Free Practice Questions for Cisco 350-501 Exam

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.

When implementing traffic shaping on a network, the goal is to control the rate of traffic being sent into the network to avoid congestion. This is done by buffering excess packets and then scheduling them to be sent out at a steady rate.

Option A is correct because traffic shaping requires a queue with sufficient memory to buffer excess packets. When the traffic rate exceeds the configured maximum rate (shaping rate), the excess packets are temporarily stored in the queue until they can be sent out, ensuring a smooth flow of traffic without overwhelming the network1.

Option B is also correct as traffic shaping involves configuring token values in bytes. Tokens are used to represent permission to send a certain amount of data. The token bucket is filled with tokens at a steady rate, and packets can only be sent if there are enough tokens in the bucket. The token values determine the size of the bucket and the rate at which it is refilled, which in turn controls the rate of traffic1.

Option C is incorrect because packet remarking for excess traffic is not a component of traffic shaping. Packet remarking is typically used in conjunction with policing, where packets that exceed the rate limit can be remarked to a lower priority for downstream handling1.

Option D is incorrect in the context of traffic shaping. While a scheduling function is used to handle the packets that are delayed due to buffering, the scheduling itself is not part of the shaping mechanism but rather a function of the queuing system that works alongside shaping1.

Option E is incorrect as it pertains to traffic policing, not shaping. In traffic policing, packets that exceed a certain threshold are discarded or remarked, whereas shaping delays excess packets by buffering them1.

References: The information provided here is based on the Quality of Service (QoS) Configuration Guide from Cisco, which details the components and implementation of QoS, including traffic shaping1.

When a prefix list is applied to a BGP neighbor, it filters routes based on the specified conditions. In this scenario, the prefix list is designed to permit prefixes that are equal to or longer than /17 but shorter than or equal to /19. Therefore:

A: 192.168.0.0/19 is denied because it falls outside the specified range.

D: 192.168.0.0/16 is denied as it is shorter than the minimum length of /17.

E: 192.168.0.0/16 is permitted because it is the exact prefix specified in the prefix list, and the ge and le modifiers apply to more specific routes derived from this prefix. References: Implementing and Operating Cisco Service Provider Network Core Technologies (SPCOR) - Cisco official courseware.

During the traceback phase of the six-phase approach to service provider security, the action that occurs is tracing the attack flows from the attacked sections of the network toward the network edges. This phase entails identifying the source of the attack by analyzing the path that the attack traffic has taken through the network.

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.

References: For more detailed information, please refer to the Implementing and Operating Cisco Service Provider Network Core Technologies (SPCOR) course materials, specifically the sections covering MPLS and Layer 2 VPNs.

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

References: For more detailed information, please refer to the MPLS section in the Implementing and Operating Cisco Service Provider Network Core Technologies (SPCOR) course materials.