I – An Extension of format for IPv6 Scoped Addresses: Draft-ietf-ipngwg-scopedaddr-format-02.txt

Publisher Summary This chapter defines an extension of the format for IPv6 scoped addresses. In the format, a zone identifier is attached to a scoped address to supplement ambiguity of the semantics of the address. Using the format with some library routines will make scope-aware applications simpler. There are several types of scoped addresses defined in the “IPv6 Addressing Architecture” [ADDRARCH]. Because uniqueness of a scoped address is guaranteed only within a corresponding zone [SCOPEARCH], the semantics for a scoped address is ambiguous on a zone boundary. For example, when a user specifies to send a packet from a node to a link-local address of another node, the user must specify the link of the destination as well, if the node is attached to more than one link. This characteristic of scoped addresses may introduce additional cost to scope-aware applications; a scope-aware application may have to provide a way to specify a scope zone for each scoped address (e.g., a specific link for a link-local address) that the application uses. Also, it is hard for a user to “cut and paste” a scoped address because of the ambiguity of its scope.