Preserving 802.1p priority

QoS operates in VLAN-tagged and VLAN-untagged environments. If your network does not use multiple VLANs, you can still implement the 802.1Q VLAN capability for packets to carry their 802.1p priority to the next downstream device. To do so, configure ports as VLAN-tagged members on the links between switches and routers in your network infrastructure.

Summary of QoS capabilities

Outbound packet options

Port membership in VLANs

Tagged Untagged

Control port queue priority for packet types

Yes

Yes

Carry 802.1p priority assignment to next downstream device

Yes

No

Carry DSCP policy to downstream devices. The policy includes:

  • Assigning a ToS Codepoint

  • Assigning an 802.1p Priority to the Codepoint

Yes

Yes2