DSCP and VLAN

[RanjnaAggarwal]

if DSCP configuration is done from the application and vlan configuration is done at vswitch and switch is standard switch as it is layer 2 switch then what vswitch will do with tag? will it preserve the tag or make it as zero?

[vfk]

see this post qos and virtual standard switches

[RanjnaAggarwal]

but what would happen if this is with vlan.

[MKguy]

DSCP operates on layer 3 with the IPv4 ToS header field. 802.1q VLAN tagging occurs at layer 2.

As such it doesn't care about layer 3 information and will not interfere with the DSCP bits in the IPv4 header.

You can explicitly configure dvSwitch Network IO Control with DSCP tagging, but that too is independent from layer 2 VLAN encapsulation.