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Mobility for IPv4 (mip4) (WG)

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In addition to this official charter maintained by the IETF Secretariat, there is additional information about this working group on the Web at:
Additional MIP4 Web Page

Additional information is available at


Internet Area Director(s):

Internet Area Advisor:

Meeting Slides


Request for Comments:

Charter (as of 2009-08-18)

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

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

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

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:

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