2.
Assign a priority to the aggregates.
If you prefer
lan900
to be the active port when both link aggregates have the same number
of operational ports, assign
lan900
a higher priority. If you do not, the active port changes
when one of the link aggregates becomes more efficient (has more operational ports or higher
bandwidth). In this example, you assign
lan900
a priority of 5 and
lan901
a priority of 3.
3.
Edit the
lanconfig.ascii
configuration file.
FAILOVER_GROUP lan902
STATIONARY_IP 192.19.20.2
# Primary/Standby Interface Priority : Cost
# –––––––––––––––––––––––+–––––––––––––+––––––––––––––––
PRIMARY lan900 5 : 1
STANDBY lan901 3 : 1
Table C-1
lists
lan900
events for this example and how proactive failover determines the active
port for
lan902
.
Table C-1 lan900 Events and Proactive Failover (Equal Network Costs)
Active Port
lan901 Normalized Port
Cost
lan900 Normalized Port
Cost
lan900 Event
lan900
2
1/200, or .005
1/300, or .003
Failover group constructed
1
lan900
3
1/200, or .005
1/200, or .005
1 port fails
lan901
4
1/200, or .005
1/100, or .01
1 port fails
lan900
5
1/200, or .005
1/200, or .005
DOWN port becomes active
1
All ports in the link aggregates are operational.
2
Normalized port cost is lower than
lan901
.
3
Normalized port cost is the same, but it has a higher priority than
lan901
.
4
Normalized port cost is lower than
lan900
.
5
Normalized port cost is the same, but it has a higher priority than
lan901
.
If the priorities were the same,
lan901
would continue as the active port until the third port in
lan900
became
active.
Example 2
You want to configure a failover group (
lan902
) for proactive failover. You decide that the
failover group consists of two link aggregates:
lan900
and
lan901
. The
lan900
aggregate
consists of ports 2 and 3; the
lan901
aggregate consists of ports 4 and 5. Ports 2, 3, 4, and 5 have
speeds of 100 Mb/s. In addition, the link aggregates are connected to different routers using
different speeds to connect to the network.
To configure the failover group for proactive failover, do the following:
1.
Determine network efficiency.
In this example, you determine that the router connected to
lan900
is 1.5 times more efficient
at delivering traffic to the network than the router connected to
lan901
. You assign
lan900
a cost of 1 and
lan901
a cost of 1.5. However, you must express cost values in the
lanconfig.ascii
file using whole numbers (no decimal points). The ratio of 1 to 1.5 is
the same as the ratio of 2 to 3. Therefore,
lan900
has a cost of 2 and
lan901
has a cost of
3.
2.
Assign a priority to the aggregates.
Because you prefer
lan900
over
lan901
, you assign
lan900
a priority of 8 and
lan901
a priority of 7. That way, if both ports have the same normalized port cost,
lan900
has
precedence over
lan901
.
Editing configuration files for link aggregates
103
