At-Gs920 Feature Descriptions; Duplex Mode; Store And Forward - Allied Telesis AT-GS920/16 Installation And User Manual

AT-GS920 Feature Descriptions

Duplex Mode

Store and
Forward
An Ethernet switch interconnects network devices, such as workstations,
printers, routers, and other Ethernet switches, so that they can
communicate with each other by sending and receiving Ethernet frames.
This section discusses the following features:
"Duplex Mode"


"Store and Forward"


"Multicast Frame Pass-Through"

"Energy Efficiency Ethernet (EEE)"

"Loop Prevention"

"Flooding"

"Backpressure and Flow Control"

Duplex mode refers to how an end node receives and transmits data. If an
end node can receive or transmit data, but not both simultaneously, it is
operating in half-duplex mode. If an end node can both receive and
transmit data simultaneously, the end node is operating in full-duplex
mode. As such an end node capable of operating in full-duplex can handle
data much faster than an end node that can only operate in half-duplex
mode.
The twisted pair ports on the GS920 Series switch can operate in half- or
full-duplex mode for 10/100 Mbps. They are IEEE 802.3u-compliant and
use Auto-Negotiation to set the duplex mode setting for you automatically.
Note
In order for a switch port to successfully Auto-Negotiate its duplex
mode with a 10 or 100 Mbps end-node, the end-node should also be
configured for Auto-Negotiation. Otherwise, a duplex mode
mismatch can occur. A switch port using Auto-Negotiation defaults
to half-duplex if it detects that the end-node is not using
Auto-Negotiation. This results in a mismatch if the end-node is
operating at a fixed duplex mode of full-duplex.
The GS920 Series switch uses store-and-forward as the method for
receiving and transmitting frames. When an Ethernet frame is received on
a switch port, the switch does not retransmit the frame out the destination
port until it has received the entire frame and stored the frame in a port
buffer. It then examines the frame to determine if it is a valid frame. Invalid
frames such as fragments or runts are discarded by the switch. This
insures that only valid frames are transmitted out the switch ports and that
damaged frames are not propagated on your network.
Chapter 1: Product Description
27