Segment Routing - Traffic Engineering

Question 1

SR-TE uses a ________ to steer traffic through the network.

Answer 1

Policy

Question 2

An SR-TE policy path is expressed as a ___________

Answer 2

List of segments

Question 3

There are two types of SR-TE policies: 1 _________ 2 _________

Answer 3

Dynamic and explicit

Question 4

Which nodes maintain states in SR-TE?

Answer 4

Only the headend

Question 5

Both SR-TE and RSVP-TE support ECMP.

Answer 5

False

Question 6

Both SR-TE and RSVP-TE were engineered for SDN.

Answer 6

True

Question 7

Which entities are responsible for determining the path in SR-TE?

Answer 7

Node local or headend / distributed method, PCE / centralized method

Question 8

The paths are chosen based on: __________ __________

Answer 8

Metrics (cost, latency, bandwidth, and so on) and constraints (color, affinity, node, and so on)

Question 9

Steering traffic onto SR-TE: Who determines the policy: ____ or _____. How is policy created: ___________

Answer 9

Local or central, static, autoroute, BGP SR-TE dynamic

Question 10

Because many SR-TE policies require a tunnel-te interface, the term ‘tunnel’ is also used in the context of SR-TE

Answer 10

False: Because many SR-TE policies do not require a tunnel-te interface, the term ‘tunnel’ is avoided in the context of SR-TE

Question 11

An ___________ is expressed as a SID list—the list of segments that specifies the path.

Answer 11

SR-TE policy path

Question 12

________ segment is a fundamental building block of SR-TE: The ________ segment is a local segment identifying an SR-TE policy: Each SR-TE policy is associated 1-for-1 with a ________ SID. The ________ SID can be used to steer traffic into the SR-TE policy:

Answer 12

Binding

Question 13

The ________ SID is a local label, statically or dynamically allocated for each SR-TE policy: ____________ SIDs can be manually configured if desired, per policy in some cases. A ____________ SID can also be allocated for RSVP-TE tunnels (configurable). The ____________-SID label is allocated when the SR-TE policy is instantiated. Bringing down an SR-TE policy does not remove its ____________ SID.

Answer 13

Binding

Question 14

The SR-TE policy interface tunnel-te down does not remove the binding SID. If SR-TE policy is deleted, binding SID is moved to the __________________ ‘zombie’ table. It holds on to that label for about 30 minutes.

Answer 14

Label Switching Database (LSD)

Question 15

Valid constraints are: Include and/or exclude traffic engineering affinity. Include and/or exclude IP address. Include and/or exclude SRLG. Maximum accumulated metric (IGP, traffic engineering, and delay). Maximum number of SIDs in the solution SID list.

Answer 15

True

Question 16

SR-TE can be deployed using a centralized controller; it cannot be a router or a virtualized router.

Answer 16

False: It may be simply a conventional stateful path computation element (PCE) running on a physical or virtualized router.

Question 17

Weighted ECMP SR Policy allows balancing traffic over unequal cost paths by controlling how much traffic can be sent to each path based on their capacities.

Answer 17

True

Question 18

In SR-TE, what is the primary traffic steering mechanism?

Answer 18

Binding SID

Question 19

______________ automatically directs traffic to an SR-TE Policy based on color community markings.

Answer 19

BGP SR-TE Steering