Configuring Cost Calculation For A Link - HP 7102dl - ProCurve Secure Router Configuration Manual

IP Routing—Configuring RIP, OSPF, BGP, and PBR
Configuring OSPF
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15-56
advertise only one default route for all of them. Or the router in a virtual private
network (VPN) may receive routes from an ISP router that the ISP has
tunneled from a remote site.
For example, suppose that a router receives an external route for a network
that uses private addresses in 10.2.0.0 /16 range. Enter this command to enable
the router to advertise these networks to routers in the OSPF network:
ProCurve(config-ospf)# summary-address 10.2.0.0 255.255.0.0
You can also specify that the ASBR not advertise routes to that range of
external addresses with the not-advertise option.
Another reason you might want your ASBR to advertise route summaries
rather than a default route is that your organization multihomes—that is, it
connects to more than one ISP. One ASBR can advertise part of the Internet
address space, and the other can advertise the rest. Routers will then balance
external traffic over both the connections to the Internet. (See "Load Balanc-
ing" on page 15-76 for a more detailed discussion of load balancing with BGP.)
To configure an ASBR to advertise only half of the Internet address space,
enter:
ProCurve(config-ospf)# summary-address 0.0.0.0 128.0.0.0
ProCurve(config-ospf)# summary-address 128.0.0.0 128.0.0.0 not-advertise
Do not confuse the summary-address command with the area <area ID>
range command. The first is for summary LSAs to external networks; the
second is for summaries to networks in an internal area.

Configuring Cost Calculation for a Link

OSPF was designed for great flexibility in computing a route's metric. An
OSPF route's metric is the sum of the cost for each link between the router
and the destination. Originally, network administrators were supposed to be
able to configure routers to calculate a link's cost according to several fields
in a type of service (ToS) header. However, in practice, OSPF determines cost
primarily by inverse bandwidth.
Typically, there is no need to configure an interface with the link's cost. The
ProCurve Secure Router handles metric computations automatically. It
divides 100 by the bandwidth of the link in Mbps and assigns that value to
the link.