ATM Configuration and Troubleshooting Guide

Configuring EMS High Availability over ATM
Types of Failures Managed by EMS HA-ATM
Chapter 6 103
secondary ELAN interfaces on the secondary ATM adapter. Figure 6-5
below shows this situation (the dotted lines represent the failure of
adapter atm0).
Figure 6-5 Primary ELAN Interfaces Transferred to Secondary
Interfaces—Local Recovery
The IP addresses for the primary ELAN interfaces are associated with
the secondary ELAN interfaces. The transfer is transparent to any
application accessing one of those IP addresses. If the secondary adapter
fails, and there are no more secondary adapters, the IP addresses are
transferred back to the primary adapter. Note that this transfer back to
the primary adapter happens regardless of whether the primary adapter
has become active again.
If local recovery of an ELAN is not possible, and remote recovery has
been configured, the hatmmon daemon monitoring that ELAN notifies
MC/ServiceGuard. MC/ServiceGuard then initiates remote recovery.
If local recovery is not possible, hatmmon continues monitoring the ELAN
interfaces. Then, when the primary adapter, or any secondary adapter,
becomes active again, the IP addresses are transferred to that adapter.
ela0 ela1 elb0 elb1
atm0 adapter
atm1 adapter