Showing results for 
Search instead for 
Did you mean: 

3850 QOS query


i have some old 3550s that are being swapped out for 3850s, some of the QOS config from 3550 wont tranfer accross, not know much about it i hoped someone could tell me how to achieve same on 3850, here is 3550 config im talking about


class-map match-all cda_urgent
  match access-group 104
class-map match-all cda_high
  match access-group 105
policy-map cda_policy
  class cda_urgent
    set ip dscp 56
  class cda_high
    set ip dscp 46


interface GigabitEthernet0/1
 switchport access vlan 101
 switchport mode access
 wrr-queue bandwidth 1 2 3 4
 service-policy input cda_policy


VIP Mentor

all that qos is doing is classifying voice DSCP 46 and CS7 not sure why your using that usually CS6 for mgmt , then your matching it based on the access-list subnets

Now 3850 is auto qos so depending on the command you enter at access port is based on the class/policy maps that are generated , depending onteh syntax you use alters the ytype of auto class-maps and polices generated

Now if you check this doc and got to Configuration Examples for Auto-QoS you will see which maps wil be created , i think you would get away with using auto qos trust by itself and it wil generate a class/policy map that should easily cover both of those DSCP markings , obviuosly it will create a bit more so i would look at the examples

you could tweak the auto polices or try create a smaller custom policy

thanks for that


One other thing if DSCP is being marked at the source say by a phone as most would on your access ports , you actually don't need to apply anything on a 36/3850 switch , ios-xe software trusts DSCP markings by default and does not alter them unlike your older 3550 , the fact your not setting anything in the original qos but to make sure those subnets get those values the 3850 will do the same for those 2 subnets once the end devices mark at the source already

so if its a load of Cisco phones or Lync softphone they mark at the source and DSCP wil be carried by default without any config through the 3850
Content for Community-Ad