Hello Wasaq,
you haven't specified the supervisor model and the IOS image running on the device(s).
So I have taken as a reference a QoS configuration guide for IOS XE release 3.7xE aka 15.2.3Ex.
You are using C4500 at access layer. Are they used as stand alone switches or they are grouped in pairs using VSS feature?
For standalone configuration of autoQoS you can reference the following document
https://content.cisco.com/chapter.sjs?uri=%2Fsearchable%2Fchapter%2Fwww.cisco.com%2Fcontent%2Fen%2Fus%2Ftd%2Fdocs%2Fswitches%2Flan%2Fcatalyst4500%2FXE3-7-0E%2F15-23E%2Fconfiguration%2Fguide%2Fxe-370-configuration%2Fqos_mrg.html.xml#14327
For autoQoS on VSS systems see
https://content.cisco.com/chapter.sjs?uri=%2Fsearchable%2Fchapter%2Fwww.cisco.com%2Fcontent%2Fen%2Fus%2Ftd%2Fdocs%2Fswitches%2Flan%2Fcatalyst4500%2FXE3-7-0E%2F15-23E%2Fconfiguration%2Fguide%2Fxe-370-configuration%2Fqos_mrg.html.xml#91778
Let us follow the document for stand alone switches.
The first note tells that autoQoS cannot be applied to Vlans or etherchannels (port-channels)
>> Auto-QoS cannot be applied to VLANs or EtherChannel interfaces.
However, this does mean that you cannot use auto QoS.
Because after auto QoS has made its job introducing several class-maps and policy-maps and applying them to interfaces you can modify the configuration with manual commands and you can also deal with etherchannels.
To make autoQoS to start you need a global command like
auto qos srnd4
The switch will create all the necessary command lines to configure class-maps, policy-maps and ot appy them to ports .
seven policy-maps are created with the following names
- There are 7 policy maps that must be defined (5 Input, 2 output)
- AutoQos-4.0-Input-Policy
- AutoQos-VoIP-Input-Cos-Policy
- AutoQos-VoIP-Input-Dscp-Policy
- AutoQos-4.0-Cisco-Phone-Input-Policy
- AutoQos-4.0-Output-Policy
- AutoQos-4.0-Cisco-Softphone-Input-Policy
- AutoQos-VoIP-Output-Policy
the class-maps can match on CoS bits that are within 802.1Q header on a trunk or they can match on DSCP field in IPV4 header on L2 access ports or L3 routed ports.
Be aware that untagged frames like native Vlan frames on trunk or standard frames received on a L2 access port have no CoS field to match and are treated like frames with CoS = 0.
Auto QoS uses CDP to understand where a Cisco IP phone is connected to a port to decide what policy-maps to use on the port (one for inbound direction one for outbound direction).
You need to have some basic knowledge of QoS to be able to understand what auto QoS does and to make the necessary configurations.
A good starting point for learning can be the QoS FAQ
https://www.cisco.com/c/en/us/support/docs/quality-of-service-qos/qos-policing/22833-qos-faq.html?dtid=osscdc000283
So Auto QoS is a good tool for you if you are using Cisco IP phones. If you are using third party IP phones some considerations is needed and auto QoS might not be the right tool to use.
Hope to help
Giuseppe
