HP-UX Mobile IPv4 A.02.
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Contents The Mobile Internet .................................................................. 1 Mobilty for Internet Protocol (IPv4)...................................... 2 How Mobile IP Works .................................................................... 2 Roles ............................................................................................... 2 The Role of the Mobile Node ..................................................... 2 The Role of the Foreign Agent ...........................
THE MOBILE INTERNET 1 The increasing popularity of mobile devices, such as PDAs, handhelds, and digital cellular phones, is beginning to change our perceptions of the Internet. A need has been generated to allow users to attach to any domain convenient to their current location. Confident access to the Internet anytime and anywhere will help free users from the ties that bind them to their desktops.
MOBILTY FOR INTERNET PROTOCOL (IPv4) Mobile nodes were not considered when the Internet Protocol (IPv4) was designed. Then and now, a node's IP address, which indicates its point of attachment to the Internet, is assumed to remain unchanged for the duration of a session.
How a Mobile Node Receives Packets When the Mobile Node is not attached to its home network, the Home Agent receives all packets destined for the Mobile Node's home address. The Home Agent encapsulates the original IP packet and directs it to the Mobile Node's Care-of Address. When the packet arrives at the Care-of Address, the original IP packet is extracted and delivered to the Mobile Node. This encapsulation is also called tunneling.
Agent Advertisements Home Agents and Foreign Agents, at regular intervals (every few seconds), broadcast on their subnet, messages known as Agent Advertisements. The Agent Advertisement is designed as an extension of the already existing ICMP router advertisement [RFC 1256] message. The agent advertisement conveys the following information: o Whether the agent is a Home Agent or a Foreign Agent. o A list of available Care-of Addresses (in case of the Foreign Agents).
Location Updates - Registering the COA When a Mobile Node attaches to a new foreign network, it sends a Registration Request to its Home Agent to register its Care-of Address. If the Mobile Node is using a Foreign Agent Care-of Address, the Registration Request is sent via the Foreign Agent. The Registration Request includes an extension with a cryptographic authentication value (HMAC-MD5 or keyed MD5).
HP-UX MOBILE IPv4 HP-UX Mobile IPv4 runs on HP-UX 11i and provides mobility support for mobile devices as they roam about from one network to another on the Internet. Version A.02.01 is designed for a wide-ranging commercial deployment of Mobile IP that requires AAA (Authentication, Authorization, and Accounting) services and support. Product Features The following are the salient features of the HP-UX Mobile IPv4 product.
Reverse tunneling is useful for installations with ingress filtering (filters that check inbound packets for topologically correct source addresses). With reverse tunneling, the packet leaving the foreign network will have a topologically correct source address, because the source address in the outermost IP header will be an address from the foreign network (the Care-of Address) instead of the Mobile Node’s home address.
AAA SUPPORT In a Mobile IPv4 environment, remote nodes and users may visit networks outside their home domain. Administrators in the networks being visited may want to use AAA (Authentication, Authorization, and Accounting) to restrict or grant access to local resources. HP-UX Mobile IPv4 is designed for wide-ranging commercial deployment of Mobile IP that requires AAA services and support.
Fig 1-2. Mobile Node Authentication 9 1. Mobile Node sends a registration request message to the Foreign Agent. 2. The Foreign Agent sends a Diameter AA-Mobile Node Request (AMR) message to the local AAA Server (AAAF) that includes the Mobile IP registration request in it. 3. The AAAF forwards the AMR message to the AAA Server (AAAH) in the home network. 4. The AAAH builds a Diameter Home Agent MIP Request (HAR) message from the information in the AMR and forwards it to the Home Agent.
Dynamic Key Generation and Distribution The Diameter Mobile IPv4 protocol allows for the FA to request the AAAH server to generate dynamic keys for authenticating messages between the following entities: o Mobile Node and Home Agent o Mobile Node and Foreign Agent o Home Agent and Foreign Agent Use of dynamically generated keys increases packet security. Using different keys makes it more difficult for someone examining network packets to determine a key’s value.
REFERENCES 11 Mobile IP technology is built around drafts and specifications proposed by IETF.
FOR MORE INFORMATION HP-UX Mobile IPv4 White Paper Visit Mobile IPv4 documentation on docs.hp.com for more information.
