flow-control negotiation
Function
The flow-control negotiation command enables flow control auto-negotiation on an Ethernet interface.
The undo flow-control negotiation command disables flow control auto-negotiation on an Ethernet interface.
By default, flow control auto-negotiation is disabled on an Ethernet interface.
Views
Ethernet interface view, GE interface view, XGE interface view, MultiGE interface view, 25GE interface view, port group view
Usage Guidelines
Usage Scenario
Network congestion causes packet loss. Flow control can prevent packet loss. If congestion occurs on a device, the device sends a message to request the peer device to stop sending packets, which prevents packet loss. Flow control auto-negotiation enables a device to determine whether to enable flow control by negotiating with the peer device.
Prerequisites
Run the negotiation auto command to configure the Ethernet interface to work in auto negotiation mode.
Precautions
Electrical interfaces support flow control auto-negotiation.
If flow control auto-negotiation is enabled on an interface, it must also be enabled on the peer interface.
- If flow control has been enabled on an Ethernet interface using the flow-control command, run the undo flow-control command to disable flow control before running the flow-control negotiation command. Otherwise, the flow-control negotiation command fails to be executed.
XGE interfaces on the S5720-32C-HI-24S-AC, the first 12 XGE interfaces on the S6720-50L-HI-48S, and XGE interfaces and the last eight GE interfaces on the S5720-56C-HI-AC, S5720-56C-PWR-HI-AC, and S5720-56C-PWR-HI-AC1 do not support flow control auto-negotiation.
This command can be used on an XGE optical interface that has a GE copper module installed.
- This command can be used on a GE optical interface that has a GE optical module or GE copper module installed.
- This command can be used on an 25GE optical interface that has a GE copper module installed. Before installing a GE copper module on a 25GE optical interface, you need to run the port mode ge command to configure the interface to work at the rate of 1 Gbit/s.
On the S2720-52TP-EI, S5720-52P-LI-AC, if interfaces 0 to 23 work as inbound interfaces (or outbound interfaces) and interfaces 24 to 47 work as outbound interfaces (or inbound interfaces), flow control auto-negotiation does not take effect on these interfaces.
For the S5735-L, S5735S-L, S5735S-L-M, S5735-S, S5735-S-I, and S5735S-S, the multicast functions (both Layer 2 and Layer 3 multicast functions) conflict with the flow control function.