Concept Guide

PFC Shared Buffer: Buffer used by ingress priority groups for shared usage.
PFC Headroom Buffer: Buffer used by ingress priority group for shared headroom usage.
PFC Available Buffer: Current buffer available for new lossless queues to be
Provisioned.
stack-unit Total Buffer PFC Total Buffer PFC Shared Buffer PFC Headroom Buffer PFC Available
Buffer
PP (KB) (KB) (KB) (KB)
(KB)
------------------------------------------------------------------------------------------------
-----
1 0.0 3399 2656 1040 1040 567
1 0.1 3399 2656 1040 1040 576
1 0.2 3399 2656 1040 1040 567
1 0.3 3399 2656 1040 1040 576
DellEMC#
Following table shows the XPE numbering scheme in Dell EMC Networking OS:
Table 17. XPE Numbering on Dell EMC Networking OS
XPE Numbering
XPE A of MMU Slice R 0.0
XPE A of MMU Slice S 0.1
XPE B of MMU Slice R 0.2
XPE B of MMU Slice S 0.3
Enabling Data Center Bridging
DCB is automatically congured when you congure FCoE or iSCSI optimization.
Data center bridging supports converged enhanced Ethernet (CEE) in a data center network. DCB is disabled by default. It must be
enabled to support CEE.
• Priority-based ow control
• Enhanced transmission selection
• Data center bridging exchange protocol
• FCoE initialization protocol (FIP) snooping
DCB processes virtual local area network (VLAN)-tagged packets and dot1p priority values. Untagged packets are treated with a dot1p
priority of 0.
For DCB to operate eectively, you can classify ingress trac according to its dot1p priority so that it maps to dierent data queues. The
dot1p-queue assignments used are shown in the following table.
To enable DCB, enable either the iSCSI optimization conguration or the FCoE conguration.
NOTE
: Dell EMC Networking OS Behavior: DCB is not supported if you enable link-level ow control on one or more interfaces.
For more information, refer to Ethernet Pause Frames.
272 Data Center Bridging (DCB)