Transition Networks
SGFEB 10/100/1000 Bridging Media Converter User Guide
33601 Rev. D
Page 12 of 25
Product Features
Auto-Negotiation
The Auto-Negotiation feature allows the SGFEB10xx to automatically configure itself to achieve the best
possible mode of operation over a link. The media converter broadcasts its speed (10 Mb/s, 100 Mb/s, or
1000 Mb/s) and duplex capabilities (full or half) to the other devices and negotiates the best mode of
operation. Auto-Negotiation allows quick and easy installation because the optimal link is established
automatically. No user intervention is required to determine the best mode of operation.
A scenario where the media converter is linked to a non-negotiating device is a case where the user may
want to disable Auto-Negotiation. In this instance, the mode of operation will drop to the least common
denominator between the two devices (e.g. 100 Mb/s, half-duplex). Disabling this feature gives the user
the ability to force the connection to the best mode of operation.
Note
: The SGFEB10xx-13x supports 1000 Mbps fiber Auto-Negotiation.
Link Pass-Through (LPT)
The Link Pass-Through feature allows the media converter to monitor both the fiber and copper RX
(receive) ports for loss of signal. In the event of a loss of an RX signal (1), the media converter will
automatically disable the TX (transmit) signal (2), thus, “passing through” the link loss (3). The far-end
device is automatically notified of the link loss (4), which prevents the loss of valuable data unknowingly
being transmitted over an invalid link. Note that LPT is an option on 2 port versions.
The LPT firmware algorithm will detect both fiber and Cu RX link loss; the link transmitter is disabled to
propagate loss indication. Link Pass Through is a troubleshooting feature that allows the media converter
to monitor both the fiber and copper RX ports for loss of signal. In the event of a loss of RX signal on one
media port, the converter will automatically disable the TX signal of the other media port, thus "passing
through" the link loss.
Full-Duplex Network
In a full-duplex network, maximum cable lengths are determined by the type of cables that are used.
See pages 3 and 4 for the cable specifications for the different SGFEB models. The 512-Bit Rule does
not apply in a full-duplex network.
Half-Duplex Network (512-Bit Rule)
In a half-duplex network, the maximum cable lengths are determined by the round trip delay limitations of
each Fast Ethernet collision domain. (A collision domain is the longest path between any two terminal
devices, e.g. a terminal, switch, or router.) The 512-Bit Rule determines the maximum length of cable
permitted by calculating the round-trip delay in bit-times (BT) of a particular collision domain. If the result
is less than or equal to 512 BT, the path is good. For more information on the 512-Bit Rule, see the white
paper titled “Collision Domains” on the Transition Networks website at:
