Brocade BigIron RX Series Configuration Guide - Manual (Page 863)

BigIron RX Series Configuration Guide 785
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Configuring OSPF
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For example, if you configure 10.10.10.0/24 as a candidate default network route, if the IP route
table does not contain an explicit default route (0.0.0.0/0), the software uses the default network
route and automatically uses that route's next hop gateway as the default gateway. If a topology
change occurs and as a result the default network route's next hop gateway changes, the software
can still use the default network route.
Configuring a default network route
You can configure up to four default network routes. To configure a default network route, enter
commands such as the following.
BigIron RX(config)# ip default-network 209.157.22.0
BigIron RX(config)# write memory
Syntax: ip default-network <ip-addr>
The <ip-addr> parameter specifies the network address.
To verify that the route is in the route table, enter the following command at any level of the CLI.
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.
BigIron RX(config)# show ip route
Total number of IP routes: 2
Start index: 1 B:BGP D:Connected R:RIP S:Static O:OSPF *:Candidate default
Destination Gateway Port Cost Type
1 209.157.20.0 0.0.0.0 lb1 1 D
2 209.157.22.0 0.0.0.0 4/11 1 *D