HP X.25/9000 User's Guide HP-UX 11i v3 (5900-1523, August 2011)

MAC address is uMAC for that LAN segment. It is initially assigned to the card lan0 on primary
system A.
Figure 19 Before the failover
If the SG package for XOL detects an error in the XOL interface, the package is stopped on the
primary system and the equivalent package starts on the standby system. When the SG package
is stopped on system A, the XOL interfaces (and optionally applications) on the failed LAN card
are stopped. An attempt is made to configure LAN card on system A with the factory default MAC
address. When the SG package starts on system B, the LAN card on system B is configured with
the unique MAC (uMAC) address, and the XOL interfaces (and optionally applications) start on it.
When the failed LAN card on system A comes up later, it is configured with the factory default
MAC address.
Figure 20 After the failover
Configuring the high availability feature for X.25 over LLC2 65