Specifications

White Paper
© 2009 Cisco Systems, Inc. All rights reserved. This document is Cisco Public Information. Page 6 of 89
PFC Policy Feature Card is a daughter card that sits on the Supervisor providing hardware
accelerated L3/L4 switching, QoS and Security
PFC1 Policy Feature Card supported on a Supervisor 1 or Supervisor 1A
PFC2 Policy Feature Card supported on a Supervisor 2
PFC3A Policy Feature Card supported on a Supervisor 720
PFC3B Policy Feature Card supported on a Supervisor 720-3B
PFC3BXL Policy Feature Card supported on a Supervisor 720-3BXL
PFC3C Policy Feature Card supported on a Supervisor 720-10GE-3C
PFC3CXL Policy Feature Card supported on a Supervisor 720-10GE-3CXL
Policing Process of ensuring identified traffic flow is limited to a predefined flow rate; excess traffic above
this level is either dropped or has its QoS value marked down.
QoS Quality of Service
TCAM Specialized memory (Table) for storing ACL’s used on the PFC1, PFC2, and PFC3 as well as
the DFC and DFC3.
Threshold A utilization level in a buffer used by a congestion management algorithm to determine when to
start dropping identified frames
ToS Type of Service field is a one-byte field in the IP V4 header used in part to denote the priority of
that IP packet.
VoIP Voice over IP
WRED Weighted Random Early Discard—a buffer management algorithm that uses CoS bits to identify
which frames to drop at times of congestion
WRR Weighted Round Robin is a scheduling algorithm that uses weights assigned to queues to
determine how much data will be emptied from a queue before moving to the next queue.
Abstract
This document explains the Quality of Service (QoS) capabilities available in the Catalyst 6500 Switch as it applies to
PFC QoS for IPv4 data. This document does not cover QoS features on the WAN linecards like the FlexWAN, OSM
and SIP modules, nor does it cover QoS for MPLS. This document covers QoS configuration capabilities and
provides some examples of QoS implementation. It focuses on shipping hardware as of the date of this publication.
This paper is not meant to be a configuration guide. Configuration examples are used throughout this paper to assist
in the explanation of QoS features of the Catalyst 6500 hardware and software. This paper uses Cisco IOS
configuration examples when required. For syntax reference for QoS command structures, please refer to the
configuration and command guides for the Catalyst 6500 on Cisco Connection Online at
http://www.cisco.com/univercd/cc/td/doc/product/lan/cat6000/index.htm