auto qos voip trust behaviour.

[Jaime Cadete]

Hi,

Given the following configuration in a uplink port

interface GigabitEthernet0/2

switchport trunk encapsulation dot1q

switchport mode trunk

srr-queue bandwidth share 10 10 60 20

srr-queue bandwidth shape  10  0  0  0

queue-set 2

mls qos trust cos

auto qos voip trust

My understanding is that it will apply the QoS based on the CoS and

the packets will not be remark i.e. DSCP will stay untouched (auto qos voip trust)

Now with this configuration

interface FastEthernet0/48

switchport access vlan 175

switchport mode access

srr-queue bandwidth share 10 10 60 20

srr-queue bandwidth shape  8  0  0  0

mls qos trust dscp

auto qos voip trust

Will it remark the CoS of the input packets?

Thanks,

  Jaime Cadete

[islam.kamal]

Dear

because you configure your switchport as access mode  , the port trust state to Cos . If the port is not configured with the switchport command, sets the port trust state to trust DSCP,Kindly find the below link

http://www.cisco.com/en/US/docs/switches/lan/catalyst6500/ios/12.2SX/configuration/guide/auto_qos.html

Default CoS-to-DSCP Map

CoS value	# 0	# 1	# 2	# 3	# 4	# 5	# 6	# 7
DSCP value	# 0	# 8	# 16	# 24	# 32	# 40	# 48	# 56

thank you

please rate

[Jaime Cadete]

Hi,

My question is will it remark the CoS (according with the DSCP) of the input packets in port Fa0/48 with that config?

Thanks,

  Jaime Cadete

[islam.kamal]

HI

yes , you are completely true and i give you the reason above.

thak you

please rate if this will help

[Jaime Cadete]

Hi,

Where exactly do you see the reason?

I cannot find the exact answer.

So the "auto qos voip trust" command would be redundant,

but in a cos trust port the dscp are not remarked.

Thanks,

  Jaime Cadete