IDR Working Group G. Van de Velde, Ed. Internet-Draft Nokia Intended status: Standards Track K. Patel Expires:MarchSeptember 3, 2017Cisco SystemsArrcus Z. Li Huawei TechnologiesAugust 30, 2016March 2, 2017 Flowspec Indirection-id Redirectdraft-ietf-idr-flowspec-path-redirect-00draft-ietf-idr-flowspec-path-redirect-01 Abstract Flowspec is an extension to BGP that allows for the dissemination of traffic flow specification rules. This has many possible applications but the primary one for many network operators is the distribution of traffic filtering actions for DDoS mitigation. The flow-spec standard RFC5575 [2] defines a redirect-to-VRF action for policy-based forwarding but this mechanism is not always sufficient, particularly if the redirected traffic needs to be steered into an engineered path or into a service plane. This document defines a new extended community known as redirect-to- indirection-id (32-bit) flowspec action to provide advanced redirection capabilities on flowspec clients. When activated, the flowspec extended community is used by a flowspec client to find the correct next-hop entry within a localised indirection-id mapping table. The functionality present in this draft allows a network controller to decouple flowspec functionality from the creation and maintainance of the network's service plane itself including the setup of tunnels and other service constructs that could be managed by other network devices. Requirements Language The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119 [1]. Status of This Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at http://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." This Internet-Draft will expire onMarchSeptember 3, 2017. Copyright Notice Copyright (c)20162017 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 2. indirection-id and indirection-id table . . . . . . . . . . . 3 3. Use Case Scenarios . . . . . . . . . . . . . . . . . . . . . 4 3.1. Redirection shortest Path tunnel . . . . . . . . . . . . 4 3.2. Redirection to path-engineered tunnels . . . . . . . . . 5 3.3. Redirection toNext-next-hopcomplex dynamically constructed tunnels .. . . . . . . . .6 4. Redirect to indirection-id Community . . . . . . . . . . . . 7 5. Redirect using localised indirection-id mapping table . . . .98 6. Validation Procedures . . . . . . . . . . . . . . . . . . . . 9 7. Security Considerations . . . . . . . . . . . . . . . . . . .109 8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . .109 9. Contributor Addresses . . . . . . . . . . . . . . . . . . . .109 10. IANA Considerations . . . . . . . . . . . . . . . . . . . . .1110 11. References . . . . . . . . . . . . . . . . . . . . . . . . .1211 11.1. Normative References . . . . . . . . . . . . . . . . . .1211 11.2. Informative References . . . . . . . . . . . . . . . . .1312 Appendix A. Additional indirection_id types waiting for use-case description . . . . . . . . . . . . . . . . . . . . 12 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 13 1. Introduction Flowspec RFC5575 [2] is an extension to BGP that allows for the dissemination of traffic flow specification rules. This has many possible applications, however the primary one for many network operators is the distribution of traffic filtering actions for DDoS mitigation. Every flowspec policy route is effectively a rule, consisting of a matching part (encoded in the NLRI field) and an action part (encoded in one or more BGP extended communities). The flow-spec standard RFC5575 [2] defines widely-used filter actions such as discard and rate limit; it also defines a redirect-to-VRF action for policy-based forwarding. Using the redirect-to-VRF action to steer traffic towards an alternate destination is useful for DDoS mitigation but using this technology can be cumbersome when there is need to steer the traffic onto an engineered traffic path. This draft proposes a new redirect-to-indirection-id flowspec action facilitating an anchor point for policy-based forwarding onto an engineered path or into a service plane. The flowspec client consuming and utilizing the new flowspec indirection-id extended- communityfindsconstructs the redirection information based upon information found within a localised indirection-id mapping table. The localised mapping table is a tableconstruct providing at one side theconstruct, sequenced by a tablekey and at the other sidekey, providing next-hop information. Thetable key consists out the combination of indirection-id type and indirection-id 32-bit value. Theredirect-to-indirection-id flowspec action is encoded in a newly defined BGP extended community.In addition, theThe type of redirectioncan be configuredis identified as an extended community indirection-id type field. This draft defines the indirection-id extended-community andthea few wellknown indirection-id types. The specificsolutionmechanics to constructthea localised indirection-id mapping table are out-of-scope of this document. 2. indirection-id and indirection-id table An indirection-id is an abstract number (32-bit value) used as identifier for a localised indirection decision. The indirection-id will allow a flowspec client to redirect traffic into a service plane or consequently onto an engineered traffic path. For example, when a BGP flowspec controller signals a flowspec client the indirection-id extended community, then the flowspec client uses the indirection-id to make a recursive lookup toretrievefind the next-hop information. The indirection-id is used to find the corresponding next-hop informationfound in awithin the localised indirection mapping table. The indirection-id table isa routerlocalisedtable.on the router. The indirection-id table is constructed out of tablekeyskeys, each mapped toflowspec clientlocalised redirection information.TheEach table key iscreatedcomposed by thecombination of thecombining indirection-id type andthean indirection-id 32-bit value. Each entry in the indirection-table key maps to sufficient information (parameters regarding encapsulation,interface,egress-interface, QoS, etc...) to successfully redirecttraffic.traffic according flowspec controller expectations. 3. Use Case Scenarios This section describes use-case scenarios when deploying redirect-to- indirection-id. 3.1. Redirection shortest Path tunnelPossibleExample: Indirection-IDtype examples:community types to be used: o 0 (localised ID): Whendeploying on flowspec clientthe intent is to use a localised Indirection-idtable: 0 (localised ID) o When deployingtable on the flowspec client o 1 (Node ID): When the intent is to use a Segment Routing based Indirection-idtable: 1 (Node ID)table on the flowspec client Description:AThe first use-caseis allowing a BGP Flowspec controller to senddescribes an example where a single flowspecpolicyroute (i.e. flowspec_route#1) is sent by a flowspec controller to many BGP flowspec clients. This single flowspec routesignals thewill instruct all Flowspec clients to redirecttrafficmatching dataflows onto a shortest-path tunnel pointing towards a single IP destination address. For this first use-case scenario,theeach flowspec client receivesfrom the flowspec controllera flowspec route(i.e. flowspec_route#1) including(flowspec_route#1) which has theredirect-to-indirection-idredirect-to- indirection-id extendedcommunity.community attached. Theredirect-to-indirection-idextended redirect- to-indirection-id community contains the table key(indirection-idconsisting out of the indirection-id type+and indirection-id 32-bitvalue)value. The table key is used on the flowspec client to map toselectthe correspondingnext-hopnext- hop informationfromwithin theflowpsec client localisedlocal indirection-id table. Theresulting next-hop information forfinite result of thisuse-caseoperation is a remote tunnel end-point IP address together with accordingly sufficient tunnel encapsulation information to forward and encapsulate thepacketdata-packet accordingly. Requirements: For redirect to shortest path tunnel it is required that the tunnel MUST be operational and allow packets to be exchanged between tunnel head- and tail-end. 3.2. Redirection to path-engineered tunnelsPossibleExample: Indirection-IDtype examples:community types to be used: o 0 (localised ID): Whendeploying on flowspec clientthe intent is to use a localised Indirection-idtable: 0 (localised ID) o When deployingtable on the flowspec client o 6 (Binding Segment ID): When the intent is to use a Segment Routing based Indirection-idtable: 6 (Binding Segment ID) Description: For a second use-case, it is expected thattable on the flowspec clientredirect traffic matches theDescription: The second use-case describes an example where a flowspecrule,controler injects a single flowspec route which gets distributed to many BGP flowspec clients. This single flowspec route intends to instruct all Flowspec clients to redirect corresponding dataflows onto a path engineered tunnel.TheIt is expected that each of the path engineeredtunnel on the flowspec client SHOULD be createdtunnels is instantiated by out-of-band mechanisms. Each used path engineered tunneldeployed for flowspec redirection,has a unque table keyas anidentifier. consequently, the table key(=indirection-id type and indirection-id 32-bit value)uniquely identifiesa single path engineered tunnel on the flowspec client. The localised indirection-id mapping table is the collection of all keys corresponding allexactly -one- path engineeredtunnels on the flowspec client. Fortunnel. In thisseconduse-casescenario,example, the flowspec controller sends a flowspec route(i.e. flowspec_route#2)tosome flowspec clients. The flowspec clients, respectively receiveeach of the flowspecroute.clients and this flowspec route has a redirect-to-indirection-id extended community attached. The redirect-to-indirection-id extended communitycontainsembeds table key information and hence provides sufficient informationfor the flowspec clientsto select the corresponding path-engineered tunneland consequently provides sufficient tunnel encapsulation informationto redirect the packet according the flowspec controller expectations. Segment Routing Example: A concrete embodiment of a Segment Routing use-case exampleof this use-case can beis found insegment routednetworks where path engineered tunnelscan be setupare created bymeans ofacontroller signaling explicit paths to peering routers.Segment Routing MPLS label stack. In such acase,deployment, the indirection-idreferencesprovides an anchorpoint reference to a Segment Routing BindingSID, whileSID. However, the indirection-id typereferencesprovides a pointer to theBindgingBinding SIDsemantic.semantics to be used. The Binding SID is a segment identifier value (as per segment routing definitions in [I-D.draft-ietf-spring- segment-routing] [6]) used to associatewithan explicitpathpath. The Binding SID and corresponding path engineered tunnel can for example be setup by a controller using BGP as specified in [I-D.sreekantiah- idr-segment-routing-te] [5] or by usingPCEPCEP as detailed indraft-ietf- pce-segment-routingdraft- ietf-pce-segment-routing [7].WhenTo conclude, when a BGP speaker at some point in time receives a flow-spec route witha 'redirect to Binding SID'an extended 'redirect-to-indirection-id' community, it installs a traffic filtering rule that matchestheparticular packetsdescribed by the NLRI fieldand redirects themto theonto an explicit path associated with the corresponding Binding SID. Theexplicit path is specified as a set/stack of segment identifiers as detailed in the previous documents. The stack of segment identifiers is now imposed on packets matching the flow-spec rule to perform redirection as per the explicit path setup prior. Theencoding of the Binding SIDvaluewithin the redirect-to-indirection-id extended community is specified in section4, with the indirection-id field now encoding the associated value for the binding SID.4. Requirements: For redirect to path engineered tunnels it is required that the engineered tunnel MUST beoperationalactive and allow packets to be exchanged between tunnel head- and tail-end. 3.3. Redirection toNext-next-hopcomplex dynamically constructed tunnelsPossibleExample: Indirection-IDtype examples:community types to be used: o 0 (localised ID) with TID: Whendeploying on flowspec client usingthe intent is to use a localised Indirection-idtable thetable, then TID(Table ID) is used: one indirection-id community of type 0 (localised ID) with TID=0 and second indirection-id community(Table-ID) field could be used to sequence multiple redirect-to-indirection-id actions together to construct a more complex path engineered tunnel. The order oftype 0 with TID=1sequencing the redirection information may be identified by using the TID field. Description: AThirdthird use-case describes the application and redirection towards complex dynamically constructed tunnels. For this use-caseis whena BGPFlowspecflowspec controllersendsinjects asingleflowspecpolicyrouteto flowspec clients to signal redirection towards next-next-hop tunnels. In this use-case Thewith multiple 'redirect- to-indirection-id' communities attached. A recipient flowspecrule is instructing the Flowspecclient may use the Table-ID (TID) field embedded within each 'redirect-to- indirection-id' community toredirect traffic using asequenceof indirection-id extended communities.the redirect information. Thesequence of indirection- idscomplex dynamically constructed tunnel ismanaged using Tunnel IDs (TID).the product of concatenating the available redirect information (i.e. MPLS Segment Routing Labels). Segment Routing Example: i.e. a classic Segment Routing examplewould beusing complex tunnels is found in DDoS mitigationtowardsand traffic offload. Suspicious traffic (e.g. dirty traffic flows) may be steered into a Segment Routing Central Egress Path Engineered tunnel [4].To steer DDoS traffic towards egress peer engineering paths,For this particular complex dynamic redirect tunnel embodiment, a firstindirection-idredirect-to-indirection- id (i.e. TID=0)will steeris used to redirect trafficontointo a tunnelto antowards a particlar egress router, whilethea secondindirection-id (TID=1)redirect-to-indirection-id (i.e. TID=1) is used to steer traffic beyond the particular egress routerarrived traffic ontotowards a pre-identifiedinterface/ peer. The flowspec client will forinterface/peer. For thisuse-caseDDoS use-case, in its simplest embodiment, thesimpliest implementationflowspec client must dynamically append 2 MPLS labels. A first MPLS label (the outer label)is usedto steer the original packet to the egressnode, while the nextnode (and hence using a shortest path tunnel), while a second MPLS label(the inner label, corresponding(matching redirect-to-indirection-id with TID=1), theindirection-id identified with TID=1) instructsinner label, to steer on the egress routerto steerthe original packet to a pre-definedinterface/peer correspondinginterface/peer. The basic data-plane principles are documented by [4]. Requirements: To achievethis type ofredirectionto next-next-hoptowards complex dynamically constructed tunnels, for each flowspec route, multiple indirection-ids, each using a unique Tunnel IDaremay imposed upon athegiven flowspec policy rule. It is required that there is synchronisation established between thelabels used by the Egress Peer Engineering egress routerdata- andthe flowspec client originally imposing the sequenscontrol-plane ofEPE Segment Routing segments. It is required that the the engineered next-next-hopall relevant devices involved. Each complex dynamically constructed tunnel MUST be operational and allow packets to be exchanged between tunnel head- andtail-end.tail-end before it should be used to redirect traffic. 4. Redirect to indirection-id Community This document defines a new BGP extended community known as a Redirect-to-indirection-id extended community. This extended community is a new transitive extended community with the Type and the Sub-Type field to be assigned by IANA. The format of this extended community is show in Figure 1. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type | Sub-Type | Flags(1 octet)| Indirection ID| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Generalized indirection_id | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 1 The meaning of the extended community fields are as follows: Type: 1 octet to be assigned by IANA. Sub-Type: 1 octet to be assigned by IANA. Flags: 1 octet field. Following Flags are defined. 0 1 0 1 2 3 4 5 6 7 +-+-+-+-+-+-+-+-+ | RES | TID |C| +-+-+-+-+-+-+-+-+ Figure 2 The least-significant Flag bit is defined as the 'C' (or copy) bit. When the 'C' bit is set the redirection applies to copies of the matching packets and not to the original traffic stream. The 'TID' field identifies a 4 bit Table-id field. This field is used to provide the flowspec client an indication how and where to sequence the received indirection-ids to redirecting traffic. TID value 0 indicates that Table-id field is NOT set and SHOULD be ignored. All bits other than the 'C' and 'TID' bits MUST be set to 0 by the originating BGP speaker and ignored by receiving BGP speakers. Indirection ID: 1 octet value. This draft defines following indirection_id Types: 0 - Localised ID (The flowspec client uses the received indirection-id to lookup the redirection information in the localised indirection-id table.) 1 - Node ID (The flowspec client uses the received indirection-id as a Segment Routing Node ID to redirect traffic towards)2 - Agency ID (The flowspec client uses the received indirection- id as a Segment Routing Agency ID to redirect traffic towards) 3 - AS (Autonomous System) ID (The flowspec client uses the received indirection-id as a Segment Routing Autonomous System ID to redirect traffic towards) 4 - Anycast ID (The flowspec client uses the received indirection- id as a Segment Routing Anycast ID to redirect traffic towards) 5 - Multicast ID (The flowspec client uses the received indirection-id as a Segment Routing Multicast ID to redirect traffic towards)6 - Binding Segment ID (The flowspec client uses the received indirection-id as a Segment Routing Binding Segment ID to redirect traffic towards) [I-D.draft-ietf-spring-segment-routing] [6]7 - VPN ID (The flowspec client uses the received5. Redirect using localised indirection-idasmapping table When aSegment Routing VPN ID to redirect traffic towards) 8 - OAM ID (TheBGP flowspec clientuses the received indirection-id asreceives aSegment Routing OAM ID to redirect traffic towards) 9 - ECMP (Equal Cost Multi-Path) ID (Theflowspecclient uses the received indirection-id aspolicy route with aSegment Routing PeerSet ID'redirect toredirect traffic towards) 10 - QoS ID (The flowspec client usesindirection-id' extended community attached and thereceived indirection-id asroute represents the best BGP path, it will install aSegment Routing QoS ID to redirect traffic towards) 11 - Bandwidth-Guarantee ID (Theflowspecclient uses the received indirection-id as a Segment Routing Bandwidth-Guarantee ID to redirect traffic towards) 12 - Security ID (The flowspec client uses the received indirection-id as a Segment Routing Security ID to redirect traffic towards) 13 - Multi-Topology ID (The flowspec client uses the received indirection-id as a Segment Routing Multi-Topology ID to redirect traffic towards) 5. Redirect using localised indirection-id mapping table When a BGP speaker receives a flowspec policy route with a 'redirect to indirection-id' extended community and this route represents the one and only best path or an equal cost multipath, it installs atraffic filtering rulethat matchesmatching thepacketsIP tupples described by the flowpsec NLRI field and consequently redirectsthemthe flow (C=0) or copiesthem (C=1) towards the indirection-id local recursed path. To constructthelocal recursed path, the flowspec client does a local indirection-id mapping table lookup (i.e. indirection-id type = 0)flow (C=1) using thekey comprised of the indirection-id 32-bit value and indirection-id type (=0) to retrieveinformation identified by thecorrect redirection information.'redirect-to-indirection-id' community. 6. Validation Procedures The validation check described in RFC5575 [2] and revised in [3] SHOULD be applied by default to received flow-spec routes with a 'redirect to indirection-id' extended community. This means that a flow-spec route with a destination prefix subcomponent SHOULD NOT be accepted from an EBGP peer unless that peer also advertised the best path for the matching unicast route. While it MUST NOT happen, and is seen as invallid combination, it is possible from a semenatics perspective to have multiple clashing redirect actions defined within a single flowspec rule. For best and consistant RFC5575 flowspec redirect behavior the redirect as documented by RFC5575 MUST not be broken, and hence when a clash occurs, then RFC5575 based redirect SHOULD take priority. Additionally, if the 'redirect to indirection-id' does not result in a valid redirection, then the flowspec rule must be processed as if the 'redirect to indirection-id' community was not attached to the flowspec route and MUST provide an indication within the BGP routing table that the respective 'redirect to indirection-id' resulted in an invalid redirection action. 7. Security Considerations A system using 'redirect-to-indirection-id' extended community can cause during the redirect mitigation of a DDoS attack result in overflow of traffic received by the mitigation infrastructure. 8. Acknowledgements This document received valuable comments and input from IDR working group including Adam Simpson, Mustapha Aissaoui, Jan Mertens, Robert Raszuk, Jeff Haas, Susan Hares and Lucy Yong. 9. Contributor Addresses Below is a list of other contributing authors in alphabetical order: Arjun Sreekantiah Cisco Systems 170 W. Tasman Drive San Jose, CA 95134 USA Email: asreekan@cisco.com Nan Wu Huawei Technologies Huawei Bld., No. 156 Beiquing Rd Beijing 100095 China Email: eric.wu@huawei.com Shunwan Zhuang Huawei Technologies Huawei Bld., No. 156 Beiquing Rd Beijing 100095 China Email: zhuangshunwan@huawei.com Wim Henderickx Nokia Antwerp BE Email: wim.henderickx@nokia.com Figure 3 10. IANA Considerations This document requests a new type and sub-type for the Redirect to indirection-id Extended community from the "Transitive Extended community" registry. The Type name shall be "Redirect to indirection-id Extended Community" and the Sub-type name shall be 'Flow-spec Redirect to 32-bit Path-id'. In addition, this document requests IANA to create a new registry for Redirect to indirection-id Extended Community INDIRECTION-IDs as follows: Under "Transitive Extended Community:" Registry: "Redirect Extended Community indirection_id" Reference: [RFC-To-Be] Registration Procedure(s): First Come, First Served Registry: "Redirect Extended Community indirection_id" Value Code Reference 0 Localised ID [RFC-To-Be] 1 Node ID [RFC-To-Be] 2 Agency ID [RFC-To-Be] 3 AS (Autonomous System) ID [RFC-To-Be] 4 Anycast ID [RFC-To-Be] 5 Multicast ID [RFC-To-Be] 6 Tunnel ID (Tunnel Binding ID ) [RFC-To-Be] 7 VPN ID [RFC-To-Be] 8 OAM ID [RFC-To-Be] 9 ECMP (Equal Cost Multi-Path) ID [RFC-To-Be] 10 QoS ID [RFC-To-Be] 11 Bandwidth-Guarantee ID [RFC-To-Be] 12 Security ID [RFC-To-Be] 13 Multi-Topology ID [RFC-To-Be] Figure 4 11. References 11.1. Normative References [1] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997, <http://xml.resource.org/public/rfc/html/rfc2119.html>. [2] Marques, P., Sheth, N., Raszuk, R., Greene, B., Mauch, J., and D. McPherson, "Dissemination of Flow Specification Rules", RFC 5575, DOI 10.17487/RFC5575, August 2009, <http://www.rfc-editor.org/info/rfc5575>. 11.2. Informative References [3] Uttaro, J., Filsfils, C., Alcaide, J., and P. Mohapatra, "Revised Validation Procedure for BGP Flow Specifications", January 2014. [4] Filsfils, C., Previdi, S., Aries, E., Ginsburg, D., and D. Afanasiev, "Segment Routing Centralized Egress Peer Engineering", October 2015. [5] Sreekantiah, A., Filsfils, C., Previdi, S., Sivabalan, S., Mattes, P., and S. Lin, "Segment Routing Traffic Engineering Policy using BGP", October 2015. [6] Filsfils, C., Previdi, S., Decraene, B., Litkowski, S., Shakir, R., Bashandy, A., Horneffer, M., Henderickx, W., Tantsura, J., Crabbe, E., Milojevic, I., and S. Ytti, "Segment Routing Architecture", December 2015. [7] Sivabalan, S., Medved, M., Filsfils, C., Litkowski, S., Raszuk, R., Bashandy, A., Lopez, V., Tantsura, J., Henderickx, W., Hardwick, J., Milojevic, I., and S. Ytti, "PCEP Extensions for Segment Routing", December 2015. Appendix A. Additional indirection_id types waiting for use-case description This section is a placeholder and collection of potential additional indirection_id types. The current use-cases do not require these particular indirection types, however at later stage when use-cases are identified they may be added to the body of teh draft. 2 - Agency ID (The flowspec client uses the received indirection-id as a Segment Routing Agency ID to redirect traffic towards) 3 - AS (Autonomous System) ID (The flowspec client uses the received indirection-id as a Segment Routing Autonomous System ID to redirect traffic towards) 4 - Anycast ID (The flowspec client uses the received indirection-id as a Segment Routing Anycast ID to redirect traffic towards) 5 - Multicast ID (The flowspec client uses the received indirection- id as a Segment Routing Multicast ID to redirect traffic towards) 7 - VPN ID (The flowspec client uses the received indirection-id as a Segment Routing VPN ID to redirect traffic towards) 8 - OAM ID (The flowspec client uses the received indirection-id as a Segment Routing OAM ID to redirect traffic towards) 9 - ECMP (Equal Cost Multi-Path) ID (The flowspec client uses the received indirection-id as a Segment Routing PeerSet ID to redirect traffic towards) 10 - QoS ID (The flowspec client uses the received indirection-id as a Segment Routing QoS ID to redirect traffic towards) 11 - Bandwidth-Guarantee ID (The flowspec client uses the received indirection-id as a Segment Routing Bandwidth-Guarantee ID to redirect traffic towards) 12 - Security ID (The flowspec client uses the received indirection- id as a Segment Routing Security ID to redirect traffic towards) 13 - Multi-Topology ID (The flowspec client uses the received indirection-id as a Segment Routing Multi-Topology ID to redirect traffic towards) Authors' Addresses Gunter Van de Velde (editor) Nokia Antwerp BE Email: gunter.van_de_velde@nokia.com Keyur PatelCisco Systems 170 W. Tasman Drive San Jose, CA 95134Arrcus USA Email:keyupate@cisco.comkeyur@arrcus.com Zhenbin Li Huawei Technologies Huawei Bld., No. 156 Beiquing Rd Beijing 100095 China Email: lizhenbin@huawei.com