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Checking references for intended status: Informational ---------------------------------------------------------------------------- ** Obsolete normative reference: RFC 2460 (Obsoleted by RFC 8200) == Outdated reference: A later version (-05) exists of draft-ietf-nvo3-gue-02 == Outdated reference: A later version (-82) exists of draft-templin-aerolink-63 == Outdated reference: A later version (-04) exists of draft-templin-intarea-grefrag-01 Summary: 2 errors (**), 0 flaws (~~), 4 warnings (==), 1 comment (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Network Working Group F. Templin, Ed. 3 Internet-Draft Boeing Research & Technology 4 Intended status: Informational January 05, 2016 5 Expires: July 8, 2016 7 AERO Minimal Encapsulation 8 draft-templin-aeromin-02.txt 10 Abstract 12 Asymmetric Extended Route Optimization (AERO) specifies both a 13 control messaging and data packet forwarding facility for managing 14 tunnels over an enterprise network or other Internetwork. Although 15 AERO can operate with any tunnel encapsulation format, the base 16 document considers Generic UDP Encapsulation (GUE) as the default. 17 This document presents minimal encapsulation formats for AERO using 18 other encapsulation types. 20 Status of This Memo 22 This Internet-Draft is submitted in full conformance with the 23 provisions of BCP 78 and BCP 79. 25 Internet-Drafts are working documents of the Internet Engineering 26 Task Force (IETF). Note that other groups may also distribute 27 working documents as Internet-Drafts. The list of current Internet- 28 Drafts is at http://datatracker.ietf.org/drafts/current/. 30 Internet-Drafts are draft documents valid for a maximum of six months 31 and may be updated, replaced, or obsoleted by other documents at any 32 time. It is inappropriate to use Internet-Drafts as reference 33 material or to cite them other than as "work in progress." 35 This Internet-Draft will expire on July 8, 2016. 37 Copyright Notice 39 Copyright (c) 2016 IETF Trust and the persons identified as the 40 document authors. All rights reserved. 42 This document is subject to BCP 78 and the IETF Trust's Legal 43 Provisions Relating to IETF Documents 44 (http://trustee.ietf.org/license-info) in effect on the date of 45 publication of this document. Please review these documents 46 carefully, as they describe your rights and restrictions with respect 47 to this document. Code Components extracted from this document must 48 include Simplified BSD License text as described in Section 4.e of 49 the Trust Legal Provisions and are provided without warranty as 50 described in the Simplified BSD License. 52 Table of Contents 54 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 55 2. Minimal AERO Encapsulation . . . . . . . . . . . . . . . . . 3 56 3. When to Insert an Encapsulation Fragment Header . . . . . . . 4 57 4. Considerations for Using Minimal Encapsulation . . . . . . . 4 58 5. AERO Operation Over Native Links . . . . . . . . . . . . . . 5 59 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5 60 7. Security Considerations . . . . . . . . . . . . . . . . . . . 5 61 8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 5 62 9. References . . . . . . . . . . . . . . . . . . . . . . . . . 5 63 9.1. Normative References . . . . . . . . . . . . . . . . . . 5 64 9.2. Informative References . . . . . . . . . . . . . . . . . 6 65 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 7 67 1. Introduction 69 Asymmetric Extended Route Optimization (AERO) [I-D.templin-aerolink] 70 specifies both a control messaging and data packet forwarding 71 facility for forwarding Internet Protocol (IP) packets [RFC0791] 72 [RFC2460] over an enterprise network or other Internetwork through a 73 process known as tunneling. Although AERO can operate with any 74 tunnel encapsulation format, the base document specifies the 75 insertion of a User Datagram Protocol (UDP) header [RFC0768] between 76 the inner and outer IP headers per the Generic UDP Encapsulation 77 (GUE) [I-D.ietf-nvo3-gue] specification. This document presents 78 minimal encapsulation formats for AERO using other encapsulation 79 types. 81 AERO can use common minimal encapsulations such as IP-in-IP 82 [RFC2003][RFC2473][RFC4213], Generic Routing Encapsulation (GRE) 83 [RFC2784][RFC2890] and others. The encapsulation is therefore only 84 differentiated from non-AERO tunnels through the application of AERO 85 control messaging. 87 Regardless of the encapsulation type, AERO requires an encapsulation 88 layer fragment header that serves the same purpose as for GUE 89 fragmentation [I-D.herbert-gue-fragmentation] . For simple IP-in-IP 90 encapsulation, an IPv6 fragment header is inserted directly between 91 the inner and outer IP headers when needed, i.e., even if the outer 92 header is IPv4. The IPv6 Fragment Header is identified to the outer 93 IP layer by its IP protocol number, and the Next Header field in the 94 IPv6 Fragment Header identifies the inner IP header version. For GRE 95 encapsulation, a GRE fragmentation header is inserted within the GRE 96 header as specified in [I-D.templin-intarea-grefrag]. Other tunnel 97 types similarly require an encapsulation layer fragment header in 98 order to properly support AERO. 100 2. Minimal AERO Encapsulation 102 Figure 1 shows the AERO IP-in-IP minimal encapsulation format before 103 any fragmentation is applied: 105 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 106 | Outer IPv4 Header | | Outer IPv6 Header | 107 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 108 |IPv6 Fragment Header (optional)| |IPv6 Fragment Header (optional)| 109 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 110 | Inner IP Header | | Inner IP Header | | 111 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 112 | | | | 113 ~ ~ ~ ~ 114 ~ Inner Packet Body ~ ~ Inner Packet Body ~ 115 ~ ~ ~ ~ 116 | | | | 117 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 119 Minimal Encapsulation in IPv4 Minimal Encapsulation in IPv6 121 Figure 1: Minimal Encapsulation Format using IP-in-IP 123 GRE encapsulation can be used instead of simple IP-in-IP 124 encapsulation when GRE facilities such as keys and checksums are 125 desired. In that case, AERO can include a GRE fragmentation header 126 in the encapsulation [I-D.templin-intarea-grefrag] as shown in 127 Figure 2: 129 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 130 | Outer IP Header | 131 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 132 | GRE Header | 133 | (with checksum, key, etc..) | 134 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 135 | GRE Fragment Header (optional)| 136 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 137 | Inner IP Header | 138 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 139 | | 140 ~ ~ 141 ~ Inner Packet Body ~ 142 ~ ~ 143 | | 144 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 146 Minimal Encapsulation Using GRE 148 Figure 2: Minimal Encapsulation Using GRE 150 3. When to Insert an Encapsulation Fragment Header 152 An encapsulation fragment header is inserted whenever the AERO tunnel 153 ingress needs to apply fragmentation to accommodate packets that must 154 be delivered without loss due to a size restriction. Fragmentation 155 is performed on the inner packet while encapsulating each inner 156 packet fragment in identical outer IP and any additional 157 encapsulation headers. Fragmentation follows the same procedure as 158 for standard IPv6 fragmentation. 160 The fragment header can also be inserted in order to include a 161 coherent Identification value with each packet, e.g., to aid in 162 Duplicate Packet Detection (DPD). In this way, networking devices 163 can cache the Identification values of recently-seen packets and use 164 the cached values to determine whether a newly-arrived packet is in 165 fact a duplicate. 167 Finally, the Identification value within each packet could provide a 168 rough indicator of packet reordering, e.g., in cases when the tunnel 169 egress wishes to discard packets that are grossly out of order. 171 4. Considerations for Using Minimal Encapsulation 173 Minimal encapsulation is preferred in environments where GUE 174 encapsulation would add unnecessary overhead. For example, certain 175 low-bandwidth wireless data links may benefit from a reduced 176 encapsulation overhead. This is not likely to be a prime 177 consideration for many modern wireless data links nor for most modern 178 wired-line data links. 180 GUE encapsulation can traverse network paths that are inaccessible to 181 minimal encapsulation, e.g., for crossing Network Address Translators 182 (NATs). More and more, network middleboxes are also being configured 183 to discard packets that include anything other than a well-known IP 184 protocol such as UDP and TCP. It may therefore be necessary to 185 consider the potential for middlebox filtering before enabling 186 minimal encapsulation in a given environment. 188 5. AERO Operation Over Native Links 190 AERO can also operate over native links using no encapsulation at 191 all. In that case, AERO Clients can identify AERO Servers on the 192 link through their link-layer MAC addresses, and the AERO DHCPv6-PD, 193 mobility management and route optimization facilities operate on the 194 native link the same as over an NBMA tunnel overlay. Furthermore, 195 AERO Clients can manage associations with multiple Servers for fault 196 tolerance purposes. 198 6. IANA Considerations 200 This document introduces no IANA considerations. 202 7. Security Considerations 204 Security considerations are discussed in the base AERO specification 205 [I-D.templin-aerolink]. 207 8. Acknowledgements 209 TBD 211 9. References 213 9.1. Normative References 215 [RFC0768] Postel, J., "User Datagram Protocol", STD 6, RFC 768, 216 DOI 10.17487/RFC0768, August 1980, 217 . 219 [RFC0791] Postel, J., "Internet Protocol", STD 5, RFC 791, 220 DOI 10.17487/RFC0791, September 1981, 221 . 223 [RFC2003] Perkins, C., "IP Encapsulation within IP", RFC 2003, 224 DOI 10.17487/RFC2003, October 1996, 225 . 227 [RFC2460] Deering, S. and R. Hinden, "Internet Protocol, Version 6 228 (IPv6) Specification", RFC 2460, DOI 10.17487/RFC2460, 229 December 1998, . 231 [RFC2473] Conta, A. and S. Deering, "Generic Packet Tunneling in 232 IPv6 Specification", RFC 2473, DOI 10.17487/RFC2473, 233 December 1998, . 235 [RFC2784] Farinacci, D., Li, T., Hanks, S., Meyer, D., and P. 236 Traina, "Generic Routing Encapsulation (GRE)", RFC 2784, 237 DOI 10.17487/RFC2784, March 2000, 238 . 240 [RFC2890] Dommety, G., "Key and Sequence Number Extensions to GRE", 241 RFC 2890, DOI 10.17487/RFC2890, September 2000, 242 . 244 [RFC4213] Nordmark, E. and R. Gilligan, "Basic Transition Mechanisms 245 for IPv6 Hosts and Routers", RFC 4213, 246 DOI 10.17487/RFC4213, October 2005, 247 . 249 9.2. Informative References 251 [I-D.herbert-gue-fragmentation] 252 Herbert, T. and F. Templin, "Fragmentation option for 253 Generic UDP Encapsulation", draft-herbert-gue- 254 fragmentation-02 (work in progress), October 2015. 256 [I-D.ietf-nvo3-gue] 257 Herbert, T., Yong, L., and O. Zia, "Generic UDP 258 Encapsulation", draft-ietf-nvo3-gue-02 (work in progress), 259 December 2015. 261 [I-D.templin-aerolink] 262 Templin, F., "Asymmetric Extended Route Optimization 263 (AERO)", draft-templin-aerolink-63 (work in progress), 264 August 2015. 266 [I-D.templin-intarea-grefrag] 267 Templin, F., "GRE Tunnel Fragmentation", draft-templin- 268 intarea-grefrag-01 (work in progress), August 2015. 270 Author's Address 272 Fred L. Templin (editor) 273 Boeing Research & Technology 274 P.O. Box 3707 275 Seattle, WA 98124 276 USA 278 Email: fltemplin@acm.org