Dell BigIron RX Series, Configuration Manual

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BigIron RX Series Configuration Guide 711
53-1002253-01
Configuring OSPF
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This example shows two routes. Both of the routes are directly attached, as indicated in the Type
column. However, one of the routes is shown as type “*D”, with an asterisk (*). The asterisk
indicates that this route is a candidate default network route.
Modify SPF timers
The BigIron RX uses the following timers when calculating the shortest path for OSPF routes:
•
SPF delay – When the BigIron RX receives a topology change, the software waits before it
starts a Shortest Path First (SPF) calculation. By default, the software waits 0 (zero) seconds.
You can configure the SPF delay to a value from 0 – 65535 seconds. If you set the SPF delay to
0 seconds, the software immediately begins the SPF calculation after receiving a topology
change.
•
SPF hold time – The BigIron RX waits for a specific amount of time between consecutive SPF
calculations. By default, the BigIron RX waits ten seconds. You can configure the SPF hold time
to a value from 0 – 65535 seconds. If you set the SPF hold time to 0 seconds, the software
does not wait between consecutive SPF calculations.
NOTE
OSPF incrementally updates the OSPF routing table when new Type-3 or Type-4 Summary, Type-5
External or Type-7 External NSSA LSAs are received.
You can set the delay and hold time to lower values to cause the BigIron RX to change to alternate
paths more quickly in the event of a route failure. Note that lower values require more CPU
processing time.
You can change one or both of the timers.
To change the SPF delay and hold time, enter commands such as the following.
BigIron RX(config-ospf-router)# timers spf 10 20
The command in this example changes the SPF delay to 10 seconds and changes the SPF hold
time to 20 seconds.
Syntax: timers spf <delay> <hold-time>
The <delay> parameter specifies the SPF delay.
The <hold-time> parameter specifies the SPF hold time.
To set the timers back to their default values, enter a command such as the following.
BigIron RX(config-ospf-router)# no timers spf 10 20
Modify redistribution metric type
The redistribution metric type is used by default for all routes imported into OSPF unless you
specify different metrics for individual routes using redistribution filters. Type 2 specifies a big
metric (three bytes). Type 1 specifies a small metric (two bytes). The default value is type 2.
To modify the default value to type 1, enter the following command.
BigIron RX(config-ospf-router)# metric-type type1
Syntax: metric-type type1 | type2
The default is type2.