Use this command to enable the OSPFv3 routing protocol on an interface.

Use the set form of this command to enable OSPFv3 on an interface.

Use the delete form of this command to remove all OSPFv3 configuration and disable OSPFv3 on an interface.

Use the show form of this command to display OSPFv3 configuration.

Use this command to manually override the default OSPFv3 cost computed by the system for an interface. You can assign only one cost for each interface.

By default, the metric associated with a link is computed as follows:

Cost = 108/bandwidth

The cost of reaching any destination is the sum of the costs of the individual hops. Costs are always rounded to the nearest integer. Costs lower than 1 are rounded up to 1.

OSPF Costs for Common Media Types shows the OSPFv3 costs for some common media types.

The values show how OSPFv3 fails to distinguish between interfaces faster than 100 Mbps, for example, between Fast Ethernet (100 Mbps) and Gigabit Ethernet (1000 Mbps) interfaces. If you want to distinguish interfaces equal to or greater than 100 Mbps, you must manually configure the cost of the interface by using this command.

Use the set form of this command to specify the OSPFv3 cost for the interface.

Use the delete form of this command to restore the default cost.

Use the show form of this command to display cost configuration.

Use this command to specify the interval during which an interface should expect a hello packet from its neighbor.

If the dead interval passes without the interface receiving a hello packet from the neighbor, the status of the neighbor is changed to out-of-service, and all associated state is cleared.

The dead interval must be the same for all routers that are to establish two-way communication within a network. If two routers do not agree on these parameters, they do not establish adjacencies and disregard communication from each other.

Use the set form of this command to specify the dead interval.

Use the delete form of this command to restore the default dead interval.

Use the show form of this command to display dead-interval configuration.

Use this command to set the interval at which OSPFv3 Hello packets are sent for an interface.

A hello packet is an OSPFv3 packet used to detect and maintain relationships with neighbors on the same network (directly connected routers). The greater the interval between Hello packets, the less router traffic occurs, but the longer it takes for topological changes to be detected.

The hello interval must be the same for all routers that are to establish two-way communication within a network. If two routers do not agree on these parameters, they do not establish adjacencies and disregard communication from each other.

Use the set form of this command to set the hello interval.

Use the delete form of this command to restore the default hello interval.

Use the show form of this command to display hello-interval configuration.

Use this command to suppress the origination of the link-LSAs. If this feature is enabled, and the interface type is not broadcast or Non-Broadcast Multi-Access (NBMA), the router does not originate a link-LSA for the interface.

Use the set form of this command to suppress the origination of the link-LSAs.

Use the delete form of this command to restore the default setting.

Use the show form of this command to display whether link-LSA suppression is enabled.

Use this command to disable MTU mismatch detection on an OSPFv3 interface.

OSPFv3 sends the MTU of the interface in a database description packet. If the MTUs of OSPFv3 neighbors do not match, they cannot form an OSPFv3 adjacency. MTU mismatch detection detects MTU mismatches and indicates them in the form of a debug message.

MTU mismatch is an important troubleshooting feature. If MTU mismatch is not enabled, MTU mismatches can be detected only by examining the configuration for both interfaces.

MTU mismatches are unavoidable in some network setups and are even part of the normal setup. MTU mismatch detection should be disabled for these networks, so that normal OSPFv3 adjacencies can be formed.

Use the set form of this command to disable MTU mismatch detection.

Use the delete form of this command to re-enable MTU mismatch detection.

Use the show form of this command to display the OSPFv3 configuration.

Use this command to configure an IPv6 address for neighbor parameters on an interface.

Use the set form of this command to configure an IPv6 address for neighbor parameters.

Use the delete form of this command to remove the neighbor parameters.

Use the show form of this command to display the OSPFv3 configuration.

Use this command to configure and display the OSPFv3 network type for an interface.

Use the set form of this command to specify the network type.

Use the delete form of this command to remove the network type.

Use the show form of this command to display the network type.

Use this command to set the priority for an interface on the broadcast network to which the interface is connected. The priority determines which routers are selected as the Designated Router (DR) and Backup Designated Router (BDR) of the area.

The DR and BDR are used to reduce the amount of traffic in OSPFv3 overhead on broadcast networks, by reducing the number of adjacent routers to which a router must flood its topological information. In broadcast networks (such as Ethernet), each router establishes an adjacency with only the DR and the BDR, rather than with every router in its area. The DR and the BDR then flood this information to all other routers on the network segment.

Priority can range from 0 to 255. In general, the router with the highest priority is elected as the DR, and the router with the second-highest priority is elected as the BDR. The higher the number, the higher the priority.

Routers with a priority of 0 are ineligible for election.

Use the set form of this command to specify the OSPFv3 priority.

Use the delete form of this command to restore the default priority.

Use the show form of this command to display priority configuration.

Use this command to specify how long an interface waits for an acknowledgment of a link-state update before resending the update.

The link-state update packet is part of the exchange of topology databases between routers. When the initial database description (DD) packet is sent, it contains only the headers of the LSAs. If the receiving router determines that it requires that piece of the OSPFv3 topology, it sends a link-state request packet to request the complete LSA from the sending router.

After the update packet is sent, the sending router waits for an acknowledgement, either implicit or explicit, from the receiving router. In an explicit acknowledgement, the receiving router sends a link-state acknowledge (LS-Ack) packet to the router that sent the update. In an implicit acknowledgement, the router that sent the update receives an LSA from the receiving router that contains the update information.

If the retransmit interval passes with neither an explicit nor an implicit acknowledgement, the sending router retransmits the link-state update packet.

Too high an interval slows network convergence. Too small an interval causes unnecessary retransmission.

Use the set form of this command to set the OSPFv3 retransmit interval for an interface.

Use the delete form of this command to restore the default retransmit interval.

Use the show form of this command to display retransmit interval configuration.

Use this command to set the transmit delay for an interface. This delay is the estimated time required to send a link-state update (LSU) packet.

This timer is used to accommodate transmission and propagation delays on the network, particularly on low-speed networks in which delays may be significant. The router increments the age of link-state advertisements (LSA) in LSU packets to account for these delays.

The value includes both the transmission time and the propagation delay across the network. The transmit delay is added to the age of the LSA packet before the LSA is transmitted. The LSA age is used to help the network sequence LSAs, so that it can determine which of competing LSAs is the more recent and trustworthy.

LSAs are numbered in sequence, but the sequence numbers are finite, and so cannot be used as the sole determinant of the most recent LSA. Instead, OSPFv3 also tracks the age of LSAs. Each time an LSA is forwarded to another router, its current age is incremented by the transmit delay. The age of a packet, together with its sequence number, helps the receiving router to determine which version of a received LSA is more recent, and therefore to be used.

Use the set form of this command to set the transmit delay.

Use the delete form of this command to restore the default transmit delay.

Use the show form of this command to display transmit-delay configuration.