Managing Serviceguard A.11.20, March 2013

Figure 25 Cluster Before Local Network Switching
Node 1 and Node 2 are communicating over LAN segment 2. LAN segment 1 is a standby.
In Figure 26, we see what would happen if the LAN segment 2 network interface card on Node
1 were to fail.
Figure 26 Cluster After Local Network Switching
As the standby interface takes over, IP addresses will be switched to the hardware path associated
with the standby interface. The switch is transparent at the TCP/IP level. All applications continue
to run on their original nodes. During this time, IP traffic on Node 1 will be delayed as the transfer
occurs. However, the TCP/IP connections will continue to be maintained and applications will
continue to run. Control of the packages on Node 1 is not affected.
NOTE: On Ethernet networks, Serviceguard supports local failover between network interfaces
configured with “Ethernet protocol” or between network interfaces configured with “SNAP
encapsulation within IEEE 802.3 protocol.” You cannot use both protocols on the same interface,
nor can you have a local failover between interfaces that are using different protocols.
72 Understanding Serviceguard Software Components