Free Cisco 350-501 Practice Exam with Questions & Answers | Set: 2

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.

References: Implementing and Operating Cisco Service Provider Network Core Technologies (SPCOR)

In the context of regular expressions, the caret (^) is used to indicate the start of a string. This is a fundamental concept in pattern matching using regular expressions, where ^ matches the position at the beginning of the string.

References: This information is consistent with regular expression syntax as described in various Cisco documentation and resources related to Cisco IOS software configurations.

 In OSPF (Open Shortest Path First), the Hello interval is a critical parameter for OSPF neighbor formation. It defines the frequency at which Hello packets are sent on an OSPF interface. For two OSPF routers to become neighbors, they must have matching Hello and Dead intervals. In the provided configuration, Router 1 has a hello-interval of 1 second while Router 2 has a hello-interval of 2 seconds. Adjusting them to match will reestablish the OSPF neighbor relationship between Router 1 and Router 2. References: Implementing and Operating Cisco Service Provider Network Core Technologies (SPCOR) - Cisco

 To monitor memory consumption and buffer statistics securely on P and PE devices in an MPLS core, especially considering the high CPU usage, the engineering team should implement SNMP version 3 for its security features. Therefore, option A is correct as it specifies SNMP version 3 with authentication. Option B is also correct as it enables traps for memory buffer peak, which is essential for monitoring memory thresholds and ensuring quick response to potential issues.

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.

Cisco MPLS TE (Traffic Engineering) tunnels provide a way to optimize traffic routing within an MPLS network. However, there are certain constraints to be aware of:

• QoS-aware tunneling: Unfortunately, Cisco MPLS TE tunnels do not inherently support Quality of Service (QoS) awareness. This means that the tunnels themselves do not directly consider QoS parameters when making routing decisions. QoS policies must be applied separately at the network level, and the TE tunnels do not inherently take QoS into account during path selection.
• Tunnels spanning multiple OSPF areas: Contrary to option A, Cisco MPLS TE tunnels can indeed span multiple OSPF areas. The use of OSPF areas does not inherently restrict the creation of MPLS TE tunnels across area boundaries.
• ISIS metrics: Option B is incorrect. When using ISIS (Intermediate System to Intermediate System) as the Interior Gateway Protocol (IGP), newer-style metrics (such as wide metrics) are supported. Older-style metrics are not the only option.
• Tunnels over IP unnumbered links: Option C is also incorrect. Cisco MPLS TE tunnels can be configured over IP unnumbered links, allowing efficient use of IP addresses.

In summary, the primary constraint is the lack of built-in QoS awareness within MPLS TE tunnels.

References:

• Implementing an MPLS VPN over TE Tunnels - Cisco Support
• Configuring Basic MPLS TE - Cisco NX-OS

• In Cisco Unified MPLS, BGP (Border Gateway Protocol) is used to transport labels along with network layer reachability information. RFC 3107 defines BGP/MPLS IP Virtual Private Networks (VPNs) and allows BGP to carry MPLS labels, enhancing scalability and flexibility in MPLS networks.

References

1: Cisco. “Implementing and Operating Cisco Service Provider Network Core Technologies (SPCOR).” Link