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Miscellaneous warnings: ---------------------------------------------------------------------------- == The copyright year in the IETF Trust and authors Copyright Line does not match the current year -- The document date (March 3, 2016) is 2974 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(See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) == Outdated reference: A later version (-15) exists of draft-ietf-bfd-optimizing-authentication-01 Summary: 1 error (**), 0 flaws (~~), 2 warnings (==), 1 comment (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Routing Working Group A. Mishra 3 Internet-Draft Ciena Corporation 4 Intended status: Standards Track M. Jethanandani 5 Expires: September 4, 2016 Cisco Systems 6 A. Saxena 7 Ciena Corporation 8 S. Pallagatti 9 Juniper Networks 10 M. Chen 11 Huawei 12 P. Fan 13 China Mobile 14 March 3, 2016 16 BFD Stability 17 draft-ashesh-bfd-stability-04.txt 19 Abstract 21 This document describes extensions to the Bidirectional Forwarding 22 Detection (BFD) protocol to measure BFD stability. Specifically, it 23 describes a mechanism for detection of BFD frame loss as well as 24 local delay measurements for BFD transmitter and receiver. 26 Requirements Language 28 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 29 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 30 document are to be interpreted as described in RFC 2119 [RFC2119]. 32 Status of This Memo 34 This Internet-Draft is submitted in full conformance with the 35 provisions of BCP 78 and BCP 79. 37 Internet-Drafts are working documents of the Internet Engineering 38 Task Force (IETF). Note that other groups may also distribute 39 working documents as Internet-Drafts. The list of current Internet- 40 Drafts is at http://datatracker.ietf.org/drafts/current/. 42 Internet-Drafts are draft documents valid for a maximum of six months 43 and may be updated, replaced, or obsoleted by other documents at any 44 time. It is inappropriate to use Internet-Drafts as reference 45 material or to cite them other than as "work in progress." 47 This Internet-Draft will expire on September 4, 2016. 49 Copyright Notice 51 Copyright (c) 2016 IETF Trust and the persons identified as the 52 document authors. All rights reserved. 54 This document is subject to BCP 78 and the IETF Trust's Legal 55 Provisions Relating to IETF Documents 56 (http://trustee.ietf.org/license-info) in effect on the date of 57 publication of this document. Please review these documents 58 carefully, as they describe your rights and restrictions with respect 59 to this document. Code Components extracted from this document must 60 include Simplified BSD License text as described in Section 4.e of 61 the Trust Legal Provisions and are provided without warranty as 62 described in the Simplified BSD License. 64 Table of Contents 66 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 67 2. Use Cases . . . . . . . . . . . . . . . . . . . . . . . . . . 3 68 3. BFD Null-Authentication TLV . . . . . . . . . . . . . . . . . 3 69 4. Theory of Operations . . . . . . . . . . . . . . . . . . . . 3 70 4.1. Loss Measurement . . . . . . . . . . . . . . . . . . . . 3 71 4.2. Delay Measurement . . . . . . . . . . . . . . . . . . . . 4 72 5. IANA Requirements . . . . . . . . . . . . . . . . . . . . . . 4 73 6. Security Consideration . . . . . . . . . . . . . . . . . . . 4 74 7. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 4 75 8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 5 76 9. Normative References . . . . . . . . . . . . . . . . . . . . 5 77 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 5 79 1. Introduction 81 The Bidirectional Forwarding Detection (BFD) [RFC5880] protocol 82 operates by transmitting and receiving control frames, generally at 83 high frequency, over the datapath being monitored. In order to 84 prevent significant data loss due to a datapath failure, the 85 tolerance for lost or delayed frames in the Detection Time, as 86 defined in BFD [RFC5880] is set to the smallest feasible value. 88 This document proposes a mechanism to detect delayed or lost frames 89 in a BFD session in addition to the datapath fault detection 90 mechanisms of BFD. Such a mechanism presents significant value to 91 measure the stability of BFD sessions and provides data to the 92 operators for the cause of a BFD failure. 94 This document does not propose BFD extension to measure data traffic 95 loss or delay on a link or tunnel and the scope is limited to BFD 96 frames. 98 2. Use Cases 100 Legacy BFD cannot detect any BFD frame delay or loss if delay or loss 101 does not last for dead interval. This draft proposes a method to 102 distinguish between a dropped and a delayed frame on the receiver. 103 For example, if the receiver receives BFD CC frame k at time t but 104 receives frame k+1 at time t+9.9ms for a 3.3ms BFD interval, the 105 frame is delayed. However, if the receiver receives frame k+3 at 106 time t+10ms, and never receives frame k+1 and/or k+2, then it has 107 experienced a drop. Delays can be because of congestion in the 108 network or because of delays in the BFD transmitter or receiver. 110 This proposal enables BFD engine to generate diagnostic information 111 on the health of each BFD session that could be used to preempt a 112 failure on a link that BFD was monitoring by allowing time for a 113 corrective action to be taken. 115 In a faulty datapath scenario, operator can use BFD health 116 information to trigger delay and loss measurement OAM protocol 117 (Connectivity Fault Management (CFM) or Loss Measurement (LM)-Delay 118 Measurement (DM)) to further isolate the issue. 120 3. BFD Null-Authentication TLV 122 The functionality proposed for BFD stability measurement is achieved 123 by appending the Null-Authentication TLV (as defined in Optimizing 124 BFD Authentication [I-D.ietf-bfd-optimizing-authentication] ) to the 125 BFD control frame that do not have authentication enabled. 127 4. Theory of Operations 129 This mechanism allows operator to measure the loss, transmitter delay 130 and receiver delay of BFD CC frames. 132 When using MD5 or SHA authentication, BFD uses authentication TLV 133 that carries the Sequence Number. However, if non-meticulous 134 authentication is being used, or no authentication is in use, then 135 the non-authenticated BFD frames MUST include NULL-Auth TLV. 137 4.1. Loss Measurement 139 Loss measurement counts the number of BFD control frames missed at 140 the receiver during any Detection Time period. The loss is detected 141 by comparing the Sequence Number field in the Auth TLV (NULL or 142 otherwise) in successive BFD CC frames. The Sequence Number in each 143 successive control frame generated on a BFD session by the 144 transmitter is incremented by one. 146 The first BFD NULL-Auth TLV processed by the receiver that has a non- 147 zero sequence number is used for bootstrapping the logic. Each 148 successive frame after this is expected to have a Sequence Number 149 that is one greater than the Sequence Number in the previous frame. 150 When the Sequence Number wraps around it should start from 1 instead 151 of 0. 153 4.2. Delay Measurement 155 Delay measurement can be done locally & independently on the 156 transmitter & receiver. Hence it is out of the scope of this 157 document. Following is an example of how the delay measurement can 158 be achieved on both sides: 160 Transmitter Delay: 162 Delay measurements on the transmitter can be made by 163 calculating the time difference between software BFD engine 164 transmitting the frame and the time when the hardware puts the 165 frame on the wire. 167 Receiver Delay: 169 Delay measurement can be made using the time difference between 170 the time hardware received a BFD Frame and the time software 171 BFD Engine processed the frame. 173 While a constant delay may not be indicator of instability, large 174 transient delays can decrease the BFD session stability 175 significantly. BFD MAY choose to inform the operator about any of 176 the delays when the delay measurement crosses a particular threshold 177 value. 179 5. IANA Requirements 181 N/A 183 6. Security Consideration 185 Other than concerns raised in BFD [RFC5880] there are no new concerns 186 with this proposal. 188 7. Contributors 190 Manav Bhatia 192 8. Acknowledgements 194 Authors would like to thank Nobo Akiya, Jeffery Haas, Peng Fan, 195 Dileep Singh, Basil Saji, Sagar Soni and Mallik Mudigonda who also 196 contributed to this document. 198 9. Normative References 200 [I-D.ietf-bfd-optimizing-authentication] 201 Jethanandani, M., Mishra, A., Saxena, A., and M. Bhatia, 202 "Optimizing BFD Authentication", draft-ietf-bfd- 203 optimizing-authentication-01 (work in progress), February 204 2016. 206 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 207 Requirement Levels", BCP 14, RFC 2119, 208 DOI 10.17487/RFC2119, March 1997, 209 . 211 [RFC5880] Katz, D. and D. Ward, "Bidirectional Forwarding Detection 212 (BFD)", RFC 5880, DOI 10.17487/RFC5880, June 2010, 213 . 215 Authors' Addresses 217 Ashesh Mishra 218 Ciena Corporation 219 3939 North 1st Street 220 San Jose, CA 95134 221 USA 223 Email: mishra.ashesh@outlook.com 224 URI: www.ciena.com 226 Mahesh Jethanandani 227 Cisco Systems 228 170 W. Tasman Drive 229 San Jose, CA 95134 230 USA 232 Email: mjethanandani@gmail.com 233 URI: www.cisco.com 234 Ankur Saxena 235 Ciena Corporation 236 3939 North 1st Street 237 San Jose, CA 95134 238 USA 240 Email: ankurpsaxena@gmail.com 241 URI: www.ciena.com 243 Santosh Pallagatti 244 Juniper Networks 245 Juniper Networks, Exora Business Park 246 Bangalore, Karnataka 560103 247 India 249 Email: santoshpk@juniper.net 251 Mach Chen 252 Huawei 254 Email: mach.chen@huawei.com 256 Peng Fan 257 China Mobile 258 32 Xuanwumen West Street 259 Beijing, Beijing 260 China 262 Email: fanp08@gmail.com