idnits 2.17.1 draft-decraene-lsr-lag-indication-00.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 == The document seems to lack the recommended RFC 2119 boilerplate, even if it appears to use RFC 2119 keywords -- however, there's a paragraph with a matching beginning. Boilerplate error? (The document does seem to have the reference to RFC 2119 which the ID-Checklist requires). -- The document date (April 6, 2021) is 1115 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(See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) == Outdated reference: A later version (-18) exists of draft-ietf-lsr-dynamic-flooding-08 ** Downref: Normative reference to an Experimental draft: draft-ietf-lsr-dynamic-flooding (ref. 'I-D.ietf-lsr-dynamic-flooding') Summary: 1 error (**), 0 flaws (~~), 3 warnings (==), 1 comment (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Network Working Group B. Decraene 3 Internet-Draft Orange 4 Intended status: Standards Track S. Hegde 5 Expires: October 8, 2021 Juniper Networks Inc. 6 April 6, 2021 8 LAG indication 9 draft-decraene-lsr-lag-indication-00 11 Abstract 13 This document defines a new link flag to advertise that a layer-three 14 link is composed of multiple layer-two sub-links, such as when this 15 link is a Link Aggregation Group (LAG). This allows a large single 16 flow (an elephant flow) to be aware that the link capacity will be 17 lower than expected as this single flow is not load-balanced across 18 the multiple layer-two sub-links. A path computation logic may use 19 that information to route that elephant flow along a different path. 21 Status of This Memo 23 This Internet-Draft is submitted in full conformance with the 24 provisions of BCP 78 and BCP 79. 26 Internet-Drafts are working documents of the Internet Engineering 27 Task Force (IETF). Note that other groups may also distribute 28 working documents as Internet-Drafts. The list of current Internet- 29 Drafts is at https://datatracker.ietf.org/drafts/current/. 31 Internet-Drafts are draft documents valid for a maximum of six months 32 and may be updated, replaced, or obsoleted by other documents at any 33 time. It is inappropriate to use Internet-Drafts as reference 34 material or to cite them other than as "work in progress." 36 This Internet-Draft will expire on October 8, 2021. 38 Copyright Notice 40 Copyright (c) 2021 IETF Trust and the persons identified as the 41 document authors. All rights reserved. 43 This document is subject to BCP 78 and the IETF Trust's Legal 44 Provisions Relating to IETF Documents 45 (https://trustee.ietf.org/license-info) in effect on the date of 46 publication of this document. Please review these documents 47 carefully, as they describe your rights and restrictions with respect 48 to this document. Code Components extracted from this document must 49 include Simplified BSD License text as described in Section 4.e of 50 the Trust Legal Provisions and are provided without warranty as 51 described in the Simplified BSD License. 53 Table of Contents 55 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 56 1.1. Requirements Language . . . . . . . . . . . . . . . . . . 2 57 2. Protocol extensions . . . . . . . . . . . . . . . . . . . . . 3 58 2.1. IS-IS extension . . . . . . . . . . . . . . . . . . . . . 3 59 2.2. OSPF extension . . . . . . . . . . . . . . . . . . . . . 3 60 3. Operational considerations . . . . . . . . . . . . . . . . . 3 61 4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 3 62 4.1. IS-IS . . . . . . . . . . . . . . . . . . . . . . . . . . 3 63 4.2. OSPF . . . . . . . . . . . . . . . . . . . . . . . . . . 4 64 5. Security Considerations . . . . . . . . . . . . . . . . . . . 4 65 6. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 4 66 7. References . . . . . . . . . . . . . . . . . . . . . . . . . 5 67 7.1. Normative References . . . . . . . . . . . . . . . . . . 5 68 7.2. Informative References . . . . . . . . . . . . . . . . . 5 69 Appendix A. Changes / Author Notes . . . . . . . . . . . . . . . 5 70 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 6 72 1. Introduction 74 An IP link may be composed a multiple layer two sub-links not visible 75 to the IGP routing topology. When traffic crossing that IP link is 76 load-balanced on a per flow basis, a large elephant flow will only 77 benefit from the capacity of a single sub-link. This is an issue for 78 the routing logic which only see the aggregated bandwidth of the IP 79 link, and hence may incorrectly route a large flow over a link which 80 is incapable of transporting that flow. 82 This document defines a new link flag to signal that an IP link is a 83 Link Aggregate Group composed of multiple layer two sub-links. This 84 flag may be automatically be set by routing nodes connected to such 85 links, without requiring manual tagging by the network operator. A 86 path computation logic such as a PCE or a CSPF computation on the 87 ingress, may use that information to avoid such links for elephant 88 flows. 90 1.1. Requirements Language 92 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 93 "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and 94 "OPTIONAL" in this document are to be interpreted as described in BCP 95 14 RFC 2119 [RFC2119] RFC 8174 [RFC8174] when, and only when, they 96 appear in all capitals, as shown here. 98 2. Protocol extensions 100 2.1. IS-IS extension 102 To advertise that a layer-three link is composed of multiple layer- 103 two sub-components this document defines a new bit in the IS-IS link- 104 attribute sub-TLV RFC 5029 [RFC5029]. 106 L2 LAG (Link Aggregation Group) TBD1. When set, this layer-three 107 link is composed of multiple layer-two sub-components performing per 108 flow load balancing. 110 2.2. OSPF extension 112 To advertise that a layer-three link is composed of multiple layer- 113 two sub-components this document defines a new bit in the OSPF Link 114 Attributes Bits TLV [I-D.ietf-lsr-dynamic-flooding]. 116 L2 LAG (Link Aggregation Group) TBD2. When set, this layer-three 117 link is composed of multiple layer-two sub-components performing per 118 flow load balancing. 120 3. Operational considerations 122 A node supporting this extension SHOULD automatically advertise the 123 L2 LAG flag for IP links composed of multiple layer-two sub- 124 components. Configuration knob MAY be provided to override this 125 default. 127 In order to handle nodes not supporting this extension, network 128 operator may need to use an admin group (color) [RFC5305] [RFC7308] 129 in order to flag those links on legacy nodes. 131 4. IANA Considerations 133 4.1. IS-IS 135 IANA is requested to allocate one bit value from the registry: link- 136 attribute bit values for sub-TLV 19 of TLV 22 (Extended IS 137 reachability TLV). 139 Value Name 140 ---- -------------------------------- 141 TBD1 L2 LAG (Link Aggregation Group) 143 Figure 1 145 4.2. OSPF 147 IANA is requested to allocate one bit number from the registry: OSPF 148 Link Attributes Sub-TLV Bit Values. 150 Bit Number Description 151 ---------- -------------------------------- 152 TBD2 L2 LAG (Link Aggregation Group) 154 Figure 2 156 5. Security Considerations 158 This extension advertises additional information and capabilities 159 about a link. 161 An attacker having access to this information would gain knowledge 162 that this link has sub components and that sending a large amount of 163 traffic via a single flow (hence not a DOS) is more likely to 164 overload that sub-component. On the other hand, this overloading 165 would be limited to this specific sub-component and hence not affect 166 other sub-component. 168 An attacker been capable of adding this information may gain ability 169 to change the routing of some flow crossing the links, typically 170 large elephant flows specifically configured to avoid such link. 172 An attacker been capable of removing this information may gain the 173 ability to change the routing and direct a large elephant flow on 174 this link, which would overload a sub component of this link and 175 likely create packet drop for this specific flow. 177 However, in those two cases, the attacker would equally have the 178 capability to change other routing information such as the link 179 metric, link usability and any link characteristics. Hence this new 180 information does not add new security considerations. Besides, as 181 with others TLV advertisements, the use of a cryptographic 182 authentication as defined in [RFC5304] or [RFC5310] allows the 183 authentication of the peer and the integrity of the message and 184 remove the ability for an attacker to modify such information. 186 . 188 6. Acknowledgments 190 TBD. 192 7. References 194 7.1. Normative References 196 [I-D.ietf-lsr-dynamic-flooding] 197 Li, T., Psenak, P., Ginsberg, L., Chen, H., Przygienda, 198 T., Cooper, D., Jalil, L., Dontula, S., and G. Mishra, 199 "Dynamic Flooding on Dense Graphs", draft-ietf-lsr- 200 dynamic-flooding-08 (work in progress), December 2020. 202 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 203 Requirement Levels", BCP 14, RFC 2119, 204 DOI 10.17487/RFC2119, March 1997, 205 . 207 [RFC5029] Vasseur, JP. and S. Previdi, "Definition of an IS-IS Link 208 Attribute Sub-TLV", RFC 5029, DOI 10.17487/RFC5029, 209 September 2007, . 211 [RFC5304] Li, T. and R. Atkinson, "IS-IS Cryptographic 212 Authentication", RFC 5304, DOI 10.17487/RFC5304, October 213 2008, . 215 [RFC5310] Bhatia, M., Manral, V., Li, T., Atkinson, R., White, R., 216 and M. Fanto, "IS-IS Generic Cryptographic 217 Authentication", RFC 5310, DOI 10.17487/RFC5310, February 218 2009, . 220 [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 221 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 222 May 2017, . 224 7.2. Informative References 226 [RFC5305] Li, T. and H. Smit, "IS-IS Extensions for Traffic 227 Engineering", RFC 5305, DOI 10.17487/RFC5305, October 228 2008, . 230 [RFC7308] Osborne, E., "Extended Administrative Groups in MPLS 231 Traffic Engineering (MPLS-TE)", RFC 7308, 232 DOI 10.17487/RFC7308, July 2014, 233 . 235 Appendix A. Changes / Author Notes 237 [RFC Editor: Please remove this section before publication] 239 00: Initial version. 241 Authors' Addresses 243 Bruno Decraene 244 Orange 246 Email: bruno.decraene@orange.com 248 Shraddha Hegde 249 Juniper Networks Inc. 250 Exora Business Park 251 Bangalore, KA 560103 252 India 254 Email: shraddha@juniper.net