IDR Working Group N. Wu Internet-Draft Z. Zhuang Intended status: Standards Track H. Chen Expires: October 19, 2019 Huawei April 17, 2019 BGP Extensions for IDs Allocation draft-wu-idr-bgp-segment-allocation-ext-02 Abstract This document describes extensions to the BGP-LS for IDs allocation. The IDs are SIDs for segment routing and indirection IDs for flow redirect. They are distributed to their domains if needed. 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 [RFC2119]. 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 https://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 on October 19, 2019. Copyright Notice Copyright (c) 2019 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 (https://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents Wu, et al. Expires October 19, 2019 [Page 1] Internet-Draft BGP for IDs Allocation April 2019 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 . . . . . . . . . . . . . . . . . . . . . . . . 2 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 2 3. Protocol Extensions . . . . . . . . . . . . . . . . . . . . . 3 3.1. Node NLRI for IDs Allocation . . . . . . . . . . . . . . 3 3.2. Link NLRI for IDs Allocation . . . . . . . . . . . . . . 4 3.3. Prefix NLRI for IDs Allocation . . . . . . . . . . . . . 5 4. Application Examples . . . . . . . . . . . . . . . . . . . . 6 4.1. Allocating IDs for DC BGP Network . . . . . . . . . . . . 6 4.1.1. Node-SID Distribution via Prefix NLRI . . . . . . . . 7 4.1.2. Adj-SID Distribution via Link NLRI . . . . . . . . . 8 4.1.3. IID Distribution via Node NLRI . . . . . . . . . . . 9 4.2. Allocating IDs for IGP Network . . . . . . . . . . . . . 9 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10 6. Security Considerations . . . . . . . . . . . . . . . . . . . 10 7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 10 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 10 8.1. Normative References . . . . . . . . . . . . . . . . . . 10 8.2. Informative References . . . . . . . . . . . . . . . . . 11 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 12 1. Introduction In a network with a central controller, the controller has the link state information of the network, including traffic engineering information. In addition, the controller allocates and manages the resources of the network in general. It is natural and beneficial for the controller to allocate and manage IDs as a kind of network resources. This document proposes extensions to the BGP-LS as a controller for allocating Segment Identifers (SIDs) for segment routing (SR) and indirection identifiers (IIDs) for flow redirect. If needed, some IDs will be distributed into their network domains. 2. Terminology The following terminology is used in this document. SR: Segment Routing. Wu, et al. Expires October 19, 2019 [Page 2] Internet-Draft BGP for IDs Allocation April 2019 SID: Segment Identifier. IID: Indirection Identifier. SR-Path: Segment Routing Path. SR-Tunnel: Segment Routing Tunnel. RR: Route Reflector. MPP: MPLS Path Programming. NAI: Node or Adjacency Identifier. GTID: Global Tunnel Identifier. It is used to identify a tunnel in a network. TED: Traffic Engineering Database. 3. Protocol Extensions This section defines a new Protocol-ID, called IDs-Allocation (IDA), in the Procotol-ID field of Link State NLRI. The use of the new Protocol-ID allows separation and differentiation between the NLRIs carrying IDs Allocation information from the NLRIs carrying IGP link- state information defined in [RFC7752]. 3.1. Node NLRI for IDs Allocation The Node NLRI with the new Protocol-ID is used for allocating the IDs associated with a node. It has the same format (refer to the Figure below) as that defined in [RFC7752] and may contain the descriptor and attributes defined in [RFC7752]. 0 1 2 3 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 +-+-+-+-+-+-+-+-+ |IDs-Allocation | Protocol-ID +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Identifier | | (64 bits) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ~ Local Node Descriptor ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ~ Node IDs Allocation ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Where: Wu, et al. Expires October 19, 2019 [Page 3] Internet-Draft BGP for IDs Allocation April 2019 Protocol-ID: set to IDs-Allocation, a new Protocol-ID. Local Node Descriptor: defined in [RFC7752], can be reused. Node IDs Allocation: TLVs or sub-TLVs for IDs associated with the node given by the Local Node Descriptor. Node IDs Allocation field may contain some of the followings: SR-Capabilities TLV (1034): It contains the Segment Routing Global Base (SRGB) range(s) allocated for the node. SR Local Block TLV (1036): The SR Local Block (SRLB) TLV contains the range(s) of SIDs/labels allocated to the node for local SIDs. IID Flow Redirect TLV (TBD): A new TLV that contains an Indireection ID (IID) and a Flow Specification for redirecting traffic flow given by the Flow Specification to the tunnel indicated by the IID. Its format is shown below. 0 1 2 3 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: Flow Redirect (TBD) | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Reserved | Flags(1 octet)| ID-Type | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Indirection ID | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ~ Flow Specification ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ IID Flow Redirect TLV Where Flags, ID-Type and Indirection ID are the same as those defined in [I-D.ietf-idr-flowspec-path-redirect]. The contents of Flow Specification is the same as that defined in [RFC5575]. 3.2. Link NLRI for IDs Allocation The Link NLRI with the new Protocol-ID is used for allocating the IDs associated with a link. It has the same format (refer to the Figure below) as that defined in in [RFC7752] and may contain the descriptors and attributes defined in [RFC7752]. Wu, et al. Expires October 19, 2019 [Page 4] Internet-Draft BGP for IDs Allocation April 2019 0 1 2 3 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 +-+-+-+-+-+-+-+-+ |IDs-Allocation | Protocol-ID +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Identifier | | (64 bits) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ~ Local Node Descriptor ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ~ Remote Node Descriptor ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ~ Link Descriptor ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ~ Link IDs Allocation ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Where: Protocol-ID: set to IDs-Allocation, a new Protocol-ID. Node Descriptors: defined in [RFC7752], can be reused. Link Descriptor: defined in [RFC7752], can be reused. Link IDs Allocation: TLVs or sub-TLVs for IDs associated with the link given by the Link Descriptor. Link IDs Allocation field may contain some of the followings: Adj-SID TLV (1099): It contains the Segment Identifier (SID) allocated for the link/adjacency. LAN Adj-SID TLV (1100): It contains the Segment Identifier (SID) allocated for the adjacency/link to a non-DR router on a broadcast, NBMA, or hybrid link. 3.3. Prefix NLRI for IDs Allocation The Prefix NLRI with the new Protocol-ID is used for allocating the IDs associated with a prefix. It has the same format (refer to the Figure below) as that defined in in [RFC7752] and may contain the descriptors and attributes defined in [RFC7752]. Wu, et al. Expires October 19, 2019 [Page 5] Internet-Draft BGP for IDs Allocation April 2019 0 1 2 3 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 +-+-+-+-+-+-+-+-+ |IDs-Allocation | Protocol-ID +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Identifier | | (64 bits) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ~ Local Node Descriptor ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ~ Prefix Descriptor ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ~ Prefix IDs Allocation ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Where: Protocol-ID: set to IDs-Allocation, a new Protocol-ID. Local Node Descriptor: defined in [RFC7752], can be reused. Prefix Descriptor: defined in [RFC7752], can be reused. Prefix IDs Allocation: TLVs or sub-TLVs for IDs associated with the prefix given by the Prefix Descriptor. Prefix IDs Allocation field may contain some of the followings: Prefix-SID TLV (1158): It contains the Segment Identifier (SID) allocated for the prefix. Prefix Range TLV (1159): It contains a range of prefixes and the Segment Identifier (SID)s allocated for the prefixes. 4. Application Examples 4.1. Allocating IDs for DC BGP Network BGP may be the only routing protocol in some networks, such as the DC network described in [I-D.ietf-rtgwg-bgp-routing-large-dc]. If SR is used in this case, it is better for a controller to allocate SIDs and distribute them in the network. In the DC network shown below, it is assumed: Node NX has a loopback 1.1.1.X/32. For example, N7 has loopback 1.1.1.7/32. Wu, et al. Expires October 19, 2019 [Page 6] Internet-Draft BGP for IDs Allocation April 2019 Each node peers with its neighbors and the Controller via BGP session. The BGP Router ID and AS of Node NX are 1.1.1.X and X respectively. /----------\ | | | Controller | | | \----------/ | +-----------------------+-------------------------------+ | | | | +------+ | +------+ | | | N7 |-+-| N8 | Tier-1 | | +------+ +------+ | | | | | | | | +---------+ | | +----------+ | | | +-------+--+-------+--+-------+ | | | | | | | | | | | | | +----+ +----+ +----+ +----+ | | | N3 |-----| N4 | | N5 |-----| N6 | Tier-2 | | +----+ +----+ +----+ +----+ | | | | | | | | | +-----+ | | +-----+ | | | +-| N1 |-+ +-| N2 |-+ Tier-3 | | +-----+ +-----+ | | | | | | | | | | <- Servers -> <- Servers -> | +-------------------------------------------------------+ After the controller gets the topology information of this BGP network, it can start to allocate SIDs and distribute them in the network. 4.1.1. Node-SID Distribution via Prefix NLRI In order to distribute a Node-SID for a router (e.g., N7), Controller allocates a SID for its loopback and advertises a Prefix NLRI containing the SID for the loopback as a prefix to all the routers in the BGP Network. The following is an example of Prefix NLRI for Node N7's SID. o Protocol-ID set to the new Protocol-ID: IDs-Allocation o Local Node Descriptor contains * BGP Router-ID: 1.1.1.7 Wu, et al. Expires October 19, 2019 [Page 7] Internet-Draft BGP for IDs Allocation April 2019 * Local ASN: 7 o Prefix Descriptor * 1.1.1.7/32 o Prefix Attribute contains * Prefix-SID TLV (1158): SID for 1.1.1.7/32 with N-Flag=1 (Node- Flag). * Other Prefix Attributes. 4.1.2. Adj-SID Distribution via Link NLRI In order to distribute a Adj-SID for a router, Controller allocates a SID for the adjacency/link and advertise a Link NLRI containing the SID for the adjacency to all the routers of the BGP Network. The following is an example of Link NLRI for the SID of the adjacency/ link from N7 to N8. o Protocol-ID set to the new Protocol-ID: IDs-Allocation o Local Node Descriptors contains * BGP Router-ID: 1.1.1.7 * Local ASN: 7 o Remote Node Descriptor contains * BGP Router-ID: 1.1.1.8 * Local ASN: 8 o Link Descriptor * BGP session IPv4 local address: 1.1.1.7 * BGP session IPv4 peer address: 1.1.1.8 o Link Attribute contains * Adj-SID TLV (1099): SID for Adjacency from N7 to N8 * Other Link Attributes. Wu, et al. Expires October 19, 2019 [Page 8] Internet-Draft BGP for IDs Allocation April 2019 4.1.3. IID Distribution via Node NLRI In order to distribute an IID Flow Redirect, Controller allocates an IID for a Flow Specification and advertises a Node NLRI containing the IID and the Flow Specification to all the routers in the BGP Network. The following is an example of Node NLRI for the IID Flow Redirect, where Local Node Descriptor describes the Controller (its BGP Router-ID is 7.7.7.7 and ASN is 7777). o Protocol-ID set to the new Protocol-ID: IDs-Allocation o Local Node Descriptor contains * BGP Router-ID: 7.7.7.7 * Local ASN: 7777 o Node Attribute contains * IID Flow Redirect TLV (TBD): IID and Flow Specification * Other Node Attributes. 4.2. Allocating IDs for IGP Network In an IGP network with SR capability, a controller may allocate SIDs for SR and send the SIDs to their responding nodes in the network. Each of the nodes distributes the SIDs it receives to the other nodes in the network through IGP. For example, for a node A, the controller may allocate a SID for a loopback of the node A and send the SID to the node A through using a Prefix NLRI. The node A distributes the SID to the other nodes in the network via IGP. The Prefix NLRI contains: o Protocol-ID set to the new Protocol-ID: IDs-Allocation o Local Node Descriptor indicating the node A o Prefix Descriptor describing the loopback as prefix o Prefix Attribute containing * Prefix-SID TLV (1158): SID for the loopback with N-Flag=1 (Node-Flag). * Other Prefix Attributes. Wu, et al. Expires October 19, 2019 [Page 9] Internet-Draft BGP for IDs Allocation April 2019 5. IANA Considerations This document requests assigning a code-point from the registry "BGP- LS Protocol-IDs" as follows: +-------------+-----------------------------------+-------------+ | Protocol-ID | Description | Reference | +-------------+-----------------------------------+-------------+ | TBD | IDs Allocation | Section 3 | +-------------+-----------------------------------+-------------+ This document requests assigning a code-point from the registry "BGP- LS Node Descriptor, Link Descriptor, Prefix Descriptor, and Attribute TLVs" as follows: +----------------+-----------------------------------+-------------+ | TLV Code Point | Description | Reference | +----------------+-----------------------------------+-------------+ | TBD | IID Flow Redirect | Section 3.1 | +----------------+-----------------------------------+-------------+ 6. Security Considerations Protocol extensions defined in this document do not affect the BGP security other than those as discussed in the Security Considerations section of [RFC7752]. 7. Acknowledgements The authors would like to thank Robin Li, and others for their valuable suggestions and comments on this draft. 8. References 8.1. Normative References [I-D.ietf-idr-flowspec-path-redirect] Velde, G., Patel, K., and Z. Li, "Flowspec Indirection-id Redirect", draft-ietf-idr-flowspec-path-redirect-07 (work in progress), December 2018. [I-D.ietf-isis-segment-routing-extensions] Previdi, S., Ginsberg, L., Filsfils, C., Bashandy, A., Gredler, H., and B. Decraene, "IS-IS Extensions for Segment Routing", draft-ietf-isis-segment-routing- extensions-23 (work in progress), March 2019. Wu, et al. Expires October 19, 2019 [Page 10] Internet-Draft BGP for IDs Allocation April 2019 [I-D.ietf-rtgwg-bgp-routing-large-dc] Lapukhov, P., Premji, A., and J. Mitchell, "Use of BGP for routing in large-scale data centers", draft-ietf-rtgwg- bgp-routing-large-dc-11 (work in progress), June 2016. [I-D.ietf-spring-segment-routing] Filsfils, C., Previdi, S., Ginsberg, L., Decraene, B., Litkowski, S., and R. Shakir, "Segment Routing Architecture", draft-ietf-spring-segment-routing-15 (work in progress), January 2018. [I-D.ietf-spring-segment-routing-ldp-interop] Bashandy, A., Filsfils, C., Previdi, S., Decraene, B., and S. Litkowski, "Segment Routing interworking with LDP", draft-ietf-spring-segment-routing-ldp-interop-15 (work in progress), September 2018. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . [RFC5575] 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, . [RFC7752] Gredler, H., Ed., Medved, J., Previdi, S., Farrel, A., and S. Ray, "North-Bound Distribution of Link-State and Traffic Engineering (TE) Information Using BGP", RFC 7752, DOI 10.17487/RFC7752, March 2016, . 8.2. Informative References [I-D.gredler-idr-bgp-ls-segment-routing-extension] Gredler, H., Ray, S., Previdi, S., Filsfils, C., Chen, M., and J. Tantsura, "BGP Link-State extensions for Segment Routing", draft-gredler-idr-bgp-ls-segment-routing- extension-02 (work in progress), October 2014. [I-D.ietf-idr-bgpls-segment-routing-epe] Previdi, S., Talaulikar, K., Filsfils, C., Patel, K., Ray, S., and J. Dong, "BGP-LS extensions for Segment Routing BGP Egress Peer Engineering", draft-ietf-idr-bgpls- segment-routing-epe-18 (work in progress), March 2019. Wu, et al. Expires October 19, 2019 [Page 11] Internet-Draft BGP for IDs Allocation April 2019 Authors' Addresses Nan Wu Huawei Huawei Bld., No.156 Beiqing Rd. Beijing 100095 China Email: eric.wu@huawei.com Shunwan Zhuang Huawei Huawei Bld., No.156 Beiqing Rd. Beijing 100095 China Email: zhuangshunwan@huawei.com Huaimo Chen Huawei Boston, MA USA Email: Huaimo.chen@huawei.com Wu, et al. Expires October 19, 2019 [Page 12]