Port Flow Control

Flow control is the process of managing the rate of data transmission between two nodes to prevent a fast sender from overrunning a slow receiver. It provides a mechanism for the receiver to control the transmission speed. Flow control helps prevent congestion. Flow control should be distinguished from congestion control, which is used for controlling the flow of data when congestion has actually occurred. Flow control on a port is configured for whether the port sends, receives or both sends and receives flow control packets.

When auto-negotiation is enabled the port flow control settings have no bearing on flow control. Pause is negotiated through the predefined advertised settings. The port flow control settings take effect when auto-negotiation is disabled.

Use the set port flowcontrol command to both enable flow control and configure the flow control setting for all or the specified ports.

The following example sets flow control on port ge.1.1 to both send and receive flow control packets:

System(rw)->set port flowcontrol ge.1.1 both enable
System(rw)->