Cisco WS-X6248-RJ-45 - Catalyst 6000 Expansion Module Manual de usuario descargar pdf (Pagina 31)

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Conﬁguring QoS Policies

TheconﬁgurationofQoSpoliciesdifferssigniﬁcantly between the Cisco IOS Software and CatOS. For CatOS, a QoS

ACL statement is used to conﬁgure all match and action parameters for marking and policing. Cisco IOS QoS

supports classiﬁcation, marking, and policing using the Modular QoS CLI (MQC) syntax.

A Cisco IOS policy uses trafﬁc classes (with the class-map statement) to identify interesting trafﬁc. These trafﬁc

classescanbedeﬁnedfordifferent types of trafﬁc ﬂows—for example, a user could have a different class for IP trafﬁc,

IPX trafﬁc, and MAC trafﬁc. Each trafﬁc class uses IOS based access control lists and/or class match statements to

identify trafﬁc. The policy-map includes the desired action for the matched trafﬁc (mark, police, trust, etc.). The

policy deﬁned by a policy-map is mapped to an interface using the service-policy command.

Examples of both are included below.

Trust with an ACL

As an alternative to setting the trust state for all trafﬁc on a port (as described above), a QoS policy can be created

to trust trafﬁc that matches a speciﬁc QoS ACL. This functionality is available in both CatOS and the Cisco IOS

Software. As such, it is a straightforward example of the conﬁguration differences between the CatOS QoS ACL

syntax and the Cisco IOS MQC syntax described above. In this example, the function of using an ACL for trusting

the CoS on all trafﬁc coming into port gigabit into port gigabit 3/1 is compared.

When a CatOS ACL is created, modiﬁed, or deleted, the changes exist temporarily in an edit buffer in memory.

CatOS requires that the ACL be committed for it to take effect. Cisco IOS Software does not utilize the edit buffer

concept. Once a policy has been built in IOS, it must then be mapped to either a port or a VLAN for that policy to

take effect. When a policy is mapped to an “up” interface, the ASIC hardware is programmed with the necessary

information and that policy is in effect.

Policers

The policing function is primarily used for rate limiting trafﬁc to a conﬁgured speed. If trafﬁc exceeds the conﬁgured

speed,thenitcaneither be dropped or marked down to a lower priority. This is usefultoensurecompliancetoservice

level agreements or for security protection. The policer can either be an aggregate or a microﬂow policer. An

aggregate policer will rate limit all trafﬁc in a class or group of classes to one combined (or aggregate) rate. A

microﬂow policer will rate limit each ﬂow (a unique SA/DA MAC address, SA/DA IP address, and TCP/UDP port

numbers) in a trafﬁc class to an individual rate. A total of 63 microﬂows and 1023 aggregates can be conﬁgured per

chassis (independent of the operating system).

CatOS Cisco IOS Software

set qos acl ip CatOS trust-cos any

commit qos acl CatOS

set qos acl map CatOS 3/1

access-list 101 permit ip any any

policy-map IOS

class IOS access-group 101

trust cos

interface gigabitethernet 3/1

service-policy input IOS

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Cisco WS-X6248-RJ-45 - Catalyst 6000 Expansion Module Manual de usuario Pagina 31