QoS L2 and Layer 3

[Rockyy]

Hi,

I have a network consisting of L2 (Cisco Catalyst 3850) with a direct homerun to the backbone Layer 3 Cisco Catalyst 6800XL Chassis.

We've broken the broadcast into multiple i.e. VoIP, Data, etc VLANs, the VLAN passes through L2, and end at the backbone switch at Layer 3.

We had an issue in the past where there were intermittent connectivity issues with our Multicast stream. I have configured NetFlow to clear my doubt regarding the QoS and that was it! All multicast traffic on the interface is going through the default queue CS0.

So here is my input policy and it is applied on the access switch Layer 3 interface where the multicast sender resides. However, Netflow still shows all traffic being marked as ToS CS0. Netflow is applied on the uplink ports. I am not sure where I am doing the mistake. The policy-map show command also shows the policy being matched and hits.

ip access-list extended QOS-IPTV
permit udp any any range 5001 5050
!
!
class-map match-any QOS-ACCESS-IPTV
 match access-group name QOS-IPTV
!
!
policy-map QOS-INPUT-POLICY
class QOS-ACCESS-IPTV
 set ip dscp af41
 police cir 400000000
  conform-action transmit
  exceed-action drop

show policy-map interface gigabitEthernet 1/0/22

GigabitEthernet1/0/22

Service-policy input: QOS-INPUT-POLICY]
Class-map: QOS-ACCESS-IPTV (match-any)
2608661078 packets
Match: access-group name QOS-IPTV
QoS Set
dscp af41
police:
cir 400000000 bps, bc 12500000 bytes
conformed 4669078944624 bytes; actions:
transmit
exceeded 0 bytes; actions:
drop
conformed 670505000 bps, exceeded 0000 bps

Class-map: class-default (match-any)
1036 packets
Match: any

interface GigabitEthernet1/0/22

no switchport

ip address 10.1.1.165 255.255.255.252

ip pim sparse-mode

service-policy input QOS-INPUT-POLICY

service-policy output QOS-INPUT-POLICY

end

[Georg Pauwen]

Hello,

do you have 'mls qos trust dscp' on the layer 3 switch ?

[Rockyy]

Hi Georg,

I think MLS was in 3750 or previous switches and no longer supported syntax in 3850 switches as MLS has evovled into MQC.

Thanks,

[JimWicks]

Been a while since I was on the CLI of a Cat3850, but does it let you specify "set dscp af41" in the class-map (ie remove the "ip") as that's what the docs suggest the syntax should be - though I realize that docs on CCO are not always to be taken verbatim.

Also, if you are not looking to actually police your multicast traffic-rate, then try removing the policer and just have the set-dscp as the action within the class-map as I can't remember what those horrible table-maps does by default.

[Rockyy]

I did try changing that but as expected no effect. The only difference is that ip dscp is for IPV4 vs set dscp is v4 and v6 both.