Managing Serviceguard Fifteenth Edition, reprinted May 2008

Understanding Serviceguard Software Components
How the Network Manager Works
Chapter 3 111
• A maximum of 30 network interfaces per node is supported. The
interfaces can be physical NIC ports, VLAN interfaces, APA
aggregates, or any combination of these.
• Local failover of VLANs must be onto the same link types. For
example, you must fail over from VLAN-over-Ethernet to
VLAN-over-Ethernet.
• The primary and standby VLANs must have same VLAN ID (or tag
ID).
• VLAN configurations are only supported on HP-UX 11i releases.
• Only port-based and IP-subnet-based VLANs are supported.
Protocol-based VLAN is not supported because Serviceguard does
not support any transport protocols other than TCP/IP.
• Each VLAN interface must be assigned an IP address in a unique
subnet, unless it is a standby for a primary VLAN interface.
• Failover from physical LAN interfaces to VLAN interfaces or vice
versa is not supported because of restrictions in VLAN software.
• Using VLAN in a Wide Area Network cluster is not supported.
• If CVM disk groups are used, you must not configure the
Serviceguard heartbeat over VLAN interfaces.
Additional Heartbeat Requirements
VLAN technology allows great flexibility in network configuration. To
maintain Serviceguard’s reliability and availability in such an
environment, the heartbeat rules are tightened as follows when the
cluster is using VLANs:
1. VLAN heartbeat networks must be configured on separate physical
NICs or APA aggregates, to avoid single points of failure.
2. Heartbeats are still recommended on all cluster networks, including
VLANs.
3. If you are using VLANs, but decide not to use VLANs for heartbeat
networks, heartbeats are recommended for all other physical
networks or APA aggregates specified in the cluster configuration
file.