[mif] Updated charter

[Hui Deng <[e-mail]>]

Hello all,

We will not make big change this time, basically DHCP and DNS items will be
removed, only architecture work item will be added, thanks for your comment,

Best regards,

-Hui

Charter for 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. After completing some of its initial goals in 2010 the
 group is also developing three specific extensions:
 1) Handling sets of network configuration objects by nodes, attached to
 multiple networks: a solution could include a set of requirements for
 changes to protocols used to provide configuration information. For
 example:
 - requirements for DHCPv6 options, Neighbor Discovery options etc. to
   communicate association of the objects with particular
   provisioning domains
 - best practices for nodes how to group the configuration objects
   into sets and use them for network connectivity
 - APIs to expose the sets to the applications which require that
   information
 2) MIF API: While no changes are required for applications to run on
 multiple interface hosts, a new API could provide additional services
 to applications running on hosts attached to multiple provisioning
 domains. For instance, these services could assist advanced
 applications in having greater control over first-hop, source address
 and/or DNS selection, interface selection, and PVD selection issues.
 This API will be defined as an abstract interface specification,
 i.e., specific details about mapping to operating system primitives
 or programming language will be left out.

 Network discovery and selection on lower layers as defined by RFC 5113
 is out of scope. With the exception of support for additional DHCP
 options in DHCP servers, 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.
 Future work in this area requires rechartering the working group or
 asking other, specialized working groups (such as DHC or 6MAN) to deal
 with specific issues.




Nov 2013
Architecture draft adopted as the working group document



Dec 2013
Working group last call for MIF API document