idnits 2.17.1 draft-ietf-ieprep-reflexive-dscp-02.txt: Checking boilerplate required by RFC 5378 and the IETF Trust (see https://trustee.ietf.org/license-info): ---------------------------------------------------------------------------- ** Looks like you're using RFC 2026 boilerplate. This must be updated to follow RFC 3978/3979, as updated by RFC 4748. Checking nits according to https://www.ietf.org/id-info/1id-guidelines.txt: ---------------------------------------------------------------------------- == No 'Intended status' indicated for this document; assuming Proposed Standard Checking nits according to https://www.ietf.org/id-info/checklist : ---------------------------------------------------------------------------- ** The document seems to lack separate sections for Informative/Normative References. All references will be assumed normative when checking for downward references. ** There are 8 instances of too long lines in the document, the longest one being 9 characters in excess of 72. Miscellaneous warnings: ---------------------------------------------------------------------------- == The copyright year in the RFC 3978 Section 5.4 Copyright Line does not match the current year == The document seems to lack the recommended RFC 2119 boilerplate, even if it appears to use RFC 2119 keywords. (The document does seem to have the reference to RFC 2119 which the ID-Checklist requires). -- The document seems to lack a disclaimer for pre-RFC5378 work, but may have content which was first submitted before 10 November 2008. If you have contacted all the original authors and they are all willing to grant the BCP78 rights to the IETF Trust, then this is fine, and you can ignore this comment. If not, you may need to add the pre-RFC5378 disclaimer. (See the Legal Provisions document at https://trustee.ietf.org/license-info for more information.) -- The document date (June 30, 2003) is 7599 days in the past. Is this intentional? Checking references for intended status: Proposed Standard ---------------------------------------------------------------------------- (See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) == Unused Reference: '2' is defined on line 181, but no explicit reference was found in the text == Unused Reference: '3' is defined on line 185, but no explicit reference was found in the text == Unused Reference: '4' is defined on line 189, but no explicit reference was found in the text == Unused Reference: '5' is defined on line 192, but no explicit reference was found in the text ** Downref: Normative reference to an Informational RFC: RFC 2475 (ref. '3') ** Downref: Normative reference to an Informational RFC: RFC 2998 (ref. '5') Summary: 5 errors (**), 0 flaws (~~), 7 warnings (==), 2 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Internet Emergency Preparedness R. Atarashi 3 Working Group IIJ Research Laboratory 4 Internet-Draft F. Baker 5 Expires: December 29, 2003 Cisco Systems 6 June 30, 2003 8 Reflexive DSCP Policy 9 draft-ietf-ieprep-reflexive-dscp-02 11 Status of this Memo 13 This document is an Internet-Draft and is in full conformance with 14 all provisions of Section 10 of RFC2026. 16 Internet-Drafts are working documents of the Internet Engineering 17 Task Force (IETF), its areas, and its working groups. Note that other 18 groups may also distribute working documents as Internet-Drafts. 20 Internet-Drafts are draft documents valid for a maximum of six months 21 and may be updated, replaced, or obsoleted by other documents at any 22 time. It is inappropriate to use Internet-Drafts as reference 23 material or to cite them other than as "work in progress." 25 The list of current Internet-Drafts can be accessed at http:// 26 www.ietf.org/ietf/1id-abstracts.txt. 28 The list of Internet-Draft Shadow Directories can be accessed at 29 http://www.ietf.org/shadow.html. 31 This Internet-Draft will expire on December 29, 2003. 33 Copyright Notice 35 Copyright (C) The Internet Society (2003). All Rights Reserved. 37 Abstract 39 In reviewing the specific use of the Differentiated Services 40 Architecture for supporting the Internet Emergency Preparedness 41 System, we found what we believe is a general issue. This is that 42 even though a client or peer can connect to a server or peer with a 43 predictable DSCP value, the response does not have a predictable DSCP 44 value. We consider the issues, and recommend an approach to 45 application policy regarding the DSCP. 47 1. Introduction 49 In reviewing the specific use of the Differentiated Services 50 Architecture for supporting the Internet Emergency Preparedness 51 System, we found what we believe is a general issue. This is that 52 even though a client or peer can connect to a server or peer with a 53 predictable DSCP value, the response does not have a predictable DSCP 54 value. We consider the issues, and recommend an approach to 55 application policy regarding the DSCP. 57 As such, we will make specific recommendations for all applications. 58 In doing so, we will use the language described in RFC 2119 [1]. The 59 key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 60 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 61 document are to be interpreted as described in RFC 2119 [1]. 63 1.1 Problem Statement 65 Figure 1 presents a connection being placed between two applications 66 across a differentiated services network. 68 . . . . . . . . . . . . . . . 69 . . . . . . 70 . Client . . . . Server . 71 . /-----------/ . . /------------/ . . /---------------/. 72 . Router -----/----- Router Router -----/----- Router . 73 . . . . . . 74 . . . . . . 75 . . . . . . . . . . . . . . . 77 Figure 1: Connection across a network 79 A behavior aggregate originated in part by a certain client toward a 80 given server in a remote network may have certain application 81 requirements, such as requiring service appropriate to an ERP 82 application, videostream or voice. One application may use different 83 aggregates for different purposes, and therefore have different 84 requirements. So the application may not be able to tell a priori 85 what DSCP it should use or respond with. 87 In addition, DSCPs have local significance in the Differentiated 88 Services Architecture. It is possible and perhaps likely that a 89 behavior aggregate might use different code points in different 90 networks. 92 2. Policy recommendations 94 We consider that there are a number of possible approaches to this 95 issue. The simplest, which we fear is currently standard in 96 Differentiated Services hosts, is to simply select a default value, 97 such as "always make TCP applications use AF11". For some 98 applications, such as voice (EF), this approach is appropriate, but 99 for many it is not. 101 2.1 Default DSCP policy in a responder 103 When a system accepts sessions initiated from another system, and 104 there is no specific local policy, the responder SHOULD use the same 105 DSCP Group as its request. Thus, if a TCP SYN arrives using any of 106 AF11, AF12, or AF13, the TCP SYN-ACK and subsequent messages SHOULD 107 use AF11 as the DSCP. When in doubt as to the set of DSCP code points 108 comprising a DSCP Group, it SHOULD respond with exactly the same 109 DSCP. 111 There has been interest of late in changing the quality of service 112 behavior for different portions of the same session, such as on a 113 per-URL basis. The requester could initiate this. Thus, if the DSCP 114 received on one TCP segment differs from the TCP used on a prior TCP 115 segment in a session, the new DSCP SHOULD be reflected unless local 116 policy prevents this. 118 One way to implement this requires the receiving transport (TCP, 119 SCTP, etc) to save the received DSCP and use an API to determine the 120 correct responding DSCP from a configuration file. The configuration 121 file lists the 64 possible DSCP values and the correct response. In 122 most cases, the two SHOULD be the same, but the AFxy code points map 123 to AFx1. Local policy MAY update this mapping. 125 2.2 Application-directed DSCP policy 127 The originator of a session, which is to say the application that 128 opens it, SHOULD normally select the DSCP value used. This, of 129 course, needs to be consistent with local network policy, and may be 130 dictated entirely by that policy. 132 The application would do this through an API, ideally one that maps 133 the application to a DSCP value through local administrative policy. 134 Thus, the API could set the DSCP for signaling of voice calls to a 135 specific value, such as AF31. It would be better, though, if the API 136 were to set it to a key word such as "VoiceSignaling" or 137 "DatabaseAccess", and enable the network administration to interpret 138 the key word to an appropriate code point. One way to implement this 139 would be for the API code to look the key word up in a file or an 140 LDAP Policy. 142 It is possible for the responding application to use this same API. 143 For example, separate policies might apply to database records of one 144 type and database records of another type, something that only the 145 database access application could determine. It is also possible for 146 the application exchange to communicate a desired DSCP, and the 147 responding application to use the API accordingly. In such a case, 148 the application exchange MUST specify the key word or metadata rather 149 than the specific DSCP, as it cannot know the applicable policy in 150 the responder's network. 152 3. IANA Considerations 154 No action has been requested of IANA. 156 4. Security Considerations 158 This document discusses policy, and describes a recommended default 159 policy, for the use of a Differentiated Services Code Point by 160 transports and applications. If implemented as described, it should 161 ask the network to do nothing that the network has not already 162 allowed. If that is the case, no new security issues should arise 163 from the use of such a policy. 165 It is possible, however, for the policy to be applied incorrectly, or 166 for another policy to be applied, which would be incorrect in the 167 network. In that case, a policy issue exists which the network must 168 detect, assess, and deal with. This is a known security issue in any 169 network dependent on policy-directed behavior. 171 5. Acknowledgements 173 The authors would like to thank Hiroyuki Ohno, Toshio Shimojo, 174 Shigeru Miyake and Yoshifumi Atarashi for their suggetions. 176 References 178 [1] Bradner, S., "Key words for use in RFCs to Indicate Requirement 179 Levels", BCP 14, RFC 2119, March 1997. 181 [2] Nichols, K., Blake, S., Baker, F. and D. Black, "Definition of 182 the Differentiated Services Field (DS Field) in the IPv4 and 183 IPv6 Headers", RFC 2474, December 1998. 185 [3] Blake, S., Black, D., Carlson, M., Davies, E., Wang, Z. and W. 186 Weiss, "An Architecture for Differentiated Services", RFC 2475, 187 December 1998. 189 [4] Heinanen, J., Baker, F., Weiss, W. and J. Wroclawski, "Assured 190 Forwarding PHB Group", RFC 2597, June 1999. 192 [5] Bernet, Y., Ford, P., Yavatkar, R., Baker, F., Zhang, L., Speer, 193 M., Braden, R., Davie, B., Wroclawski, J. and E. Felstaine, "A 194 Framework for Integrated Services Operation over Diffserv 195 Networks", RFC 2998, November 2000. 197 Authors' Addresses 199 Ray S. Atarashi 200 IIJ Research Laboratory 201 Jinbocho Mitsui Bldg., 1-105 Kanda Jinbo-cho 202 Chiyoda-ku, Tokyo 101-0051 203 JP 205 Phone: +81-3-5205-6464 206 Fax: +81-3-5205-6466 207 EMail: ray@iijlab.net 209 Fred Baker 210 Cisco Systems 211 1121 Via Del Rey 212 Santa Barbara, CA 93117 213 US 215 Phone: +1-408-526-4257 216 Fax: +1-413-473-2403 217 EMail: fred@cisco.com 219 Intellectual Property Statement 221 The IETF takes no position regarding the validity or scope of any 222 intellectual property or other rights that might be claimed to 223 pertain to the implementation or use of the technology described in 224 this document or the extent to which any license under such rights 225 might or might not be available; neither does it represent that it 226 has made any effort to identify any such rights. Information on the 227 IETF's procedures with respect to rights in standards-track and 228 standards-related documentation can be found in BCP-11. Copies of 229 claims of rights made available for publication and any assurances of 230 licenses to be made available, or the result of an attempt made to 231 obtain a general license or permission for the use of such 232 proprietary rights by implementors or users of this specification can 233 be obtained from the IETF Secretariat. 235 The IETF invites any interested party to bring to its attention any 236 copyrights, patents or patent applications, or other proprietary 237 rights which may cover technology that may be required to practice 238 this standard. Please address the information to the IETF Executive 239 Director. 241 Full Copyright Statement 243 Copyright (C) The Internet Society (2003). All Rights Reserved. 245 This document and translations of it may be copied and furnished to 246 others, and derivative works that comment on or otherwise explain it 247 or assist in its implementation may be prepared, copied, published 248 and distributed, in whole or in part, without restriction of any 249 kind, provided that the above copyright notice and this paragraph are 250 included on all such copies and derivative works. However, this 251 document itself may not be modified in any way, such as by removing 252 the copyright notice or references to the Internet Society or other 253 Internet organizations, except as needed for the purpose of 254 developing Internet standards in which case the procedures for 255 copyrights defined in the Internet Standards process must be 256 followed, or as required to translate it into languages other than 257 English. 259 The limited permissions granted above are perpetual and will not be 260 revoked by the Internet Society or its successors or assignees. 262 This document and the information contained herein is provided on an 263 "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING 264 TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING 265 BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION 266 HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF 267 MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. 269 Acknowledgement 271 Funding for the RFC Editor function is currently provided by the 272 Internet Society.