Configuring 31-Bit Subnet Masks On Point-To-Point Networks - Brocade Communications Systems FastIron SX 800 Configuration Manual

Configuring IP parameters - Layer 3 switches
Configuring IP follow on a virtual routing interface
IP Follow allows multiple virtual routing interfaces to share the same IP address. With this feature, one virtual routing interface is
configured with an IP address, while the other virtual routing interfaces are configured to use that IP address, thus, they "follow" the virtual
routing interface that has the IP address. This feature is helpful in conserving IP address space.
Configuration limitations and feature limitations for IP Follow on a virtual routing interface
• When configuring IP Follow, the primary virtual routing interface should not have ACL or DoS Protection configured. It is
recommended that you create a dummy virtual routing interface as the primary and use the IP-follow virtual routing interface for
the network.
• Global Policy Based Routing is not supported when IP Follow is configured.
• IPv6 is not supported with IP Follow.
• FastIron devices support IP Follow with OSPF and VRRP protocols only.
Configuration syntax for IP Follow on a virtual routing interface
Configure IP Follow by entering commands such as the following.
device(config)# vlan 2 name IP-Subnet_10.1.2.0/24
device(config-vlan-2)# untag ethernet 1 to 4
device(config-vlan-2)# router-interface ve 1
device(config-vlan-2)# interface ve 1
device(config-vif-1)# ip address 10.10.2.1/24
device(config-vif-1)# interface ve 2
device(config-vif-2)# ip follow ve 1
device(config-vif-2)# interface ve 3
device(config-vif-3)# ip follow ve 1
Syntax:[no] ip follow ve number
For number, enter the ID of the virtual routing interface.
Use the no form of the command to disable the configuration.
Virtual routing interface 2 and 3 do not have their own IP subnet addresses, but share the IP address of virtual routing interface 1.
Deleting an IP address
To delete an IP address, enter the no ip address command.
device(config-if-e1000-1)# no ip address 10.1.2.1
This command deletes IP address 10.1.2.1. You do not need to enter the subnet mask.
To delete all IP addresses from an interface, enter the no ip address * command.
device(config-if-e1000-1)# no ip address *
Syntax: [no] ip address ip-addr | *

Configuring 31-bit subnet masks on point-to-point networks

NOTE
31-bit subnet masks are supported on FSX, FCX, ICX 6450, ICX 6610, ICX 7250, ICX 7450, and ICX 7750 devices running
the full Layer 3 image.
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FastIron Ethernet Switch Layer 3 Routing
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