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 (iesg@ietf.org) 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.
