Reference Guide

Data Center Bridging (DCB) | 57

Figure 6-4. show interfaces Command Example: DCB disabled and Flow Control enabled

When DCB is Enabled

When a server-facing interface receives DCBX protocol packets, it automatically enables DCB and

disables link-level flow control. The DCB input and output policies and the flow control configuration are

removed as shown in Figure 6-5.

When no DCBX TLVs are received on a DCB-enabled interface for 180 seconds, DCB is automatically

disabled and flow control is re-enabled. When all 10GbE server-facing interfaces have DCB disabled,

DCB is also disabled on all 40GbE uplink interfaces.

Figure 6-5. show interfaces Command Example: DCB enabled and Flow Control disabled

Lossless Traffic Handling

In auto-DCB-enable mode, Aggregator ports operate with the auto-detection of DCBX traffic. At any

moment, some ports may operate with link-level flow control while others operate with DCB-based PFC

enabled.

As a result, lossless traffic is ensured only if traffic ingresses on a PFC-enabled port and egresses on

another PFC-enabled port.

Lossless traffic is not guaranteed when it is transmitted on a PFC-enabled port and received on a link-level

flow control-enabled port, or transmitted on a link-level flow control-enabled port and received on a

PFC-enabled port.

FTOS#show interfaces tengigabitethernet 0/2

interface TenGigabitEthernet 0/2

mtu 12000

portmode hybrid

switchport

auto vlan

flowcontrol rx on tx off

dcb-policy input smux-dcb-in

dcb-policy output smux-dcb-out

protocol lldp

advertise management-tlv system-name

dcbx port-role auto-downstream

no shutdown