Pass the Nokia Service Routing Architect 4A0-116 Questions and answers with ValidTests

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.

Seamless-BFD is a mechanism that allows the detection of faults in MPLS LSPs more quickly by using BFD (Bidirectional Forwarding Detection) protocol. Seamless-BFD responses are sent back using the MPLS data-plane, not the LSP label stack.

PCE does not have the capability to reserve bandwidth, This is a function of a Resource Reservation Protocol (RSVP) or a Label Distribution Protocol (LDP) and is done locally on the PE.

PCE can have advantages such as:

The ability to create cross-area TE-constrained LSP paths

The ability to create LSPs with primary and secondary paths

The ability to ensure that some LSP paths are disjoint

it can be used to optimize the path computation by centralizing the path calculation and by taking into account a global view of the network.

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.

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.

In SR-TE, the admin-group is represented by a 32-bit value, where each bit represents a different admin-group. The value Ox11 in binary is 000100010001, which has two bits set to 1, indicating that the interface belongs to two different admin groups. The exact admin-groups that the interface belongs to depends on how the admin-groups have been configured on the router.

R-LFA (Remote Loop-Free Alternate) is a method that can select either an immediate neighbor or a remote router to be used as a backup next hop, as long as the backup path coincides with the path that will become active after IGP reconvergence.

A router advertises its local Node-SID as a local SRGB and an index only if it is configured as an index: This statement is not true, A router will advertise its local Node-SID as a local SRGB and an index, whether it is configured as an index or not.

To create a flex-algo instance in a network, it's mandatory to configure at least one router in the network to create and advertise the flex-algo definition, This is the first step in creating a flex-algo instance, and it's done by defining the flex-algo instance and its properties on one or more routers in the network.

The other steps are important to fine-tune the flex-algo instance, but not mandatory to create it.

Configuring the proper values for the shared-risk link groups (SRLGs) that will define the flex-algo topology.

Specifying whether the LSP paths will be computed locally or by an external path computation element (PCE).

Configuring LSPs between every pair of PE routers.