802.1p and 802.1Q Best Practices

In a network, to map the 802.1p user priority bits, use 802.1Q-tagged encapsulation on customer-premises equipment (CPE). You require encapsulation because the switch does not provide classification when it operates in bridging mode.

To ensure consistent Layer 2 QoS boundaries within the service provider network, you must use 802.1Q encapsulation to connect a CPE directly to the switch access node. If you do not require packet classification, use Ethernet Routing Switch 5600 to connect to the access node. In this case, configure the traffic classification functions in the Ethernet Routing Switch 5600.

At the egress access node, packets are examined to determine if their IEEE 802.1p or DSCP values must be re-marked before leaving the network. Upon examination, if the packet is a tagged packet, the IEEE 802.1p tag is configured based on the QoS level-to-IEEE 802.1p-bit mapping. For bridged packets, the DSCP is re-marked based on the QoS level.