Data Center Bridging (DCB) | 119
QoS dot1p Traffic Classification and Queue Assignment
DCB supports PFC, ETS, and DCBX to handle converged Ethernet traffic that is assigned to an egress
queue according to the following quality of service (QoS) methods:
• Honor dot1p: Using the
service-class dynamic dot1p command in INTERFACE Configuration mode, you
can honor dot1p priorities in ingress traffic at the port or global switch level (refer to Honoring dot1p
Values on Ingress Packets).
• Layer 2 class maps: You can use dot1p priorities to classify traffic in a class map and apply a service
policy to an ingress port to map traffic to egress queues (refer to Policy-Based QoS Configurations).
Table 8-1. dot1p Priority-Queue Assignment
Important: of two
Note: Dell Force10 does not recommend mapping all ingress traffic to a single queue when using PFC
and ETS. Ingress traffic classification using the service-class dynamic dot1p command (honor dot1p) is
recommended on all DCB-enabled interfaces. If you use L2 class maps to map dot1p priority traffic to
egress queues, take into account the default dot1p-queue assignments in Table 8-1 and the maximum
number of two lossless queues supported on a port (refer to Configuring Lossless Queues).
Although FTOS allows you to change the default dot1p priority-queue assignments (refer to service-class
dot1p-mapping on page 462), DCB policies applied to an interface may become invalid if dot1p-queue
mapping is reconfigured. If the configured DCB policy remains valid, the change in the dot1p-queue
assignment is allowed. For DCB ETS enabled interfaces, traffic destined to queue that is not mapped to
any dot1p priority will be dropped.
dot1p Value in Incoming Frame Egress Queue Assignment
00
10
20
31
42
53
63
73
Note: If you reconfigure the global dot1p-queue mapping, an automatic re-election of the DCBX
configuration source port is performed (see Configuration Source Election).
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