 - In Internet routing, a care-of address is a temporary IP address for a mobile node (mobile device) that enables message delivery when the device is connecting from somewhere other than its home network. The care-of address identifies a mobile node's current point of attachment to the Internet and makes it possible to connect from a different location without changing the device's home address (permanent IP address). This works similarly to the way the postal system might forward letters through a care-of address: messages sent to the known permanent address are rerouted to the care-of address while the recipient can be reached there. Thus, the recipient avoids having to change their official address to the temporary one when they change their location, and change it back again when they return home.
When a mobile device is away from its home network, it is assigned a care-of address. This may be a foreign agent care-of address, which is the static IP address of a foreign agent on a visited network, or a colocated care-of address, which is a temporary IP address assigned to the mobile node. A colocated care-of address may be acquired through some means such as Dynamic Host Configuration Protocol (DHCP), or may be a longer-term address assigned a device for connecting through a specific foreign network. Mobile IP, as defined in the Internet Engineering Task Force (IETF) RFC 2002 specifications, registers the care-of address with a home agent, which resides on the home network. When a message for the mobile node is delivered to the home network, the home agent intercepts the message and tunnels it to the recipient at the care-of address.
 |
Learn more about IP Networking |
| How to subnet: Subnetting calculations and shortcuts: Learn how subnetting works in this tip and quiz on how to calculate a subnet mask. IP address classes and bit values of octets are explained in detail. |
| IP addressing and subnetting explained: Our IP addressing and subnetting crash course provides an overview of IP addressing-related topics, including IPv4 and IPv6, subnetting, DHCP, and calculating subnet masks. |
| Troubleshooting IP Routing -- 'CCNA Official Exam Certification Library, 3rd Edition,' Chapter 7: Learn how to troubleshoot IP routing in preparation for the Cisco CCNA exam in this chapter from 'CCNA Official Exam Certification Library, 3rd Edition.' |
| IP address management -- from 'Network troubleshooting and diagnostics': Learn how IP address management and maintenance tools can help manage the scope of IP addresses on your network. |
| IP Accounting -- from Network Management: Accounting and Performance Strategies: IP Accounting, Chapter 6 of Network Management: Accounting and Performance Strategies, describes the IP Accounting features and functions in Cisco IOS, and SNMP MIB. |
| Basic IP Connectivity and CEF Troubleshooting -- Chapter 4 of "Cisco Express Forwarding": This chapter presents the general troubleshooting used on Cisco IOS routers and switches as a first step in troubleshooting IP connectivity problems. |
| LAST UPDATED: |
28 Jun 2003
|
 |
Do you have something to add to this definition? Let us know.
Send your comments to techterms@whatis.com
|
|
More resources from around the web:
|
 |
 |
| |
RELATED GLOSSARY TERMS
| Terms from Whatis.com − the technology online dictionary |
 |
32-bit IP addressing
(SearchNetworking.com)
32-bit IP addressing is the IP address scheme used in Internet Protocol 4 (IPv6 uses a 128-bit system)... (Continued)
|
|
fixed-length subnet mask
(SearchNetworking.com)
A fixed-length subnet mask (FLSM) is a sequence of numbers of unchanging length that streamlines packet routing within the subnets of a proprietary...
|
|
|
Show me everything on 