QoS Class-Based Packet Marking

Next discuss about Class-Based Packet Marking. To perform it, you must either configure an IP Precedence value or an IP differentiated services code point (DSCP) value.

Here is the compare values for IP precedence and Differentiated Services Code Point (DSCP).

## IP precedence=CoS ## DSCP ## Comment
## 0=routine         ## 0    ## Best effort
## 1=priority        ## 8    ##
## 2=immediate       ## 16   ##
## 3=Flash           ## 24   ##
## 4=FlashOver       ## 32   ##
## 5=critical        ## 40   ##
## 6=internet        ## 48   ##
## 7=network         ## 56   ##

#### Define class-name (class-map)

IOS(config)# class-map SSH-Class
IOS(config-cmap)# match protocol ssh

#### Define IP Precedence policy-name (policy-map)

IOS(config)# policy-map SSH-Prec-1 
IOS(config-pmap)# class SSH-Class 
IOS(config-pmap-c)# set ip precedence 1

#### Define IP DSCP policy-name (policy-map)

IOS(config)# policy-map SSH-DSCP-8 
IOS(config-pmap)# class SSH-Class 
IOS(config-pmap-c)# set ip dscp 8

#### Apply Traffic Policy to interface (service-policy)

IOS(config-if)#
service-policy input SSH-Prec-1
service-policy output SSH-DSCP-8

#### Verify Traffic Policy

IOS#show class-map
 Class Map match-any class-default (id 0)
   Match any 

 Class Map match-all SSH-Class (id 1)
   Match protocol ssh
   
IOS#show policy-map
  Policy Map SSH-Prec-1
    Class SSH-Class
      set ip precedence 1
  Policy Map SSH-DSCP-8
    Class SSH-Class
      set ip dscp cs1

IOS#show policy-map interface
 FastEthernet1/1 

  Service-policy input: SSH-Prec-1

    Class-map: SSH-Class (match-all)
      0 packets, 0 bytes
      5 minute offered rate 0 bps, drop rate 0 bps
      Match: protocol ssh
      QoS Set
        precedence 1
          Packets marked 0

    Class-map: class-default (match-any)
      8 packets, 788 bytes
      5 minute offered rate 0 bps, drop rate 0 bps
      Match: any 

  Service-policy output: SSH-DSCP-8

    Class-map: SSH-Class (match-all)
      0 packets, 0 bytes
      5 minute offered rate 0 bps, drop rate 0 bps
      Match: protocol ssh
      QoS Set
        dscp cs1
          Packets marked 0

    Class-map: class-default (match-any)
      3 packets, 272 bytes
      5 minute offered rate 0 bps, drop rate 0 bps
      Match: any