Mobility for IPv4 (mip4)

Last modified: 2015-08-27

Additional information is available at Additional MIP4 Web Page


Internet Area Director

Mailing Lists:

General Discussion:
To Subscribe:

Description of Working Group:

IP mobility support for IPv4 nodes (hosts and routers) is specified in RFC3344. RFC 3344 mobility allows a node to continue using its "permanent" home address as it moves around the Internet. The Mobile IP protocols support transparency above the IP layer, including maintenance of active TCP connections and UDP port bindings. Besides the basic Mobile IPv4 (MIPv4) protocols, several other drafts deal with concerns such as optimization, security, extensions, AAA support, and deployment issues.

MIPv4 is currently being deployed on a wide basis (e.g., in cdma2000 networks). The scope of the deployment is on a fairly large scale and accordingly, the MIP4 WG will focus on deployment issues and on addressing known deficiencies and shortcomings in the protocol that have come up as a result of deployment experience. Specifically, the working group will complete the work items to facilitate interactions with AAA environments, interactions with enterprise environments when MIPv4 is used therein, and updating existing protocol specifications in accordance with deployment needs and advancing those protocols that are on the standards track.

Work expected to be done by the MIP4 WG as proposed by this charter is as follows:

1. MIPv4 has been a Proposed Standard for several years. It has been adopted by other standard development organizations and has been deployed commercially. One of the next steps for the WG is to advance the protocol to draft standard status. As part of advancing base Mobile IP specifications to Draft Standard, the MIPv4 NAI RFC (2794) will be revised to reflect implementation experience.

2. The WG will complete the MIB specifications for the Mobile IPv4 base protocol and the UDP tunneling extension.

3. A requirements document for RADIUS MIP4 support was previously completed and published as RFC 5030. Based on these requirements, the WG will complete the specification of MIPv4 RADIUS attributes, solicit feedback from the RADEXT WG, adjust, and submit this for publication. Note that the work may require extensions to the RADIUS attribute space which will be handled outside the MIP4 WG.

4. Like fixed nodes, mobile nodes sometimes need to be dynamically configured with parameters such as DNS server IP addresses. Previous work in the WG proposed to put a generic container for host configuration options into Mobile IPv4 signaling. However, it may be easier for mobile nodes to implement the already existing DHCP specification, and to run DHCP over the tunnel established with an initial registration. The WG will take on a draft describing any modifications to Mobile IPv4 that may be needed to facilitate this mode of operation, and submit for publication as a Proposed Standard or Best Current Practice as appropriate.

5. The proliferation of devices with multiple interface technologies and the desire to use each interface for the type of traffic most appropriate to it (even simultaneously with other interfaces active at the same time) has led to requirements for supporting multiple simultaneous tunnels between the Home Agent and Mobile Node. The WG will adopt and take to publication as an Experimental RFC one draft that describes how to manage such tunnels and how to direct traffic to use the appropriate tunnel when multiple choices are available. This work will be coordinated with similar Mobile IPv6 work ongoing in the mext working group. In particular, we will strive to converge on a consistent set of architectural decisions (such as which entities are responsible for signaling flow-to-tunnel bindings) and we will share protocol definitions wherever practical (such as the layout of packet flow filters).

6. The WG has published a basic Network Mobility (NEMO) specification as RFC 5177. The WG has taken up an extension to NEMO that will allow for dynamic home network prefix allocation to a moving network. The WG will finish work on this draft and publish as a Proposed Standard.

7. Route optimization has been the focus of a large amount of effort in the Mobile IPv6 WG. For Mobile IPv4, however, the usage case is less clear due to a variety of factors, including the inability to modify already deployed correspondent nodes. Recently a specific use case has been proposed involving route optimization for a more closed network where modifications are made to site routers and a centralized Home Agent to enable offloading of traffic from the Home Agent. The WG will take on and publish a draft on this topic as a Experimental RFC.

8. The use of GRE tunneling with Mobile IPv4 enables support for multiple overlapping private address spaces within the same mobility agent. However, to distinguish flows from two different mobile nodes that happen to share the same (private) IP address, the GRE Key field needs to be populated with a unique identifier that will enable the mobility agent to demultiplex the flows. The value used for the Key needs to be signaled at the time of tunnel establishment, which means a new Mobile IPv4 extension is needed for this purpose. The WG will take on an publish a draft on this topic as a Proposed Standard.

9. Support for multicast and broadcast packets in Mobile IPv4 as specified in RFC 3024 currently requires encapsulated delivery style for all packets. This leads to inefficiencies on the MN-to-FA link because even unicast packets must be encapsulated. Eliminating this inefficiency is possible if there is a mechanism to negotiate a mode of operation where only multicast/broadcast packets are encapsulated, while unicast packets can use direct delivery style. The WG will take on a draft to solve this problem and publish as a Proposed Standard.

Goals and Milestones

May 2010 Multiple tunnel support and flow binding (Experimental) to IESG
Apr 2010 Multiple/Broadcast delivery style (Proposed Std.) to IESG
Mar 2010 Home Agent Assisted Route Optimization (Experimental) to the IESG
Feb 2010 RADIUS Extensions for MIPv4 (Proposed Std.) to the IESG
Dec 2009 MIB for UDP encapsulation (Proposed Std.) to IESG
Nov 2009 RADIUS Extensions for MIPv4 to the RADEXT WG for comment
Nov 2009 Revised rfc2794bis (NAI extension) (Proposed Std.) to the IESG
Nov 2009 GRE Key Extension (Proposed Std) to IESG
Aug 2009 NEMO Dynamic Address Assignment (Proposed Std.) to IESG
Jul 2009 Revised MIB for MIPv4 (Proposed Std.) to IESG
Jul 2009 Revised MIPv4 specification (Proposed Std.) to IESG
Done Notification Mechanism (Draft Std.) to IESG
Done Dual-stack MIPv4 (Draft Std.) to IESG
Done Base MIPv4 Mobile Network Support (Draft Std.) to IESG
Done MIPv4 VPN interaction (BCP) to the IESG
Done FMIPv4 (Experimental) to the IESG
Done MIPv4 Extension for Config. Options (Proposed Std.) to the IESG
Done MIPv4 RADIUS Extensions Requirements to the IESG
Done MIPv4 Mobike interaction (BCP) to the IESG
Done Generic Strings for MIPv4 (Proposed Std.) to the IESG
Done Regional registration document to IESG
Done Revised MIPv4 Challenge/Response (3012bis) to IESG
Done Dynamic Home Agent assignment protocol solution to IESG
Done Experimental MIPv4 message and extensions draft to IESG
Done Low latency handover to experimental
Done MIPv4 VPN interaction problem statement to IESG
Done AAA Keys for MIPv4 to IESG

No Internet-Drafts

Request for Comments


Internet SocietyAMSHome - Tools Team - Datatracker - IASA - IAB - RFC Editor - IANA - IRTF - IETF Trust - ISOC - IETF Journal - Store - Contact Us
Secretariat services provided by Association Management Solutions, LLC (AMS).
Please send problem reports to: