Dell BigIron RX Series, Configuration Manual

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698 BigIron RX Series Configuration Guide
53-1002253-01
Configuring OSPF
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Configuring an OSPF non-broadcast interface
OSPF routers generally use broadcast packets to establish neighbor relationships and broadcast
route updates on Ethernet and virtual routing interfaces (ves). Beginning with BigIron RX software
releases 02.3.00, you can configure an interface to send OSPF unicast packets rather than
broadcast packets to its neighbor by configuring non-broadcast multi-access (NBMA) networks.
NBMA networks are similar to broadcast networks except the packets are sent as unicast. This type
of network can be useful in situations where multicast traffic is not feasible (for example when a
firewall does not allow multicast packets).
You configure NBMAs on an interface. The routers at the other end of that interface must have a
non-broadcast neighbor configured. There is no restriction on the number of routers sharing a
non-broadcast interface (for example, through a hub or switch).
To configure NBMA on an interface, do the following.
1. Create an OSPF area on an interface, then enable NBMA on that interface.
BigIron RX(config)# int ve 20
BigIron RX(config-vif-20)# ip ospf area 0
BigIron RX(config-vif-20)# ip ospf network non-broadcast
BigIron RX(config-vif-20)# exit
Syntax: [no] ip ospf network non-broadcast
2. Then under the router OSPF level, specify the IP address of the neighbor in the OSPF
configuration. The non-broadcast interface configuration must be done on the OSPF routers on
both ends of the link.
For example, the following commands configure VE 20 as a non-broadcast interface.
The following commands specify 1.1.20.1 as an OSPF neighbor address. The address specified
must be in the same sub-net as a non-broadcast interface.
BigIron RX(config)# router ospf
BigIron RX(config-ospf-router)# neighbor 1.1.20.1
Syntax: neighbor <ip-address>
MD5 Authentication Wait Time This parameter determines when a newly configured MD5 authentication
key is valid. This parameter provides a graceful transition from one MD5
key to another without disturbing the network. All new packets transmitted
after the key activation wait time interval use the newly configured MD5
Key. OSPF packets that contain the old MD5 key are accepted for up to five
minutes after the new MD5 key is in operation.
The range for the key activation wait time is from 0 – 14400 seconds. The
default value is 300 seconds.
Hello Interval The length of time between the transmission of hello packets. The range is
1 – 65535 seconds. The default is 10 seconds. On NBMA, the default is
30 seconds.
Retransmit Interval The interval between the re-transmission of link state advertisements to
router adjacencies for this interface. The range is 0 – 3600 seconds. The
default is 5 seconds.
Transmit Delay The period of time it takes to transmit Link State Update packets on the
interface. The range is 0 – 3600 seconds. The default is 1 second.