nokia 4a0-116 practice test
Nokia Segment Routing
Question 1
Which of the following statements about Multi-Protocol Label Switching networks is FALSE?
- A. MPLS uses a signaling protocol to exchange labels between routers.
- B. An LSR forwards data based on the MPLS labels.
- C. An LSP is a bi-directional tunnel that uses MPLS labels to forward data.
- D. The data is transparently carried from end to end.
Answer:
D
Explanation:
The data is transparently carried from end to end: This statement is not true, MPLS does not provide
data transparency, which means that the data is not carried unmodified from end to end. MPLS uses
labels to forward data, so the original IP packets are encapsulated in new MPLS packets, and the
original IP headers are not visible at the egress LSR.
Question 2
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.
Answer:
D
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 3
Which of the following statements about Segment Routing is FALSE?
- A. No path signaling is required to establish an SR tunnel.
- B. Intermediate routers do not maintain any tunnel informal
- C. A link-state IGP is required to distribute SID information.
- D. For TE-constrained tunnels, each data packet typically carries a single MPLS label to specify the tunnel path.
Answer:
B
Explanation:
Intermediate routers do not maintain any tunnel informal: this statement is false, Intermediate
routers do maintain tunnel information, such as the Forwarding Information Base (FIB) to forward
the packets according to the path specified in the packets.
Question 4
Which of the following statements about a Segment Routing SID is FALSE?
- A. A local Node-SID can be configured directly as an MPLS label.
- B. A router advertises its local Node-SID as a local SRGB and an index only if it is configured as an index.
- C. All routers do NOT need to have the same SRGB range configured.
- D. A local Node-SID can be configured as an index.
Answer:
B
Explanation:
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.
Question 5
When OSPF is used to support Segment Routing, the first byte of the link-state ID associated with
each of the opaque LSAs indicates the type of information being advertised. Which of the following
associations between the first-byte value and its meaning is FALSE?
- A. Value 1 - Traffic Engineering
- B. Value 4 - Router Info
- C. Value 7 - SRGB Range
- D. Value 8 - Extended Link Info
Answer:
D
Explanation:
Value 8 - Extended Link Info: This statement is not true, value 8 is not used to indicate Extended Link
Info. It is used for different types of information, such as Link-Local/Remote Identifiers (LLS/RLS)
Identifiers and Node SID/Adj-SID.
Question 6
Which of the following steps is NOT required when configuring IS-IS to support Segment Routing?
- A. MPLS label range reserved for Segment Routing.
- B. Enable interfaces used for Segment Routing under
- C. The flooding scope of Segment Routing information.
- D. The Segment Routing Global Block range.
Answer:
B
Explanation:
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.
Question 7
OSPF type-10 Opaque LSAs can carry different types of advertisements. What type of advertisement
carries a router's local 5RGB information?
- A. Extended Prefix Info
- B. Router Info
- C. Extended Link Info
- D. Traffic Engineering Info
Answer:
B
Explanation:
This type of advertisement carries a router's local SRGB information, which is used to distribute
information about the local SID allocation range
Question 8
Which of the following is not required to be advertised by a router participating in Segment Routing?
- A. Local Node-SID
- B. Adjacency-SIDs
- C. Support for SR-MPLS for IPv4 or IPv6, or SRv6
- D. SRGB when SRv6 is configured
Answer:
D
Explanation:
SRGB when SRv6 is configured: This is not required to be advertised, SRGB(Segment Routing Global
Block) is only used for SR-MPLS and is not needed when SRv6 is configured. Instead, SRv6 uses the
IANA-assigned IPv6 address space.
Question 9
Which of the following statements about Segment Routing tunnels is FALSE?
- A. A Segment Routing tunnel defined by a Node-SID uses the shortest IGP Path.
- B. A Segment Routing tunnel can be defined by multiple Node-SIDs.
- C. A Segment Routing tunnel can be defined by a combination of Node-SIDs and Adjacency-SIDs.
- D. For a Segment Routing tunnel, an intermediate router will always forward the packet based on the best IGP path.
Answer:
D
Explanation:
an intermediate router in a Segment Routing tunnel may forward packets based on the specific SIDs
defined in the Segment Routing tunnel and not always the best IGP path.
Question 10
Which of the following is NOT one of the main goals of traffic engineering?
- A. Utilizing redundant links.
- B. Avoiding potential congestion points in the network.
- C. Defining traffic paths based on various constraints.
- D. Using the shortest possible path through the network to the destination.
Answer:
D
Question 11
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.
Answer:
C
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 12
A router participating in SR-TE is advertising a value of Ox11 for the admin-group membership of one
of its interfaces. Which of the following statements is TRUE?
- A. The interface belongs to admin group RED, configured with a value of 17.
- B. The interface belongs to two different admin groups.
- C. The interface belongs to three different admin groups.
- D. The interface belongs to four different admin groups.
Answer:
B
Explanation:
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.
Question 13
Which of the following statements about enabling and using traffic engineering for Segment Routing
is FALSE?
- A. One interface can belong to an admin group and SRLG group at the same time.
- B. A link attribute has to be assigned to a particular interface under the [/configure router interface] context
- C. Bandwidth availability as a link attribute cannot be configured.
- D. The interfaces used for SR-TE LSPs have to be added to the MPLS context.
Answer:
C
Explanation:
Bandwidth availability can be configured as a link attribute in SR-TE, it is used to control the amount
of traffic that can be sent over a particular link.
Question 14
Which of the following list of SR-TE attributes has to be advertised among routers?
- A. Administrative groups that each link belongs to, TE metric of links, bandwidth availability of each link, SRLG that each link belongs to.
- B. Administrative groups that each link belongs to, TE metric of links, SRLG that each link belongs to.
- C. Administrative groups that each link belongs to, TE metric of links, bandwidth availability of each link, SRLG that each link belongs to, link status up/down.
- D. Administrative groups that each link belongs to, TE metric of links, SRLG that each link belongs to, link status up/down.
Answer:
A
Explanation:
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.
Question 15
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.
Answer:
A