Brocade Access Gateway Administrator's Guide - Supporting Fabric OS v5.3.0 (53-1000633-01, June 2007)

8 Access Gateway Administrator’s Guide
53-1000633-01
Failback policy
1
Only the originally mapped F_Ports fail back. In the case of multiple N_Port failures, only F_Ports
that were mapped to the recovered N_Port experience failback. The remaining F_Ports are not
redistributed among the online N_Ports during the failback.
NOTE
The failback policy is an N_Port parameter. The failback policy is enabled by default.
The following sequence describes how a failback event occurs:
1. When an N_Port comes back online, the F_Ports that were originally mapped to it are disabled.
2. The F_Port is reenabled on the original N_Port.
3. The host establishes a new connection with the fabric.
Example: Failback Policy
In Example 3, the Brocade Access Gateway N_1 remains disabled because the corresponding F_A1
port is offline. However N_2 comes back online. See Figure 5 on page 7 for the original failover
scenario.
In Example 3, the ports F_1 and F_2 are mapped to N_1 and continue to be routed to N_3. The
ports F_3 and F_4 were originally mapped to N_2 and are disabled. They are rerouted to N_2 and
then enabled.
FIGURE 6 Failback policy behavior
F_A2
Hosts
Access Gateway
Edge Switch
Fabric
(Switch_A)
enabled
NPIV
F_4
F_3
F_2
F_1
N_1
F_A1
enabled
NPIV
N_3
F_B1
enabled
NPIV
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
enabled
NPIV
N_2
Legend
Physical connection
Mapped online
Failover route online
Original mapped route
(offline)
Example 3