D-Link DGS-1520 Emulator - Page 787

DGS-1520 Series Gigabit Ethernet Smart Managed Switch CLI Reference Guide Default No IPv6 OSPF virtual link is defined. hello-interval SECONDS: 10 seconds. dead-interval SECONDS: 40 seconds. transmit-delay SECONDS: 1 seconds. retransmit-interval SECONDS: 5 seconds. Command Mode Router Configuration Mode. Command Default Level Level: 12. Usage Guideline All areas in an IPv6 OSPF autonomous system must be physically connected to the backbone area (area 0). In some cases where this physical connection is not possible, you can use a virtual link to connect to the backbone through a non-backbone area. As mentioned above, you can also use virtual links to connect two parts of a partitioned backbone through a non-backbone area. The area through which you configure the virtual link, known as a transit area, must have full routing information. The transit area cannot be a stub area. Configure the hello-interval to be the same for all routers attached to a common network. A short hello interval results in the router detecting topological changes faster but also an increase in the routing traffic. As with the hello interval, the value of dead-interval must be the same for all routers and access servers attached to a common network. The retransmit-interval is the expected round-trip delay between any two routers in a network. Set the value to be greater than the expected round-trip delay to avoid needless retransmissions. The transmit-delay is the time taken to transmit a link state update packet on the interface. Before transmission, the LSUs are incremented by this amount. Set the transmit-delay to be greater than zero. Also, take into account the transmission and propagation delays for the interface. To configure a virtual link in IPv6 OSPF, you must use a router ID instead of an address. In IPv6 OSPF, the virtual link takes the router ID rather than the IPv6 prefix of the remote router. Example This example shows how to establish a virtual link with default values for all optional parameters. Switch#configure terminal Switch(config)#ipv6 router ospf 1000 Switch(config-rtr)#area 0.0.0.1 virtual-link 192.168.255.1 Switch(config-rtr)# 71-5 auto-cost reference-bandwidth This command is used to control the reference value IPv6 OSPF uses when calculating metrics for interfaces. To return the reference value to its default, use the no form of this command. auto-cost reference-bandwidth MBPS no auto-cost reference-bandwidth 783