Multiple Interfaces (mif) ------------------------- Charter Last Modified: 2009-04-27 Current Status: Active Working Group Chair(s): Margaret Wasserman Hui Deng Internet Area Director(s): Ralph Droms Jari Arkko Internet Area Advisor: Jari Arkko Mailing Lists: General Discussion:mif@ietf.org To Subscribe: https://www.ietf.org/mailman/listinfo/mif Archive: http://www.ietf.org/mail-archive/web/mif Description of Working Group: Many hosts have the ability to attach to multiple networks simultaneously. This can happen over multiple physical network interfaces, a combination of physical and virtual interfaces (VPNs or tunnels), or even indirectly through multiple default routers being on the same link. For instance, current laptops and smartphones typically have multiple access network interfaces. A host attached to multiple networks has to make decisions about default router selection, address selection, DNS server selection, choice of interface for packet transmission, and the treatment of configuration information received from the various networks. Some configuration objects are global to the node, some are local to the interface, and some are related to a particular prefix. Various issues arise when contradictory configuration objects that are global to the node are received on different interfaces. At best, decisions about these matters have an efficiency effect. At worst, they have more significant effects such as security impacts, or even lead to communication not being possible at all. A number of operating systems have implemented various techniques to deal with attachments to multiple networks. Some devices employ only one interface at a time and some allow per-host configuration of preferences between the interfaces but still use just one at a time. Other systems allow per-application preferences or implement sophisticated policy managers that can be configured by users or controlled externally. The purpose of the MIF working group is to describe the issues of attaching to multiple networks on hosts and document existing practice. The group shall also analyze the impacts and effectiveness of these existing mechanisms. The WG shall employ and refer to existing IETF work in this area, including, for instance, strong/weak models (RFC 1122), address selection (RFC 3484), ICE and other mechanisms higher layers can use for address selection, DHCP mechanisms, Router Advertisement mechanisms, and DNS recommendations. The focus of the working group should be on documenting the system level effects to host IP stacks and identification of gaps between the existing IETF recommendations and existing practice. The working group shall address both IPv4 and IPv6 as well as stateless and stateful configuration. Network discovery and selection on lower layers as defined by RFC 5113 is out of scope. Also, the group shall not develop new protocol or policy mechanisms; recommendations and gap analysis from the group are solely based on existing solutions. The group shall not assume any software beyond basic IP protocol support on its peers or in network nodes. No work will be done to enable traffic flows to move from one interface to another. The group recognizes existing work on mechanisms that require peer or network support for moving traffic flows such as RFC 5206, RFC 4980 and the use of multiple care-of addresses in Mobile IPv6. This group does not work on or impact such mechanisms. Once the group has completed its work items, the IETF can make an informed decision about rechartering the working group to define new mechanisms or asking other, specialized working groups (such as DHC or 6MAN) to deal with specific issues. Goals and Milestones: May 2009 WG chartered Jul 2009 Initial draft on problem statement adopted by the WG Sep 2009 Initial draft on existing practices adopted by the WG Dec 2009 Initial draft on analysis of existing practices adopted by the WG Mar 2010 Problem statement draft submitted to the IESG for publication as an Informational RFC Jul 2010 Existing practices draft submitted to the IESG for publication as an Informational RFC Sep 2010 Analysis draft submitted to the IESG for publication as an Informational RFC Oct 2010 Recharter or close Internet-Drafts: Posted Revised I-D Title ------ ------- -------------------------------------------- Oct 2009 Oct 2009 Multiple Interfaces Problem Statement Request For Comments: None to date.