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

transparent from the XOL router side or peer system, which sees the same MAC address associated
with the active interface.
NOTE: To avoid MAC address collision, the system administrator must identify an unused, unique
MAC address in their LAN subnet. The lanadmin command is used to change the MAC address
of the card. After failover, the failed LAN card is reconfigured with its factory default MAC address.
XOL is not supported over APA (Auto Port Aggregation).
Before you run the lanadmin command to set up the unique MAC address, you may test whether
the MAC address chosen by you is selected by running the linkloop command. For more
information, see linkloop((1m)). The uniqueness of the MAC address is verified on the LAN cards
currently active in the LAN segment. The linkloop command sends an OK message if the MAC
address is already in use.
NOTE: The routing table of the router connected to the host system must be updated with the
unique MAC address identified by the user. If the XOL router supports the Hunt Group facility for
XOL HA, the unique MAC address may not be required to achieve the HA functionality for XOL
interface. For more information on Hunt Group facility, see “Configuring the high availability
feature for X.25 over LLC2” (page 61).
WARNING! When several highly available XOL interfaces are configured on a given LAN card,
failover of all the highly available XOL interfaces to the standby LAN card occurs immediately after
one XOL interface fails. This is because the same unique MAC address is used by all XOL interfaces
on the given LAN card.
Local failover
NOTE: You need not install ServiceGuard for Local failover.
For local failover to happen, you must define a standby LAN card in the X.25 configuration file.
The primary X.25 configuration file is used to configure the XOL interface on the standby LAN card
after the local failover. As a result, the standby LAN card inherits all the configuration parameters
from the primary interface, including the XOL logical port-id (also called box-id). The XOL interface
starts first on the primary LAN card. If this XOL interface fails, an attempt is made to restart it on
the standby LAN card. If the XOL interface fails on the standby LAN card, an attempt is made to
failover back to the primary LAN card. This failover succeeds only if the primary LAN card is back
UP and operational. Otherwise, the XOL interface goes down.
For more information on how to use this local failover functionality, see “Configuring XOL HA for
local failover without ServiceGuard” (page 62).
Configuring XOL HA for local failover without ServiceGuard
In Figure 17 (page 63), system A has two LAN cards, namely, lan0 (the primary LAN card) and
lan1 (the standby LAN card). The standby LAN card provides local failover for the XOL interface
with X.121 address 1111. The user supplied, unique MAC address that is specified in the XOL
configuration file as a value for the field XOL_floating_macaddr, for that LAN segment is uMAC.
The XOL interface with X.121 address 1111 is brought up on lan0 on system A (uMAC is
automatically assigned to lan0 on system A when the XOL interface is initialized).
62 Configuration