Brocade Access Gateway Administrator's Guide Supporting Fabric OS v7.0.0 (53-1002156-01, April 2011)

50 Access Gateway Administrator’s Guide
53-1002156-01
Failback policy
3
Failback policy configurations in Access Gateway
The following sequence describes how a failback event occurs:
• When an N_Port comes back online, with the Failback policy enabled, the F_Ports that were
originally mapped to it are temporarily disabled.
• The F_Port is rerouted to the primary mapped N_Port, and then re-enabled.
• The host establishes a new connection with the fabric.
NOTE
The failback period is quite fast and rarely causes an I/O error at the application level.
Failback example
In Example 3, described in Figure 11 on page 50, the Access Gateway N_1 remains disabled
because the corresponding F_A1 port is offline. However, N_2 comes back online. See Figure 10
on page 46 for the original failover scenario.
Ports F_1 and F_2 are mapped to N_1 and continue routing to N_3. Ports F_3 and F_4, which were
originally mapped to N_2, are disabled and rerouted to N_2, and then enabled.
FIGURE 11 Failback behavior
F_A2
Hosts
Access Gateway
Edge Switch
Fabric
(Switch_A)
F_4
F_3
F_2
F_1
N_1
F_A1
N_3
F_B1
Host_1
Host_2
Host_3
Host_4
F_5
Host_5
F_6
Host_6
F_7
Host_7
F_8
Host_8
Edge Switch
(Switch_B)
N_4
F_B2
N_2
Legend
Physical connection
Mapped online
Failover route online
Original mapped route
(offline)
Example 3