Question No : 1
Which of the following is NOT a valid option to steer traffic into a flex-algo segment-routing tunnel?

• A.Using a flex-algo Node-SID as an explicit hop in the path definition of an SR-TE LSP and enabling the sr-te tunnel type for a VPN service.
• B.Specifying the flex-algo instance ID as an additional TE constraint for an SR-TE LSP and enabling the sr-te tunnel type for a VPN service.
• C.Configuring and applying a VRF import policy to a VPRN service and enabling the sr-is-is or sr-ospf tunnel type for the service, depending on the underlying routing protocol.
• D.Configuring and applying a VSI import policy to an EVPN service and enabling the sr-is-is or sr-ospf tunnel type for the service, depending on the underlying routing protocol.

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Answer:
Explanation:
Applying a VSI import policy to an EVPN service and enabling the sr-is-is or sr-ospf tunnel type for the service is not a valid option for steering traffic into a flex-algo segment-routing tunnel, VSI is not related to flex-algo SR.

Question No : 2
Based upon the exhibit, which of the following statements regarding the configuration is FALSE?

• A.Traffic engineering information will only be advertised for the interfaces that have both MPLS and RSVP enabled.
• B.The Node-SID assigned to this router is the second label in the defined range.
• C.Traffic engineering has been enabled on this router.
• D.Adjacency-SID labels will not be advertised as they have not been defined under the physical interfaces.

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Answer:

Question No : 3
An SR-TE LSP with a path definition that includes router R4 as a loose hop and for which Seamless-BFD has been enabled is following the path shown in the exhibit.



What happens after router R4 fails if the routers along the path follow the default behavior?

• A.The head end will periodically try to calculate a new path at a rate defined by the retry timer.
• B.The head end will periodically try to calculate a new path at a rate defined by the resignal timer.
• C.The head end will continue forwarding traffic to the current next-hop indefinitely, which will be discarded at the point of failure.
• D.The head end will continue forwarding traffic to the current next-hop indefinitely, and R2 will redirect the traffic to R3 after IGP reconvergence.

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Answer:
Explanation:
When an SR-TE LSP with Seamless-BFD enabled, the BFD sessions are established between the routers along the path to detect any failures quickly. If a failure happens in the path, the router will stop forwarding the traffic and send a BFD control packet to the head-end router. In this case, R4 failed, BFD sessions will detect the failure and send a message to the head-end router, but since R4 is a loose hop, the path doesn't have to be re-calculate. The head-end router will continue forwarding traffic to the current next-hop, R2, which will be discarded at the point of failure (R4) as it doesn't know about the failure. And the traffic will not be redirected to R3 after IGP reconvergence.

Question No : 4
Which of the following statements about a Segment Routing SID is FALSE?

• A.A Node-SID is usually associated with a router's system interface.
• B.Adjacency-SID values are taken from the SRGB configured for the routing protocol.
• C.A Prefix-SID can be configured directly as a label value or indirectly as an index.
• D.An Adjacency-SID does not have to be configured.

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Answer:
Explanation:
An Adjacency-SID does not have to be configured: this statement is not true, An Adjacency-SID is associated with a neighbor router, it is used to identify an adjacency between two routers. An Adjacency-SID must be configured to identify the adjacency.

Question No : 5
Which of the following statements about SR-TE administrative constraints is FALSE?

• A.A strict hop must be adjacent to the previous hop in the list.
• B.The TE metric for a link is by default the same as the IGP metric.
• C.Shared-Risk-Link Groups are only taken into account when calculating the secondary path.
• D.The head-end router may calculate a path that takes into account max hop count and bandwidth constraints.

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Answer:
Explanation:
Shared-Risk-Link Groups (SRLG) is taken into account when calculating both primary and secondary path to avoid routing over the same physical link.

Question No : 6
The exhibit presents packets being transmitted inside an LSP's multi-segment primary path going from router R1 to router R8.



The LSP also has a standby secondary path, and Seamless-BFD has been enabled on the primary path. The link between routers R1 and R2 fails, and fast re-route (FRR) is triggered.
As a result, router R1 forwards the packets to router R3 and adds the proper FRR encapsulation to reach which router?

• A.To reach router R2, which is the LSP's intended next-hop.
• B.To reach router R5, which is the shortest way to go back to the original path.
• C.To reach router R4, which is the tail-end of the active segment.
• D.To reach router R8, which is the tail-end of the LS

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Answer:

Question No : 7
In the context of a network that includes a Path Computation Element (PCE), what is a PCC-initiated LSP?

• A.An LSP that needs to be explicitly configured on the head-end router.
• B.An LSP for which the initial path is calculated by the head-end router.
• C.An LSP for which the path repairs and re-optimizations must be triggered by the head-end router.
• D.An LSP whose existence and state are reported to the PC

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Answer:
Explanation:
A PCC-initiated LSP is an LSP that is established and controlled by the PCC (Path Computation Client) which is typically a head-end router. The PCC sends LSP setup and teardown requests to the PCE and also reports the existence and state of the LSPs to the PCE. The PCE then uses this information to perform path computation and to monitor the state of the LSPs.

Question No : 8
In which of the following aspects does the configuration of flex-algo LSPs have an advantage over the configuration of SR-TE LSPs?

• A.Label stack size of the encapsulated data packets
• B.List of traffic-engineering constraint types available to choose from
• C.Ability to associate one primary and up to two secondary paths to the same LSP
• D.Flexibility of configuring each LSP with its own set of traffic-engineering constraints

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Answer:
Explanation:
Flex-Algo LSPs are a type of LSP that allows for greater flexibility in configuring traffic engineering constraints. This is because flex-algo LSPs can be configured with a unique set of traffic engineering constraints for each LSP, whereas SR-TE LSPs use a predefined set of traffic engineering constraints that applies to all LSPs. Label stack size of the encapsulated data packets, List of traffic-engineering constraint types available to choose from, and Ability to associate one primary and up to two secondary paths to the same LSP are not the advantages of flex-algo LSPs over SR-TE LSPs