Brocade FastIron Ethernet Switch Layer 3 Routing Configuration Guide - Manual (Page 39)

The ospf-ignore and ospf-passive parameters modify the Layer 3 switch defaults for adjacency
formation and interface advertisement. Use one of these parameters if you are configuring multiple IP
subnet addresses on the interface but you want to prevent OSPF from running on some of the subnets:
• ospf-passive - This option disables adjacency formation with OSPF neighbors. By default, when
OSPF is enabled on an interface, the software forms OSPF router adjacencies between each primary
IP address on the interface and the OSPF neighbor attached to the interface.
• ospf-ignore - This option disables OSPF adjacency formation and also disables advertisement of the
interface into OSPF. The subnet is completely ignored by OSPF.
NOTE
The ospf-passive option disables adjacency formation but does not disable advertisement of the
interface into OSPF. To disable advertisement in addition to disabling adjacency formation, you must
use the ospf-ignore option.
Use the secondary parameter if you have already configured an IP address within the same subnet on
the interface.
NOTE
When you configure more than one address in the same subnet, all but the first address are secondary
addresses and do not form OSPF adjacencies.
NOTE
All physical IP interfaces on BrocadeFastIron Layer 3 devices share the same MAC address. For this
reason, if more than one connection is made between two devices, one of which is a BrocadeFastIron
Layer 3 device, Brocade recommends the use of virtual interfaces. It is not recommended to connect
two or more physical IP interfaces between two routers.
Assigning an IP address to a loopback interface
Loopback interfaces are always up, regardless of the states of physical interfaces. They can add
stability to the network because they are not subject to route flap problems that can occur due to
unstable links between a Layer 3 switch and other devices. You can configure up to eight loopback
interfaces on a Chassis Layer 3 switch devices. You can configure up to four loopback interfaces on a
Compact Layer 3 switch.
You can add up to 24 IP addresses to each loopback interface.
NOTE
If you configure the BrocadeLayer 3 switch to use a loopback interface to communicate with a BGP4
neighbor, you also must configure a loopback interface on the neighbor and configure the neighbor to
use that loopback interface to communicate with the BrocadeLayer 3 switch. Refer to
Assigning an IP
address to a loopback interface .
To add a loopback interface, enter commands such as those shown in the following example.
device(config-bgp-router)# exit
device(config)# interface loopback 1
device(config-lbif-1)# ip address 10.0.0.1/24
Syntax: interface loopback num
Assigning an IP address to a loopback interface
FastIron Ethernet Switch Layer 3 Routing Configuration Guide 39
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