Advanced POWER Virtualization on IBM System p5 - Previous ...

You must select different priorities for the two SEAs by setting all virtual Ethernet
adapters of each SEA to that priority value. The priority value defines which of
the two SEAs will be the primary (active) and which will be the backup (standby).
The lower the priority value, the higher the priority, thus priority=1 means highest
priority.
The SEA can also be configured with an IP address that it will periodically try to
ping to confirm network connectivity is available. This is similar to the IP address
to ping that may be configured with Network Interface Backup.
There are basically four different cases that will initiate a SEA Failover:
1. The standby SEA detects that keep-alive messages from the active SEA are
no longer received over the control channel.
2. The active SEA detects that a loss of the physical link is reported by the
physical Ethernet adapter’s device driver.
3. On the Virtual I/O Server with the active SEA, a manual failover can be
initiated by setting the active SEA to standby mode.
4. The active SEA detects that it cannot ping a given IP address anymore.
An end of the keep-alive messages would occur when the Virtual I/O Server with
the primary SEA is shut down or halted, has stopped responding, or has been
deactivated from the HMC.
There may also be some types of network failures that would not trigger a failover
of the SEA, because keep-alive messages are only sent over the control
channel. No keep-alive messages are sent over other SEA networks, especially
not over the external network. But the SEA Failover feature can be configured to
periodically check the reachability of a given IP address. The SEA will
periodically ping this IP address, so it can detect some other network failures.
You may already know this feature from AIX 5L Network Interface Backup (NIB).
Important: The Shared Ethernet Adapters must have network interfaces with
IP addresses associated to be able to use this periodic reachability test.
These IP addresses have to be unique and you have to use different IP
addresses on both SEAs.
The SEAs must have IP addresses to provide as return-to-address for the
ICMP-Echo-Requests sent and ICMP-Echo-Replies received when pinging the
given IP address. These IP addresses must be different.
Chapter 4. Setting up virtual I/O: advanced 195