Segment Routing - Traffic Engineering Flashcards
SR-TE uses a ________ to steer traffic through the network.
Policy
An SR-TE policy path is expressed as a ___________
List of segments
There are two types of SR-TE policies: 1 _________ 2 _________
Dynamic and explicit
Which nodes maintain states in SR-TE?
Only the headend
Both SR-TE and RSVP-TE support ECMP.
False
Both SR-TE and RSVP-TE were engineered for SDN.
True
Which entities are responsible for determining the path in SR-TE?
Node local or headend / distributed method, PCE / centralized method
The paths are chosen based on: __________ __________
Metrics (cost, latency, bandwidth, and so on) and constraints (color, affinity, node, and so on)
Steering traffic onto SR-TE: Who determines the policy: ____ or _____. How is policy created: ___________
Local or central, static, autoroute, BGP SR-TE dynamic
Because many SR-TE policies require a tunnel-te interface, the term ‘tunnel’ is also used in the context of SR-TE
False: Because many SR-TE policies do not require a tunnel-te interface, the term ‘tunnel’ is avoided in the context of SR-TE
An ___________ is expressed as a SID list—the list of segments that specifies the path.
SR-TE policy path
________ 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:
Binding
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.
Binding
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.
Label Switching Database (LSD)
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.
True
SR-TE can be deployed using a centralized controller; it cannot be a router or a virtualized router.
False: It may be simply a conventional stateful path computation element (PCE) running on a physical or virtualized router.
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.
True
In SR-TE, what is the primary traffic steering mechanism?
Binding SID
______________ automatically directs traffic to an SR-TE Policy based on color community markings.
BGP SR-TE Steering
