IP R
OUTING

3-157

Web - Click IP, General, Routing Interface. Specify an IP interface for each
VLAN that will support routing to other subnets. First specify a primary
address, and click Set IP Configuration. If you need to assign secondary
addresses, enter these addresses one at a time, and click Set IP
Configuration after entering each address.
CLI - This example sets a primary IP address for VLAN 1, and then adds
a secondary IP address for a different subnet also attached to this router
interface.

Address Resolution Protocol

If IP routing is enabled (page 3-154), the router uses its routing tables to
make routing decisions, and uses Address Resolution Protocol (ARP) to
forward traffic from one hop to the next. ARP is used to map an IP
address to a physical layer (i.e., MAC) address. When an IP frame is
received by this router (or any standards- based router), it first looks up the
MAC address corresponding to the destination IP address in the ARP
cache. If the address is found, the router writes the MAC address into the
Console(config)#interface vlan 1
Console(config-if)#ip address 10.1.0.253 255.255.255.0 4-216
Console(config-if)#ip address 10.1.9.253 255.255.255.0 secondary
Console(config-if)#