IANA-Reserved IPv4 Prefix for Shared Address Space

This document requests the allocation of an IPv4 /10 address block to be used as Shared Address Space to accommodate the needs of Carrier-Grade NAT (CGN) devices. It is anticipated that Service Providers will use this Shared Address Space to number the interfaces that connect CGN devices to Customer Premises Equipment (CPE). Shared Address Space is distinct from RFC 1918 private address space because it is intended for use on Service Provider networks. However, it may be used in a manner similar to RFC 1918 private address space on routing equipment that is able to do address translation across router interfaces when the addresses are identical on two different interfaces. Details are provided in the text of this document. Information about the current status of this document, any errata, and how to provide feedback on it may be obtained at A number of operators have expressed a need for the special-purpose IPv4 address allocation described by this document. During deliberations, the IETF community demonstrated very rough consensus in favor of the allocation. While operational expedients, including the special-purpose address allocation described in this document, may help solve a short-term operational problem, the IESG and the IETF remain committed to the deployment of IPv6. in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License.