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Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Internet Engineering Task Force H. Chen 3 Internet-Draft Futurewei 4 Intended status: Standards Track October 2, 2019 5 Expires: April 4, 2020 7 OSPF Abnormal State Information 8 draft-chen-ospf-abnormal-state-info-03.txt 10 Abstract 12 This document describes a couple of options for an OSPF router to 13 advertise its abnormal state information in a routing domain. 15 Status of this Memo 17 This Internet-Draft is submitted to IETF in full conformance with the 18 provisions of BCP 78 and BCP 79. 20 Internet-Drafts are working documents of the Internet Engineering 21 Task Force (IETF). Note that other groups may also distribute 22 working documents as Internet-Drafts. The list of current Internet- 23 Drafts is at http://datatracker.ietf.org/drafts/current/. 25 Internet-Drafts are draft documents valid for a maximum of six months 26 and may be updated, replaced, or obsoleted by other documents at any 27 time. It is inappropriate to use Internet-Drafts as reference 28 material or to cite them other than as "work in progress." 30 This Internet-Draft will expire on April 4, 2020. 32 Copyright Notice 34 Copyright (c) 2019 IETF Trust and the persons identified as the 35 document authors. All rights reserved. 37 This document is subject to BCP 78 and the IETF Trust's Legal 38 Provisions Relating to IETF Documents 39 (http://trustee.ietf.org/license-info) in effect on the date of 40 publication of this document. Please review these documents 41 carefully, as they describe your rights and restrictions with respect 42 to this document. Code Components extracted from this document must 43 include Simplified BSD License text as described in Section 4.e of 44 the Trust Legal Provisions and are provided without warranty as 45 described in the Simplified BSD License. 47 Table of Contents 49 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 50 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . 3 51 3. Conventions Used in This Document . . . . . . . . . . . . . . . 3 52 4. OSPF Router State Information LSA . . . . . . . . . . . . . . . 3 53 4.1. OSPFv2 Router State Information (RSI) Opaque LSA . . . . . 3 54 4.2. OSPFv3 Router State Information (RSI) Opaque LSA . . . . . 5 55 4.3. OSPF Router State Information (RSI) TLV . . . . . . . . . . 5 56 5. Attach RSI TLV to Router Inforamtion LSA . . . . . . . . . . . 6 57 6. Notify Other Systems . . . . . . . . . . . . . . . . . . . . . 7 58 7. Security Considerations . . . . . . . . . . . . . . . . . . . 7 59 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 7 60 9. Acknowledgement . . . . . . . . . . . . . . . . . . . . . . . . 7 61 10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 7 62 10.1. Normative References . . . . . . . . . . . . . . . . . . . 7 63 10.2. Informative References . . . . . . . . . . . . . . . . . . 8 64 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 8 66 1. Introduction 68 There may be some states that are not normal in an OSPF router, which 69 include the state that a link state advertisement (LSA) stays in a 70 retransmission list on the router for more than a given time period 71 such as more than hello dead interval, and may include the state that 72 a database description (DD) packet does not get acknowledged for a 73 given period of time. 75 If a link state advertisement (LSA) with a topology change in a 76 router can not get through over an OSPF interface for a given time 77 period, some of the routers in the routing domain may have different 78 view of the real network topology, thus routing loops may occur and 79 some traffic may get dropped. 81 It is useful for an OSPF router in a routing domain to advertise its 82 abnormal state information to other routers, or notify some systems 83 such as an event management or monitoring system for its abnormal 84 state. 86 This document describes a couple of options for an OSPF router to 87 advertise its abnormal state information in a routing domain. 89 2. Terminology 91 This document uses terminologies defined in RFC 4970, RFC 2328, and 92 RFC 2740. 94 3. Conventions Used in This Document 96 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 97 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 98 document are to be interpreted as described in RFC 2119. 100 4. OSPF Router State Information LSA 102 OSPF routers MAY advertise their state information in a area-scoped 103 or AS-scoped router state information LSA with a router state 104 informatioin TLV. 106 4.1. OSPFv2 Router State Information (RSI) Opaque LSA 108 OSPFv2 routers will advertise an area-scoped or AS-scoped Router 109 State Information Opaque-LSA [RFC 2370], which has an Opaque type of 110 5 and Opaque ID of 0. 112 The RSI LSA will be originated initially by an OSPF router when an 113 OSPF instance is created and re-originated in every refresh interval 114 (LSRefreshTime) with the current state information of the router. 115 When the current state information changes, the RSI LSA will also be 116 originated. 118 0 1 2 3 119 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 1 120 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 121 | LS age | Options | 10/11 | 122 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 123 | 5 | 0 | 124 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 125 | Advertising Router | 126 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 127 | LS sequence number | 128 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 129 | LS checksum | length | 130 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 131 | | 132 +- TLVs -+ 133 | ... | 135 OSPFv2 Router State Information Opaque LSA 137 The format of the TLVs within the body of a RSI LSA is the same as 138 the format used by the Traffic Engineering Extensions to OSPF [RFC 139 3630]. The LSA payload consists of one or more nested Type/Length/ 140 Value (TLV) triplets. The format of each TLV is: 142 0 1 2 3 143 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 1 144 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 145 | Type | Length | 146 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 147 | Value... | 148 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 150 TLV Format 152 The Length field defines the length of the value portion in octets 153 (thus a TLV with no value portion would have a length of 0). The TLV 154 is padded to 4-octet alignment; padding is not included in the length 155 field (so a 3-octet value would have a length of 3, but the total 156 size of the TLV would be 8 octets). Nested TLVs are also 32-bit 157 aligned. For example, a 1-byte value would have the length field set 158 to 1, and 3 octets of padding would be added to the end of the value 159 portion of the TLV. Unrecognized types are ignored. 161 4.2. OSPFv3 Router State Information (RSI) Opaque LSA 163 TBD. 165 4.3. OSPF Router State Information (RSI) TLV 167 A router advertising a RSI LSA MAY include the Router State 168 Information TLV. If included, it MUST be the first TLV in the LSA. 169 Additionally, the TLV MUST accurately reflect the OSPF router's state 170 information in the scope advertised. 172 The format of the Router State Information TLV is as follows: 174 0 1 2 3 175 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 1 176 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 177 | Type (1) | Length | 178 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 179 | State Information sub-TLVs | 180 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 182 Type A 16-bit field set to 1. 184 Length A 16-bit field that indicates the length of the value 185 portion in octets and will be the total number of 186 octets that state information sub-TLVs use. 188 Value A variable length sequence of router state 189 information sub-TLVs. 191 The format of the Router State Information LSA retranmission time 192 sub-TLV is as follows: 194 0 1 2 3 195 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 1 196 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 197 | Type (1) | Length (2) | 198 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 199 | Max LSA retransmission time | Padding | 200 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 202 Type A 16-bit field set to 1. 204 Length A 16-bit field that indicates the length of the value 205 portion in octets and will be 2. 207 Value A 16-bit field set to the current maximum time 208 (in seconds) that an LSA stays in a retransmission 209 list in a router. 211 The format of the sub-TLV for the maximum time that a Database 212 Description packet is not acknowledged is illustrated below. 214 0 1 2 3 215 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 1 216 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 217 | Type (2) | Length (2) | 218 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 219 | Max time DD not acked | Padding | 220 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 222 Type A 16-bit field set to 2. 224 Length A 16-bit field that indicates the length of the value 225 portion in octets and will be 2. 227 Value A 16-bit field set to the current maximum time 228 (in seconds) for which a DD packet is not acknowledged 229 in a router. 231 5. Attach RSI TLV to Router Inforamtion LSA 233 Instead of using a Router State Information LSA to advertise the 234 abnormal state information for a router, we may use the existing 235 Router Information LSA defined in RFC 4970 to advertise the state 236 information through adding the Router State Information (RSI) TLV 237 into the Router Inforamtion LSA. 239 When a Router State Information (RSI) TLV is put into a Router 240 Information LSA, the type of the TLV may be different from the one 241 mentioned in the section above. 243 6. Notify Other Systems 245 An OSPF router may also notify other systems such as an event 246 management system about its abnormal state when the abnormal state 247 occurs in the router. 249 7. Security Considerations 251 The mechanism described in this document does not raise any new 252 security issues for the OSPF protocols. 254 8. IANA Considerations 256 tb 258 9. Acknowledgement 260 The author would like to thank people for their valuable comments on 261 this draft. 263 10. References 265 10.1. Normative References 267 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 268 Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/ 269 RFC2119, March 1997, 270 . 272 [RFC2328] Moy, J., "OSPF Version 2", STD 54, RFC 2328, DOI 10.17487/ 273 RFC2328, April 1998, 274 . 276 [RFC2370] Coltun, R., "The OSPF Opaque LSA Option", RFC 2370, 277 DOI 10.17487/RFC2370, July 1998, 278 . 280 [RFC2740] Coltun, R., Ferguson, D., and J. Moy, "OSPF for IPv6", 281 RFC 2740, DOI 10.17487/RFC2740, December 1999, 282 . 284 [RFC3630] Katz, D., Kompella, K., and D. Yeung, "Traffic Engineering 285 (TE) Extensions to OSPF Version 2", RFC 3630, 286 DOI 10.17487/RFC3630, September 2003, 287 . 289 [RFC4970] Lindem, A., Ed., Shen, N., Vasseur, JP., Aggarwal, R., and 290 S. Shaffer, "Extensions to OSPF for Advertising Optional 291 Router Capabilities", RFC 4970, DOI 10.17487/RFC4970, 292 July 2007, . 294 10.2. Informative References 296 Author's Address 298 Huaimo Chen 299 Futurewei 300 Boston, MA 301 US 303 Email: Huaimo.chen@futurewei.com