When implementing MPLS DS-TE on Cisco IOS XR routers, all aggregate Cisco MPLS TE traffic
is mapped to which class type by default?
A.
class-type 0 (bandwidth global pool)
B.
class-type 1 (bandwidth subpool)
C.
class-type 2 (bandwidth priority)
D.
class type class-default (bandwidth best-effort)
Explanation:
Differentiated Services Traffic Engineering
MPLS Differentiated Services (Diff-Serv) Aware Traffic Engineering (DS-TE) is an extension of the
regular
MPLS-TE feature. Regular traffic engineering does not provide bandwidth guarantees to different
trafficclasses. A single bandwidth constraint is used in regular TE that is shared by alltraffic. Tosupport variousclasses of service (CoS), users can configure multiple bandwidth constraints.
These bandwidth constraints canbe treated differently based on the requirement for the traffic
class using that constraint.
MPLS diff-serv traffic engineering provides the ability to configure multiple bandwidth constraints
on an MPLSenabledinterface. Available bandwidths from all configured bandwidth constraints are
advertised using IGP.
TE tunnel is configured with bandwidth value and class-type requirements. Path calculation and
admissioncontrol take the bandwidth and class-type into consideration. RSVP is used to signal the
TE tunnel withbandwidth and class-type requirements.
Diff-Serv TE can be deployed with either Russian Doll Model (RDM) or Maximum Allocation Model
(MAM) forbandwidth calculations.
DiffServ-aware Traffic Engineering extends MPLS traffic engineering to enable you to perform constraint-based routing of “guaranteed” traffic, which satisfies a more restrictive bandwidth constraint than that satisfied by CBR for regular traffic. The more restrictive bandwidth is termed a sub-pool, while the regular TE tunnel bandwidth is called the global pool. (The sub-pool is a portion of the global pool. In the new IETF-Standard, the global pool is called BC0 and the sub-pool is called BC1.)
Having configured two bandwidth pools, you now can
•Use one pool, the sub-pool, for tunnels that carry traffic requiring strict bandwidth guarantees or delay guarantees
•Use the other pool, the global pool, for tunnels that carry traffic requiring only Differentiated Service.
Global Pool—The total bandwidth allocated to an MPLS traffic engineering link.
Sub-pool—The more restrictive bandwidth in an MPLS traffic engineering link. The sub-pool is a portion of the link’s overall global pool bandwidth.
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