To separate services that are converged and to prevent a
broadcast storm resulting from a service loop, you can configure a
split horizon group for the E-LAN services at the specified nodes.
After the configuration, the logical ports in one split horizon
group cannot forward packets to each other.
Figure 1 shows a typical application of the split horizon group.
NEs on the network are configured with E-LAN services, and the east
and west ports and service access ports are configured as mounted
ports of a bridge. In this case, if a split horizon group is not
configured at NE1, broadcast storm occurs due to a network loop as
the east and west ports can forward packets to each other. If a
split horizon group is created at NE1 and the east and west ports
are configured as members of the split horizon group, the east and
west ports do not forward packets to each other. Therefore, a
service loop is prevented.
Figure 1 Split horizon group
NOTE:
ERPS can prevent a service loop on a ring network. If ERPS is
already enabled for a ring network, a split horizon group is not
needed as it may affect ERPS operation.
On the OptiX RTN 950, only the split horizon group configuration
based on physical ports is supported. Therefore, if a physical port
is mapped into several logical ports and one of these logical ports
is a member of a split horizon group, the other logical ports are
added to the split horizon group automatically.
