information, please refer to the official Cisco documentation on Segment Routing and IPv6. Unfortunately, I cannot directly cite specific pages from the provided resources, but you can find relevant details in the Cisco documentation.

 The ip igmp join-group command is used on a router interface to simulate the presence of an IGMP host for a specific multicast group. By issuing the command ip igmp join-group 239.10.10.10, the router is configured to join the multicast group 239.10.10.10 and will receive multicast traffic for this group. This is useful for testing or when the router itself needs to receive the multicast stream.

Option B is the correct answer because it meets all the given requirements. The configuration “snmp-server community comaccess ro 10” allows read-only access for all objects to members of Access-List 10 that use the comaccess community string. The “snmp-server host ABC.com informs version 2c public” command ensures SNMP authentication failure traps are sent to SNMPv2c and then to the host using SNMPv2c with the public community string.

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.

The configuration applies a QoS policy to the pos0/2/0/0 interface, which affects traffic as it exits the interface. The policy map “ciscopolicy” references the class map “ciscotest”, where traffic matching the class map criteria will be remarked. The command set precedence 1 within the class map “ciscotest” indicates that the traffic will be remarked to IP precedence 1. Therefore, the correct effect of this configuration is that traffic identified by the “ciscotest” class map will be remarked from its original IP precedence to IP precedence 1 when it exits the pos0/2/0/0 interface.

RSVP (Resource Reservation Protocol) is used with MPLS (Multiprotocol Label Switching) traffic engineering tunnels primarily to reserve bandwidth along the path of the tunnel. This ensures that sufficient resources are allocated for the traffic to meet quality of service requirements, which is crucial for maintaining the performance of critical applications that traverse the network. References := For more information on RSVP and MPLS traffic engineering, refer to the Implementing and Operating Cisco Service Provider Network Core Technologies (SPCOR) course materials, which provide detailed explanations on how these technologies work together to optimize network traffic1.

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.

 To implement a PIM-SSM (Protocol Independent Multicast - Source Specific Multicast) configuration for streaming live traffic across different domains, the network operator must ensure that IGMPv3 (Internet Group Management Protocol version 3) is enabled on R1. IGMPv3 is required for SSM because it allows the receiver to specify the source IP address of the desired traffic, which is a key feature of SSM. The operator would configure IGMPv3 on the interfaces that connect to the users who will be accessing the multicast stream. Additionally, PIM-SSM must be enabled on the router, and the multicast sources and groups must be properly defined.

When router A is the Rendezvous Point (RP), Protocol Independent Multicast - Sparse Mode (PIM-SM) is the appropriate mode to configure. In PIM-SM, multicast traffic is initially sent to the RP by the sources. The receivers express their interest in receiving specific multicast traffic by sending join messages towards the RP. This mode is efficient for networks with sparse multicast groups where not all members participate in every multicast session. References: = Implementing and Operating Cisco Service Provider Network Core Technologies course materials.

 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

Ansible is widely recognized as a robust network automation tool that facilitates provisioning, configuration, and management of network devices. It uses simple, human-readable YAML syntax for its playbooks, making it easy to define tasks and orchestrate workflows for automated network operations1.

 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.

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.

The URL in the exhibit is used with REST API to send a message to the APIC (Application Policy Infrastructure Controller) to perform an operation on a managed object or class operator. In Cisco’s ACI (Application Centric Infrastructure), REST API requests are used for managing, configuring, and retrieving data from the APIC. The URL structure typically includes the IP address of the APIC and specific paths that refer to objects or classes within the ACI fabric. References: Implementing and Operating Cisco Service Provider Network Core Technologies source documents or study guide

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 keyword ‘none’ is essential in management plane security using TACACS to ensure that authentication can still succeed when the TACACS+ server is unreachable. This fallback mechanism allows network resources to remain accessible even if the TACACS+ server fails or becomes unreachable. References: Implementing and Operating Cisco Service Provider Network Core Technologies (SPCOR) - Management Plane Security section.

 The configuration in the exhibit shows that R1 is configured with “mpls ldp graceful-restart”, which enables LDP Graceful Restart on the router. This means that R1 can support a graceful restart operation on the peer, even if graceful restart is disabled on the peer. This feature allows LDP to recover from failures without affecting the forwarding plane, ensuring network stability and minimal packet loss during failovers.

When implementing LDP NSF (Nonstop Forwarding) on the network, an engineer must perform the following tasks:

Implement direct connections for LDP peers: This ensures that LDP sessions can be reestablished quickly after a switchover.

Enable NSF for the link-state routing protocol in use on the network: This allows the routing protocol to maintain its state during a switchover, ensuring seamless operation.

For example, if OSPF is the link-state routing protocol, enabling NSF for OSPF ensures that OSPF adjacencies are maintained during a switchover

The command “traceroute mpls ipv4 10.20.0.1/32 ttl 4” is used to trace the route that packets take to get from the source to the destination in an MPLS network, specifically for IPv4 addresses with a maximum of 4 hops (Time To Live). This command will provide information on all labels and hop-by-hop IP addresses for the specified destinations, meeting the requirements stated in the question.

References := For more detailed information, you can refer to the Implementing and Operating Cisco Service Provider Network Core Technologies training, which covers the configuration, verification, troubleshooting, and optimization of Service Provider IP network infrastructures, including MPLS operations