Allied Telesis AT-S97 - Manual (Page 96)

Chapter 5: Port and Module Commands
96
The DUPLEX parameter can also be used to set the duplex mode on a
fiber optic port in a media converter channel.
For best network performance, all the elements of a media converter
channel, meaning the two ports of a channel and the two network devices
connected to the ports, should be using the same duplex mode. A media
converter channel may have to discard packets if its two ports are
operating in different modes, one half-duplex and the other full-duplex.
This could result in a decrease of network performance if the network
devices have to frequently retransmit packets.
For example, if the network device connected to the twisted pair port of a
media converter channel is only capable of half-duplex mode, then both
ports of the channel and the network device connected to the fiber optic
port in the channel should be configured to operate in half-duplex mode as
well.
Also featured on the twisted pair ports of a media converter module is
auto-MDI/MDI-X, which automatically adjusts the wiring configuration of a
twisted pair port to either MDI or MDI-X, depending on the wiring
configuration of the end node. This feature allows the use of a straight-
through twisted pair cable regardless of the wiring configuration of the port
on the network device.
The auto-MDI/MDI-X feature is only available when a twisted pair port is
using Auto-Negotiation, the default setting. Disabling Auto-Negotiation
and manually configuring a port’s speed and duplex mode also disables
this feature. The wiring configuration of a port defaults to the MDI-X
setting. Disabling Auto-Negotiation may require the manual configuration
of the MDI/MDI-X setting on a port or the use a crossover cable,
depending on the wiring configuration of the network device connected to
the port on the module.
The INGRESS-RATE-LIMIT and EGRESS-RATE-LIMIT parameters
control the flow of network traffic to and from a port in a channel to its
network device. The rate limits, which are in kilobits and megabits per
second, can be applied separately to the two ports of a channel. The rate
limits can be used for storm prevention and to protect against the
formation of bottlenecks in a network topology,
The INGRESS-RATE-LIMIT feature controls the number of bits per
second a port will accept from the device connected to it. The port
discards frames after the limit is exceeded. For example, an ingress rate
limit of 128 limits a port to no more than 128 kilobits per second in traffic
flow from its network device.
The EGRESS-RATE-LIMIT controls the number of bits per second a port
will transmit to the network device connected to it.
The 10/100/100Base-T Management port on the management module
does not support ingress or egress rate limits.