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Binet 4 Intended status: Standards Track France Telecom 5 Expires: April 7, 2013 October 4, 2012 7 IPv6 RA Option for SIP Proxy Server 8 draft-boucadair-6man-sip-proxy-01 10 Abstract 12 This document specifies a new optional extension to IPv6 Router 13 Advertisement messages to advertise SIP Proxy Server (e.g., P-CSCF) 14 addresses to IPv6 hosts. 16 The provisioning of the SIP Proxy Server address is crucial for the 17 delivery of SIP-based services. Means to ensure reliable delivery of 18 this information to connecting SIP User Agents is a must. 20 Requirements Language 22 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 23 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 24 document are to be interpreted as described in RFC 2119 [RFC2119]. 26 Status of this Memo 28 This Internet-Draft is submitted in full conformance with the 29 provisions of BCP 78 and BCP 79. 31 Internet-Drafts are working documents of the Internet Engineering 32 Task Force (IETF). Note that other groups may also distribute 33 working documents as Internet-Drafts. The list of current Internet- 34 Drafts is at http://datatracker.ietf.org/drafts/current/. 36 Internet-Drafts are draft documents valid for a maximum of six months 37 and may be updated, replaced, or obsoleted by other documents at any 38 time. It is inappropriate to use Internet-Drafts as reference 39 material or to cite them other than as "work in progress." 41 This Internet-Draft will expire on April 7, 2013. 43 Copyright Notice 45 Copyright (c) 2012 IETF Trust and the persons identified as the 46 document authors. All rights reserved. 48 This document is subject to BCP 78 and the IETF Trust's Legal 49 Provisions Relating to IETF Documents 50 (http://trustee.ietf.org/license-info) in effect on the date of 51 publication of this document. Please review these documents 52 carefully, as they describe your rights and restrictions with respect 53 to this document. Code Components extracted from this document must 54 include Simplified BSD License text as described in Section 4.e of 55 the Trust Legal Provisions and are provided without warranty as 56 described in the Simplified BSD License. 58 Table of Contents 60 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 61 1.1. Needs . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 62 1.2. Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 63 2. SIP Proxy Server Option . . . . . . . . . . . . . . . . . . . . 4 64 3. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 5 65 4. Security Considerations . . . . . . . . . . . . . . . . . . . . 5 66 5. References . . . . . . . . . . . . . . . . . . . . . . . . . . 5 67 5.1. Normative References . . . . . . . . . . . . . . . . . . . 5 68 5.2. Informative References . . . . . . . . . . . . . . . . . . 5 69 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 6 71 1. Introduction 73 1.1. Needs 75 Access to SIP-based service offerings (e.g., telephony) relies on the 76 provisioning of the IP address or FQDN of the outbound SIP Proxy 77 Server [RFC3261]. Two means have been defined in the past to 78 provision such information: 80 1. DHCPv6 SIP options [RFC3319]. 82 2. Dedicated 3GPP PCO to convey the address of the P-CSCF [CORE]. 84 Nevertheless, these means are not sufficient because of the following 85 reasons: 87 1. PCO-IE is not mandatory in 3G networks (e.g., PCO information may 88 not be supported by terminals); 90 2. DHCPv6 is not required in all 3GPP releases. Moreover, the 91 support of DHCPv6 client is not mandatory in the IETF IPv6 node 92 requirements. 94 3. PCO-IE is not available in non-3GPP networks. This is very 95 critical when the UE (User Equipment) performs a network 96 attachment in a non-3GPP network because the user won't have 97 access to SIP-based services if no alternative means are 98 supported. 100 As a conclusion, auto-configuration [RFC4861] is required so that a 101 SIP UA (User Agent) can learn one or multiple SIP Proxy Servers. 103 1.2. Scope 105 This document defines a new ND option called SIP Proxy Server option 106 that contains the domain name of SIP Proxy Server(s). This option 107 follows the procedures defined in [RFC4861]. The IPv6 host embedding 108 a SIP UA can learn a list of SIP Proxy Servers using this option. 110 This option can be sent along with other options, such as DNS 111 information [RFC6106], in the same RA message. 113 The router sending the SIP Proxy Server in RA must be configured with 114 the Proxy Server information. 116 2. SIP Proxy Server Option 118 The SIP Proxy Server Option contains a domain name representing the 119 SIP outbound Proxy Server (e.g., SBE, P-CSCF). Figure 1 shows the 120 format of the SIP Proxy Server Option. 122 0 1 2 3 123 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 124 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 125 | Type | Length | Reserved | 126 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 127 | Lifetime | 128 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 129 | | 130 : SIP Server Domain Name : 131 | | 132 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 134 Figure 1 136 Where 138 o Type: To be assigned (RA SIP Proxy Server Option). 140 o Length is a 8-bit unsigned integer. The length of the option is 141 in unit of 8 octets. 143 o Reserved is for future use. 145 o Lifetime is a 16-bit unsigned integer. Same as in [RFC6106]. 147 o SIP Server Domain Name: The domain names of the SIP outbound proxy 148 servers for the client to use. The domain names are encoded as 149 specified Section 3.1 of [RFC1035]. The domain names MUST NOT be 150 encoded in a compressed form, as described in Section 4.1.4 of 151 [RFC1035]. 153 Upon receipt of an RA SIP Proxy Server option, the IPv6 host MUST 154 verify that the option length does not exceed 255 octets [RFC1035]. 155 The IPv6 host MUST verify the FQDN is properly encoded as detailed in 156 Section 3.1 of [RFC1035]. 158 Once the FQDN conveyed in a SIP Proxy Server RA option is validated, 159 the included name is passed to the name resolution library (e.g., 160 Section 6.1.1 of [RFC1123] or [RFC6055]) to retrieve the 161 corresponding IP address. 163 3. IANA Considerations 165 This document requests IANA to assign a new option code for: 167 SIP Proxy Server 169 4. Security Considerations 171 The security considerations discussed in [RFC4861] and [RFC3261] must 172 be taken into account. 174 This option can be used to inject a fake proxy server which will 175 discover the security credentials used by legitimate user to connect 176 to their SIP services. This threat is similar to what is discussed 177 in [RFC6106]. 179 5. References 181 5.1. Normative References 183 [RFC1035] Mockapetris, P., "Domain names - implementation and 184 specification", STD 13, RFC 1035, November 1987. 186 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 187 Requirement Levels", BCP 14, RFC 2119, March 1997. 189 [RFC3261] Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston, 190 A., Peterson, J., Sparks, R., Handley, M., and E. 191 Schooler, "SIP: Session Initiation Protocol", RFC 3261, 192 June 2002. 194 [RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman, 195 "Neighbor Discovery for IP version 6 (IPv6)", RFC 4861, 196 September 2007. 198 5.2. Informative References 200 [CORE] 3GPP 24.008, "3GPP 24.008 -- Mobile radio interface Layer 201 3 specification; Core network protocols; Stage 3", 202 December 2008. 204 [RFC1123] Braden, R., "Requirements for Internet Hosts - Application 205 and Support", STD 3, RFC 1123, October 1989. 207 [RFC3319] Schulzrinne, H. and B. Volz, "Dynamic Host Configuration 208 Protocol (DHCPv6) Options for Session Initiation Protocol 209 (SIP) Servers", RFC 3319, July 2003. 211 [RFC6055] Thaler, D., Klensin, J., and S. Cheshire, "IAB Thoughts on 212 Encodings for Internationalized Domain Names", RFC 6055, 213 February 2011. 215 [RFC6106] Jeong, J., Park, S., Beloeil, L., and S. Madanapalli, 216 "IPv6 Router Advertisement Options for DNS Configuration", 217 RFC 6106, November 2010. 219 Authors' Addresses 221 Mohamed Boucadair 222 France Telecom 223 Rennes, 35000 224 France 226 Email: mohamed.boucadair@orange.com 228 David Binet 229 France Telecom 230 Rennes 231 France 233 Email: david.binet@orange.com