Brocade Multi-Service IronWare Switching Configuration Guide (Supporting R05.6.00) - Manual (Page 765)

Multi-Service IronWare Switching Configuration Guide 735
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Configuring IP parameters
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Brocade (config-vlan-30)# router-interface ve 30
Brocade (config-vlan-30)# interface ve 30
Brocade (config-vif-30)# ip unnumbered loopback 1
Configure the DHCP server. In this example, the DHCP server address is 10.40.40.4.
Brocade (config-vif-30)# interface ethernet 1/2
Brocade (config-if-e1000-1/2)# ip address 10.40.40.1/24
Brocade (config-if-e1000-1/2)# dhcp-snooping-trust
Configure the DHCP server address in the unnumbered interfaces.
Brocade (config-if-e1000-1/2)# interface ve 20
Brocade (config-vif-20)# ip helper-address 10.40.40.4
Brocade (config-vif-20)# interface ve 30
Brocade (config-vif-30)# ip helper-address 10.40.40.4
Brocade (config-vif-30)# exit
Configure DHCP option 82 in the unnumbered interface VLANs.
Brocade (config)# ip dhcp-snooping vlan 20 to 30 insert-relay-information
Support for a 31-bit subnet mask on point-to-point networks
NOTE
The configuration of an IPv4 address with a 31-bit subnet mask is supported on Brocade MLX series,
Brocade NetIron XMR, and Brocade NetIron CER and Brocade NetIron CES devices.
In an effort to conserve IPv4 address space, a 31-bit subnet mask can be assigned to point-to-point
networks. Support for an IPv4 address with a 31-bit subnet mask is described in RFC 3021.
Previously, four IP addresses with a 30-bit subnet mask were allocated on point-to-point networks.
A 31-bit subnet mask uses only two IP addresses; all zero bits and all one bits in the host portion of
the IP address. The two IP addresses are interpreted as host addresses, and do not require
broadcast support because any packet that is transmitted by one host is always received by the
other host at the receiving end. Therefore, directed broadcast on a point-to-point interface is
eliminated. Also, a broadcast address with all one bits in the host portion of the IP address is not
allocated for point-to-point interface configuration.
NOTE
IP-directed broadcast CLI configuration at the global level, or the per- interface level, is not
applicable on interfaces configured with a 31-bit subnet mask IP address.
Configuring an IPv4 address with a 31-bit subnet mask
To configure an IPv4 address with a 31-bit subnet mask, enter the following commands.
NOTE
You can configure an IPv4 address with a 31-bit subnet mask on any interface (for example,
Ethernet, loopback, VE, or tunnel interfaces), and on all VRFs (default and non-default VRFs).
Brocade(config)# interface ethernet 1/5
Brocade(config-if-e1000-1/5)# ip address 10.9.9.9 255.255.255.254