Subject: WG Review: Detecting Network Attachment (dna)

From: The IESG <[email-masked]>
Date: Wed, 28 Jan 2004 11:48:40 -0500

A new IETF working group has been proposed in the Internet Area.  The IESG has not made
any determination as yet.  The following description was submitted, and is provided 
for informational purposes only.  Please send your comments to the IESG mailing list 
([email-masked]) by February 4th.

 Detecting Network Attachment (dna)
 ----------------------------------

 Current Status: Proposed Working Group

 Description:

 When an IP node detects or suspects that its
 underlying link layer (L2) connectivity has or may
 have undergone a change, it needs to check whether
 its IP layer (L3) configuration and connectivity are
 still valid or have changed. In the case that the L3
 connectivity has changed, the node needs to
 reconfigure and may need to initiate mobility
 procedures, such as sending Mobile IP binding
 updates. Changes in an L2 connection do not
 necessarily mean that there has been change in L3
 connectivity.

 For the purposes of detecting network attachment, an
 L3 link is defined by the range within which IP
 packets may be sent without resorting to forwarding.
 In other words, a link is the range where a given IP
 configuration is valid.

 In IPv6, the IP layer configuration information
 includes the set of valid unicast addresses[RFC2462,
 RFC3315], the DAD status of the addresses[RFC2462],
 valid routing prefixes[RFC2461], set of default
 routers[RFC2461], neighbor and destination
 caches[RFC2461], multicast listener (MLD)
 state[RFC2710]. The current IPv6 stateless and
 stateful autoconfiguration procedures may take a
 fairly long time due to delays associated with Router
 Discovery and Duplicate Address Detection processes.

 In some wireless technologies, the link layer state
 and events may not be accurate and unambiguous from
 the IP point of view. For example, a host may be able
 to see a base station but still be unable to deliver
 or receive IP packets within the link. Similarily, a
 hardware indication that a radio link is up does not
 necessarily mean that all link layer configuration,
 such as authentication or virtual LAN connectivity
 has been completed.

 The purpose of the DNA working group is to define
 standards track and BCP documents that allow hosts to
 detect their IP layer configuration and connectivity
 status quickly, proposing some optimization to the
 current specifications that would allow a host to
 reconfigure its IPv6 layer faster than today.

 Initiation of link change detection procedures can be
 achieved either through reception of messages at the
 IP layer or through indications from other layers.
 The working group will produce a document that
 contains a catalogue of the indications available
 from a number of link layer technologies.

 The working group will produce a document explaining
 how a node can make best use of the existing L2 and
 L3 information for detecting network attachment.

 The working group will define a set extensions to the
 current IPv6 configuration protocols [RFC2461, 2462,
 possibly RFC3315] that allow the nodes to discover
 whether L3 configuration or connectivity may have
 changed more reliably and easily than today.

 The DNA WG will not define new procedures or APIs
 related to link layers.