ASIP: AS-Structured Internet Protocol (128-bit)

ASIP (AS-Structured Internet Protocol; IP version 8 on the wire) is a 128-bit network protocol that defines a new address family alongside IPv4. ASIP is NOT a wire-level superset of IPv4: an unmodified IPv4 device cannot send, receive, or forward an ASIP packet. Interoperation between ASIP-aware endpoints and legacy IPv4 networks is provided by a defined transition mechanism (stateless translation at AS boundaries and encapsulation across non-upgraded transit), not by wire compatibility. ASIP's addressing architecture arranges the 128-bit address as four 32-bit fields (ASN routing locator, zone, subnet, host). The ASN locator is used as a routing hint rather than a hard identity binding; multihoming, ASN transfer, and cross-ASN anycast remain possible through multi-address semantics defined in Sections 8, 11, and 14. This structure is intended to reduce operational friction during transition (familiar dotted-decimal notation, clean aggregation at the ASN boundary) rather than to achieve wire-level IPv4 compatibility. This document specifies the core protocol: address format, packet header, address classes, routing behavior, transition mechanisms, and security considerations. The Zone Server reference architecture (Section 16) is Informative and non-normative. The Cost Factor routing metric (Section 17) is OPTIONAL and is specified in a separate companion document (draft-asip-cf-00); Section 17 of this document is a one-paragraph forward reference. Interplanetary realm reservations (Section 3.12) are reserved allocations only; delay- tolerant transport is out of scope for this document. Operators MAY deploy ASIP addressing without any of the above. This specification extends the ASN-locator addressing model of [I-D.thain-ipv8] to a 128-bit four-field address format; see Section 1.3 for the relationship between the two proposals.