Catalyst 4500E Supervisor VI QoS changes

Unanswered Question
Jun 7th, 2010

I have upgraded a Cisco 4506 with a Supervisor 4 to a Supervisor 6-E and low & behold, my CoS/QoS settings no longer work.  I see from a white paper that Cisco upgraded the supervisor capabilities to MQC, which is more inline with the IOS routers.  There are a couple differences though.  Does anyone have any links or other tips that is not covered in white  paper?

I'm having a hard time converting my previous 4500 QoS settings for voice (Avaya phones) to the new syntax on the Supervisor 6-E.  I used a Cisco Press book called End-to-End QoS Network Design, but being a few years old it doesn't include the latest Sup 6 from the 4500's.

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valnar Tue, 06/08/2010 - 07:49

I'm reading it now, but I still don't understand a couple things.

1) Table maps are not explained.  How do I know if I am changing CoS or DSCP?

2) If I apply a policy to a VLAN, does it affect every L2 switchport on that VLAN?  Or only when it flows through the L3 vlan interface? (behavior similar to a router)

valnar Wed, 06/09/2010 - 10:05

I also don't understand what qos-groups are and why they are needed.

After initiating auto-qos on a port, the exerpt below was configured on the switch.  I don't use auto-qos personally, but it does give insight into the functionality.

Notice the redundancy between dscp24/26 and qos-group24/26.  Why??

class-map match-all AutoQos-VoIP-Control-Dscp26
match  dscp af31
class-map match-all AutoQos-VoIP-Control-Dscp24
match  dscp cs3
class-map match-all AutoQos-VoIP-Control-QosGroup24
match qos-group 24
class-map match-all AutoQos-VoIP-Control-QosGroup26
match qos-group 26
class-map match-all AutoQos-VoIP-Control-Cos
match cos  3
class-map match-all AutoQos-VoIP-Bearer-Cos
match cos  5
class-map match-all AutoQos-VoIP-Bearer-QosGroup
match qos-group 46
class-map match-all AutoQos-VoIP-Bearer-Dscp
match  dscp ef

policy-map AutoQos-VoIP-Input-Dscp-Policy
class AutoQos-VoIP-Bearer-Dscp
  set qos-group 46
class AutoQos-VoIP-Control-Dscp26
  set qos-group 26
class AutoQos-VoIP-Control-Dscp24
  set qos-group 24
policy-map AutoQos-VoIP-Input-Cos-Policy
class AutoQos-VoIP-Bearer-Cos
  set qos-group 46
class AutoQos-VoIP-Control-Cos
  set qos-group 24
policy-map AutoQos-VoIP-Output-Policy
class AutoQos-VoIP-Bearer-QosGroup
  set dscp ef
  set cos 5
    police cir percent 33
class AutoQos-VoIP-Control-QosGroup26
  set dscp af31
  set cos 3
    bandwidth remaining percent 5
class AutoQos-VoIP-Control-QosGroup24
  set dscp cs3
  set cos 3
    bandwidth remaining percent 5
class class-default

interface GigabitEthernet2/1
auto qos voip trust
service-policy input AutoQos-VoIP-Input-Cos-Policy
service-policy output AutoQos-VoIP-Output-Policy

darrenriley5 Mon, 03/19/2012 - 09:05


Just wondered if someone would be able to explain the qos groups are as I don't understand it myself. I've tried reading the documentation but it doesn't seem to explain it very well.



Surya ARBY Mon, 09/09/2013 - 01:57

A Qos-group is an internal marker, just like the old "internal DSCP" was; but qos-group may be used if all the traffic embedded into a class is not IP-based.


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