User manual

Chapter 4 - Layer 3 Command Set - IP Networking OSPFv2 (Dynamic Routing Protocol Module)
Alvarion BreezeNET B130/B300 GigE 153 Operational User Manual
A method for metric configuration described above is used for all links for which
interfaces a specific cost is not set. To set an individual cost (metric) for links one
can using the following command in config-if mode:
cost <1-65535> [A.B.C.D]
In order to get into config-if mode for the particular interface, the following
command is used:
interface IFNAME
Example:
OSPF> configure
OSPF(config)# interface eth0
OSPF(config-if)# cost 4 192.168.15.1
OSPF(config-if)#
In cost command an IP-address is specified which is assigned to the interface in a
subnet which is connected to this subnet. If this parameter is not specified every
link for this interface will have a specified cost (metric) regardless from the
destination subnet.
4.7.8 OSPF System Areas
OSPF protocol has an ability to join adjacent networks and hosts into special
groups. This group along with a router that has a link to one (any) of the networks
included into the group is called an area. In each area an independent copy of
OSPF is functioning. That means that each area has its own database and a
corresponding graph.
A router that is configured to advertise only internal links is called an internal
router (IR). A router connected to networks in more that one area is called area
border router (ABR). A router that advertises its link to external destinations
(redistribute command) is called AS Boundary Router (ASBR).
Each area is assigned a unique identifier area-id. An area with area-id equal to
zero is called a backbone of OSPF system. OSPF backbone area always includes
all ABR. Backbone area is responsible for routing information distribution
between other (non-backbone) areas. Backbone area should be contiguous but it
does not always imply a physical adjacency - backbone connections can be
organized using virtual connections.
4.7.8.1 ABR models
OSPF router supports four models of ABR: