IPv4

This document provides guidelines and documents best current practice for operating authoritative DNS servers, recursive resolvers, and stub resolvers in a mixed IPv4/IPv6 environment. This document recommends that both authoritative DNS servers and recursive resolvers support IPv4 and IPv6. It also provides guidance on how recursive DNS resolvers should select upstream DNS servers, including when IPv4-embedded IPv6 addresses are available.

This document obsoletes RFC 3901.

This document defines version 3 of the Virtual Router Redundancy Protocol (VRRP) for IPv4 and IPv6. It obsoletes RFC 5798, which previously specified VRRP (version 3). RFC 5798 obsoleted RFC 3768, which specified VRRP (version 2) for IPv4. VRRP specifies an election protocol that dynamically assigns responsibility for a Virtual Router to one of the VRRP Routers on a LAN. The VRRP Router controlling the IPv4 or IPv6 address(es) associated with a Virtual Router is called the Active Router, and it forwards packets routed to these IPv4 or IPv6 addresses. Active Routers are configured with virtual IPv4 or IPv6 addresses, and Backup Routers infer the address family of the virtual addresses being advertised based on the IP protocol version. Within a VRRP Router, the Virtual Routers in each of the IPv4 and IPv6 address families are independent of one another and always treated as separate Virtual Router instances. The election process provides dynamic failover in the forwarding responsibility should the Active Router become unavailable. For IPv4, the advantage gained from using VRRP is a higher-availability default path without requiring configuration of dynamic routing or router discovery protocols on every end-host. For IPv6, the advantage gained from using VRRP for IPv6 is a quicker switchover to Backup Routers than can be obtained with standard IPv6 Neighbor Discovery mechanisms.

Several IPv6 transition technologies have been developed to provide customers with IPv4-as-a-Service (IPv4aaS) for ISPs with an IPv6-only access and/or core network. These technologies have their advantages and disadvantages. Depending on existing topology, skills, strategy, and other preferences, one of these technologies may be the most appropriate solution for a network operator.

This document examines the five most prominent IPv4aaS technologies and considers a number of different aspects to provide network operators with an easy-to-use reference to assist in selecting the technology that best suits their needs.

This document defines an extension to the Babel routing protocol that allows announcing routes to an IPv4 prefix with an IPv6 next hop, which makes it possible for IPv4 traffic to flow through interfaces that have not been assigned an IPv4 address.

This document specifies a method to find which Registration Data Access Protocol (RDAP) server is authoritative to answer queries for a requested scope, such as domain names, IP addresses, or Autonomous System numbers. This document obsoletes RFC 7484.

This specification defines two Concise Binary Object Representation (CBOR) tags for use with IPv6 and IPv4 addresses and prefixes.

This document specifies new Internet Key Exchange Protocol Version 2 (IKEv2) notification status types to better manage IPv4 and IPv6 coexistence by allowing the responder to signal to the initiator which address families are allowed.

This document updates RFC 7296.

Multiprotocol BGP (MP-BGP) specifies that the set of usable next-hop address families is determined by the Address Family Identifier (AFI) and the Subsequent Address Family Identifier (SAFI). The AFI/SAFI definitions for the IPv4 address family only have provisions for advertising a next-hop address that belongs to the IPv4 protocol when advertising IPv4 Network Layer Reachability Information (NLRI) or VPN-IPv4 NLRI.

This document specifies the extensions necessary to allow the advertising of IPv4 NLRI or VPN-IPv4 NLRI with a next-hop address that belongs to the IPv6 protocol. This comprises an extension of the AFI/SAFI definitions to allow the address of the next hop for IPv4 NLRI or VPN-IPv4 NLRI to also belong to the IPv6 protocol, the encoding of the next hop to determine which of the protocols the address actually belongs to, and a BGP Capability allowing MP-BGP peers to dynamically discover whether they can exchange IPv4 NLRI and VPN-IPv4 NLRI with an IPv6 next hop. This document obsoletes RFC 5549.

When using Traffic Engineering (TE) in a dual-stack IPv4/IPv6 network, the Multiprotocol Label Switching (MPLS) TE Label Switched Path (LSP) infrastructure may be duplicated, even if the destination IPv4 and IPv6 addresses belong to the same remote router. In order to achieve an integrated MPLS TE LSP infrastructure, OSPF routes must be computed over MPLS TE tunnels created using information propagated in another OSPF instance. This issue is solved by advertising cross-address family (X-AF) OSPF TE information.

This document describes an update to RFC 5786 that allows for the easy identification of a router's local X-AF IP addresses.

This document defines YANG modules for the configuration and operation of IPv4-in-IPv6 softwire Border Relays and Customer Premises Equipment for the Lightweight 4over6, Mapping of Address and Port with Encapsulation (MAP-E), and Mapping of Address and Port using Translation (MAP-T) softwire mechanisms.

During the transition to IPv6, there are scenarios where a backbone network internally running one IP address family (referred to as the internal IP or I-IP family) connects client networks running another IP address family (referred to as the external IP or E-IP family). In such cases, the I-IP backbone needs to offer both unicast and multicast transit services to the client E-IP networks.

This document describes a mechanism for supporting multicast across backbone networks where the I-IP and E-IP protocol families differ. The document focuses on the IPv4-over-IPv6 scenario, due to lack of real-world use cases for the IPv6-over-IPv4 scenario.

This document specifies the IPv4 service continuity requirements for IPv6 Customer Edge (CE) routers that are provided either by the service provider or by vendors who sell through the retail market.

Specifically, this document extends the basic requirements for IPv6 CE routers as described in RFC 7084 to allow the provisioning of IPv6 transition services for the support of IPv4-as-a-Service (IPv4aaS) by means of new transition mechanisms. The document only covers IPv4aaS, i.e., transition technologies for delivering IPv4 in IPv6-only access networks. IPv4aaS is necessary because there aren't sufficient IPv4 addresses available for every possible customer/ device. However, devices or applications in the customer Local Area Networks (LANs) may be IPv4-only or IPv6-only and still need to communicate with IPv4-only services on the Internet.

DHCPv4 over DHCPv6 (RFC 7341) is a mechanism for dynamically configuring IPv4 for use as an over-the-top service in an IPv6-only network. Softwires are an example of such a service. For DHCPv4 over DHCPv6 (DHCP 4o6) to function with some IPv4-over-IPv6 softwire mechanisms and deployment scenarios (e.g., RFC 7596 or RFC 7597), the operator needs to know the IPv6 address that the client will use as the source of an IPv4-in-IPv6 softwire tunnel. This address, in conjunction with the client's IPv4 address, and (in some deployments) the Port Set ID are used to create a binding table entry in the operator's softwire tunnel concentrator. This memo defines a DHCPv6 option to convey IPv6 parameters for establishing the softwire tunnel and a DHCPv4 option (to be used only with DHCP 4o6) to communicate the source tunnel IPv6 address between the DHCP 4o6 client and server. It is designed to work in conjunction with the IPv4 address allocation process.

"DHCPv6 Options for Configuration of Softwire Address and Port-Mapped Clients" (RFC 7598) describes a deterministic DHCPv6-based mechanism for provisioning softwires. This document updates RFC 7598, allowing OPTION_S46_BR (90) to be enumerated in the DHCPv6 client's Option Request Option (ORO) request and to appear directly within subsequent messages sent by the DHCPv6 server.

This document defines a YANG module for the Network Address Translation (NAT) function.

Network Address Translation from IPv4 to IPv4 (NAT44), Network Address and Protocol Translation from IPv6 Clients to IPv4 Servers (NAT64), customer-side translator (CLAT), Stateless IP/ICMP Translation (SIIT), Explicit Address Mappings (EAM) for SIIT, IPv6-to-IPv6 Network Prefix Translation (NPTv6), and Destination NAT are covered in this document.

This document defines a YANG module for the Dual-Stack Lite (DS-Lite) Address Family Transition Router (AFTR) and Basic Bridging BroadBand (B4) elements.

This memo updates the IP Performance Metrics (IPPM) framework defined by RFC 2330 with new considerations for measurement methodology and testing. It updates the definition of standard-formed packets to include IPv6 packets, deprecates the definition of minimal IP packet, and augments distinguishing aspects, referred to as Type-P, for test packets in RFC 2330. This memo identifies that IPv4-IPv6 coexistence can challenge measurements within the scope of the IPPM framework. Example use cases include, but are not limited to, IPv4-IPv6 translation, NAT, and protocol encapsulation. IPv6 header compression and use of IPv6 over Low-Power Wireless Area Networks (6LoWPAN) are considered and excluded from the standard-formed packet evaluation.

This document provides guidelines on how to make Interactive Connectivity Establishment (ICE) conclude faster in multihomed and IPv4/IPv6 dual-stack scenarios where broken paths exist. The provided guidelines are backward compatible with the original ICE specification (see RFC 5245).

Many communication protocols operating over the modern Internet use hostnames. These often resolve to multiple IP addresses, each of which may have different performance and connectivity characteristics. Since specific addresses or address families (IPv4 or IPv6) may be blocked, broken, or sub-optimal on a network, clients that attempt multiple connections in parallel have a chance of establishing a connection more quickly. This document specifies requirements for algorithms that reduce this user-visible delay and provides an example algorithm, referred to as "Happy Eyeballs". This document obsoletes the original algorithm description in RFC 6555.

This document reserves the IPv6 prefix 64:ff9b:1::/48 for local use within domains that enable IPv4/IPv6 translation mechanisms.

This memo updates the IANA IPv4 and IPv6 Special-Purpose Address Registries to address issues raised by the definition of a "global" prefix. It also corrects several errors in registry entries to ensure the integrity of the IANA Special-Purpose Address Registries.

This memo updates RFC 6890.

In IPv6-only provider networks, transporting IPv4 packets encapsulated in IPv6 is a common solution to the problem of IPv4 service continuity. A number of differing functional approaches have been developed for this, each having their own specific characteristics. As these approaches share a similar functional architecture and use the same data plane mechanisms, this memo specifies a DHCPv6 option, whereby a single instance of Customer Premises Equipment (CPE) can interwork with all of the standardized and proposed approaches to providing encapsulated IPv4-in-IPv6 services by providing a prioritization mechanism.

RFC 3263 defines how a Session Initiation Protocol (SIP) implementation, given a SIP Uniform Resource Identifier (URI), should locate the next-hop SIP server using Domain Name System (DNS) procedures. As SIP networks increasingly transition from IPv4-only to dual-stack, a quality user experience must be ensured for dual- stack SIP implementations. This document updates the DNS procedures described in RFC 3263 for dual-stack SIP implementations in preparation for forthcoming specifications for applying "Happy Eyeballs" principles to SIP.

This document defines a mechanism to use IPv4 to transport OSPFv3 packets. Using OSPFv3 over IPv4 with the existing OSPFv3 Address Family extension can simplify transition from an OSPFv2 IPv4-only routing domain to an OSPFv3 dual-stack routing domain. This document updates RFC 5838 to support virtual links in the IPv4 unicast address family when using OSPFv3 over IPv4.

This document recommends that networks provide general-purpose end hosts with multiple global IPv6 addresses when they attach, and it describes the benefits of and the options for doing so.

This document defines procedures for using Seamless Bidirectional Forwarding Detection (S-BFD) in IPv4, IPv6, and MPLS environments.

This document describes the Stateless IP/ICMP Translation Algorithm (SIIT), which translates between IPv4 and IPv6 packet headers (including ICMP headers). This document obsoletes RFC 6145.

This document defines a profile that is a superset of the connection to IPv6 cellular networks defined in the IPv6 for Third Generation Partnership Project (3GPP) Cellular Hosts document. This document defines a profile that is a superset of the connections to IPv6 cellular networks defined in "IPv6 for Third Generation Partnership Project (3GPP) Cellular Hosts" (RFC 7066).

Both mobile hosts and mobile devices with the capability to share their 3GPP mobile connectivity are in scope.

RFC 6598 specifies that "Reverse DNS queries for Shared Address Space addresses [100.64.0.0/10] MUST NOT be forwarded to the global DNS infrastructure."

This document formally directs IANA to add the associated zones to the "IPv4 Locally-Served DNS Zones Registry" to prevent such queries from accidentally leaking to the global DNS infrastructure.

This document clarifies and updates several requirements of RFCs 4787, 5382, and 5508 based on operational and development experience. The focus of this document is Network Address Translation from IPv4 to IPv4 (NAT44).

This document updates RFCs 4787, 5382, and 5508.

This document introduces new sub-TLVs to support advertisement of IPv4 and IPv6 prefix attribute flags and the source router ID of the router that originated a prefix advertisement.

This document describes the use of the Stateless IP/ICMP Translation Algorithm (SIIT) in an IPv6 Internet Data Center (IDC). In this deployment model, traffic from legacy IPv4-only clients on the Internet is translated to IPv6 upon reaching the IDC operator's network infrastructure. From that point on, it may be treated the same as traffic from native IPv6 end users. The IPv6 endpoints may be numbered using arbitrary (non-IPv4-translatable) IPv6 addresses. This facilitates a single-stack IPv6-only network infrastructure, as well as efficient utilization of public IPv4 addresses.

The primary audience is IDC operators who are deploying IPv6, running out of available IPv4 addresses, and/or feeling that dual stack causes undesirable operational complexity.

This document describes an extension of the Stateless IP/ICMP Translation for IPv6 Internet Data Center Environments (SIIT-DC) architecture, which allows applications, protocols, or nodes that are incompatible with IPv6 and/or Network Address Translation to operate correctly with SIIT-DC. This is accomplished by introducing a new component called an SIIT-DC Edge Relay, which reverses the translations made by an SIIT-DC Border Relay. The application and/or node is thus provided with seemingly native IPv4 connectivity that provides end-to-end address transparency.

The reader is expected to be familiar with the SIIT-DC architecture described in RFC 7755.

This document extends the Stateless IP/ICMP Translation Algorithm (SIIT) with an Explicit Address Mapping (EAM) algorithm and formally updates RFC 6145. The EAM algorithm facilitates stateless IP/ICMP translation between arbitrary (non-IPv4-translatable) IPv6 endpoints and IPv4.

This document discusses issues induced by the change of the Dual- Stack Lite (DS-Lite) Basic Bridging BroadBand (B4) IPv6 address and sketches a set of recommendations to solve those issues.

In some use cases, e.g., Lightweight 4over6, the client may require not just one port, but a port set. This document defines an extension to the Port Control Protocol (PCP) that allows clients to manipulate a set of ports as a whole. This is accomplished using a new MAP option: PORT_SET.

During the transition from IPv4 to IPv6, customer equipment may have to support one of the various transition methods that have been defined for carrying IPv4 packets over IPv6. This document enumerates the information that needs to be provisioned on a customer edge router to support a list of transition techniques based on tunneling IPv4 in IPv6, with a view to defining reusable components for a reasonable transition path between these techniques. To the extent that the provisioning is done dynamically, Authentication, Authorization, and Accounting (AAA) support is needed to provide the information to the network server responsible for passing the information to the customer equipment. This document specifies Diameter (RFC 6733) Attribute-Value Pairs (AVPs) to be used for that purpose.

This memo describes the dynamic allocation of shared IPv4 addresses to clients using DHCPv4. Address sharing allows a single IPv4 address to be allocated to multiple active clients simultaneously, with each client being differentiated by a unique set of transport- layer source port numbers. The necessary changes to existing DHCPv4 client and server behavior are described, and a new DHCPv4 option for provisioning clients with shared IPv4 addresses is included.

Due to the nature of IP address sharing, some limitations to its applicability are necessary. This memo describes these limitations and recommends suitable architectures and technologies where address sharing may be utilized.

This document describes a set of scenarios in which complications when identifying which policy to apply for a host are encountered. This problem is abstracted as "host identification". Describing these scenarios allows commonalities between scenarios to be identified, which is helpful during the solution design phase.

This document does not include any solution-specific discussions.

Dual-Stack Lite (DS-Lite) (RFC 6333) describes an architecture for transporting IPv4 packets over an IPv6 network. This document specifies an extension to DS-Lite called "Lightweight 4over6", which moves the Network Address and Port Translation (NAPT) function from the centralized DS-Lite tunnel concentrator to the tunnel client located in the Customer Premises Equipment (CPE). This removes the requirement for a Carrier Grade NAT function in the tunnel concentrator and reduces the amount of centralized state that must be held to a per-subscriber level. In order to delegate the NAPT function and make IPv4 address sharing possible, port-restricted IPv4 addresses are allocated to the CPEs.

This document specifies a stateless solution for service providers to progressively deploy IPv6-only network domains while still offering IPv4 service to customers. The solution's distinctive properties are that TCP/UDP IPv4 packets are valid TCP/UDP IPv6 packets during domain traversal and that IPv4 fragmentation rules are fully preserved end to end. Each customer can be assigned one public IPv4 address, several public IPv4 addresses, or a shared address with a restricted port set.

This document specifies extensions to Generic Aggregate RSVP (RFC 4860) for support of the Pre-Congestion Notification (PCN) Controlled Load (CL) and Single Marking (SM) edge behaviors over a Diffserv cloud using PCN.

Dual-Stack Lite (DS-Lite), defined in RFC 6333, directs IANA to reserve 192.0.0.0/29 for the Basic Bridging BroadBand (B4) element. Per this memo, IANA has generalized that reservation to include other cases where a non-routed IPv4 interface must be numbered as part of an IPv6 transition solution.

IPv4 connectivity is still needed as networks migrate towards IPv6. Users require IPv4 configuration even if the uplink to their service provider supports IPv6 only. This document describes a mechanism for obtaining IPv4 configuration information dynamically in IPv6 networks by carrying DHCPv4 messages over DHCPv6 transport. Two new DHCPv6 messages and two new DHCPv6 options are defined for this purpose.

This document discusses the security implications of native IPv6 support and IPv6 transition/coexistence technologies on "IPv4-only" networks and describes possible mitigations for the aforementioned issues.

This document provides advice on the filtering of IPv4 packets based on the IPv4 options they contain. Additionally, it discusses the operational and interoperability implications of dropping packets based on the IP options they contain.

This document provides an overview of various ways to tunnel IPv6 packets over IPv4 networks. It covers mechanisms in current use, touches on several mechanisms that are now only of historic interest, and discusses some newer tunnel mechanisms that are not widely used at the time of publication. The goal of the document is helping people with an IPv6-in-IPv4 tunneling need to select the mechanisms that may apply to them.

This document describes a mechanism called Public 4over6, which is designed to provide IPv4 Internet connectivity over an IPv6 access network using global IPv4 addresses. Public 4over6 was developed in the IETF and is in use in some existing deployments but is not recommended for new deployments. Future deployments of similar scenarios should use Lightweight 4over6. Public 4over6 follows the Hub and Spoke softwire model and uses an IPv4-in-IPv6 tunnel to forward IPv4 packets over an IPv6 access network. The bidirectionality of the IPv4 communication is achieved by explicitly allocating global non-shared IPv4 addresses to end users and by maintaining IPv4-IPv6 address binding on the border relay. Public 4over6 aims to provide uninterrupted IPv4 services to users, like Internet Content Providers (ICPs), etc., while an operator makes the access network transition to an IPv6-only access network.

NAT444 is an IPv4 extension technology being considered by Service Providers as a means to continue offering IPv4 service to customers while transitioning to IPv6. This technology adds an extra Carrier- Grade NAT (CGN) in the Service Provider network, often resulting in two NATs. CableLabs, Time Warner Cable, and Rogers Communications independently tested the impacts of NAT444 on many popular Internet services using a variety of test scenarios, network topologies, and vendor equipment. This document identifies areas where adding a second layer of NAT disrupts the communication channel for common Internet applications. This document was updated to include the Dual-Stack Lite (DS-Lite) impacts also.

This document describes a routing scenario where IPv4 packets are transported over an IPv6 network, based on the methods described in RFCs 6145 and 6052, along with a separate OSPFv3 routing table for IPv4-embedded IPv6 routes in the IPv6 network.

Many end-user sites in the Internet today still have predominantly IPv4 internal infrastructures. These sites range in size from small home/office networks to large corporate enterprise networks, but share the commonality that IPv4 provides satisfactory internal routing and addressing services for most applications. As more and more IPv6-only services are deployed, however, end-user devices within such sites will increasingly require at least basic IPv6 functionality. This document therefore provides operational guidance for deployment of IPv6 within predominantly IPv4 sites using the Intra-Site Automatic Tunnel Addressing Protocol (ISATAP).

The IPv6 Rapid Deployment on IPv4 Infrastructures (6rd) provides both IPv4 and IPv6 connectivity services simultaneously during the IPv4/IPv6 coexistence period. The Dynamic Host Configuration Protocol (DHCP) 6rd option has been defined to configure the 6rd Customer Edge (CE). However, in many networks, the configuration information may be stored in the Authentication Authorization and Accounting (AAA) servers, while user configuration is mainly acquired from a Broadband Network Gateway (BNG) through the DHCP protocol. This document defines a Remote Authentication Dial-In User Service (RADIUS) attribute that carries 6rd configuration information from the AAA server to BNGs.

Due to specific problems, Network Address Translation - Protocol Translation (NAT-PT) was deprecated by the IETF as a mechanism to perform IPv6-IPv4 translation. Since then, new efforts have been undertaken within IETF to standardize alternative mechanisms to perform IPv6-IPv4 translation. This document analyzes to what extent the new stateful translation mechanisms avoid the problems that caused the IETF to deprecate NAT-PT.

This memo reiterates the assignment of an IPv4 address block (192.0.0.0/24) to IANA. It also instructs IANA to restructure its IPv4 and IPv6 Special-Purpose Address Registries. Upon restructuring, the aforementioned registries will record all special-purpose address blocks, maintaining a common set of information regarding each address block.

This specification defines a new mobility option, the IPv4 Traffic Offload Selector option, for Proxy Mobile IPv6. This option can be used by the local mobility anchor and the mobile access gateway for negotiating IPv4 traffic offload policy for a mobility session. Based on the negotiated IPv4 traffic offload policy, a mobile access gateway can selectively offload some of the IPv4 traffic flows in the access network instead of tunneling back to the local mobility anchor in the home network.

A number of ICMPv4 message types have become obsolete in practice, but have never been formally deprecated. This document deprecates such ICMPv4 message types, thus cleaning up the corresponding IANA registry. Additionally, it updates RFC 792 and RFC 950, obsoletes RFC 1788, and requests the RFC Editor to change the status of RFC 1788 to Historic.

The IPv4 Identification (ID) field enables fragmentation and reassembly and, as currently specified, is required to be unique within the maximum lifetime for all datagrams with a given source address/destination address/protocol tuple. If enforced, this uniqueness requirement would limit all connections to 6.4 Mbps for typical datagram sizes. Because individual connections commonly exceed this speed, it is clear that existing systems violate the current specification. This document updates the specification of the IPv4 ID field in RFCs 791, 1122, and 2003 to more closely reflect current practice and to more closely match IPv6 so that the field's value is defined only when a datagram is actually fragmented. It also discusses the impact of these changes on how datagrams are used. [STANDARDS-TRACK]

A number of IPv4 options have become obsolete in practice, but have never been formally deprecated. This document deprecates such IPv4 options, thus cleaning up the corresponding IANA registry. Additionally, it obsoletes RFCs 1385, 1393, 1475, and 1770, and requests that the RFC Editor change their status to Historic. [STANDARDS-TRACK]

A stateless IPv4/IPv6 translator may receive ICMPv6 packets containing non-IPv4-translatable addresses as the source. These packets should be passed across the translator as ICMP packets directed to the IPv4 destination. This document presents recommendations for source address translation in ICMPv6 headers to handle such cases. [STANDARDS-TRACK]

This note defines an experimental ICMP message type for IPv4 used with the Identifier-Locator Network Protocol (ILNP). ILNP is an experimental, evolutionary enhancement to IP. The ICMP message defined herein is used to dynamically update Identifier/Locator bindings for an existing ILNP session. This is a product of the IRTF Routing Research Group. This document defines an Experimental Protocol for the Internet community.

This document defines two new IPv4 Options that are used only with the Identifier-Locator Network Protocol for IPv4 (ILNPv4). ILNP is an experimental, evolutionary enhancement to IP. This document is a product of the IRTF Routing Research Group. This document defines an Experimental Protocol for the Internet community.

This document defines an Address Resolution Protocol (ARP) extension to support the Identifier-Locator Network Protocol for IPv4 (ILNPv4). ILNP is an experimental, evolutionary enhancement to IP. This document is a product of the IRTF Routing Research Group. This document defines an Experimental Protocol for the Internet community.

In customer sites having IPv4-only Customer Premises Equipment (CPE), Teredo (RFC 4380, RFC 5991, RFC 6081) provides last-resort IPv6 connectivity. However, because it is designed to work without the involvement of Internet Service Providers, it has significant limitations (connectivity between IPv6 native addresses and Teredo addresses is uncertain; connectivity between Teredo addresses fails for some combinations of NAT types). 6a44 is a complementary solution that, being based on ISP cooperation, avoids these limitations. At the beginning of 6a44 IPv6 addresses, it replaces the Teredo well-known prefix, present at the beginning of Teredo IPv6 addresses, with network-specific /48 prefixes assigned by local ISPs (an evolution similar to that from 6to4 to 6rd (IPv6 Rapid Deployment on IPv4 Infrastructures)). The specification is expected to be complete enough for running code to be independently written and the solution to be incrementally deployed and used. This document defines an Experimental Protocol for the Internet community.

The objective of Pre-Congestion Notification (PCN) is to protect the quality of service (QoS) of inelastic flows within a Diffserv domain. The overall rate of PCN-traffic is metered on every link in the PCN- domain, and PCN-packets are appropriately marked when certain configured rates are exceeded. Egress nodes pass information about these PCN-marks to Decision Points that then decide whether to admit or block new flow requests or to terminate some already admitted flows during serious pre-congestion.

This document specifies how PCN-marks are to be encoded into the IP header by reusing the Explicit Congestion Notification (ECN) codepoints within a PCN-domain. The PCN wire protocol for non-IP protocol headers will need to be defined elsewhere. Nonetheless, this document clarifies the PCN encoding for MPLS in an informational appendix. The encoding for IP provides for up to three different PCN marking states using a single Diffserv codepoint (DSCP): not-marked (NM), threshold-marked (ThM), and excess-traffic-marked (ETM). Hence, it is called the 3-in-1 PCN encoding. This document obsoletes RFC 5696. [STANDARDS-TRACK]

This document proposes an alternative IPv6 Rapid Deployment on IPv4 Infrastructures (6rd) deployment model to that of RFC 5969. The basic 6rd model allows IPv6 hosts to gain access to IPv6 networks across an IPv4 access network using 6-in-4 tunnels. 6rd requires support by a device (the 6rd customer edge, or 6rd-CE) on the customer site, which must also be assigned an IPv4 address. The alternative model described in this document initiates the 6-in-4 tunnels from an operator-owned Gateway collocated with the operator's IPv4 network edge rather than from customer equipment, and hence is termed "Gateway-initiated 6rd" (GI 6rd). The advantages of this approach are that it requires no modification to customer equipment and avoids assignment of IPv4 addresses to customer equipment. The latter point means less pressure on IPv4 addresses in a high-growth environment. This document is not an Internet Standards Track specification; it is published for informational purposes.

This document explains how to employ address translation in networks that serve a large number of individual customers without requiring a correspondingly large amount of private IPv4 address space. [STANDARDS-TRACK]

The base Network Mobility for Mobile IPv4 (NEMOv4) specification defines extensions to Mobile IPv4 for mobile networks. This specification defines a dynamic prefix allocation mechanism for NEMOv4. [STANDARDS-TRACK]

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.

This document details the allocation of an additional special-use IPv4 address block and updates RFC 5735. This memo documents an Internet Best Current Practice.

This document specifies protocol enhancements that allow Mobile IPv4 entities to send and receive explicit notification messages using a Mobile IPv4 message type designed for this purpose. [STANDARDS-TRACK]

Given the global lack of available IPv4 space, and limitations in IPv4 extension and transition technologies, this document advises that IPv6 support is no longer considered optional. It also cautions that there are places in existing IETF documents where the term "IP" is used in a way that could be misunderstood by implementers as the term "IP" becomes a generic that can mean IPv4 + IPv6, IPv6-only, or IPv4-only, depending on context and application. This memo documents an Internet Best Current Practice.

The amount of time it takes to establish a session using common transport APIs in dual-stack networks and networks with filtering such as proposed in BCP 38 is a barrier to IPv6 deployment. This note describes a test that can be used to determine whether an application can reliably establish sessions quickly in a complex environment such as dual-stack (IPv4+IPv6) deployment or IPv6 deployment with multiple prefixes and upstream ingress filtering. This test is not a test of a specific algorithm, but of the external behavior of the system as a black box. Any algorithm that has the intended external behavior will be accepted by it. This document is not an Internet Standards Track specification; it is published for informational purposes.

This document describes a home agent-assisted route optimization functionality for the IPv4 Network Mobility Protocol. The function is designed to facilitate optimal routing in cases where all nodes are connected to a single home agent; thus, the use case is route optimization within a single organization or similar entity. The functionality enables the discovery of eligible peer nodes (based on information received from the home agent) and their network prefixes, and the establishment of a direct tunnel between such nodes. This document defines an Experimental Protocol for the Internet community.

Bump-in-the-Host (BIH) is a host-based IPv4 to IPv6 protocol translation mechanism that allows a class of IPv4-only applications that work through NATs to communicate with IPv6-only peers. The host on which applications are running may be connected to IPv6-only or dual-stack access networks. BIH hides IPv6 and makes the IPv4-only applications think they are talking with IPv4 peers by local synthesis of IPv4 addresses. This document obsoletes RFC 2767 and RFC 3338. [STANDARDS-TRACK]

To provide Multicast VPN (MVPN) service, Provider Edge routers originate BGP Update messages that carry Multicast-VPN ("MCAST-VPN") BGP routes; they also originate unicast VPN routes that carry MVPN-specific attributes. These routes encode addresses from the customer's address space, as well as addresses from the provider's address space. These two address spaces are independent, and the address family (IPv4 or IPv6) of the two spaces may or may not be the same. These routes always contain an "address family" field that specifies whether the customer addresses are IPv4 addresses or whether they are IPv6 addresses. However, there is no field that explicitly specifies the address family of the provider addresses. To ensure interoperability, this document specifies that provider IPv4 addresses are always encoded in these update messages as 4-octet addresses, and that the distinction between IPv4 and IPv6 is signaled solely by the length of the address field. Specific cases are explained in detail. This document updates RFC 6514. [STANDARDS-TRACK]

It has been common for network administrators to filter IP traffic from and BGP prefixes of unallocated IPv4 address space. Now that there are no longer any unallocated IPv4 /8s, this practise is more complicated, fragile, and expensive. Network administrators are advised to remove filters based on the registration status of the address space.

This document explains why any remaining packet and BGP prefix filters for unallocated IPv4 /8s should now be removed on border routers and documents those IPv4 unicast prefixes that should not be routed across the public Internet. This memo documents an Internet Best Current Practice.

This document defines two Huawei IPCP (IP Control Protocol) options used to convey a set of ports. These options can be used in the context of port range-based solutions or NAT-based solutions for port delegation and forwarding purposes. This document is not an Internet Standards Track specification; it is published for informational purposes.

The File Transfer Protocol (FTP) has a very long history, and despite the fact that today other options exist to perform file transfers, FTP is still in common use. As such, in situations where some client computers only have IPv6 connectivity while many servers are still IPv4-only and IPv6-to-IPv4 translators are used to bridge that gap, it is important that FTP is made to work through these translators to the best possible extent.

FTP has an active and a passive mode, both as original commands that are IPv4-specific and as extended, IP version agnostic commands. The only FTP mode that works without changes through an IPv6-to-IPv4 translator is extended passive. However, many existing FTP servers do not support this mode, and some clients do not ask for it. This document specifies a middlebox that may solve this mismatch. [STANDARDS-TRACK]

We are facing the exhaustion of the IANA IPv4 free IP address pool. Unfortunately, IPv6 is not yet deployed widely enough to fully replace IPv4, and it is unrealistic to expect that this is going to change before the depletion of IPv4 addresses. Letting hosts seamlessly communicate in an IPv4 world without assigning a unique globally routable IPv4 address to each of them is a challenging problem.

This document proposes an IPv4 address sharing scheme, treating some of the port number bits as part of an extended IPv4 address (Address plus Port, or A+P). Instead of assigning a single IPv4 address to a single customer device, we propose to extend the address field by using bits from the port number range in the TCP/UDP header as additional endpoint identifiers, thus leaving a reduced range of ports available to applications. This means assigning the same IPv4 address to multiple clients (e.g., Customer Premises Equipment (CPE), mobile phones), each with its assigned port range. In the face of IPv4 address exhaustion, the need for addresses is stronger than the need to be able to address thousands of applications on a single host. If address translation is needed, the end-user should be in control of the translation process -- not some smart boxes in the core. This document defines an Experimental Protocol for the Internet community.

This document revisits the dual-stack model and introduces the Dual- Stack Lite technology aimed at better aligning the costs and benefits of deploying IPv6 in service provider networks. Dual-Stack Lite enables a broadband service provider to share IPv4 addresses among customers by combining two well-known technologies: IP in IP (IPv4- in-IPv6) and Network Address Translation (NAT). [STANDARDS-TRACK]

When a private network or internetwork grows very large, it is sometimes not possible to address all interfaces using private IPv4 address space because there are not enough addresses. This document describes the problems faced by those networks, the available options, and the issues involved in assigning a new block of private IPv4 address space.

While this informational document does not make a recommendation for action, it documents the issues surrounding the various options that have been considered. This document is not an Internet Standards Track specification; it is published for informational purposes.

This document describes a framework for how the current IPv4 address space can be divided into two new address categories: a core address space (Area Locators, ALOCs) that is globally unique, and an edge address space (Endpoint Locators, ELOCs) that is regionally unique. In the future, the ELOC space will only be significant in a private network or in a service provider domain. Therefore, a 32x32 bit addressing scheme and a hierarchical routing architecture are achieved. The hierarchical IPv4 framework is backwards compatible with the current IPv4 Internet.

This document also discusses a method for decoupling the location and identifier functions -- future applications can make use of the separation. The framework requires extensions to the existing Domain Name System (DNS), the existing IPv4 stack of the endpoints, middleboxes, and routers in the Internet. The framework can be implemented incrementally for endpoints, DNS, middleboxes, and routers. This document defines an Experimental Protocol for the Internet community.

In the wake of IPv4 exhaustion and deployment of IP address sharing techniques, this document recommends that Internet-facing servers log port number and accurate timestamps in addition to the incoming IP address. This memo documents an Internet Best Current Practice.

The completion of IPv4 address allocations from IANA and the Regional Internet Registries (RIRs) is causing service providers around the world to question how they will continue providing IPv4 connectivity service to their subscribers when there are no longer sufficient IPv4 addresses to allocate them one per subscriber. Several possible solutions to this problem are now emerging based around the idea of shared IPv4 addressing. These solutions give rise to a number of issues, and this memo identifies those common to all such address sharing approaches. Such issues include application failures, additional service monitoring complexity, new security vulnerabilities, and so on. Solution-specific discussions are out of scope.

Deploying IPv6 is the only perennial way to ease pressure on the public IPv4 address pool without the need for address sharing mechanisms that give rise to the issues identified herein. This document is not an Internet Standards Track specification; it is published for informational purposes.

The Generic Routing Encapsulation (GRE) specification contains a Key field, which MAY contain a value that is used to identify a particular GRE data stream. This specification defines a new Mobile IP extension that is used to exchange the value to be used in the GRE Key field. This extension further allows the Mobility Agents to set up the necessary protocol interfaces prior to receiving the mobile node traffic. The new extension allows a Foreign Agent to request GRE tunneling without disturbing the Home Agent behavior specified for Mobile IPv4. GRE tunneling with the Key field allows the operators to have home networks that consist of multiple Virtual Private Networks (VPNs), which may have overlapping home addresses. When the tuple <Care of Address, Home Address, and Home Agent Address> is the same across multiple subscriber sessions, GRE tunneling will provide a means for the Foreign Agent and Home Agent to identify data streams for the individual sessions based on the GRE key. In the absence of this key identifier, the data streams cannot be distinguished from each other -- a significant drawback when using IP-in-IP tunneling. [STANDARDS-TRACK]

When IPv6 was designed, it was expected that the transition from IPv4 to IPv6 would occur more smoothly and expeditiously than experience has revealed. The growth of the IPv4 Internet and predicted depletion of the free pool of IPv4 address blocks on a foreseeable horizon has highlighted an urgent need to revisit IPv6 deployment models. This document provides an overview of deployment scenarios with the goal of helping to understand what types of additional tools the industry needs to assist in IPv4 and IPv6 co-existence and transition.

This document was originally created as input to the Montreal co- existence interim meeting in October 2008, which led to the rechartering of the Behave and Softwire working groups to take on new IPv4 and IPv6 co-existence work. This document is published as a historical record of the thinking at the time, but hopefully will also help readers understand the rationale behind current IETF tools for co-existence and transition. This document is not an Internet Standards Track specification; it is published for informational purposes.

This RFC attempts to document various aspects of the IP service model and how it has evolved over time. In particular, it attempts to document the properties of the IP layer as they are seen by upper- layer protocols and applications, especially properties that were (and, at times, still are) incorrectly perceived to exist as well as properties that would cause problems if changed. The discussion of these properties is organized around evaluating a set of claims, or misconceptions. Finally, this document provides some guidance to protocol designers and implementers. This document is not an Internet Standards Track specification; it is published for informational purposes.

This document presents the China Education and Research Network (CERNET)'s IVI translation design and deployment for the IPv4/IPv6 coexistence and transition.

The IVI is a prefix-specific and stateless address mapping mechanism for "an IPv6 network to the IPv4 Internet" and "the IPv4 Internet to an IPv6 network" scenarios. In the IVI design, subsets of the ISP's IPv4 addresses are embedded in the ISP's IPv6 addresses, and the hosts using these IPv6 addresses can therefore communicate with the global IPv6 Internet directly and can communicate with the global IPv4 Internet via stateless translators. The communications can either be IPv6 initiated or IPv4 initiated. The IVI mechanism supports the end-to-end address transparency and incremental deployment. The IVI is an early design deployed in the CERNET as a reference for the IETF standard documents on IPv4/IPv6 stateless translation. This document is not an Internet Standards Track specification; it is published for informational purposes.

This note describes a framework for IPv4/IPv6 translation. This is in the context of replacing Network Address Translation - Protocol Translation (NAT-PT), which was deprecated by RFC 4966, and to enable networks to have IPv4 and IPv6 coexist in a somewhat rational manner while transitioning to an IPv6 network. This document is not an Internet Standards Track specification; it is published for informational purposes.

This document describes stateful NAT64 translation, which allows IPv6-only clients to contact IPv4 servers using unicast UDP, TCP, or ICMP. One or more public IPv4 addresses assigned to a NAT64 translator are shared among several IPv6-only clients. When stateful NAT64 is used in conjunction with DNS64, no changes are usually required in the IPv6 client or the IPv4 server.

DNS64 is a mechanism for synthesizing AAAA records from A records. DNS64 is used with an IPv6/IPv4 translator to enable client-server communication between an IPv6-only client and an IPv4-only server, without requiring any changes to either the IPv6 or the IPv4 node, for the class of applications that work through NATs. This document specifies DNS64, and provides suggestions on how it should be deployed in conjunction with IPv6/IPv4 translators. [STANDARDS-TRACK]

This document specifies how Label Edge Routers (LERs) should behave when determining whether to MPLS encapsulate an IPv4 packet with header options. Lack of a formal standard has resulted in different LER forwarding behaviors for IPv4 packets with header options despite being associated with a prefix-based Forwarding Equivalence Class (FEC). IPv4 option packets that belong to a prefix-based FEC, yet are forwarded into an IPv4/MPLS network without being MPLS- encapsulated, present a security risk against the MPLS infrastructure. Further, LERs that are unable to MPLS encapsulate IPv4 packets with header options cannot operate in certain MPLS environments. While this newly defined LER behavior is mandatory to implement, it is optional to invoke. [STANDARDS-TRACK]

This document specifies protocol enhancements that allow transparent routing of IP datagrams to mobile nodes in the Internet. Each mobile node is always identified by its home address, regardless of its current point of attachment to the Internet. While situated away from its home, a mobile node is also associated with a care-of address, which provides information about its current point of attachment to the Internet. The protocol provides for registering the care-of address with a home agent. The home agent sends datagrams destined for the mobile node through a tunnel to the care-of address. After arriving at the end of the tunnel, each datagram is then delivered to the mobile node. [STANDARDS-TRACK]

This document discusses the algorithmic translation of an IPv6 address to a corresponding IPv4 address, and vice versa, using only statically configured information. It defines a well-known prefix for use in algorithmic translations, while allowing organizations to also use network-specific prefixes when appropriate. Algorithmic translation is used in IPv4/IPv6 translators, as well as other types of proxies and gateways (e.g., for DNS) used in IPv4/IPv6 scenarios. [STANDARDS-TRACK]

This specification defines an extension to the multicast addressing architecture of the IP Version 4 protocol. The extension presented in this document allows for unicast-prefix-based assignment of multicast addresses. By delegating multicast addresses at the same time as unicast prefixes, network operators will be able to identify their multicast addresses without needing to run an inter-domain allocation protocol. [STANDARDS-TRACK]

This note discusses a feature to support building Greynets for IPv4 and IPv6. This document is not an Internet Standards Track specification; it is published for informational purposes.

IEEE 802.16 is an air interface specification for wireless broadband access. IEEE 802.16 has specified multiple service-specific Convergence Sublayers for transmitting upper-layer protocols. The Packet CS (Packet Convergence Sublayer) is used for the transport of all packet-based protocols such as the Internet Protocol (IP) and IEEE 802.3 (Ethernet). The IP-specific part of the Packet CS enables the transport of IPv4 packets directly over the IEEE 802.16 Media Access Control (MAC) layer.

This document specifies the frame format, the Maximum Transmission Unit (MTU), and the address assignment procedures for transmitting IPv4 packets over the IP-specific part of the Packet Convergence Sublayer of IEEE 802.16. [STANDARDS-TRACK]

This document specifies an automatic tunneling mechanism tailored to advance deployment of IPv6 to end users via a service provider's IPv4 network infrastructure. Key aspects include automatic IPv6 prefix delegation to sites, stateless operation, simple provisioning, and service, which is equivalent to native IPv6 at the sites that are served by the mechanism. [STANDARDS-TRACK]

This document describes the use of the Bidirectional Forwarding Detection (BFD) protocol over IPv4 and IPv6 for single IP hops. [STANDARDS-TRACK]

This document specifies a stable naming scheme for the nameservers that serve the zones IN-ADDR.ARPA and IP6.ARPA in the DNS. These zones contain data that facilitate reverse mapping (address to name). This memo documents an Internet Best Current Practice.

This document specifies extensions to the Proxy Mobile IPv6 protocol for adding IPv4 protocol support. The scope of IPv4 protocol support is two-fold: 1) enable IPv4 home address mobility support to the mobile node, and 2) allow the mobility entities in the Proxy Mobile IPv6 domain to exchange signaling messages over an IPv4 transport network. [STANDARDS-TRACK]

This document provides guidance for the Internet Assigned Numbers Authority (IANA) in assigning IPv4 multicast addresses. It obsoletes RFC 3171 and RFC 3138 and updates RFC 2780. This memo documents an Internet Best Current Practice.

The emerging and growing deployment of IPv6 networks will introduce cases where connectivity with IPv4 networks crossing IPv6 transit backbones is desired. This document describes a mechanism for automatic discovery and creation of IPv4-over-IPv6 tunnels via extensions to multiprotocol BGP. It is targeted at connecting islands of IPv4 networks across an IPv6-only backbone without the need for a manually configured overlay of tunnels. The mechanisms described in this document have been implemented, tested, and deployed on the large research IPv6 network in China. This document defines an Experimental Protocol for the Internet community.

The Intra-Site Automatic Tunnel Addressing Protocol (ISATAP) specifies a Non-Broadcast, Multiple Access (NBMA) interface type for the transmission of IPv6 packets over IPv4 networks using automatic IPv6-in-IPv4 encapsulation. The original specifications make no provisions for the encapsulation and transmission of IPv4 packets, however. This document specifies a method for transmitting IPv4 packets over ISATAP interfaces. This document is not an Internet Standards Track specification; it is published for informational purposes.

Mobile IPv4 is a standard mobility protocol that enables an IPv4 device to move among networks while maintaining its IP address. The mobile device has the Mobile IPv4 client function to signal its location to the routing anchor, known as the Home Agent. However, there are many IPv4 devices without such capability due to various reasons. This document describes Proxy Mobile IPv4 (PMIPv4), a scheme based on having the Mobile IPv4 client function in a network entity to provide mobility support for an unaltered and mobility-unaware IPv4 device. This document also describes a particular application of PMIPv4 as specified in the WiMAX Forum and another application that is to be adopted in 3GPP2. This document is not an Internet Standards Track specification; it is published for informational purposes.

IPv6 rapid deployment on IPv4 infrastructures (6rd) builds upon mechanisms of 6to4 to enable a service provider to rapidly deploy IPv6 unicast service to IPv4 sites to which it provides customer premise equipment. Like 6to4, it utilizes stateless IPv6 in IPv4 encapsulation in order to transit IPv4-only network infrastructure. Unlike 6to4, a 6rd service provider uses an IPv6 prefix of its own in place of the fixed 6to4 prefix. A service provider has used this mechanism for its own IPv6 "rapid deployment": five weeks from first exposure to 6rd principles to more than 1,500,000 residential sites being provided native IPv6, under the only condition that they activate it. This document is not an Internet Standards Track specification; it is published for informational purposes.

Three IPv4 unicast address blocks are reserved for use in examples in specifications and other documents. This document describes the use of these blocks. This document is not an Internet Standards Track specification; it is published for informational purposes.

The current Mobile IPv6 and Network Mobility (NEMO) specifications support IPv6 only. This specification extends those standards to allow the registration of IPv4 addresses and prefixes, respectively, and the transport of both IPv4 and IPv6 packets over the tunnel to the home agent. This specification also allows the mobile node to roam over both IPv6 and IPv4, including the case where Network Address Translation is present on the path between the mobile node and its home agent. [STANDARDS-TRACK]

This specification provides IPv6 extensions to the Mobile IPv4 protocol. The extensions allow a dual-stack node to use IPv4 and IPv6 home addresses as well as to move between IPv4 and dual stack network infrastructures. [STANDARDS-TRACK]

In some Mobile IPv4 deployments, identifying the mobile node or the mobility service subscriber is not enough to distinguish among the multiple services possibly provisioned to the mobile node. The capability to specify different services in addition to the mobile node's identity can be leveraged to provide flexibility for mobility service providers to provide multiple services within a single mobility service subscription. This document describes a Service Selection extension for Mobile IPv4 that is intended to assist home agents to make specific service selections for their mobility service subscriptions during the registration procedure. This memo provides information for the Internet community.

This document updates the IANA allocation rules and registry of IPv4 and IPv6 Router Alert Option Values. [STANDARDS-TRACK]

This memo provides one possible plan for transitioning the Internet from a predominantly IPv4-based connectivity model to a predominantly IPv6-based connectivity model. This memo provides information for the Internet community.

When two hosts on the same link attempt to use the same IPv4 address at the same time (except in rare special cases where this has been arranged by prior coordination), problems ensue for one or both hosts. This document describes (i) a simple precaution that a host can take in advance to help prevent this misconfiguration from happening, and (ii) if this misconfiguration does occur, a simple mechanism by which a host can passively detect, after the fact, that it has happened, so that the host or administrator may respond to rectify the problem. [STANDARDS-TRACK]

This document outlines a solution for the Mobile IPv4 (MIPv4) and IPsec coexistence problem for enterprise users. The solution consists of an applicability statement for using Mobile IPv4 and IPsec for session mobility in corporate remote access scenarios, and a required mechanism for detecting the trusted internal network securely. [STANDARDS-TRACK]

Enterprise users require mobility and secure connectivity when they roam and connect to the services offered in the enterprise. Secure connectivity is required when the user connects to the enterprise from an untrusted network. Mobility is beneficial when the user moves, either inside or outside the enterprise network, and acquires a new IP address. This document describes a solution using Mobile IPv4 (MIPv4) and mobility extensions to IKEv2 (MOBIKE) to provide secure connectivity and mobility. This document specifies an Internet Best Current Practices for the Internet Community, and requests discussion and suggestions for improvements.

This document describes a protocol for supporting Mobile Networks between a Mobile Router and a Home Agent by extending the Mobile IPv4 protocol. A Mobile Router is responsible for the mobility of one or more network segments or subnets moving together. The Mobile Router hides its mobility from the nodes on the Mobile Network. The nodes on the Mobile Network may be fixed in relationship to the Mobile Router and may not have any mobility function.

Extensions to Mobile IPv4 are introduced to support Mobile Networks. [STANDARDS-TRACK]

The Intra-Site Automatic Tunnel Addressing Protocol (ISATAP) connects dual-stack (IPv6/IPv4) nodes over IPv4 networks. ISATAP views the IPv4 network as a link layer for IPv6 and supports an automatic tunneling abstraction similar to the Non-Broadcast Multiple Access (NBMA) model. This memo provides information for the Internet community.

This document revises the IANA guidelines for allocating new Protocol field values in IPv4 header. It modifies the rules specified in RFC 2780 by removing the Expert Review option. The change will also affect the allocation of Next Header field values in IPv6. This document specifies an Internet Best Current Practices for the Internet Community, and requests discussion and suggestions for improvements.

This document adapts the Mobile IPv6 Fast Handovers to improve delay and packet loss resulting from Mobile IPv4 handover operations. Specifically, this document addresses movement detection, IP address configuration, and location update latencies during a handover. For reducing the IP address configuration latency, the document proposes that the new Care-of Address is always made to be the new access router's IP address. This memo defines an Experimental Protocol for the Internet community.

This document provides an applicability statement as well as a scope definition for specifying Remote Authentication Dial-In User Service (RADIUS) extensions to support Mobile IPv4. The goal is to allow specification of RADIUS attributes to assist the Mobile IPv4 signaling procedures. This memo provides information for the Internet community.

The transition from a pure IPv4 network to a network where IPv4 and IPv6 coexist brings a number of extra security considerations that need to be taken into account when deploying IPv6 and operating the dual-protocol network and the associated transition mechanisms. This document attempts to give an overview of the various issues grouped into three categories:

o issues due to the IPv6 protocol itself, o issues due to transition mechanisms, and o issues due to IPv6 deployment.

This memo provides information for the Internet community.

IPv4 fragmentation is not sufficiently robust for use under some conditions in today's Internet. At high data rates, the 16-bit IP identification field is not large enough to prevent frequent incorrectly assembled IP fragments, and the TCP and UDP checksums are insufficient to prevent the resulting corrupted datagrams from being delivered to higher protocol layers. This note describes some easily reproduced experiments demonstrating the problem, and discusses some of the operational implications of these observations. This memo provides information for the Internet community.

This document describes the process of binding/associating IPv4/IPv6 addresses with MPEG-2 Transport Streams (TS). This procedure is known as Address Resolution (AR) or Neighbor Discovery (ND). Such address resolution complements the higher-layer resource discovery tools that are used to advertise IP sessions.

In MPEG-2 Networks, an IP address must be associated with a Packet ID (PID) value and a specific Transmission Multiplex. This document reviews current methods appropriate to a range of technologies (such as DVB (Digital Video Broadcasting), ATSC (Advanced Television Systems Committee), DOCSIS (Data-Over-Cable Service Interface Specifications), and variants). It also describes the interaction with well-known protocols for address management including DHCP, ARP, and the ND protocol. This memo provides information for the Internet community.

Mobile IPv4 describes how a Mobile Node can perform IPv4-layer handoffs between subnets served by different Foreign Agents. In certain cases, the latency involved in these handoffs can be above the threshold required for the support of delay-sensitive or real-time services. The aim of this document is to present two methods to achieve low-latency Mobile IPv4 handoffs. In addition, a combination of these two methods is described. The described techniques allow greater support for real-time services on a Mobile IPv4 network by minimizing the period of time when a Mobile Node is unable to send or receive IPv4 packets due to the delay in the Mobile IPv4 Registration process. This memo defines an Experimental Protocol for the Internet community.

This document specifies a new extension for use in Mobile IPv4. This extension can be added by the Home Agent and the Foreign Agent to Registration Reply messages. This extension carries a text string that is intended for the user of the Mobile Node. [STANDARDS-TRACK]

Using Mobile IP, a mobile node registers with its home agent each time it changes care-of address. This document describes a new kind of "regional registrations", i.e., registrations local to the visited domain. The regional registrations are performed via a new network entity called a Gateway Foreign Agent (GFA) and introduce a layer of hierarchy in the visited domain. Regional registrations reduce the number of signaling messages to the home network, and reduce the signaling delay when a mobile node moves from one foreign agent to another within the same visited domain. This document is an optional extension to the Mobile IPv4 protocol. This memo defines an Experimental Protocol for the Internet community.

This document gives guidance on securing manually configured IPv6-in- IPv4 tunnels using IPsec in transport mode. No additional protocol extensions are described beyond those available with the IPsec framework. This memo provides information for the Internet community.

The Dynamic Source Routing protocol (DSR) is a simple and efficient routing protocol designed specifically for use in multi-hop wireless ad hoc networks of mobile nodes. DSR allows the network to be completely self-organizing and self-configuring, without the need for any existing network infrastructure or administration. The protocol is composed of the two main mechanisms of "Route Discovery" and "Route Maintenance", which work together to allow nodes to discover and maintain routes to arbitrary destinations in the ad hoc network. All aspects of the protocol operate entirely on demand, allowing the routing packet overhead of DSR to scale automatically to only what is needed to react to changes in the routes currently in use. The protocol allows multiple routes to any destination and allows each sender to select and control the routes used in routing its packets, for example, for use in load balancing or for increased robustness. Other advantages of the DSR protocol include easily guaranteed loop-free routing, operation in networks containing unidirectional links, use of only "soft state" in routing, and very rapid recovery when routes in the network change. The DSR protocol is designed mainly for mobile ad hoc networks of up to about two hundred nodes and is designed to work well even with very high rates of mobility. This document specifies the operation of the DSR protocol for routing unicast IPv4 packets. This memo defines an Experimental Protocol for the Internet community.

This document explains how to interconnect IPv6 islands over a Multiprotocol Label Switching (MPLS)-enabled IPv4 cloud. This approach relies on IPv6 Provider Edge routers (6PE), which are Dual Stack in order to connect to IPv6 islands and to the MPLS core, which is only required to run IPv4 MPLS. The 6PE routers exchange the IPv6 reachability information transparently over the core using the Multiprotocol Border Gateway Protocol (MP-BGP) over IPv4. In doing so, the BGP Next Hop field is used to convey the IPv4 address of the 6PE router so that dynamically established IPv4-signaled MPLS Label Switched Paths (LSPs) can be used without explicit tunnel configuration. [STANDARDS-TRACK]

Mobile IP, as originally specified, defines an authentication extension (the Mobile-Foreign Authentication extension) by which a mobile node can authenticate itself to a foreign agent. Unfortunately, that extension does not provide the foreign agent any direct guarantee that the protocol is protected from replays and does not allow for the use of existing techniques (such as Challenge Handshake Authentication Protocol (CHAP)) for authenticating portable computer devices.

In this specification, we define extensions for the Mobile IP Agent Advertisements and the Registration Request that allow a foreign agent to use a challenge/response mechanism to authenticate the mobile node.