Hi all out there,
in the past on our 2650,3560 we configured on the Client/Phone ports just "trust cos", so we achieved that only tagged traffic is trusted and mapped to the particular DSCP-value . all untagged traffic should be marked with COS 0 and DSCP 0.
Now I try to achieve this with new 3650. According to the documentation in following way
table-map COS-2-DSCP-DEFAULT
default copy
policy-map MARKING-TRUST-COS
Class class-default
set cos dscp table COS-2-DSCP-DEFAULT
interface GigabitEthernet 1/0/1
switchport mode access
switchport access vlan 851
switchport voice vlan 751
service-policy input MARKING-TRUST-COS
So in my opinion the COS field should be copy to the corresponding DSCP-bits, which also means untagged traffic has no COS value , so DSCP ist set to 0.
Unfortunately with this config also tagged traffic from the ip-phone (COS 5, DSCP EF) is marked down to DSCP 0, to be honest no idea why ???
Has anybody an Explanation for this behaviour.
So I tried second way to achive that with following config:
class-map match-any COS-CLASS-0
match cos 0
class-map match-any COS-CLASS-1
match cos 1
class-map match-any COS-CLASS-2
match cos 2
class-map match-any COS-CLASS-3
match cos 3
class-map match-any COS-CLASS-4
match cos 4
class-map match-any COS-CLASS-5
match cos 5
class-map match-any COS-CLASS-6
match cos 6
class-map match-any COS-CLASS-7
match cos 7
policy-map MARKING-TRUST-COS
class COS-CLASS-7
set dscp cs7
class COS-CLASS-6
set dscp cs6
class COS-CLASS-5
set dscp ef
class COS-CLASS-4
set dscp cs4
class COS-CLASS-3
set dscp cs3
class COS-CLASS-2
set dscp cs2
class COS-CLASS-1
set dscp cs1
class COS-CLASS-0
set dscp default
interface GigabitEthernet 1/0/1
switchport mode access
switchport access vlan 851
switchport voice vlan 751
service-policy input MARKING-TRUST-COS
the third way is following:
table-map COS-2-DSCP
map from 0 to 0
map from 1 to 8
map from 2 to 16
map from 3 to 24
map from 4 to 32
map from 5 to 46
map from 6 to 48
map from 7 to 56
default copy
policy-map MARKING-TRUST-COS
Class class-default
set cos dscp table COS-2-DSCP
interface GigabitEthernet 1/0/1
switchport mode access
switchport access vlan 851
switchport voice vlan 751
service-policy input MARKING-TRUST-COS
As far as I understand all three configurations should end up in the same behaviour, but only the second way works as expected.
Could anybody explain me whats wrong in my considerations.
Thanks
Hubert
