14
User Guide
Factory Settings
This section describes the preset features on the 10/100 AutoTwister. These settings
cannot be changed.
Full-Duplex Flow Control
The AutoTwister supports flow control on each port in full duplex only. Full-duplex
flow control is provided to avoid dropping packets during network congestion. If
there is no buffer space available for incoming packets, the AutoTwister will issue
a PAUSE frame. Full-duplex flow control is only applicable to ports operating in
full duplex with auto-negotiation enabled. Additionally, during auto-negotiation, the
port’s link partner must advertise that it supports PAUSE frames.
For ports operating at half duplex, the AutoTwister does not support any type of flow
control. If there are not enough buffers available, incoming packets will be dropped.
Auto-Recovery
The AutoTwister includes an auto-recovery circuit that allows you to transparently
connect a pair of AutoTwister units between two network devices. This enables you
to design a redundant path between 10Mbps and 100Mbps devices, allowing both
end devices to lose link if any part of the connection is broken.
To activate auto-recovery, all of the following conditions must be met:
• Auto-negotiation is disabled.
• LLR is enabled.
• LLCF is enabled.
When auto-recovery is enabled, the AutoTwister attempts to establish the fiber link
between two back-to-back units. Because LLR is enabled on both AutoTwister stand-
alone units, auto-recovery is needed to prevent the two fiber ports from ending up in
a deadlock situation with each fiber port waiting for the other to transmit first. Auto-
recovery allows the deadlock to be broken by periodically sending out pulses from
the fiber port allowing the AutoTwister to reestablish its fiber link if the line is intact.
