Administrator Guide

• If priority group 1 or 2 has free bandwidth, (20 + 30)% of the free bandwidth is distributed to priority
group 3. Priority groups 1 and 2 retain whatever free bandwidth remains up to the (20+ 30)%.
Strict-priority
groups:
If two priority groups have strict-priority scheduling, trac assigned from the priority group with the higher
priority-queue number is scheduled rst. However, when three priority groups are used and two groups have
strict-priority scheduling (such as groups 1 and 3 in the example), the strict priority group whose trac is
mapped to one queue takes precedence over the strict priority group whose trac is mapped to two
queues.
Therefore, in this example, scheduling trac to priority group 1 (mapped to one strict-priority queue) takes precedence over
scheduling trac to priority group 3 (mapped to two strict-priority queues).
Troubleshooting PFC, ETS, and DCBx Operation
In the show interfaces pfc | ets | dcbx output, the DCBx operational status may be down for any of the reasons
described in the following table.
When DCBx is down, the following values display in the show output eld for DCBx Oper status:
• PFC DCBx Oper status: Down
• ETS DCBx Oper status: Down
• DCBx Oper status: Disabled.
Reason
Description
Port Shutdown Port is shut down. All other reasons for DCBx inoperation, if any, are ignored.
LLDP Rx/Tx is
disabled
LLDP is disabled (Admin Mode set to rx or tx only) globally or on the interface.
Waiting for Peer Waiting for peer or detected peer connection has aged out.
Multiple Peer
Detected
Multiple peer connections detected on the interface.
Version Conict DCBx version on peer version is dierent than the local or globally congured DCBx version.
Cong-source Down Although DCBx parameters match in auto-upstream or auto-downstream port, the conguration source
(elected dynamically or CLI-congured) is down.
Unrecognized TLV
received
Invalid TLV length TLV has been received. In the case of an invalid PFC or ETS TLV, the error displays in the
show interfaces pfc | ets output. The show interfaces dcbx output displays PFC or ETS
as down.
Admin Mode OFF
(Local)
Local Admin Mode is disabled.
Admin Mode OFF
(Remote)
Remote Admin Mode is disabled.
Waiting for ACK
from Peer
For a legacy DCBx version, a peer has not acknowledged the reception of a sent packet. This reason
displays only when a remote peer is willing to receive a DCB conguration.
Error Bit set For a legacy DCBx version, a peer has sent packets with an error bit set. This reason displays only when a
remote peer is willing to receive a DCB conguration.
Enabled with ETS
Mismatch (show
interfaces
dcbx output)
DCBx is enabled but an ETS validation failure error has occurred.
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Data Center Bridging (DCB)