Design document for Detecting Network Attachment in IPv6 Networks (DNAv6 Design)
Efficient detection of network attachment in IPv6 needs the following three components: a method for hosts to detect link change in the presence of unmodified (non-DNAv6) routers, a method for the host to query routers on the link to identify the link (Link Identification) and a method for the routers on the link to consistently respond to such a query with minimal delay (Fast RA). Solving the link identification based strictly on RFC 2461 is difficult because of the flexibility offered to routers in terms of prefixes advertised in a router advertisement (RA) message. Similarly, the random delay in responding to router solicitation messages imposed by RFC 2461 makes it difficult to receive an RA quickly. In this memo, a mechanism that was developed for detection of network attachement is documented for future reference. This memo is an informational document and thus does not define a new standard. The mechanism proposed in this informational RFC requires the hosts to monitor all the prefixes advertised on the link and use it for link identification in the presence of non-DNAv6 routers is presented. A more efficient link- identification mechanism requiring the DNAv6 routers to monitor the link for advertised prefixes to assist the hosts in link identification combined with a fast router advertisement mechanism that selects the order of response for the router deterministically is also presented.