Nexus 5k QoS Classifcation

[Ryan Newell]

Hello,

  From what I have gathered from documentation the Nexus is able to mark any DSCP value between 0-63. I would assume it would be able to classify based on any DSCP value as well.  The documentation however leads me to believe otherwise. The language for marking suggest valid values are from 0 to 63. For classification the language suggests classification can only match standard DSCP values. I would test but do not have a Nexus at my disposal. Can someone with experience please confirm?

Classification

http://www.cisco.com/en/US/docs/switches/datacenter/nexus5000/sw/command/reference/qos/n5k-qos_cmds_m.html#wp1079436

Marking

http://www.cisco.com/en/US/docs/switches/datacenter/nexus5000/sw/command/reference/qos/n5k-qos_cmds_s.html#wp1159955

regards,

ryan

[Amanda Hunt · Accepted solution]

Hi Ryan,

As you can see from my 5010 lab switch:

24.09.5010B.1(config)# policy-map type qos my_policy

24.09.5010B.1(config-pmap-qos)# class type qos my_class

24.09.5010B.1(config-pmap-c-qos)# set dscp ?

  <0-63>   DSCP value

  af11     AF11 dscp (001010)

  af12     AF12 dscp (001100)

  af13     AF13 dscp (001110)

  af21     AF21 dscp (010010)

  af22     AF22 dscp (010100)

  af23     AF23 dscp (010110)

  af31     AF31 dscp (011010)

  af32     AF32 dscp (011100)

  af33     AF33 dscp (011110)

  af41     AF41 dscp (100010)

  af42     AF42 dscp (100100)

  af43     AF43 dscp (100110)

  cs1      CS1(precedence 1) dscp (001000)

  cs2      CS2(precedence 2) dscp (010000)

  cs3      CS3(precedence 3) dscp (011000)

  cs4      CS4(precedence 4) dscp (100000)

  cs5      CS5(precedence 5) dscp (101000)

  cs6      CS6(precedence 6) dscp (110000)

  cs7      CS7(precedence 7) dscp (111000)

  default  Default dscp (000000)

  ef       EF dscp (101110)

The only DSCP values you can set are 0-63, as you suspected.

However, these are the only DSCP values you are supposed to be able to match as well:

24.09.5010B.1(config-cmap-qos)# match dscp ?

<0-63>   List of DSCP values

  af11     AF11 dscp (001010)

  af12     AF12 dscp (001100)

  af13     AF13 dscp (001110)

  af21     AF21 dscp (010010)

  af22     AF22 dscp (010100)

  af23     AF23 dscp (010110)

  af31     AF31 dscp (011010)

  af32     AF32 dscp (011100)

  af33     AF33 dscp (011110)

  af41     AF41 dscp (100010)

  af42     AF42 dscp (100100)

  af43     AF43 dscp (100110)

  cs1      CS1(precedence 1) dscp (001000)

  cs2      CS2(precedence 2) dscp (010000)

  cs3      CS3(precedence 3) dscp (011000)

  cs4      CS4(precedence 4) dscp (100000)

  cs5      CS5(precedence 5) dscp (101000)

  cs6      CS6(precedence 6) dscp (110000)

  cs7      CS7(precedence 7) dscp (111000)

  default  Default dscp (000000)

  ef       EF dscp (101110)

This output was taken on our latest version of code, and the 5500 series is the same.

- Amanda

[Ryan Newell]

Hello Amanda,

  Thank you for the reponse! I spoke with an TME yesterday and he confirmed as well. Hopefully they will update the documentation.

regards,

ryan

[Amanda Hunt]

Ryan,

I assume you're referring to this line:

Specified DSCP value or list of DSCP values. See

Table 1 for a list of valid DSCP values.

As far as I can tell the documentation does tell you you can add your own.

[Ryan Newell]

I started with the config guide which reads like this...

marking...

--you can set the DSCP value in the six most  significant bits of the DiffServ field of the IP header to a specified  value. You can enter numeric values from 0 to 63, in addition to the  standard DSCP values shown in the table below:

classification...

--Configures the traffic class by matching  packets based on the values in the dscp-list. The standard DSCP values are shown in the preceding table (only standard dscp values).

The marking section explicity states values 0 to 63. The classification does not.

When I read the command reference I wasn't sure if specified implied one from the table from table or if specified implied any DSCP 0-63.

regards,

ryan