When Dcb Is Enabled; Lossless Traffic Handling - Dell PowerEdge M IO Aggregator Command Reference Manual

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

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
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
FTOS#show interfaces
interface TenGigabitEthernet 0/2
mtu 12000
auto vlan
!
port-channel-protocol LACP
port-channel 1 mode active
!
protocol lldp
advertise management-tlv system-name
dcbx port-role auto-downstream
no shutdown

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.
tengigabitethernet 0/2
6-5.
tengigabitethernet 0/2
Data Center Bridging (DCB) | 57