--- 1/draft-ietf-ipv6-node-requirements-01.txt 2006-02-05 00:02:48.000000000 +0100 +++ 2/draft-ietf-ipv6-node-requirements-02.txt 2006-02-05 00:02:48.000000000 +0100 @@ -1,19 +1,19 @@ -Network Working Group John Loughney (ed) +IPv6 Working Group John Loughney (ed) Internet-Draft Nokia - July 1, 2002 + October 31, 2002 -Expires: December 29, 2002 +Expires: April 31, 2003 IPv6 Node Requirements - draft-ietf-ipv6-node-requirements-01.txt + draft-ietf-ipv6-node-requirements-02.txt Status of this Memo This document is an Internet-Draft and is in full conformance with all provisions of Section 10 of RFC2026. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. @@ -22,54 +22,56 @@ and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt. The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. - This Internet-Draft will expire on January 1, 2003. + This Internet-Draft will expire on April 31, 2003 Copyright Notice Copyright (C) The Internet Society (2002). All Rights Reserved. Abstract This document defines requirements for IPv6 nodes. It is expected that IPv6 will be deployed in a wide range of devices and situations. Specifying the requirements for IPv6 nodes allows IPv6 to function well and interoperate in a large number of situations and deployments. Table of Contents 1. Introduction 1.1 Scope of this Document - 1.2 Description of IPv6 Nodes & Conformance Groups + 1.2 Description of IPv6 Nodes 2. Abbreviations Used in This Document 3. Sub-IP Layer - 3.1 IPv6 over Foo + 3.1 RFC2464 - Transmission of IPv6 Packets over Ethernet Networks + 3.2 RFC2472 - IP version 6 over PPP + 3.3 RFC2492 - IPv6 over ATM Networks 4. IP Layer 4.1 General 4.2 Neighbor Discovery 4.3 Path MTU Discovery & Packet Size - 4.4 ICMPv6 + 4.4 RFC2463 - ICMP for the Internet Protocol Version 6 (IPv6) 4.5 Addressing 4.6 Other 5. Transport and DNS 5.1 Transport Layer 5.2 DNS - 5.3 Other - 6. Transition + 5.3 Dynamic Host Configuration Protocol for IPv6 (DHCPv6) + 6. IPv4 Support and Transition 6.1 Transition Mechanisms 7. Mobility 8. Security 8.1 Basic Architecture 8.2 Security Protocols 8.3 Transforms and Algorithms 8.4 Key Management Method 9. Router Functionality 9.1 General 10. Network Management @@ -90,23 +92,23 @@ required for an IPv6 node. Many IPv6 nodes will implement optional or additional features, but all IPv6 nodes can be expected to implement the requirements listed in this document. The document is written to minimize protocol discussion in this document but instead make pointers to RFCs. In case of any conflicting text, this document takes less precedence than the normative RFCs, unless additional clarifying text is included in this document. - During the process of writing this document, if any issue is raised + During the process of writing this document, any issue raised regarding the normative RFCs, the consensus is, whenever possible, to - fix the RFCs not to add text in this document. However, it may be + fix the RFCs and not to add text in this document. However, it may be useful to include this information in an appendix for informative purposes. Although the document points to different specifications, it should be noted that in most cases, the granularity of requirements are smaller than a single specification, as many specifications define multiple, independent pieces, some of which may not be mandatory. As it is not always possible for an implementer to know the exact usage of IPv6 in a node, an overriding requirement for IPv6 nodes is @@ -118,32 +120,26 @@ 1.1 Scope of this Document IPv6 covers many specifications. It is intended that IPv6 will be deployed in many different situations and environments. Therefore, it is important to develop the requirements for IPv6 nodes, in order to ensure interoperability. This document assumes that all IPv6 nodes meet the minimum requirements specified here. -1.2 Description of IPv6 Nodes & Conformance Groups - - This document defines three classes of conformance for an IPv6 node: - Unconditionally Mandatory, Conditionally Mandatory and - Unconditionally Optional. The three classes of conformance are - defined in section 1.2. +1.2 Description of IPv6 Nodes From Internet Protocol, Version 6 (IPv6) Specification [RFC-2460] we have the following definitions: Description of an IPv6 Node - - a device that implements IPv6 Description of an IPv6 router - a node that forwards IPv6 packets not explicitly addressed to itself. Description of an IPv6 Host - any node that is not a router. @@ -141,547 +137,457 @@ Description of an IPv6 router - a node that forwards IPv6 packets not explicitly addressed to itself. Description of an IPv6 Host - any node that is not a router. - Usage of IPv6 nodes - - TBD - - Conformance Group - - A conformance group is a collection of related behavioral - specifications that appear in standards. A single RFC may contain - multiple independent pieces of functionality that belong to - separate conformance groups. If a node claims compliance to a - given conformance group, that means it implements all of the - mandatory behavior therein, including implementing all MUSTs, and - none of the MUST NOTs. - - Unconditionally Mandatory - - If a node claims compliance to this document, then it must support - the behavior specified within each conformance group listed of - type unconditionally mandatory. - - Conditionally Mandatory - - Conditionally mandatory groups include those which are mandatory - only if a particular condition is true, such as whether a specific - type of hardware is present, or whether another given group is - implemented. When a conditionally mandatory specification or - group is described, the condition will also be described. A given - RFC or portion thereof can sometimes appear in multiple - conformance groups, with different conditions. - - Unconditionally Optional - Behavior that is neither unconditionally mandatory nor - conditionally mandatory is unconditionally optional for compliance - to this document. - 2. Abbreviations Used in This Document + ATM Asynchronous Transfer Mode + AH Authentication Header DAD Duplicate Address Detection ESP Encapsulating Security Payload ICMP Internet Control Message Protocol MIB Management Information Base MTU Maximum Transfer Unit NA Neighbor Advertisement + NBMA Non-Broadcast Multiple Access + ND Neighbor Discovery NS Neighbor Solicitation NUD Neighbor Unreachability Detection -3. Sub-IP Layer - - An IPv6 node must follow the RFC related to the link-layer that is - sending packet. By definition, these specifications are - conditionally mandatory, based upon what layer-2 is used. In - general, it is reasonable to be a conformant IPv6 node and NOT - support some legacy interfaces. - -3.1 A.K.A - IPv6 over Foo - -3.1.1 RFC2464 - Transmission of IPv6 Packets over Ethernet Networks - - Transmission of IPv6 Packets over Ethernet Networks [RFC-2464] is - conditionally mandatory if the node supports Ethernet interfaces. + PPP Point-to-Point Protocol -3.1.2 RFC2467 - A Method for the Transmission of IPv6 Packets over FDDI - Networks + ULP Upper Layer Protocol - A Method for the Transmission of IPv6 Packets over FDDI Networks - [RFC-2467] is conditionally mandatory if the node supports FDDI - interfaces. +3. Sub-IP Layer -3.1.3 RFC2470 - A Method for the Transmission of IPv6 Packets over Token - Ring Networks + An IPv6 node must follow the RFC related to the link-layer that is + sending packet. By definition, these specifications are required + based upon what layer-2 is used. In general, it is reasonable to be + a conformant IPv6 node and NOT support some legacy interfaces. - A Method for the Transmission of IPv6 Packets over Token Ring - Networks [RFC-2470] is conditionally mandatory if the node supports - token ring interfaces. + As IPv6 is run over new layer 2 technologies, it is expected that new + specifications will be issued. This section highlights some major + layer 2 technologies and is not intended to be complete. -3.1.4 RFC2472 - IP version 6 over PPP +3.1 RFC2464 - Transmission of IPv6 Packets over Ethernet Networks - IPv6 over PPP [RFC-2472] is conditionally mandatory if the node - supports PPP. + Transmission of IPv6 Packets over Ethernet Networks [RFC-2464] MUST + be supported for nodes supporting Ethernet interfaces. -3.1.5 RFC2491 - IPv6 over Non-Broadcast Multiple Access (NBMA) Networks +3.2 RFC2472 - IP version 6 over PPP - IPv6 over Non-Broadcast Multiple Access (NBMA) Networks [RFC2491] is - conditionally mandatory if the node supports NBMA network interfaces. + IPv6 over PPP [RFC-2472] is MUST be supported for nodes that use PPP. -3.1.6 RFC2492 - IPv6 over ATM Networks +3.3 RFC2492 - IPv6 over ATM Networks - IPv6 over ATM Networks [RFC2492] is conditionally mandatory if the - node supports ATM interfaces. Additionally, the specification - states: + IPv6 over ATM Networks [RFC2492] is MUSt be supported for nodes + supporting ATM interfaces. Additionally, the specification states: A minimally conforming IPv6/ATM driver SHALL support the PVC mode of operation. An IPv6/ATM driver that supports the full SVC mode SHALL also support PVC mode of operation. -3.1.7 RFC2497 - A Method for the Transmission of IPv6 Packets over - ARCnet Networks - - A Method for the Transmission of IPv6 Packets over ARCnet Networks - [RFC2497] is conditionally mandatory if the node supports ARCnet - network interfaces. - -3.1.8 RFC2529 - Transmission of IPv6 Packets over IPv4 Domains without - Explicit Tunnels - - Transmission of IPv6 Packets over IPv4 Domains without Explicit - Tunnels [2529] is unconditionally optional. - -3.1.9 RFC2590 - Transmission of IPv6 Packets over Frame Relay Networks - Specification - - Transmission of IPv6 Packets over Frame Relay Networks Specification - [RFC2590] is conditionally mandatory if the node supports Frame Relay - interfaces. - 4. IP Layer 4.1 General 4.1.1 RFC2460 - Internet Protocol Version 6 The Internet Protocol Version 6 is specified in [RFC-2460]. This - specification is unconditionally mandatory. + specification MUST be supported. Unrecognized options in Hop-by-Hop Options or Destination Options - extensions must be processed as described in RFC 2460. + extensions MUST be processed as described in RFC 2460. - The node must follow the packet transmission rules in RFC 2460. + The node MUST follow the packet transmission rules in RFC 2460. - Nodes must always be able to receive fragment headers. However, if it + Nodes MUST always be able to receive fragment headers. However, if it does not implement path MTU discovery it may not need to send fragment headers. However, nodes that do not implement transmission of fragment headers need to impose limitation to payload size of layer 4 protocols. - The capability of being a final destination is unconditionally - mandatory, whereas the capability of being an intermediate - destination is unconditionally optional (i.e. - host functionality - vs. router functionality). + The capability of being a final destination MUST be supported, + whereas the capability of being an intermediate destination is MAY be + supported(i.e. - host functionality vs. router functionality). RFC 2460 specifies extension headers and the processing for these headers. A full implementation of IPv6 includes implementation of the following extension headers: Hop-by-Hop Options, Routing (Type 0), Fragment, Destination Options, Authentication and Encapsulating Security Payload. [RFC2460] - It is unconditionally mandatory for an IPv6 node to process these - headers. It should be noted that there is some discussion about the - use of Routing Headers and possible security threats [IPv6-RH] caused - by them. + An IPv6 node MUST be able to process these headers. It should be + noted that there is some discussion about the use of Routing Headers + and possible security threats [IPv6-RH] caused by them. 4.2 Neighbor Discovery 4.2.1 RFC2461 - Neighbor Discovery for IPv6 - Neighbor Discovery is conditionally mandatory. RFC 2461 states: + Neighbor Discovery is SHOULD be supported. RFC 2461 states: "Unless specified otherwise (in a document that covers operating IP over a particular link type) this document applies to all link types. However, because ND uses link-layer multicast for some of its services, it is possible that on some link types (e.g., NBMA links) alternative protocols or mechanisms to implement those services will be specified (in the appropriate document covering the operation of IP over a particular link type). The services described in this document that are not directly dependent on multicast, such as Redirects, Next-hop determination, Neighbor Unreachability Detection, etc., are expected to be provided as specified in this document. The details of how one uses ND on NBMA links is an area for further study." Some detailed analysis of Neighbor discovery follows: Router Discovery is how hosts locate routers that reside on an - attached link. Router Discovery is unconditionally mandatory for - implementations. However, the implementation MAY support disabling - this feature. + attached link. Router Discovery is MUST be supported for + implementations. However, an implementation MAY support disabling + this function. Prefix Discovery is how hosts discover the set of address prefixes that define which destinations are on-link for an attached link. - Prefix discovery is unconditionally mandatory for implementation with - option to disable this function. - - Address resolution is how nodes determine the link-layer address of - an on-link destination (e.g., a neighbor) given only the - destination's IP address. It is conditionally mandatory - implementation depending on the link type support. Address Resolution - for point-to-point links may not be mandatory; working group - clarification is needed on this. + Prefix discovery is MUST be supported for implementations. However, + the implementation MAY support the option of disabling this function. - Neighbor Unreachability Detection (NUD) is conditionally mandatory. - It is unconditionally mandatory for all paths between hosts and - neighboring nodes. It is unconditionally optional for paths between - routers. It is unconditionally optional for multicast. However, when - a node receives a unicast Neighbor Solicitation (NS) message (that - may be a NUD's NS), the node MUST respond to it (i.e. send a unicast + Neighbor Unreachability Detection (NUD) MUST be supported for all + paths between hosts and neighboring nodes. It is not required for + paths between routers. It is required for multicast. However, when a + node receives a unicast Neighbor Solicitation (NS) message (that may + be a NUD's NS), the node MUST respond to it (i.e. send a unicast Neighbor Advertisement). - Duplicate Address Detection is unconditionally mandatory (RFC2462 - section 5.4 specifies DAD MUST take place on all unicast addresses). + Duplicate Address Detection is MUST be supported (RFC2462 section 5.4 + specifies DAD MUST take place on all unicast addresses). - Sending Router Solicitation is unconditionally mandatory for host - implementation, with a configuration option to disable this - functionality. + Sending Router Solicitation MUST be supported for host + implementation, but MAY support a configuration option to disable + this functionality. - Receiving and processing Router Advertisements is unconditionally - mandatory for host implementation, with a configuration option to - disable this functionality. The ability to understand specific Router - Advertisements is dependent on supporting the specification where the - RA is specified. + Receiving and processing Router Advertisements MUST be supported for + host implementation s. However, the implementation MAY support the + option of disabling this function. The ability to understand specific + Router Advertisements is dependent on supporting the specification + where the RA is specified. Sending and Receiving Neighbor Solicitation (NS) and Neighbor - Advertisement (NA) are unconditionally mandatory. NS and NA messages - are required for Duplicate Address Detection (DAD). + Advertisement (NA) MUST be supported. NS and NA messages are required + for Duplicate Address Detection (DAD). - Redirect Function is conditionally mandatory. If the node is a - router, Redirect Function is unconditionally mandatory. + Redirect Function SHOULD be supported. If the node is a router, + Redirect Function MUST be supported. 4.3 Path MTU Discovery & Packet Size 4.3.1 RFC1981 - Path MTU Discovery - Path MTU Discovery [RFC-1981] is unconditionally optional. The IPv6 - specification [RFC-2460] states in section 5 that "a minimal IPv6 - implementation (e.g., in a boot ROM) may simply restrict itself to - sending packets no larger than 1280 octets, and omit implementation - of Path MTU Discovery." + Path MTU Discovery [RFC-1981] MAY be supported. Nodes with a link + MTU larger than the minimum IPv6 link MTU (1280 octets) can use Path + MTU Discovery in order to discover the real path MTU. The relative + overhead of IPv6 headers is minimized through the use of longer + packets, thus making better use of the available bandwidth. + + The IPv6 specification [RFC-2460] states in chapter 5 that "a minimal + IPv6 implementation (e.g., in a boot ROM) may simply restrict itself + to sending packets no larger than 1280 octets, and omit + implementation of Path MTU Discovery." If Path MTU Discovery is not implemented then the sending packet size - is limited to 1280 octets (standard limit in [RFC-2460]). + is limited to 1280 octets (standard limit in [RFC-2460]). However, if + this is done, the host MUST be able to receive packets with size up + to the link MTU before reassembly. This is because the node at the + other side of the link has no way of knowing less than the MTU is + accepted. 4.3.2 RFC2675 - IPv6 Jumbograms - IPv6 Jumbograms [RFC2675] is unconditionally optional. - -4.4 ICMPv6 + IPv6 Jumbograms [RFC2675] MAY be supported. -4.1.1 RFC2463 - ICMP for the Internet Protocol Version 6 (IPv6) +4.4 RFC2463 - ICMP for the Internet Protocol Version 6 (IPv6) - ICMPv6 [RFC-2463] is unconditionally mandatory. + ICMPv6 [RFC-2463] MUST be supported. 4.5 Addressing Currently, there is discussion on-going on support for site-local addressing. 4.5.1 RFC2373 - IP Version 6 Addressing Architecture - The IPv6 Addressing Architecture [RFC-2373] is a mandatory part of - IPv6. Currently, this specification is being updated by [ADDRARCHv3]. + The IPv6 Addressing Architecture [RFC-2373] MUST be supported. + Currently, this specification is being updated by [ADDRARCHv3]. 4.5.2 RFC2462 - IPv6 Stateless Address Autoconfiguration IPv6 Stateless Address Autoconfiguration is defined in [RFC-2462]. - This specification is unconditionally mandatory for nodes that are - hosts. + This specification MUST be supported for nodes that are hosts. - It is unconditionally mandatory for nodes that are routers to - generate link local addresses as described in this specification. + Nodes that are routers MUST be able to generate link local addresses + as described in this specification. From 2462: The autoconfiguration process specified in this document applies only to hosts and not routers. Since host autoconfiguration uses information advertised by routers, routers will need to be configured by some other means. However, it is expected that routers will generate link-local addresses using the mechanism described in this document. In addition, routers are expected to successfully pass the Duplicate Address Detection procedure described in this document on all addresses prior to assigning them to an interface. - Duplicate Address Detection (DAD) is unconditionally mandatory for - all interface addresses assigned to the node. + Duplicate Address Detection (DAD) MUST be supported. 4.5.3 RFC3041 - Privacy Extensions for Address Configuration in IPv6 Privacy Extensions for Stateless Address Autoconfiguration [RFC-3041] - is unconditionally optional. Currently, there is discussion of the + MAY be supported. Currently, there is discussion of the applicability of temporary addresses. 4.5.4 Default Address Selection for IPv6 - Default Address Selection for IPv6 [DEFADDR] is conditionally - mandatory, if a node has more than one IPv6 address per interface or - a node has more that one IPv6 interface (physical or logical) - configured. + Default Address Selection for IPv6 [DEFADDR] SHOULD be supported, if + a node has more than one IPv6 address per interface or a node has + more that one IPv6 interface (physical or logical) configured. The rules specified in the document are the only MUST to implement - portion of the architecture. There is no requirement that a node be - able to be part of more than one zone. + portion of the architecture. A node MUST belong to one site. There + is no requirement that a node be able to belong to more than one. + + This draft has been approved as a proposed standard. 4.5.5 Stateful Address Autoconfiguration - IPv6 Stateless Address Autoconfiguration [RFC2462] defines stateless - address autoconfiguation. However, it does state that in the absence - of routers, hosts MUST attempt to use stateful autoconfiguration. - There is also reference to stateful address autoconfiguration being - defined elsewhere. Additionally, DHCP [DHCP] states that it is on - option for stateful address autoconfiguation. + Stateful Address Autoconfiguration MAY be supported. For those IPv6 + Nodes that implement a stateful configuration mechanism such as + [DHCPv6], those nodes MUST initiate stateful address + autoconfiguration upon the receipt of a Router Advertisement with the + Managed address flag set. In addition, as defined in [RFC2462], in + the absence of a router, hosts that implement a stateful + configuration mechanism such as [DHCPv6] MUST attempt to use stateful + address autoconfiguration. - From the current set of specification, it is not clear the level of - support that is needed for statefull Address Autoconfiguration. + For IPv6 Nodes that do not implement the optional stateful + configuration mechanisms such as [DHCPv6], the Managed Address flag + of a Router Advertisement can be ignored. Furthermore, in the + absence of a router, this type of node is not required to initiate + stateful address autoconfiguration as specified in [RFC2462]. 4.6 Other 4.6.1 RFC2473 - Generic Packet Tunneling in IPv6 Specification - Generic Packet Tunneling [RFC-2473] conditionally mandatory, with the - condition being implementing the mobile node functionality or Home - Agent functionality of Mobile IP [MIPv6]. + + Generic Packet Tunneling [RFC-2473] MUST be suppored for nodes + implementing mobile node functionality or Home Agent functionality of + Mobile IP [MIPv6]. 4.6.2 RFC2710 - Multicast Listener Discovery (MLD) for IPv6 - Multicast Listener Discovery [RFC-2710] is Conditionally Mandatory, - where the condition is if the node joins any multicast groups other - than the all-nodes-on-link group (which will always be the case if it - runs ND or DAD on the link). + Multicast Listener Discovery [RFC-2710] MUST be supported by nodes + supporting multicast applications. A primary IPv6 multicast + application is Neighbor Discovery (all those solicited-node mcast + addresses must be joined). - There has been some discussion that hosts may not be able to depend - on MLD if there is no connection to a router, therefore this may not - be Mandatory. Further discussion is needed on this. + When MLDv2 [MLDv2] has been completed, it SHOULD take precedence over + MLD. 5. Transport Layer and DNS 5.1 Transport Layer 5.1.1 RFC2147 - TCP and UDP over IPv6 Jumbograms - This specification is conditionally mandatory, if Jumbograms are - implemented [RFC-2675]. One open issue is if this document needs to - be updated, as it refers to an obsoleted document. + This specification is MUST be supported if jumbograms are implemented + [RFC-2675]. One open issue is if this document needs to be updated, + as it refers to an obsoleted document. 5.2 DNS - - Support for DNS, as described in [RFC-1034], [RFC-1035] and [RFC- - 1886], is unconditionally optional. Not all nodes will need to - resolve addresses. + DNS, as described in [RFC-1034], [RFC-1035] and [RFC-1886] MAY be + supported. Not all nodes will need to resolve addresses. 5.2.1 RFC2874 - DNS Extensions to Support IPv6 Address Aggregation and Renumbering - DNS Extensions to Support IPv6 Address Aggregation and Renumbering is - unconditionally optional + DNS Extensions to Support IPv6 Address Aggregation and Renumbering + MAY be supported. 5.2.2 RFC2732 - Format for Literal IPv6 Addresses in URL's - RFC 2732 is conditionally mandatory if the node uses URL's. + RFC 2732 is MUST be supported if applications on the node use URL's. -5.3 Other +5.3 Dynamic Host Configuration Protocol for IPv6 (DHCPv6) -5.3.1 Dynamic Host Configuration Protocol for IPv6 (DHCPv6) + The Dynamic Host Configuration Protocol for IPv6 [DHCPv6] is MAY be + supported. - The Dynamic Host Configuration Protocol for IPv6 [DHCPv6] is - unconditionally optional. +6. IPv4 Support and Transition -6. Transition + IPv6 nodes MAY support IPv4. However, this document should consider + the following cases: native IPv6 only; native IPv6 with IPv4 + supported only via tunneling over IPv6; and native IPv6 and native + IPv4 both fully supported. 6.1 Transition Mechanisms - IPv6 nodes should use native address instead of transition-based + IPv6 nodes SHOULD use native address instead of transition-based addressing. 6.1.1 RFC2893 - Transition Mechanisms for IPv6 Hosts and Routers If an IPv6 node implement dual stack and/or tunneling, then RFC2893 - is unconditionally mandatory. + MUST be supported. This document is currently being updated. 7. Mobility Currently, the MIPv6 specification [MIPv6] is nearing completion. Mobile IPv6 places some requirements on IPv6 nodes. This document is not meant to prescribe behaviors, but to capture the consensus of what should be done for IPv6 nodes with respect to Mobile IPv6. - The Mobile IP specification [MIPv6] specifies the following classes - of functionality: Correspondent Node, Mobile Node, Route Optimization - functionality and Home Agent Functionality. - - Correspondent Node functionality is Unconditionally Mandatory. - - Mobile Node functionality is Conditionally Mandatory for nodes that - need to maintain sessions while changing their point of attachment to - the Internet. + Mobile Node functionality MAY be supported. - Route Optimization functionality is conditionally mandatory for - hosts. Route Optimization is unconditionally optional for routers. - There is ongoing discussion about the role of Route Optimization. - This document should list some of the benefits of Route Optimization. + Route Optimization functionality SHOULD be supported for hosts. + Route Optimization is not required for routers. - Home Agent functionality is Unconditionally Optional. + Home Agent functionality is MAY be supported. 8. Security This section describes the specification of IPsec for the IPv6 node. Other issues that IPsec cannot resolve are described in the security considerations. 8.1 Basic Architecture - Security Architecture for the Internet Protocol [RFC-2401] is - unconditionally mandatory except of the following description. - - Requirements that this section describes explicitly MUST refer to - RFC-2401. - - IPsec transport mode is unconditionally mandatory. - - IPsec tunnel mode is unconditionally mandatory. - - [DISCUSSION: Network administrators want to make separated - networks to be a single network by using a site-local address - space. The routers should be implemented both IPsec transport - mode and a generic tunnel in this case, but if there is no - statement what it should be, the administrators must use IPsec - tunnel mode because it is used now in IPv4 network.] + Security Architecture for the Internet Protocol [RFC-2401] MUST be + supported. IPsec transport mode MUST be supported. IPsec tunnel mode + MUST be supoorted. Applying single security association of ESP [RFC-2406] to a packet is - unconditionally mandatory, although RFC-2401 defines four types of - combination of security associations that must be supported by - compliant IPsec hosts. + MUST, although RFC-2401 defines four types of combination of security + associations that must be supported by compliant IPsec hosts. - Applying single security association of AH is conditionally mandatory - if AH [RFC-2402] is implemented. + Applying single security association of AH is MUST be supported, if + AH [RFC-2402] is implemented. - The following packet type is conditionally mandatory if AH is - combined with ESP: IP|AH|ESP|ULP. + The following packet type MUST be supported if AH is combined with + ESP: IP|AH|ESP|ULP. The summary of Basic Combinations of Security Associations in section 4.5 of RFC-2401 is: - case 1-2 is unconditionally mandatory. - case 1-1 and 1-3 is conditionally mandatory if AH is implemented. - case 1-4, 1-5, 2-5 and 4 is conditionally optional if IPsec tunnel - mode is implemented. - case 2-4 is conditionally optional if IPsec tunnel mode and AH is + case 1-2 MUST be supported. + case 1-1 and 1-3 MUST be supported if AH is implemented. + case 1-4, 1-5, 2-5 and 4 MUST be supported if IPsec tunnel mode is + implemented. + case 2-4 is MUST be supported if IPsec tunnel mode and AH is implemented. case 3 is not applicable to this document. 8.2 Security Protocols - ESP [RFC-2406] is unconditionally mandatory even when ESP is not - used. AH [RFC-2402] is unconditionally mandatory also. + ESP [RFC-2406] MUST be supported. - AH is need if there is data in IP header to be protected, for - example, an extension header. + AH [RFC-2402] MUST be supported. AH is needed if there is data in IP + header to be protected, for example, an extension header. - In practice, ESP can provide the same security services as AH and as - well as confidentiality, thus there is no real need for AH. + However, in practice, ESP can provide the same security services as + AH as well as confidentiality, thus there is no real need for AH. 8.3 Transforms and Algorithms - The ESP DES-CBC Cipher Algorithm With Explicit IV [RFC-2405] is - conditionally mandatory if you need to have interoperability with old - implementation by using DES-CBC. Note the IPsec WG recommends not - using this algorithm. 3DES-CBC is conditionally mandatory so that the - part of ESP CBC-Mode Cipher Algorithms [RFC-2451] is unconditionally - mandatory. Note that the IPsec WG also recommends not using this - algorithm. AES-128-CBC [ipsec-ciph-aes-cbc] is unconditionally - mandatory but there is on-going work in the IPsec WG. NULL Encryption - algorithm [RFC-2410] is conditionally mandatory. It is only for - providing integrity service, and also for debugging use. - The use of HMAC-SHA-1-96 within ESP, described in [RFC-2404], is - unconditionally mandatory. This MUST be used if AH is implemented. - The Use of HMAC-MD5-96 within ESP, described in [RFC-2403], is - unconditionally mandatory. This MUST be used if AH is implemented. - The "HMAC-SHA-256-96 Algorithm and Its Use With IPsec" [ipsec-ciph- - sha-256] is unconditionally mandatory, but it is being discussed in - the IPsec WG. An implementer MUST refer to Keyed-Hashing for Message - Authentication [RFC-2104]. + The ESP DES-CBC Cipher Algorithm With Explicit IV [RFC-2405] is MUST + be supported if interoperability is required with old implementations + supported DES-CBC. Note, however, the IPsec WG recommends not using + this algorithm. 3DES-CBC is SHOULD be supported, so that ESP CBC-Mode + Cipher Algorithms [RFC-2451] MUST be supported. Note that the IPsec + WG also recommends not using this algorithm. -8.4 Key Management Method + AES-128-CBC [ipsec-ciph-aes-cbc] is MUST be supported. NULL + Encryption algorithm [RFC-2410] MUST be supported for providing + integrity service and also for debugging use. - Manual keying is unconditionally mandatory. + The use of HMAC-SHA-1-96 within ESP, described in [RFC-2404] MUST be + supported. This MUST be used if AH is implemented. The Use of HMAC- + MD5-96 within ESP, described in [RFC-2403] MUST be supported. This + MUST be used if AH is implemented. The "HMAC-SHA-256-96 Algorithm and + Its Use With IPsec" [ipsec-ciph-sha-256] MUST be supported, but it is + being discussed in the IPsec WG. An implementer MUST refer to Keyed- + Hashing for Message Authentication [RFC-2104]. - Automated SA and Key Management is conditionally mandatory for the - use of the anti-replay features of AH and ESP, and to accommodate - on-demand creation of SAs, session-oriented keying. +8.4 Key Management Methods - IKE [RFC-2407, RFC-2408, RFC-2409] is unconditionally optional for - unicast traffic. Note that the IPsec WG is working on the successor - to IKE [SOI]. + Manual keying MUST be supported + + Automated SA and Key Management SHOULD be supported for the use of + the anti-replay features of AH and ESP, and to accommodate on-demand + creation of SAs, session-oriented keying. + + IKE [RFC-2407, RFC-2408, RFC-2409] MAY be supported for unicast + traffic. Note that the IPsec WG is working on the successor to IKE + [SOI]. 9. Router Functionality This section defines general considerations for IPv6 nodes that act as routers. It is for future study if this document, or a separate document is needed to fully define IPv6 router requirements. Currently, this section does not discuss routing protocols. 9.1 General 9.1.1 RFC2711 - IPv6 Router Alert Option - The Router Alert Option [RFC-2711] is conditionally mandatory if the - node performs packet forwarding at the IP layer (i.e. - the node is a + The Router Alert Option [RFC-2711] is MUST be supported by nodes that + perform packet forwarding at the IP layer (i.e. - the node is a router). 9.1.2 RFC2461 - Neighbor Discovery for IPv6 - Sending Router Advertisements and processing Router Solicitation is - unconditionally mandatory. + + Sending Router Advertisements and processing Router Solicitation MUST + be supported. 10. Network Management - Network Management, is generally not a requirement for IPv6 nodes. - However, for IPv6 nodes that are embedded devices, network management - may be the only possibility to control these hosts. + Network Management, MAY be supported by IPv6 nodes. However, for + IPv6 nodes that are embedded devices, network management may be the + only possibility to control these hosts. 10.1 MIBs - In a general sense, MIBs can be considered conditionally mandatory - when the node supports an SNMP agent. This section is for further - study. It should be also noted that these specifications are being - updated updated. + In a general sense, MIBs are required by the nodes that support a + SNMP agent. It should be also noted that these specifications are + being updated. 10.1.1 RFC2452 - IPv6 Management Information Base for the Transmission Control Protocol TBA 10.1.2 RFC2454 - IPv6 Management Information Base for the User Datagram Protocol TBA @@ -710,23 +617,23 @@ implementations of IPv6 are expected to support a minimum set of security features to ensure security on the Internet. "IP Security Document Roadmap" [RFC-2411] is important for everyone to read. The security considerations in RFC2401 describes, The security features of IPv6 are described in the Security Architecture for the Internet Protocol [RFC-2401]. IPsec cannot cover all of security requirement for IPv6 node. For - example, IPsec cannot protect the node from kind of DoS attack. The - node may need a mechanism of IPv6 packet filtering functionality, and - also may need a mechanism of rate limitation. + example, IPsec cannot protect the node from some kinds of DoS attack. + The node may need a mechanism of IPv6 packet filtering functionality, + and also may need a mechanism of rate limitation. The use of ICMPv6 without IPsec can expose the nodes in question to various kind of attacks including Denial-of-Service, Impersonation, Man-in-the-Middle, and others. Note that only manually keyed IPsec can protect some of the ICMPv6 messages that are related to establishing communications. This is due to chick en-and-egg problems on running automated key management protocols on top of IP. However, manually keyed IPsec may require a large number of SAs in order to run on a large network due to the use of many addresses during ICMPv6 Neighbor Discovery. @@ -734,189 +641,184 @@ An implementer should also consider the analysis of anycast [ANYCAST]. 12. References 12.1 Normative [ADDRARCHv3] Hinden, R. and Deering, S. "IP Version 6 Addressing Architecture", Work in progress. - [DEFADDR] Draves, R., "Default Address Selection for IPv6", Work - in progress. +[DEFADDR] Draves, R., "Default Address Selection for IPv6", Work in + progress. [DHCPv6] Bound, J. et al., "Dynamic Host Configuration Protocol for IPv6 (DHCPv6)", Work in progress. - [MIPv6] Johnson D. and Perkins, C., "Mobility Support in - IPv6", Work in progress. +[MIPv6] Johnson D. and Perkins, C., "Mobility Support in IPv6", + Work in progress. - [RFC-1035] Mockapetris, P., "Domain names - implementation and - specification", STD 13, RFC 1035, November 1987. +[MLDv2] Vida, R. et al., "Multicast Listener Discovery Version 2 + (MLDv2) for IPv6", Work in Progress. - [RFC-1886] Thomson, S. and Huitema, C., "DNS Extensions to sup- - port IP version 6, RFC 1886, December 1995. +[RFC-1035] Mockapetris, P., "Domain names - implementation and specˇ + ification", STD 13, RFC 1035, November 1987. - [RFC-1981] McCann, J., Mogul, J. and Deering, S., "Path MTU - Discovery for IP version 6", RFC 1981, August 1996. +[RFC-1886] Thomson, S. and Huitema, C., "DNS Extensions to support + IP version 6, RFC 1886, December 1995. - [RFC-2104] Krawczyk, K., Bellare, M., and Canetti, R., "HMAC: - Keyed-Hashing for Message Authentication", RFC 2104, - February 1997. +[RFC-1981] McCann, J., Mogul, J. and Deering, S., "Path MTU Discovˇ + ery for IP version 6", RFC 1981, August 1996. + +[RFC-2104] Krawczyk, K., Bellare, M., and Canetti, R., "HMAC: Keyed- + Hashing for Message Authentication", RFC 2104, February + 1997. [RFC-2373] Hinden, R. and Deering, S., "IP Version 6 Addressing Architecture", RFC 2373, July 1998. - [RFC-2401] Kent, S. and Atkinson, R., "Security Architecture for - the Internet Protocol", RFC 2401, November 1998. +[RFC-2401] Kent, S. and Atkinson, R., "Security Architecture for the + Internet Protocol", RFC 2401, November 1998. - [RFC-2402] Kent, S. and Atkinson, R., "IP Authentication - Header", RFC 2402, November 1998. +[RFC-2402] Kent, S. and Atkinson, R., "IP Authentication Header", + RFC 2402, November 1998. [RFC-2403] Madson, C., and Glenn, R., "The Use of HMAC-MD5 within ESP and AH", RFC 2403, November 1998. - [RFC-2404] Madson, C., and Glenn, R., "The Use of HMAC-SHA-1 - within ESP and AH", RFC 2404, November 1998. +[RFC-2404] Madson, C., and Glenn, R., "The Use of HMAC-SHA-1 within + ESP and AH", RFC 2404, November 1998. [RFC-2405] Madson, C. and Doraswamy, N., "The ESP DES-CBC Cipher Algorithm With Explicit IV", RFC 2405, November 1998. [RFC-2406] Kent, S. and Atkinson, R., "IP Encapsulating Security Protocol (ESP)", RFC 2406, November 1998. - [RFC-2407] Piper, D., "The Internet IP Security Domain of - Interpretation for ISAKMP", RFC 2407, November 1998. +[RFC-2407] Piper, D., "The Internet IP Security Domain of Interpreˇ + tation for ISAKMP", RFC 2407, November 1998. [RFC-2408] Maughan, D., Schertler, M., Schneider, M., and Turner, J., "Internet Security Association and Key Management Protocol (ISAKMP)", RFC 2408, November 1998. - [RFC-2409] Harkins, D., and Carrel, D., "The Internet Key - Exchange (IKE)", RFC 2409, November 1998. +[RFC-2409] Harkins, D., and Carrel, D., "The Internet Key Exchange + (IKE)", RFC 2409, November 1998. [RFC-2410] Glenn, R. and Kent, S., "The NULL Encryption Algorithm and Its Use With IPsec", RFC 2410, November 1998 - [RFC-2451] Pereira, R. and Adams, R., "The ESP CBC-Mode Cipher - Algorithms", RFC 2451, November 1998 +[RFC-2451] Pereira, R. and Adams, R., "The ESP CBC-Mode Cipher Algoˇ + rithms", RFC 2451, November 1998 - [RFC-2460] Deering, S. and Hinden, R., "Internet Protocol, Ver- - sion 6 (IPv6) Specification", RFC 2460, December 1998. +[RFC-2460] Deering, S. and Hinden, R., "Internet Protocol, Version 6 + (IPv6) Specification", RFC 2460, December 1998. - [RFC-2461] Narten, T., Nordmark, E. and Simpson, W., "Neighbor - Discovery for IP Version 6 (IPv6)", RFC 2461, December - 1998. +[RFC-2461] Narten, T., Nordmark, E. and Simpson, W., "Neighbor Disˇ + covery for IP Version 6 (IPv6)", RFC 2461, December 1998. - [RFC-2462] Thomson, S. and Narten, T., "IPv6 Stateless Address - Autoconfiguration", RFC 2462. +[RFC-2462] Thomson, S. and Narten, T., "IPv6 Stateless Address Autoˇ + configuration", RFC 2462. - [RFC-2463] Conta, A. and Deering, S., "ICMP for the Internet Pro- - tocol Version 6 (IPv6)", RFC 2463, December 1998. +[RFC-2463] Conta, A. and Deering, S., "ICMP for the Internet Protoˇ + col Version 6 (IPv6)", RFC 2463, December 1998. [RFC-2472] Haskin, D. and Allen, E., "IP version 6 over PPP", RFC 2472, December 1998. - [RFC-2473] Conta, A. and Deering, S., "Generic Packet Tunneling - in IPv6 Specification", RFC 2473, December 1998. +[RFC-2473] Conta, A. and Deering, S., "Generic Packet Tunneling in + IPv6 Specification", RFC 2473, December 1998. - [RFC-2710] Deering, S., Fenner, W. and Haberman, B., "Multicast - Listener Discovery (MLD) for IPv6", RFC 2710, October - 1999. +[RFC-2710] Deering, S., Fenner, W. and Haberman, B., "Multicast Lisˇ + tener Discovery (MLD) for IPv6", RFC 2710, October 1999. [RFC-2711] Partridge, C. and Jackson, A., "IPv6 Router Alert Option", RFC 2711, October 1999. 12.2 Non-Normative - [ANYCAST] Hagino, J and Ettikan K., "An Analysis of IPv6 Any- - cast" Work in Progress. +[ANYCAST] Hagino, J and Ettikan K., "An Analysis of IPv6 Anycast" + Work in Progress. - [SOI] C. Madson, "Son-of-IKE Requirements", Work in Pro- - gress. +[SOI] C. Madson, "Son-of-IKE Requirements", Work in Progress. [RFC-793] Postel, J., "Transmission Control Protocol", RFC 793, August 1980. - [RFC-1034] Mockapetris, P., "Domain names - concepts and facili- +[RFC-1034] Mockapetris, P., "Domain names - concepts and faciliˇ ties", RFC 1034, November 1987. - [RFC-2147] Borman, D., "TCP and UDP over IPv6 Jumbograms", RFC - 2147, May 1997. +[RFC-2147] Borman, D., "TCP and UDP over IPv6 Jumbograms", RFC 2147, + May 1997. [RFC-2452] M. Daniele, "IPv6 Management Information Base for the - Transmission Control Protocol", RFC2452, December - 1998. + Transmission Control Protocol", RFC2452, December 1998. [RFC-2454] M. Daniele, "IPv6 Management Information Base for the User Datagram Protocol, RFC2454", December 1998. - [RFC-2464] Crawford, M., "Transmission of IPv6 Packets over Eth- - ernet Networks", RFC 2462, December 1998. +[RFC-2464] Crawford, M., "Transmission of IPv6 Packets over Ethernet + Networks", RFC 2462, December 1998. - [RFC-2465] D. Haskin, S. Onishi, "Management Information Base for - IP Version 6: Textual Conventions and General Group", +[RFC-2465] D. Haskin, S. Onishi, "Management Information Base for IP + Version 6: Textual Conventions and General Group", RFC2465, December 1998. - [RFC-2466] D. Haskin, S. Onishi, "Management Information Base for - IP Version 6: ICMPv6 Group", RFC2466, December 1998. - - [RFC-2467] M. Crawford, "A Method for the Tranmission of IPv6 - Packets over FDDI Networks", RFC2467, December 1998. +[RFC-2466] D. Haskin, S. Onishi, "Management Information Base for IP + Version 6: ICMPv6 Group", RFC2466, December 1998. [RFC-2470] M. Crawford, T. Narten, S. Thomas, "A Method for the Tranmission of IPv6 Packets over Token Ring Networks", RFC2470, December 1998. - [RFC-2491] G. Armitage, P. Schulter, M. Jork, G. Harter, "IPv6 - over Non-Broadcast Multiple Access (NBMA) networks", - RFC2491, January 1999. +[RFC-2491] G. Armitage, P. Schulter, M. Jork, G. Harter, "IPv6 over + Non-Broadcast Multiple Access (NBMA) networks", RFC2491, + January 1999. - [RFC-2492] G. Armitage, M. Jork, P. Schulter, G. Harter, IPv6 - over ATM Networks", RFC2492, January 1999. +[RFC-2492] G. Armitage, M. Jork, P. Schulter, G. Harter, IPv6 over + ATM Networks", RFC2492, January 1999. [RFC-2497] I. Souvatzis, "A Method for the Transmission of IPv6 Packets over ARCnet Networks", RFC2497, January 1999. [RFC-2529] Carpenter, B. and Jung, C., "Transmission of IPv6 over - IPv4 Domains without Explicit Tunnels", RFC 2529, - March 1999. + IPv4 Domains without Explicit Tunnels", RFC 2529, March + 1999. [RFC-2590] A. Conta, A. Malis, M. Mueller, "Transmission of IPv6 Packets over Frame Relay Networks Specification", RFC 2590, May 1999. - [RFC-2675] Borman, D., Deering, S. and Hinden, B., "IPv6 Jumbo- +[RFC-2675] Borman, D., Deering, S. and Hinden, B., "IPv6 Jumboˇ grams", RFC 2675, August 1999. - [RFC-2732] R. Hinden, B. Carpenter, L. Masinter, "Format for - Literal IPv6 Addresses in URL's", RFC 2732, December - 1999. +[RFC-2732] R. Hinden, B. Carpenter, L. Masinter, "Format for Literal + IPv6 Addresses in URL's", RFC 2732, December 1999. - [RFC-2851] M. Daniele, B. Haberman, S. Routhier, J. - Schoenwaelder, "Textual Conventions for Internet Net- - work Addresses", RFC2851, June 2000. +[RFC-2851] M. Daniele, B. Haberman, S. Routhier, J. Schoenwaelder, + "Textual Conventions for Internet Network Addresses", + RFC2851, June 2000. - [RFC-2874] Crawford, M. and Huitema, C., "DNS Extensions to Sup- - port IPv6 Address Aggregation and Renumbering", RFC - 2874, July 2000. +[RFC-2874] Crawford, M. and Huitema, C., "DNS Extensions to Support + IPv6 Address Aggregation and Renumbering", RFC 2874, July + 2000. - [RFC-2893] Gilligan, R. and Nordmark, E., "Transition Mechanisms - for IPv6 Hosts and Routers", RFC 2893, August 2000. +[RFC-2893] Gilligan, R. and Nordmark, E., "Transition Mechanisms for + IPv6 Hosts and Routers", RFC 2893, August 2000. - [RFC-3019] B. Haberman, R. Worzella, "IP Version 6 Management - Information Base for the Multicast Listener Discovery - Protocol", RFC3019, January 2001. +[RFC-3019] B. Haberman, R. Worzella, "IP Version 6 Management Inforˇ + mation Base for the Multicast Listener Discovery Protoˇ + col", RFC3019, January 2001. - [RFC-3041] Narten, T. and Draves, R., "Privacy Extensions for - Stateless Address Autoconfiguration in IPv6", RFC - 3041, January 2001. +[RFC-3041] Narten, T. and Draves, R., "Privacy Extensions for Stateˇ + less Address Autoconfiguration in IPv6", RFC 3041, Janˇ + uary 2001. [IPv6-RH] P. Savola, "Security of IPv6 Routing Header and Home Address Options", Work in Progress, March 2002. 13. Authors and Acknowledgements This document was written by the IPv6 Node Requirements design team: Jari Arkko [jari.arkko@ericsson.com] @@ -957,95 +859,48 @@ Dave Thaler [dthaler@windows.microsoft.com] Juha Wiljakka [juha.wiljakka@Nokia.com] The authors would like to thank Adam Machalek, Juha Ollila and Pekka Savola for their comments. 14. Editor's Contact Information - Comments or questions regarding this document should be sent to the IPv6 Working Group mailing list (ipng@sunroof.eng.sun.com) or to: + Comments or questions regarding this document should be sent to the IPv6 + Working Group mailing list (ipng@sunroof.eng.sun.com) or to: John Loughney Nokia Research Center It„merenkatu 11-13 00180 Helsinki Finland Phone: +358 50 483 6242 Email: John.Loughney@Nokia.com Appendix A: Change history The following is a list of changes since the previous version. - Small updates based upon feedback from the IPv6 mailing list. - Refomated chapters. - Added Appendix B - List of RFCs. TBD -Appendix B: List of RFCs - This is a list of RFC to look at during the editing process. They are classified by generic categories and by level of potential conformance. The * denotes some sections of the specification have lesser level of conformance required. - - RFC Section Conformance - ======================================================== - RFC-1034 5.2.1 unconditionally optional - RFC-1035 5.2.1 unconditionally optional - RFC-1886 5.2.1 unconditionally optional - RFC-1981 4.3.1 unconditionally optional - RFC-2104 8.3 conditionally mandatory - RFC-2147 5.1.1 conditionally mandatory - RFC-2373 4.5.1 unconditionally mandatory - RFC-2401 8.1 unconditionally mandatory * - RFC-2402 8.1 conditionally mandatory - RFC-2403 8.3 unconditionally mandatory - RFC-2404 8.3 unconditionally mandatory - RFC-2405 8.3 conditionally mandatory - RFC-2406 8.1 unconditionally mandatory - RFC-2407 8.4 unconditionally mandatory - RFC-2408 8.4 unconditionally mandatory - RFC-2409 8.4 unconditionally mandatory - RFC-2410 8.3 unconditionally mandatory - RFC-2451 8.3 unconditionally mandatory - RFC-2452 10.1.1 conditionally mandatory - RFC-2454 10.1.2 conditionally mandatory - RFC-2460 4.1.1 unconditionally mandatory * - RFC-2461 4.2.1 unconditionally mandatory * - RFC-2462 4.5.2 unconditionally mandatory * - RFC-2463 4.5.1 unconditionally mandatory - RFC-2464 3.1.1 conditionally mandatory - RFC-2465 10.1.3 conditionally mandatory - RFC-2466 10.1.4 conditionally mandatory - RFC-2467 3.1.2 conditionally mandatory - RFC-2470 3.1.3 conditionally mandatory - RFC-2472 3.1.4 conditionally mandatory - RFC-2473 4.6.1 conditionally mandatory - RFC-2491 3.1.5 conditionally mandatory - RFC-2492 3.1.6 conditionally mandatory - RFC-2497 3.1.7 conditionally mandatory - RFC-2529 3.1.8 unconditionally optional - RFC-2590 3.1.9 conditionally mandatory - RFC-2675 4.3.2 unconditionally optional - RFC-2710 4.6.2 conditionally mandatory - RFC-2711 9.1.1 conditionally mandatory - RFC-2732 5.2.2 conditionally mandatory - RFC-2851 10.1.5 conditionally mandatory - RFC-2874 5.3.1 unconditionally optional - RFC-2893 6.1.1 conditionally mandatory - RFC-3019 10.1.6 conditionally mandatory - RFC-3041 4.5.3 unconditionally optional - -Appendix C: Specifications Not Included +Appendix B: Specifications Not Included - Here is a list of documents considered, but not included in this document. In general, Information documents are not considered to place requirements on implementations. Experimental documents are just that, experimental, and cannot place requirements on the general behavior of IPv6 nodes. + Here is a list of documents considered, but not included in this document. + In general, Information documents are not considered to place requirements on + implementations. Experimental documents are just that, experimental, and + cannot place requirements on the general behavior of IPv6 nodes. Upper Protocols 2428 FTP Extensions For IPv6 And NATs Compression 2507 IP Header Compression 2508 Compressing IP/UDP/RTP Headers For Low-Speed Serial Links 2509 IP Header Compression Over PPP Informational