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Boucadair 3 Internet-Draft Orange 4 Updates: 7296 (if approved) November 08, 2018 5 Intended status: Standards Track 6 Expires: May 12, 2019 8 IKEv2 Notification Status Types for IPv4/IPv6 Coexistence 9 draft-ietf-ipsecme-ipv6-ipv4-codes-02 11 Abstract 13 This document specifies new IKEv2 notification status types to better 14 manage IPv4 and IPv6 co-existence. 16 This document updates RFC7296. 18 Status of This Memo 20 This Internet-Draft is submitted in full conformance with the 21 provisions of BCP 78 and BCP 79. 23 Internet-Drafts are working documents of the Internet Engineering 24 Task Force (IETF). Note that other groups may also distribute 25 working documents as Internet-Drafts. The list of current Internet- 26 Drafts is at https://datatracker.ietf.org/drafts/current/. 28 Internet-Drafts are draft documents valid for a maximum of six months 29 and may be updated, replaced, or obsoleted by other documents at any 30 time. It is inappropriate to use Internet-Drafts as reference 31 material or to cite them other than as "work in progress." 33 This Internet-Draft will expire on May 12, 2019. 35 Copyright Notice 37 Copyright (c) 2018 IETF Trust and the persons identified as the 38 document authors. All rights reserved. 40 This document is subject to BCP 78 and the IETF Trust's Legal 41 Provisions Relating to IETF Documents 42 (https://trustee.ietf.org/license-info) in effect on the date of 43 publication of this document. Please review these documents 44 carefully, as they describe your rights and restrictions with respect 45 to this document. Code Components extracted from this document must 46 include Simplified BSD License text as described in Section 4.e of 47 the Trust Legal Provisions and are provided without warranty as 48 described in the Simplified BSD License. 50 Table of Contents 52 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 53 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 54 3. Why Not INTERNAL_ADDRESS_FAILURE? . . . . . . . . . . . . . . 3 55 4. IP6_ONLY_ALLOWED and IP4_ONLY_ALLOWED Status Types . . . . . 4 56 5. An Update to RFC7296 . . . . . . . . . . . . . . . . . . . . 4 57 6. Security Considerations . . . . . . . . . . . . . . . . . . . 5 58 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5 59 8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 5 60 9. References . . . . . . . . . . . . . . . . . . . . . . . . . 5 61 9.1. Normative References . . . . . . . . . . . . . . . . . . 5 62 9.2. Informative References . . . . . . . . . . . . . . . . . 5 63 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 6 65 1. Introduction 67 As described in [RFC7849], if the subscription data or network 68 configuration allows only one IP address family (IPv4 or IPv6), the 69 cellular host must not request a second PDP-Context to the same APN 70 for the other IP address family. The Third Generation Partnership 71 Project (3GPP) network informs the cellular host about allowed Packet 72 Data Protocol (PDP) types by means of Session Management (SM) cause 73 codes. In particular, the following cause codes can be returned: 75 o cause #50 "PDP type IPv4 only allowed": This cause code is used by 76 the network to indicate that only PDP type IPv4 is allowed for the 77 requested Public Data Network (PDN) connectivity. 79 o cause #51 "PDP type IPv6 only allowed": This cause code is used by 80 the network to indicate that only PDP type IPv6 is allowed for the 81 requested PDN connectivity. 83 o cause #52 "single address bearers only allowed": This cause code 84 is used by the network to indicate that the requested PDN 85 connectivity is accepted with the restriction that only single IP 86 version bearers are allowed. 88 If the requested IPv4v6 PDP-Context is not supported by the network 89 but IPv4 and IPv6 PDP types are allowed, then the cellular host will 90 be configured with an IPv4 address or an IPv6 prefix by the network. 91 It must initiate another PDP-Context activation of the other address 92 family in addition to the one already activated for a given Access 93 Point Name (APN). The purpose of initiating a second PDP-Context is 94 to achieve dual-stack connectivity by means of two PDP-Contexts. 96 When the UE attaches the network using a WLAN access by means of 97 IKEv2 capabilities [RFC7296], there are no equivalent notification 98 codes to inform the User Equipment (UE) why an IP address family is 99 not assigned or whether that UE should retry with another address 100 family. 102 This document fills that void by introducing new IKEv2 notification 103 status types for the sake of deterministic UE behaviors (Section 4). 105 These notification status types are not specific to 3GPP 106 architectures, but can be used in other deployment contexts. 107 Cellular networks are provided as an illustration example. 109 2. Terminology 111 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 112 "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and 113 "OPTIONAL" in this document are to be interpreted as described in BCP 114 14 [RFC2119][RFC8174] when, and only when, they appear in all 115 capitals, as shown here. 117 This document makes use of the terms defined in [RFC7296]. In 118 particular, readers should be familiar with "initiator" and 119 "responder" terms used in that document. 121 3. Why Not INTERNAL_ADDRESS_FAILURE? 123 The following address assignment failures may be encountered when an 124 initiator requests assignment of IP addresses/prefixes: 126 o An initiator asks for IPvx, but IPvx address assignment is not 127 supported by the responder. 129 o An initiator requests both IPv4 and IPv6 addresses, but only IPv4 130 address assignment is supported by the responder. 132 o An initiator requests both IPv4 and IPv6 addresses, but only IPv6 133 prefix assignment is supported by the responder. 135 o An initiator asks for both IPv4 and IPv6 addresses, but only one 136 address family can be assigned by the responder for policy 137 reasons. 139 Section 3.15.4 of [RFC7296] defines a generic notification error type 140 that is related to a failure to handle an internal address failure. 141 That error type does not explicitly allow an initiator to determine 142 why a given address family is not assigned, nor whether it should try 143 using another address family. INTERNAL_ADDRESS_FAILURE is a catch- 144 all error type when an address-related issue is encountered by an 145 IKEv2 responder. 147 INTERNAL_ADDRESS_FAILURE does not provide sufficient hints to the 148 IKEv2 initiator to adjust its behavior. 150 4. IP6_ONLY_ALLOWED and IP4_ONLY_ALLOWED Status Types 152 IP6_ONLY_ALLOWED and IP4_ONLY_ALLOWED status types (see Section 7) 153 are defined to inform the initiator about the responser's address 154 family assignment support capabilities, and to report to the 155 initiator the reason why an address assignment failed. These 156 notifications are used by the initiator to adjust its behavior 157 accordingly (Section 5). 159 No data is associated with these notifications. 161 5. An Update to RFC7296 163 If the initiator is dual-stack, it MUST include both address families 164 in its request (absent explicit policy/configuration otherwise). 166 The responder MUST include IP6_ONLY_ALLOWED (or IP4_ONLY_ALLOWED) 167 status type in a response to an address assignment request in the 168 following cases: 170 1. The responder only supports IPv6 (or IPv4) address assignment, or 172 2. The responder supports both IPv4 and IPv6 address assignments, 173 but it is configured to reply to requests asking for both address 174 families with only an IPv6 prefix (or an IPv4 address). 176 The address family preference is defined by a policy that is 177 local to the responder. 179 If the initiator receives IP6_ONLY_ALLOWED or IP4_ONLY_ALLOWED 180 notification from the responder, the initiator MUST NOT send a 181 request for an alternate address family not supported by the 182 responder. 184 If a dual-stack initiator requests only an IPv6 prefix (or an IPv4 185 address) but receives IP4_ONLY_ALLOWED (or IP6_ONLY_ALLOWED) 186 notification from the responder, the initiator MUST send a request 187 for IPv4 address(es) (or IPv6 prefix(es)). 189 For other address-related error cases that have not been covered by 190 the aforementioned notification status types, the repsonder/initiator 191 MUST follow the procedure defined in Section 3.15.4 of [RFC7849]. 193 6. Security Considerations 195 This document adheres to the security considerations defined in 196 [RFC7296]. 198 7. IANA Considerations 200 This document requests IANA to update the "IKEv2 Notify Message Types 201 - Status Types" registry available at: 202 https://www.iana.org/assignments/ikev2-parameters/ 203 ikev2-parameters.xhtml with the following status types: 205 Value NOTIFY MESSAGES - STATUS TYPES Reference 206 TBD IP6_ONLY_ALLOWED [This-Document] 207 TBD IP4_ONLY_ALLOWED [This-Document] 209 8. Acknowledgements 211 Many thanks to Christian Jacquenet for the review. 213 Thanks to Paul Wouters, Yaov Nir, Valery Smyslov, Daniel Migault, and 214 Tero Kivinen for the comments. 216 9. References 218 9.1. Normative References 220 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 221 Requirement Levels", BCP 14, RFC 2119, 222 DOI 10.17487/RFC2119, March 1997, 223 . 225 [RFC7296] Kaufman, C., Hoffman, P., Nir, Y., Eronen, P., and T. 226 Kivinen, "Internet Key Exchange Protocol Version 2 227 (IKEv2)", STD 79, RFC 7296, DOI 10.17487/RFC7296, October 228 2014, . 230 [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 231 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 232 May 2017, . 234 9.2. Informative References 236 [RFC7849] Binet, D., Boucadair, M., Vizdal, A., Chen, G., Heatley, 237 N., Chandler, R., Michaud, D., Lopez, D., and W. Haeffner, 238 "An IPv6 Profile for 3GPP Mobile Devices", RFC 7849, 239 DOI 10.17487/RFC7849, May 2016, 240 . 242 Author's Address 244 Mohamed Boucadair 245 Orange 246 Rennes 35000 247 France 249 Email: mohamed.boucadair@orange.com