Configure OSPFv3 Areas, Route Summaries, and Virtual Links

You can click Edit (), or use the right-click menu to cut, copy, past, insert, and delete areas.

• Area ID—The area for which routes are to be summarized.

• Cost—The metric or cost for the summary route, which is used during OSPF SPF calculations to determine the shortest paths to the destination. Valid values range from 0 to 16777215.

• Type—Specifies Normal, NSSA, or Stub. If you select Normal, there are no other parameters to configure. If you select Stub, you can choose to send summary LSAs in the area. If you select NSSA, you can configure the next three options:

  • Allow Sending summary LSA into this area—Allows the sending of summary LSAs into the area.

  • Imports routes to normal and NSSA area—Allows redistribution to import routes to normal and not to stubby areas.

  • Defaults information originate—Generates a default external route into an OSPFv3 routing domain.

• Metric—Metric used for generating the default route. The default value is 10. Valid metric values range from 0 to 16777214.

• Metric Type—The metric type is the external link type that is associated with the default route that is advertised into the OSPFv3 routing domain. The available options are 1 for a Type 1 external route or 2 for a Type 2 external route.

You can click Edit (), or use the right-click menu to cut, copy, past, insert, and delete route summaries.

• IPv6 Prefix/Length—The IPv6 prefix. To add a new network object, click Add (). See Network for the procedure for adding networks.

• Cost—The metric or cost for the summary route, which is used during OSPF SPF calculations to determine the shortest paths to the destination. Valid values range from 0 to 16777215.

• Advertise—Advertises the summary route. Uncheck this check box to suppress routes that fall under the summary address. By default, this check box is checked.

• Peer RouterID—Choose the IP address of the peer router. To add a new network object, click Add (). See Network for the procedure for adding networks.

• TTL Security—Enables TTL security check. The value for the hop-count is a number from 1 to 254. The default is 1.

  OSPF sends outgoing packets with an IP header Time to Live (TTL) value of 255 and discards incoming packets that have TTL values less than a configurable threshold. Because each device that forwards an IP packet decrements the TTL, packets received via a direct (one-hop) connection have a value of 255. Packets that cross two hops have a value of 254, and so on. The receive threshold is configured in terms of the maximum number of hops that a packet may have traveled.

• Dead Interval—The time in seconds that hello packets are not seen before a neighbor indicates that the router is down. The default is four times the hello interval, or 40 seconds. Valid values range from 1 to 65535.

  The dead interval is an unsigned integer. The value must be the same for all routers and access servers that are attached to a common network.

• Hello Interval—The time in seconds between the hello packets sent on an interface. Valid values range from 1 to 65535. The default is 10.

  The hello interval is an unsigned integer that is to be advertised in the hello packets. The value must be the same for all routers and access servers on a specific network. The smaller the hello interval, the faster topological changes are detected, but the more traffic is sent on the interface.

• Retransmit Interval—The time in seconds between LSA retransmissions for adjacencies that belong to the interface. The retransmit interval is the expected round-trip delay between any two routers on the attached network. The value must be greater than the expected round-trip delay, and can range from 1 to 65535. The default is 5.

  When a router sends an LSA to its neighbor, it keeps the LSA until it receives the acknowledgment message. If the router receives no acknowledgment, it resends the LSA. Be conservative when setting this value, or needless retransmission can result. The value should be larger for serial lines and virtual links.

• Transmit Delay—The estimated time in seconds that is required to send an LSA packet on the interface. The integer value must be greater than zero. Valid values range from 1 to 8192. The default is 1.

  LSAs in the update packet have their own ages incremented by this amount before transmission. If the delay is not added before transmission over a link, the time in which the LSA propagates over the link is not considered. The value assigned should take into account the transmission and propagation delays for the interface. This setting has more significance on very low-speed links.