User's Guide Gigabit Ethernet Host Adapters ITIpci 5100G/GF

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Configuring Dual Homing
To configure Dual Homing in a system with two adapters, where
/etc/hostname.alt0 is the primary adapter, perform the following
procedure:
Note: Do not configure an /etc/hostname.alt<num> entry for the
redundant adapter. Also, do not configure Jumbo Frame support files for
the redundant adapter. If the primary adapter fails, the secondary adapter
takes on the configuration of the primary adapter. Serious configuration
problems will occur if there are hostname or Jumbo Frame configuration files
for the secondary adapter.
1. Enable Spanning Tree Protocol on the switch connected to your ITI-
5100G/GF adapters.
2. The port to which the secondary adapter is connected must be the port
that blocks.
If there is more than one switch in the spanning tree, be certain that the
secondary adapter is not attached to the root switch of the spanning tree.
Also, be sure that the port path cost of the switch port connected to the
secondary adapter is higher than the other ports in the loop.
Example: In the following redundant switch configuration, the switch
port connected to adapter #2 must have the highest port path cost of any
of the four ports in the loop:
Figure 8: Dual Homing Path Costs
3. Create the /etc/redund.alt1 file.
4. Use your regular text editor to put the number "
0 ", the instance
number of the primary adapter, into the file
/etc/redund.alt1 .
Put the number " 0 " in the file, without spaces or blank lines.
5. If you are finished with all optional configuration, reboot the system.
Inter-switch path is required
for loop condition. Loop
ports need lower path cost
Switch port to active
adapter needs lower
pat
h
cost
Switch port to secondary
adapter must have highest
p
ath cost to bloc
k