Gigabit Ethernet And Remote Fault Indication; Sffd Recommendations - Avaya 8800 Planning And Engineering

Redundant network design
transmitting side cannot determine that the link is broken in one direction (see
100BASE-FX FEFI
transmitting switch keeps the link active as it still receives signals from the far end. However,
the outgoing packets are dropped because of the failure.
Figure 13: 100BASE-FX FEFI
With Avaya-to-Avaya connections, to avoid loss of connectivity for devices that do not support
FEFI, you can use VLACP as an alternative failure detection method. For more information,
see End-to-end fault detection and VLACP

Gigabit Ethernet and remote fault indication

The 802.3z Gigabit Ethernet standard defines remote fault indication (RFI) as part of the
autonegotiation function. RFI provides a means for the stations on both ends of a fiber pair
to be informed when a problem occurs on one of the fibers. Because RFI is part of the
autonegotiation function, if autonegotiation is disabled, RFI is automatically disabled.
Therefore, Avaya] recommends that autonegotiation be enabled on Gigabit Ethernet links
when autonegotiation is supported by the devices on both ends of a fiber link.
For information about autonegotiation for 10 and 100 Mbit/s links, see
Autonegotiation recommendations

SFFD recommendations

The Ethernet switching devices listed in the following table do not support autonegotiation on
fiber-based Gigabit Ethernet ports. These devices are unable to participate in remote fault
indication (RFI), which is a part of the autonegotiation specification. Without RFI, and in the
56 Planning and Engineering — Network Design
on page 56). This leads to network connectivity problems because the
on page 34.
on page 57.
Figure 13:
10/100BASE-TX
November 2010