IETF News

IETF63 Review: Mobility and Wireless

By: Henri Wohlfarth


Date: September 7, 2005

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Work on mobility and wireless topics for IETF has traditionally been confined to the Mobile IP working group, but today wireless and mobile activities are spreading, especially in the Internet area. As of IETF 63, the working groups developing technology important for the wireless Internet consist of one working group in the Application Area (GEOPRIV), nine working groups in the Internet Area (6LOWPAN, DNA, EAP, HIP, MIP4, MIP6, MIPSHOP, NEMO, and PANA), one working group in the Operations and Management Area (CAPWAP), one working group in the Routing Area (MANET), and one working group in the Security Area (MOBIKE). There were also four BOFs on mobility-related topics at IETF 63:

  1. NETLMM – on standardizing a network-based, localized mobility management protocol
  2. AUTOCONF – on auto configuration for ad hoc networks
  3. ALIEN – on issues around privacy and anonymity of network identifiers, such as port numbers and IP addresses
  4. MONAMI – on dealing with multi-homed mobile hosts and routers and the associated per interface routing policies

Finally, the MOBOPTS IRTF Research Group – which reviews research on mobility related optimizations for Mobile IPv6 and recommends topics for standardization that have reached an appropriate level of maturity – typically meets at IETF meetings as well.

This is the first of what will hopefully be a regular column that focuses on mobility and wireless topics in the IETF. However, given the range of activities currently underway in the IETF, it is not possible in every column to provide a comprehensive summary of all the working groups and BOFs. Instead, each column will summarize the topic of BOFs and newly formed working groups, and take an in-depth look at the primary activities in one or two working groups dealing with wireless and mobile topics. In this issue, we’ll focus on one of the successors to the traditional Mobile IP working group, the MIP6 working group. Reader feedback on exactly how best to provide ongoing information about wireless and mobility related activity in the IETF is welcome.

The MIP6 working group has been chartered to work on a few topics related to implementation and deployment of Mobile IPv6, including updating the protocol specification. Foremost on the list is a way to bootstrap a mobile node having nontopological information (like a DNS domain name of a home mobility service provider) to the point where the mobile node has a home agent address, a home address, and an IPsec security association with a home agent. With this information, the mobile node can perform Mobile IPv6 Binding Update to register its care-of address and start getting traffic routed through the home address. At IETF 63, the design team reported back on their work in this area. The work applies primarily to cases where administrative entity authorizing the mobile node for mobility service and the administrative entity authorizing for network access service are two different entities, but is also applicable to cases where the two different services are authorized by the same entity, such as the typical cellular operator. The design team specified the use of DNS for locating a home agent address (with DHCP also applicable in some limited cases), and IKEv2-based home address configuration. The team also designed a way for the home agent to update the mobile node’s FQDN within the DNS server with the new home address, so that the mobile node is reachable by applications.

Another design team has been investigating transition issues related to Mobile IPv6. The transition scenarios addressed by the design team aim to ease the deployment of Mobile IPv6 and allow it to work independently of the access networks’ capability (i.e. IPv4 only or IPv6 only). The work will also allow mobile nodes using Mobile IPv6 to use IPv4 home addresses, which smoothes migration by allowing dual stacked hosts to use one mobility management protocol. Naturally, the design team also aims to make Mobile IPv6 work in networks using private IPv4 addresses and NATs.

An important consideration is to avoid having to run both MIP4 and MIP6 on the mobile node, since various considerations have shown that this is difficult and cumbersome to do. The mobile node is assumed to be dual stack.

Finally, the working group has also been discussing home agent reliability. The idea here is for a protocol to provide a way for home agents to communicate among themselves, and for a home agent or home agent cluster to communicate with mobile nodes, to allow failover if a home agent goes down either intentionally or inadvertently. A protocol for inter-home agent communication in an individual submission was discussed at IETF 63, as were a few protocols for home agent to mobile node communication. It wasn’t clear to the WG that there is a need for a standard protocol. Discussion will continue on the mailing list.

Note: This article does not attempt to provide a complete summary of all IETF activities in this area. It reflects a personal perspective on some current highlights.

Mobile IPv6 Working Group web page:
http://www.ietf.org/html.charters/mip6-charter.html

Mobile IPv6 Working Group Mailing List:
mip6@ietf.org

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