When no CoS value is present in incoming packet and we want to change the default CoS value assigned to a port(1 in this case) then in this case why mls qos trust cos command is required prior to the mls qos cos 1 command what are we trusting in this case?

You can not match two ACLS inside the class-map “ALL_TRAFFIC”. You can only match one criterion, e.g. a list of DSCP values of a single ACL.

To: Jimmy

There must be a type in my post. WTD (Weighted Tail Drop) is only supported on the Gigabit Ports of the 3550. Regular ports are limited to tail drop.

You show that wrr-queue threshold command is available for fast ethernet ports but my 3550 with the latest EMI image does not have this otion available. According to the Cisco documentation this command only applies to 3550 Gigabit Ethernet interfaces. So is it safe to assume that 3550 cannot do threshold dropping as described on FE interfaces? Please Advise.

attempting to complete a task on my 3550 doing PPPV to set IPP 3 on ALL traffic coming from VLAN 55. I seem to have hit a bug and crashed my switch. I attempted to define ALL traffic by using two ACLs -

mac access-list extended NON_IP_TRAFFIC
permit any any 0xFFFF 0×0

ip access-list extended IP_TRAFFIC
permit ip any any

class-map match-any ALL_TRAFFIC
match access-group name NON_IP_TRAFFIC
match access-group IP_TRAFFIC

class-map match-all VLAN55_TRAFFIC
match vlan 55
match class-map ALL_TRAFFIC

policy-map VLAN55
class VLAN55_TRAFFIC
set prec 3

interface fa0/3
service-policy input VLAN55

as soon as I pressed the enter key the switch output a message that it did not support the ACL and started a crash dump.

So my question is - what is the correct way to accomplish this?

thanks in advance.
LA

Hi Petr

i’m still confused between

mls qos min-reserve and wrr-queue bandwidth

what is the difference between the two

thx

i’m still confused between

mls qos min-reserve and mls qos min-reserve

what is the difference between the two

thx

non-IP packets get that internal DSCP value by the virtue of CoS-to-DSCP mapping table. Mon-IP packet CoS is either taken from the packet header (if they have it) or interface default value (if CoS is trusted and frame header has no 802.11p bits).

You wrote:
… For non-IP packets, new CoS value is calculated for packets from the internal DSCP using a configurable DSCP to CoS table (which is global to a switch)…
I don’t understand this completely. How the new CoS value can be calculated using DSCP to CoS table for just arrived non-IP packet? According to your explanation, at Stage 1 (Ingress) switch should perform for non-IP frames only CoS set/trust marking, and then CoS to internal DSCP marking.
Please explain it.

Thanks and best regards!

Correct, since IP packets will be marked based on the default CoS value assigned to the port.