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Cisco 12000/10700 v3.1.1 Router Manager User Guide
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Chapter 11 Layer 3 QoS CAR and WRED Overview

Implications of Engin e Ty pe

Engine type refers to different hardware architectures. From a management perspecti ve, the engine type
determines w hat f unc tio nality is availa ble to th e cli ent. Current ly, this only ap plies to Layer 3 Q oS. The
following is a summary of how engine type affects Layer 3 QoS:
•CAR—Suppor ted for Eng ine 0 and 1
•CAR—Limi ted support fo r Engine 4
•PIRC—Supporte d f or Engi ne 2 ( see “P er Inte rface Rate Contro l (PIRC) Sup port” sect ion on
page 11-6 for fur the r d etai ls ).
•WRED—Support ed for Engine 0, 2, and 4 (see “Eng ine Typ e Support for W RED” section on
page 11-22 for furt her detai ls).
Cisco 12000/10720 Router Manager will detect the engine type applicable to a giv en module (line card)
and prevent operations that are not applicable.
Note Au to-dete ction is not supporte d for Engine ty pe 4.

CAR and WRED in Cisco 12000/10720 Router Manager

CAR and WRED are modeled as objects in Cisco 12000/10720 Router Manager. There are two types of
CAR objects: CAR policies and acc ess lists. There i s two types of WRED objects: CoS (Class of Service)
queue gro ups and ToFab polic ies.
When you create these objects in Cisco 12000/10720 Router Manager, you can work within the Layer 3
QoS view to create, apply, delete or edit Layer 3 QoS objects. Created CAR policies are placed under
the CAR Policies container in the Layer 3 QoS view. Created access lists are placed under the Access
List co nta in er in th e Layer 3 Qo S view. Cr ea ted CoS qu eu e g rou ps ar e p laced unde r the WRE D-MDRR
contai ner i n the La yer 3 QoS vi e w. Created ToFab police s are pl aced u nder t he WRED- MDRR cont ainer
in the Layer3QoS view.
Tip Access lists are only supported within the realm of CAR and do not function as stand-alone
objects.
It is importa nt to note that La yer 3 QoS CAR an d WRED objec ts (access lists, pol icies, CoS que ue
groups , ToFab policies) are global , meaning th ey can be applied to any module/int erface object wit hin
Cisco 1200 0/10720 Rou ter Manag er. For exampl e, the CosQ gro ups are appli ed to interfac es where as
the ToFab policies are applied to mod ules (line cards).