Network-Based Mobility Extensions (netext)

Last modified: 2016-05-11


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Charter for Working Group:

Proxy Mobile IPv6, specified in RFC 5213, is a network-based mobility protocol. It uses a Mobile Access Gateway (MAG) and a Local Mobility Anchor (LMA) to allow hosts to move around within a domain while keeping their address or address prefix stable. Proxy Mobile IPv6 has been incorporated into a number of products and deployments are starting. Certain deployment considerations, including localized routing and bulk refresh of lifetime are already emerging.

The working group will focus on the following topics relevant for network-based mobility:

Localized Routing: a specification for routing traffic between the MAG(s) without involving the LMA. That is, allow the MAGs to route traffic between hosts from one MAG to another, without being tunneled all the way to the LMA. This reduces latency and backhaul load. Applications such as voice can benefit from the reduced latency. The working group will produce a problem statement and a specification of the localized routing mechanism.

Bulk Refresh: a specification of improving the signaling load for binding lifetime refresh. The current specifications call for the handling of each mobility session independent of each other. When a large number of hosts are served by a single MAG, a periodic refresh of the binding lifetimes can lead to a signaling storm. The purpose of the Bulk Refresh feature is to construct a protocol feature that allows such refreshes to occur on a per-MAG basis.

LMA Redirection: a specification for allowing an LMA to redirect a MAG to another LMA. This is primarily needed as a way to perform load balancing. This functionality is complementary to implementation techniques that allow distributed MAG implementations to move tasks around without a visible impact at the protocol level, and the initial LMA discovery work in the NETLMM WG. An applicability statement describing the situations where the new functionality is or is not applicable has to be included in the specification.

Hiding access technology changes from host IP layer: Proxy mobility is based on the assumption that changes in host IP stacks are undesirable. However, link layer implementations can hide the actually used physical interfaces from the IP stack. For instance, a "logical interface" at the IP layer may enable packet transmission and reception over different physical media. Such techniques can be used to achieve inter-access handovers or flow mobility, i.e., the movement of selected flows from one access technology to another. It is assumed that an IP layer interface can simultaneously and/or sequentially attach to multiple MAGs (possibly over multiple media). The hiding mechanisms also need to work together with existing RFC 5213 handover hint mechanisms. The specification of any actual link layer mechanisms is outside the scope of the working group, but the group works on the following:

- Informational applicability statement that analyzes the issues involved with this approach and characterizes the contexts in which such use is or is not appropriate.

- The working group will determine what protocol extensions are required between the Proxy Mobile IPv6 network nodes (MAGs and LMAs) to support the ability for an interface (at the IP layer) to transmit packets over different media, the ability to distribute specific traffic flows on different media components of that interface, and making this work with the handover hints in the base protocol. The relevant protocol extensions will be developed as necessary.

Radius Extensions to PMIP6: In order to enable network based mobility using PMIP6, the policy profile needs to signal a set of attributes and policies to the MAG and LMA. New Radius attributes need to be specified that are relevant to PMIP6 based mobility. This work item will specify Radius extensions and attributes specific to PMIP6.

The work in this charter is entirely internal to the network and does not affect host IP stack operation in any way (except perhaps through impacting packet forwarding capacity visible to the hosts). The working group is not allowed to specify new IP layer protocol mechanisms to signal mobility related events between the host and the network.

The proposed activity will be complementary to the existing IETF Working Groups, notably the NETLMM and MEXT WGs. The NETEXT working group will also act as the primary forum where new extensions on top of the Proxy Mobile IPv6 protocol can be developed. The addition of such new extensions to the working group involves addition of the extension to this charter through the normal rechartering process.


May 2013 Submit EAP Attributes for WiFi - EPC Integration to IESG for publication as a proposed standard
Apr 2013 Submit Logical Interface Support for multi-mode IP Hosts for publication as an Informational document
Mar 2013 Submit Service Selection for MIP6 and PMIP6 to the IESG for publication as a proposed standard
Feb 2013 Submit Proxy Mobile IPv6 Extensions to Support Flow Mobility to IESG for publication as a proposed standard
Nov 2012 Submit IPv4 Traffic Offload Selector Option for Proxy Mobile IPv6 to IESG for publication as a proposed
Oct 2012 Submit Prefix Delegation for Proxy Mobile IPv6 to IESG for publication as a proposed standard
Apr 2012 Initial WG document on EAP Attributes for WiFi - EPC Integration
Apr 2012 Initial WG document on Service Selection for MIP6 and PMIP6
Done Submit Access Network Identifier (ANI) Option for PMIP6 to IESG for publication as a proposed standard
Done Initial WG draft on Localized Routing Solution
Done Submit Localized Routing Problem Statement to IESG for publication as an Informational RFC
Done Initial WG document on RADIUS extensions to PMIP6
Done Submit LMA Redirection to IESG for publication as a Proposed Standard RFC
Done Submit Bulk Refresh to IESG for publication as a Proposed Standard RFC
Done Initial WG draft on Localized Routing Problem Statement
Done Initial WG draft on LMA Redirection
Done Decision on the inclusion of possible additional work items
Done Initial WG draft on Bulk Refresh
Done WG chartered

Request for Comments


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