Configuring IP Addressing
Configuring Address Resolution Methods
IPC-15
Cisco IOS IP Configuration Guide

Configuring Local-Area Mobility

Local-area mobility provides the ability to relocate IP hosts within a limited area without reassigning
host IP addresses and without changes to the host software. Local-area mobility is supported on Ethernet,
Token Ring, and FDDI interfaces only.
To create a mobility area with only one router, use the following commands in the interface configuration
mode:
To create larger mobility areas, you must first redistribute the mobile routes into your Interior Gateway
Protocol (IGP). The IGP must support host routes. You can use Enhanced Interior Gateway Routing
Protocol (IGRP), Open Shortest Path First (OSPF), IS-IS, or RIPv2. To redistribute the mobile routes
into your existing IGP configuration, use the following commands in configuration mode:
Mobile routes will always be preferred over a subnet boundary or summarized route because they are
more specific. It is important to ensure that configured or redistributed static routes do not include any
host routes for the potentially mobile hosts; otherwise, a longest match could come up with two routes
and cause ambiguity. Mobile routes will be seen as external routes to the configured routing protocol,
even within a summarization area; therefore, they will not be properly summarized by default. This is
the case even when these routes are advertised at a summarization boundary, if mobile hosts are not on
their home subnet.
Mapping Host Names to IP Addresses
Each unique IP address can have an associated host name. The Cisco IOS software maintains a cache of
host name-to-address mappings for use by the connect, telnet, and ping EXEC commands, and related
Telnet support operations. This cache speeds the process of converting names to addresses.
IP defines a naming scheme that allows a device to be identified by its location in the IP. This is a
hierarchical naming scheme that provides for domains. Domain names are pieced together with periods
(.) as the delimiting characters. For example, Cisco is a commercial organization that the IP identifies
by a com domain name, so its domain name is cisco.com. A specific device in this domain, the File
Transfer Protocol (FTP) system, for example, is identified as ftp.cisco.com.
Command Purpose
Step1 Router(config-if)# interface type number Enters interface configuration mode.
Step2 Router(config-if)# ip mobile arp [timers keepalive
hold-time] [access-group access-list-number | name]
Enables local-area mobility.
Command Purpose
Step1 Router(config)# router {eigrp autonomous-system |
isis [tag] | ospf process-id | rip}
Enters router configuration mode.
Step2 Router(config)# default-metric number
or
Router(config)# default-metric bandwidth delay
reliability loading mtu
Sets default metric values.
Step3 Router(config)# redistribute mobile Redistributes the mobile routes.