24 Brocade ICX 6650 Layer 3 Routing Configuration Guide
53-1002603-01
Configuring IP parameters – Layer 3 Switches
You can also enter the IP address and mask in the Classless Inter-domain Routing (CIDR) format, as
follows.
Brocade(config-if-e10000-1/1/5)# ip address 10.10.9.9/31
Syntax: [no] ip address ip-address ip-mask
Syntax: [no] ip address ip-address/subnet mask-bits
The ip-address variable specifies the host address. The ip-mask variable specifies the IP network
mask. The subnet mask-bits variable specifies the network prefix mask.
To disable configuration for an IPv4 address with a 31-bit subnet mask on any interface, use the no
form of the com mand.
You cannot configure a secondary IPv4 address with a 31-bit subnet mask on any interface. The
following error message is displayed when a secondary IPv4 address with a 31-bit subnet mask is
configured.
Error: Cannot assign /31 subnet address as secondary
Configuration example
Figure 2 shows the usage of 31- and 24-bit subnet masks in configuring IP addresses.
FIGURE 2 Configured 31- bit and 24-bit subnet masks
Router A is connected to Router B as a point-to-point link with 10.1.1.0/31 subnet. There are only
two available addresses in this subnet, 10.1.1.0 on Router A and 10.1.1.1 on Router B,
Routers B and C are connected by a regular 24-bit subnet. Router C can either be a switch with
many hosts belonging to the 10.2.2.2/24 subnet connected to it, or it can be a router.
Router A
RouterA(config)# interface ethernet 1/1/1
RouterA(config-if-e10000-1/1/1)# ip address 10.1.1.0/31
Router B
RouterB(config)# interface ethernet 1/1/1
RouterB(config-if-e10000-1/1/1)# ip address 10.1.1.1/31
RouterB(config-if-e10000-1/1/1)# exit
RouterB(config# interface ethernet 1/3/1
RouterB(config-if-e10000-1/3/1)# ip address 10.2.2.1/24
Router C
RouterC(config# interface ethernet 1/3/1
RouterC(config-if-e10000-1/3/1)# ip address 10.2.2.2/24

ABC

Router
10.1.1.0/31
10.1.1.1/31
10.2.2.1/24
10.2.2.2/24 Router