Motorola P880 manual Flow Control, Auto, Negotiation, Speed/Duplex, Advertisement, Rate Limit

Table 10. Fast Ethernet (10/100) Port Parameters

Parameter	Definition
Flow Control	Determines if flow control is used on this port.
Mode	For half-duplex links, active backpressure jams
	the sending Ethernet channel until the port’s
	buffers can receive more packets. This prevents
	lost or dropped packets.
	For full-duplex links, IEEE 802.3z pause
	control allows the port to stop a sending station
	from sending more packets if the receiving
	port’s buffers are full.
	For TX and FX ports, there is an additional
	option for Enable with Aggressive Backoff. This
	option limits the size of the bursts.
	Flow Control is recommended for use
	primarily on end-station connections. Using
	this flow control on trunk ports can cause
	unnecessary congestion on the network.
Auto	Allows you to set the port to auto-negotiate a
Negotiation	speed and duplex mode. Auto-negotiate works
Mode	best when the connection on the other end of
	the link is set to auto-negotiate as well. If you
	set a port to auto-negotiate, and the
	connection is not successful, set the port speed
	and duplex mode manually.
Auto	Determines what information the port
Negotiation	advertises when it starts auto-negotiating. In
Speed/Duplex	most cases, 10/100 and Half/Full are the best
Advertisement	settings, but there may be cases when you
	want to auto-negotiate one parameter, while
	keeping the other fixed.
Rate Limit	Prevents the switch from overwhelming the
Mode	output buffer on lower-speed ports by placing a
	threshold on the percentage of port traffic that
	can be flooded packets (unknown unicasts and
	multicasts). You can optionally include known
	multicast packets in this percentage to further
	decrease the possibility of the port’s output
	buffer being overwhelmed.
Rate Limit Rate	Determines the percentage of a port’s
	forwarded traffic that can be unknown unicast
	and multicast (flooded). Lower this value if the
	port has overflow problems.

Cajun P880 Routing Switch Installation Guide 2 - 15