To enable seamless IP-layer handover of a mobile node (MN) from one
access router (AR) to another, the MN is required to discover the
identities and capabilities of candidate ARs (CARs) for handover prior
to the initiation of the handover. The act of discovery of CARs has
two aspects: identifying the IP addresses of the CARs and finding
their capabilities. This process is called "candidate access router
discovery" (CARD). At the time of IP-layer handover, the CAR, whose
capabilities are a good match to the preferences of the MN, is chosen
as the target AR for handover. The protocol described in this document
allows a mobile node to perform CARD. This memo defines an
Experimental Protocol for the Internet community.