MRV Communications EM316SW-XY - Manual (Page 15)

Fiber Driver
®
EM316SW-XY
PN 1288003-001, Rev D2
7
2.2.3 Redundant Link
MODE1 OFF
MODE0 ON
Figure 4 -- Redundant Link Mode
In Redundant Link mode, the module acts as a copper to redundant fiber (100Base-FX)
converter. This configuration requires optical SFPs installed in ports P2 and P3 to support a pair
of redundant fiber optic paths. Ethernet port P4 is disabled in this mode; only description
commands will have any effect on P4. The Redundant Link mode provides “1:1” link protection.
Dual-homing is not supported.
In this mode, the EM316SW-XY can pass link status with LIN or with the industry standard Far
End Fault Indication (FEFI). Implementing both tools allows for backwards compatibility with the
full set of MRV Fast Ethernet media conversion solutions while supporting standard connectivity
to any standard Fast Ethernet fiber optic port.
With LIN enabled, loss of link at BOTH fiber ports (P2 and P3) disables the transmitter of the
access (Ethernet) port (P1). If one fiber optic channel fails while the other fiber optic channel is
operational, LIN does not interrupt the data. Downstream switches, routers, and other link-state
dependant devices can accurately react to changing link conditions. This feature is especially
valuable in fault-tolerant network designs. Set both DIP switches (FEFI and FEFI2) ON to
enable FEFI with LIN in Redundant Link mode.
The “select-link” command is enabled for ports P2 and P3 in Redundant Link mode to force a
port to active if it has an available link. There is no default or preferred port, so the first link
established becomes active. The “shutdown” command is not available for redundant ports P2
and P3.