Reference Guide

IP Addressing 187
The following is a sample script to define IPv4 global parameters using CLI:
IPv4 Interface
You can assign IPv4 addresses to an interface in the following ways:
• Static Assignment
•DHCP Assignment
When the interface is configured as a DHCP client, it requests an IP
address from the DHCP server, until it receives an answer. It then sends
Address Resolution Protocol (ARP) packets to confirm the uniqueness of
the IP address. If the ARP response shows that the IP address is in use, the
switch sends a DHCPDECLINE message to the DHCP server, and sends
another DHCPDISCOVER packet that restarts the process.
When an IP address is assigned, it is checked for uniqueness in the following
way:
• A gratuitous ARP request is sent three times every three seconds.
• If after (3+1)*3 = 12 seconds the switch has not received the ARP
response, the IP address is considered to be unique.
• During the procedure the switch has to reply to gratuitous ARP and probe
ARP requests with the validated IP address.
The IP address is assigned even if the above validation procedure concludes
that the IP address in question is not unique, but a SYSLOG message is
generated.
In addition to the above validation procedure every time a switch receives an
ARP request with a sender IP address that is equal to its IP address defined on
the input interface it sends a SYSLOG message informing of IP duplication,
containing the sender IP and MAC addresses, from the received ARP
message.
To configure the default route, go to the IPv4 Routing Table page.
To assign an IP address to the OOB interface or an IPv4 Interface, and to
define subnets to which traffic can be routed:
Table 8-2. Sample CLI Script to Enable IPv4 Routing
CLI Command Description
console(config)#ip routing Enables IPv4 routing.