max-reserved-bandwidth ignored when shaping??

[Keith Rance]

We have a bandwidth management policy to prioritise traffic types across Sat links as follows:

class-map match-all VOIP

match access-groupname VOIP

class-map match-all MAIL

match access-groupname MAIL

class-map match-all VTC

match access-groupname VTC

class-map match-all FILESHARE

match access-groupname FILESHARE

class-map match-all WEB

match access-groupname WEB

policy-map QOS

class VTC

  priority 256

class VOIP

  priority 128

class WEB

  bandwidth remaining percent 45

class MAIL

  bandwidth remaining percent 30

class FILESHARE

  bandwidth remaining percent 25

policy-map 2048

class class-default

  shape average 2048000

  service-policy QOS

policy-map 1024

class class-default

  shape average 1024000

  service-policy QOS

We were expecting to see 25% bandwidth reserved by default for routing traffic as per max-reserved-bandwidth default. However as we are shaping the default reserved for the class-default under the policy-map QOS is being ignored. My question is, how is the routing traffic guaranteed if the class-default became flooded with traffic? Is the only option available to create the class-default and allocate it a bandwidth within the policy-map QOS, or are there other options open. I have noted this appears to be the future solution when the max-reserved-bandwidth is fully deprecated under IOS 15. Any help would be greatly appreciated.

[Joseph W. Doherty]

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Posting

The QoS features were enhanced (significantly) with HQF (12.4.20T).  Define a class-default under your QoS policy and define its bandwidth.

[Edison Ortiz]

You can also explicitly define a class and policy for routing protocols and allocate bandwidth.

Routing protocols use CS6.

[Keith Rance]

Thanks Edison,

     I can see that will work, however even without matching the CS6 traffic and allowing it to fall into class-default the CS6 traffic appears to get through when flooding with BE traffic through the class-default. Does the CS6 traffic still get treated with priority over BE traffic within the undefined class-default?

[Joseph W. Doherty]

Disclaimer

The    Author of this posting offers the information contained within this    posting without consideration and with the reader's understanding that    there's no implied or expressed suitability or fitness for any  purpose.   Information provided is for informational purposes only and  should not   be construed as rendering professional advice of any kind.  Usage of  this  posting's information is solely at reader's own risk.

Liability Disclaimer

In    no event shall Author be liable for any damages whatsoever  (including,   without limitation, damages for loss of use, data or  profit) arising  out  of the use or inability to use the posting's  information even if  Author  has been advised of the possibility of such  damage.

Posting

Does the CS6 traffic still get treated with priority over BE traffic within the undefined class-default?

Depends on whether class-default is using FIFO or FQ and whether FQ is just FQ or WFQ.  The latter, WFQ, will give IPPrec 6 (including CS6) packets a scheduling boost.  (NB: HQF uses FQ.  I think pre-HQF, undefined class-default uses WFQ.)