Nokia Nokia Segment Routing Exam 4A0-116 Exam Dumps: Updated Questions & Answers (October 2025)

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.

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

When using Segment Routing with Traffic Engineering (SR-TE) in OSPF, the TE information is advertised using extended-link opaque LSAs. The option "sr-te false" indicates that OSPF will not advertise the TE information in the OSPF database, thus the routers will not be aware of the TE information.

Enable interfaces used for Segment Routing under: This step is not required, enabling interfaces used for Segment Routing is not necessary as the IS-IS protocol already takes care of the flooding of the routing information.

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.

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.

In SR-TE, routers need to advertise certain attributes of their links to other routers in the network in order to calculate traffic-engineered paths. These attributes include:

Administrative groups that each link belongs to: This information is used to restrict the use of certain links to specific traffic types or groups.

TE metric of links: This information is used to calculate the cost of using a particular link for a traffic-engineered path.

Bandwidth availability of each link: This information is used to control the amount of traffic that can be sent over a particular link.

SRLG that each link belongs to: This information is used to avoid routing over the same physical link. Link status up/down is not needed to be advertised as it is part of the IGP protocol and is used to check the reachability of a link.