Concept Guide

Default dot1p to queue conguration is as follows:
Conguration Example for DSCP and PFC Priorities
Consider a scenario in which the following DSCP and PFC priorities are necessary:
DSCP 0 – 5, 10 - 15 20 – 25, 30 – 35
Expected PFC
Priority
1 2
To congure the aforementioned DSCP and PFC priority values, perform the following tasks:
1 Create class-maps to group the DSCP subsets
class-map match-any dscp-pfc-1
match ip dscp 0-5,10-15
!
class-map match-any dscp-pfc-2
match ip dscp 20-25,30-35
2 Associate above class-maps to Queues Queue assignment as below.
DellEMC(conf)#do show qos dot1p-queue-mapping
Dot1p Priority : 0 1 2 3 4 5 6 7
Queue : 1 0 2 3 4 5 6 7
3 Dot1p->Queue Mapping Conguration is retained at the default value.
4 Interface Congurations on server connected ports.
a Enable DCB globally.
DellEMC(conf)#dcb enable
b Apply PFC Priority conguration. Congure priorities on which PFC is enabled.
Using PFC to Manage Converged Ethernet Trac
To use PFC for managing converged Ethernet trac, use the following command:
dcb-map stack-unit all dcb-map-name
Generation of PFC for a Priority for Untagged Packets
In order to generate PFC for a particular priority for untagged packets, and conguring PFC for that priority, you should nd the queue
number associated with priority from TABLE 1 and Associate a DCB map to forward the matched DSCP packet to that queue. PFC frames
gets generated with PFC priority associated with the queue when the queue gets congested.
Congure Enhanced Transmission Selection
ETS provides a way to optimize bandwidth allocation to outbound 802.1p classes of converged Ethernet trac.
Dierent trac types have dierent service needs. Using ETS, you can create groups within an 802.1p priority class to congure dierent
treatment for trac with dierent bandwidth, latency, and best-eort needs.
For example, storage trac is sensitive to frame loss; interprocess communication (IPC) trac is latency-sensitive. ETS allows dierent
trac types to coexist without interruption in the same converged link by:
• Allocating a guaranteed share of bandwidth to each priority group.
• Allowing each group to exceed its minimum guaranteed bandwidth if another group is not fully using its allotted bandwidth.
Data Center Bridging (DCB)
295