idnits 2.17.1 draft-ietf-dhc-dhcpv6-solmaxrt-update-01.txt: Checking boilerplate required by RFC 5378 and the IETF Trust (see https://trustee.ietf.org/license-info): ---------------------------------------------------------------------------- No issues found here. Checking nits according to https://www.ietf.org/id-info/1id-guidelines.txt: ---------------------------------------------------------------------------- No issues found here. Checking nits according to https://www.ietf.org/id-info/checklist : ---------------------------------------------------------------------------- No issues found here. Miscellaneous warnings: ---------------------------------------------------------------------------- == The copyright year in the IETF Trust and authors Copyright Line does not match the current year (Using the creation date from RFC3315, updated by this document, for RFC5378 checks: 1995-02-03) -- 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 03, 2013) is 3979 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) ** Obsolete normative reference: RFC 3315 (Obsoleted by RFC 8415) ** Obsolete normative reference: RFC 3633 (Obsoleted by RFC 8415) Summary: 2 errors (**), 0 flaws (~~), 1 warning (==), 2 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Network Working Group R. Droms 3 Internet-Draft Cisco Systems 4 Updates: 3315 (if approved) June 03, 2013 5 Intended status: Standards Track 6 Expires: December 05, 2013 8 Modification to Default Value of SOL_MAX_RT 9 draft-ietf-dhc-dhcpv6-solmaxrt-update-01 11 Abstract 13 This document updates RFC 3315 by redefining the default values for 14 SOL_MAX_RT and INF_MAX_RT, and defining options through which a 15 DHCPv6 server can override the client's default value for SOL_MAX_RT 16 and INF_MAX_RT with a new value. 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 http://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 December 05, 2013. 35 Copyright Notice 37 Copyright (c) 2013 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 (http://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 1. Introduction 52 Section 5.5 of the DHCPv6 specification [RFC3315] defines the default 53 values of SOL_MAX_RT and INF_MAX_RT to be 120 seconds. In some 54 circumstances, these defaults will lead to an unacceptably high 55 volume of aggregated traffic at a DHCPv6 server. 57 The change to SOL_MAX_RT is in response to DHCPv6 message rates 58 observed at a DHCPv6 server in a deployment in which many DHCPv6 59 clients are sending Solicit messages but the DHCPv6 server has been 60 configured not to respond to those Solicit messages. While no 61 explicit observations of traffic due to INF_MAX_RT have been 62 conducted, this document updates INF_MAX_RT for consistency with 63 SOL_MAX_RT. 65 2. Requirements Language 67 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 68 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 69 document are to be interpreted as described in RFC 2119 [RFC2119]. 71 3. Updates to SOL_MAX_RT and INF_MAX_RT in RFC 3315 73 This document changes section 5.5 of RFC 3315 [RFC3315] as follows: 75 OLD: 76 SOL_MAX_RT 120 secs Max Solicit timeout value 78 NEW: 79 SOL_MAX_RT 3600 secs Max Solicit timeout value 81 OLD: 82 INF_MAX_RT 120 secs Max Information-request timeout value 84 NEW: 85 SOL_MAX_RT 3600 secs Max Information-request timeout value 87 With this change, a DHCPv6 client that does not receive a 88 satisfactory response will send Solicit or Information-request 89 messages with the same initial frequency and exponential backoff as 90 specified in sections 17.1.2 and 18.1.5 of RFC 3315 [RFC3315]. 91 However, the long term behavior of these DHCPv6 clients will be to 92 send a Solicit or Information-request message every 3600 seconds 93 rather than every 120 seconds, significantly reducing the aggregated 94 traffic at the DHCPv6 server. 96 4. SOL_MAX_RT option 98 A DHCPv6 server sends the SOL_MAX_RT option to a client to override 99 the default value of SOL_MAX_RT. The value of SOL_MAX_RT in the 100 option replaces the default value defined in Section 3. One use for 101 the SOL_MAX_RT option is to set a longer value for SOL_MAX_RT, which 102 reduces the Solicit traffic from a client that has not received a 103 response to its Solicit messages. 105 The format of the SOL_MAX_RT option is: 107 0 1 2 3 108 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 1 109 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 110 | option-code | option-len | 111 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 112 | SOL_MAX_RT value | 113 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 115 option-code OPTION_SOL_MAX_RT (TBD). 117 option-len 4. 119 SOL_MAX_RT value Overriding value for SOL_MAX_RT 120 in seconds. 122 Figure 1 124 A DHCPv6 client MUST include the SOL_MAX_RT option code in an Option 125 Request option [RFC3315] in any message it sends. 127 The DHCPv6 server MAY include the SOL_MAX_RT option in any response 128 it sends to a client that has included the SOL_MAX_RT option code in 129 an Option Request option. The SOL_MAX_RT option is sent in the main 130 body of the message to client, not as a sub-option in, e.g., an 131 IA_NA, IA_TA [RFC3315] or IA_PD [RFC3633] option. 133 If a DHCPv6 client receives a message containing a SOL_MAX_RT option, 134 the client MUST set its internal SOL_MAX_RT parameter to the value 135 contained in the SOL_MAX_RT option. As a result of receiving this 136 option, the DHCPv6 client MUST NOT send any Solicit messages more 137 frequently than allowed by the retransmission mechanism defined in 138 sections 17.1.2 and 14 of RFC 3315 [RFC3315]. 140 5. INF_MAX_RT option 142 A DHCPv6 server sends the INF_MAX_RT option to a client to override 143 the default value of INF_MAX_RT. The value of INF_MAX_RT in the 144 option replaces the default value defined in Section 3. One use for 145 the INF_MAX_RT option is to set a longer value for INF_MAX_RT, which 146 reduces the Solicit traffic from a client that has not received a 147 response to its Solicit messages. 149 The format of the INF_MAX_RT option is: 151 0 1 2 3 152 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 1 153 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 154 | option-code | option-len | 155 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 156 | INF_MAX_RT value | 157 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 159 option-code OPTION_INF_MAX_RT (TBD). 161 option-len 4. 163 INF_MAX_RT value Overriding value for INF_MAX_RT 164 in seconds. 166 Figure 2: INF_MAX_RT option format 168 A DHCPv6 client MUST include the INF_MAX_RT option code in an Option 169 Request option [RFC3315] in any message it sends. 171 The DHCPv6 server MAY include the INF_MAX_RT option in any response 172 it sends to a client that has included the INF_MAX_RT option code in 173 an Option Request option. The INF_MAX_RT option is sent in the main 174 body of the message to client, not as a sub-option in, e.g., an 175 IA_NA, IA_TA [RFC3315] or IA_PD [RFC3633] option. 177 If a DHCPv6 client receives a message containing a INF_MAX_RT option, 178 the client MUST set its internal INF_MAX_RT parameter to the value 179 contained in the INF_MAX_RT option. As a result of receiving this 180 option, the DHCPv6 client MUST NOT send any Information-request 181 messages more frequently than allowed by the retransmission mechanism 182 defined in sections 18.1.5 and 14 of RFC 3315 [RFC3315]. 184 6. Updates for SOL_MAX_RT and INF_MAX_RT options to RFC 3315 186 Update to RFC 3315 [RFC3315], section 17.1.3: 188 OLD: 190 The client MUST ignore any Advertise message that includes a Status 191 Code option containing the value NoAddrsAvail, with the exception 192 that the client MAY display the associated status message to the 193 user. 195 NEW: 197 The client MUST ignore any Advertise message that includes a Status 198 Code option containing the value NoAddrsAvail, with the exception 199 that the client MUST process an included SOL_MAX_RT option and/or an 200 included INF_MAX_RT option and MAY display the associated status 201 message to the user. 203 Update to RFC 3315 [RFC3315], section 17.2.2: 205 OLD: 207 If the server will not assign any addresses to any IAs in a 208 subsequent Request from the client, the server MUST send an 209 Advertise message to the client that includes only a Status Code 210 option with code NoAddrsAvail and a status message for the user, a 211 Server Identifier option with the server's DUID, and a Client 212 Identifier option with the client's DUID. 214 NEW: 216 If the server will not assign any addresses to any IAs in a 217 subsequent Request from the client, the server MUST send an 218 Advertise message to the client that includes only a Status Code 219 option with code NoAddrsAvail and a status message for the user, a 220 Server Identifier option with the server's DUID, a Client 221 Identifier option with the client's DUID and (optionally) 222 SOL_MAX_RT and/or INF_MAX_RT options. 224 Add text to the end of section 14, clarifying client behavior while 225 waiting for a response from a server: 227 NEW: 229 A client is not expected to listen for a response during the entire 230 period between transmission of Solicit or Information-Request 231 messages. 233 7. Security Considerations 235 This document introduces one security consideration beyond those 236 described in RFC 3315 [RFC3315]. A malicious DHCPv6 server might 237 cause a client to set its SOL_MAX_RT and INF_MAX_RT parameters to an 238 arbitrarily high value with the SOL_MAX_RT and INF_MAX_RT options. 239 Assuming the client also receives a response from a valid DHCPv6 240 server, large values for SOL_MAX_RT and INF_MAX_RT will not have any 241 effect. 243 8. IANA Considerations 245 IANA is requested to assign an option code from the "DHCP Option 246 Codes" Registry for OPTION_SOL_MAX_RT. 248 9. Normative References 250 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 251 Requirement Levels", BCP 14, RFC 2119, March 1997. 253 [RFC3315] Droms, R., Bound, J., Volz, B., Lemon, T., Perkins, C., 254 and M. Carney, "Dynamic Host Configuration Protocol for 255 IPv6 (DHCPv6)", RFC 3315, July 2003. 257 [RFC3633] Troan, O. and R. Droms, "IPv6 Prefix Options for Dynamic 258 Host Configuration Protocol (DHCP) version 6", RFC 3633, 259 December 2003. 261 Author's Address 262 Ralph Droms 263 Cisco Systems 264 1414 Massachusetts Avenue 265 Boxborough, MA 01719 266 USA 268 Phone: +1 978 936 1674 269 Email: rdroms@cisco.com