QoS Implementation

2009-10-12 17:36:56
QoS Implementation
Command Line:
Not even the Cisco QoS Exam Certification guide covers the old command line configuration.

Modular QoS Command Line (MQC):
This tool separates classification of the traffic from the policy of the per hop behavior (PHB) on the router. The same policy can be applied to many interfaces on the same router.

There are three major commands in MQC, using the commands from NBAR Fun as examples.

  • class-map
    Defines matching parameters to separate classes into a number of named service classes. An example is:
    class-map match-any http-citrix
    match protocol http url “*citrix*”
  • policy-map
    This step defines PHB behaviors and links those behaviors to traffic classes. A policy-map is named an can associate 256 traffic classes, which are each defined by a class-map.
    An example is:
    policy-map mark-inbound-http-citrix
    class http-citrix
    set ip dscp 1
  • service-policy
    This is the application of classification and policy on an interface. It is applied to traffic that is either inbound or outbound. An example of this command:
    interface FastEthernet0/0
    ip address
    duplex auto
    speed auto
    service-policy input mark-inbound-http-citrix

On order to display and verify QoS classes and policies on a router use these commands:
show class-map
show policy-map
show policy-map interface int

The key benefit of AutoQoS is that administrators who do not understand QoS can use AutoQoS to implement features consistently and accurately across the entire network if you consistently use AutoQoS across the enterprise.

The commands to implement AutoQos are:
auto qos voip — The first generation of AutoQoS
auto discovery qos — Must have CEF and NBAR turned on, the router analyzes traffic.
auto qos — The router builds class maps and then creates and applies a policy map on the interface automagically.

Security Device Manager (SDM) QoS Wizard:
is a web based client to interact with your router. The SDM predefines three traffic classes real-time, business-critical and best-effort. SDM allows you to easily implement QoS, monitor QoS and troubleshoot QoS.

Do the SDM lab in the lab workbook. I spent more time installing Windows on a server and getting SDM to run in my browser than the lab took, but there is no sense in me trying to explain the SDM. It’s a GUI tool and if you are like me and used to working with the CLI then it’s no big loss if you don’t use it.

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