Configuring Pfc On An Ethernet Interface - HP 6125XLG Configuration Manual

Step
3. Enable generic flow control.

Configuring PFC on an Ethernet interface

PFC performs flow control based on 802.1p priorities. With PFC enabled, an interface requires its peer
to suspend sending packets with certain 802.1p priorities when congestion occurs. By decreasing the
transmission rate, PFC helps avoid packet loss.
You can enable PFC for certain 802.1p priorities at the two ends of a link. When network congestion
occurs, the local device checks the PFC status for the 802.1p priority carried in each arriving packet. The
device processes the packet depending on the PFC status as follows:
If PFC is enabled for the 802.1p priority, the local device accepts the packet and sends a PFC pause
•
frame to the peer. The peer stops sending packets carrying this 802.1p priority for an interval as
specified in the PFC pause frame. This process is repeated until the congestion is removed.
If PFC is disabled for the 802.1p priority, the local port drops the packet.
•
To configure PFC on an Ethernet interface:
Step
1. Enter system view.
2. Enter Ethernet interface view.
3. Enable PFC on the interface
through automatic negotiation
or forcibly.
4. Enable PFC for specific
802.1p priorities.
When you configure PFC, follow these guidelines:
To perform PFC on a network port of an IRF member device, configure PFC on both the network port
•
and the IRF physical ports. For information about IRF, see IRF configuration Guide.
To ensure correct operations of IRF and other protocols, HP recommends not enabling PFC for
•
802.1p priorities 0, 6, and 7.
• Perform the same PFC configuration on all ports that traffic travels through.
A port can receive PFC pause frames regardless of whether PFC is enabled on the port. However,
•
only a port with PFC enabled can process PFC pause frames. To make PFC take effect, make sure
PFC is enabled on both the local end and the peer end.
The relationship between the PFC function and the generic flow control function is shown in
Command
•
Enable TxRx mode generic
flow control:
flow-control
•
Enable Rx mode generic flow
control:
flow-control receive enable
Command
system-view
interface interface-type
interface-number
priority-flow-control { auto |
enable }
priority-flow-control no-drop
dot1p dot1p-list
8
Remarks
By default, generic flow control is
disabled on an Ethernet interface.
Remarks
N/A
N/A
By default, PFC is disabled.
By default, PFC is disabled for all
802.1p priorities.
Table 1.