L R. chen Internet-Draft Sh. Peng Intended status: Standards Track ZTE Corporation Expires: March 6, 2021 September 2, 2020 BGP-LS Extensions for Transport Slice draft-chen-idr-bgp-ls-transport-slice-02 Abstract [I-D.peng-teas-network-slicing] defines a unified TN-slice identifier, AII(administrative instance identifier), to indicate the topology, computing, storage resources of the dedicated virtual network for both intra-domain and inter-domain network slicing scenarios. This draft defines extensions to BGP-LS protocol in order to advertise the information of the transport slice. 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 March 6, 2021. Copyright Notice Copyright (c) 2020 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 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 chen & Peng Expires March 6, 2021 [Page 1] Internet-Draft BGP-LS Extensions for TS September 2020 the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 2. Requirements Language . . . . . . . . . . . . . . . . . . . . 3 3. BGP-LS Extensions for transport slice . . . . . . . . . . . . 3 3.1. Node Attribute TLVs . . . . . . . . . . . . . . . . . . . 3 3.1.1. TN-slice identifier Participation TLV . . . . . . . . 3 3.2. Link Attribute TLVs . . . . . . . . . . . . . . . . . . . 4 3.2.1. TN-slice Identifier list sub-TLV . . . . . . . . . . 4 3.2.2. L2 Bundle Member TN-Slice Identifier TLV . . . . . . 5 3.2.3. Adjacency-SID for TN-slice Identifier TLV . . . . . . 5 3.2.4. LAN-Adj-SID for TN-slice Identifier TLV . . . . . . . 6 3.3. Prefix Attribute TLVs . . . . . . . . . . . . . . . . . . 7 4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8 5. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 9 6. Normative References . . . . . . . . . . . . . . . . . . . . 9 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 10 1. Introduction For a packet network, network slicing requires the underlying network to support partitioning of the network resources to provide the client with dedicated (private) networking, computing, and storage resources drawn from a shared pool. [I-D.peng-teas-network-slicing] defines a unified TN-slice identifier, AII(administrative instance identifier), to indicate the topology, computing, storage resources of the dedicated virtual network for both intra-domain and inter- domain network slicing scenarios, and how to compute SR-BE or SR-TE path according to TN-slice Identifier combined with other criteria. [I-D.zch-lsr-isis-network-slicing] defines the IS-IS extensions required to distribute TN-slice Identifier(that is AII) information in an AS. In order to satisfy the need for applications that require topological visibility across one area or Autonomous System (AS). This document specifies extensions to the BGP Link-state address- family in order to advertise TN-slice specific information. An external component (e.g., a controller) then can collect TN-slice information in the "northbound" direction. chen & Peng Expires March 6, 2021 [Page 2] Internet-Draft BGP-LS Extensions for TS September 2020 2. Requirements Language The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all capitals, as shown here. 3. BGP-LS Extensions for transport slice BGP-LS [RFC7752] defines the link-state NLRI that can be a Node NLRI, a Link NLRI or a Prefix NLRI. The link-state information is mapped to BGP link-state NLRI within the BGP-LS Attribute. In addition, [I-D.ietf-idr-bgpls-inter-as-topology-ext] defines Stub Link NLRI that is used to describe the inter-as link. This document adds additional BGP-LS Attribute TLVs in order to encode TN-slice information. It does not introduce any changes to the encoding of the BGP-LS NLRIs. 3.1. Node Attribute TLVs 3.1.1. TN-slice identifier Participation TLV The TN-slice identifier Participation TLV is used to advertise which TN-slice a router wants to take part in. It is a new TLV of the optional BGP-LS Attribute that is associated with the node NLRI. This information is derived from TN-slice identifier Participation sub-TLV of IS-IS (section 3 of [I-D.zch-lsr-isis-network-slicing]. The TN-slice identifier Participation TLV has the following format: 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 2 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type=TBD1 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | AII for virtual networks 1 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | AII for virtual networks N | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 1: TN-slice identifier Participation TLV chen & Peng Expires March 6, 2021 [Page 3] Internet-Draft BGP-LS Extensions for TS September 2020 where: Type: TBD1 (Suggested value to be assigned by IANA) Length: variable. AII for VN: allocate different TN-slice identifier (AII) for different virtual networks. AII is used to distinguish different virtual network resources. The node can join to multiple slices at the same time. 3.2. Link Attribute TLVs The following Link Attribute TLVs are defined: +-------+---------------------------------------------+ | Type | Description | +-------+---------------------------------------------+ | TBD2 | The TN-slice Identifier list TLV | | TBD3 | L2 Bundle Member TN-Slice Identifier TLV | | TBD4 | Adjacency-SID for TN-slice Identifier TLV | | TBD5 | LAN-Adj-SID for TN-slice Identifier TLV | +-------+---------------------------------------------+ Table 1:The new Link Attribute TLVs These TLVs should only be added to the BGP-LS Attribute associated with the Link NLRI or Stub Link NLRI. 3.2.1. TN-slice Identifier list sub-TLV TN-slice Identifier can be used to color links and partition underlay resource. This section is derived from TN-slice Identifier list sub- TLV of IS-IS (section 4 of [I-D.zch-lsr-isis-network-slicing].) The TN-slice Identifier list TLV has the following format: chen & Peng Expires March 6, 2021 [Page 4] Internet-Draft BGP-LS Extensions for TS September 2020 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 2 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type=TBD2 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | AII for virtual networks 1 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | AII for virtual networks N | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 2 Type: TBD2 (Suggested value to be assigned by IANA) Length: variable. AII for VN: allocate different TN-slice identifier (AII) for different virtual networks. AII is used to distinguish different virtual network resources. The link can join to multiple slices at the same time. The link can be configured to an IGP instance, or as an inter-as link. 3.2.2. L2 Bundle Member TN-Slice Identifier TLV This TLV is used to advertise TN-slice Identifier for L2 Bundle Member associated with a parent L3 adjacency which is Point-to-Point. This information is derived from TN-slice Identifier for L2 Bundle Member sub-TLV of IS-IS (section 5 of [I-D.zch-lsr-isis-network-slicing]). The following format is defined for this sub-TLV: Type: TBD3. Length: variable L2 Bundle Member TN-slice Identifier.There MUST be one TN-slice Identifier(AII) for each of the L2 Bundle Members advertised under the preceding L2 Bundle Member Attribute Descriptor. The parrent link can be configured to an IGP instance, or as an inter-as link. 3.2.3. Adjacency-SID for TN-slice Identifier TLV This TLV is used to distinguish forwarding behavior of different virtual networks, Adjacency-SID need to be allocated per TN-slice Identifier. This information is derived from TN-slice Identifier for chen & Peng Expires March 6, 2021 [Page 5] Internet-Draft BGP-LS Extensions for TS September 2020 Adjacency-SID for TN-slice Identifier sub-TLV of IS-IS (section 7 of [I-D.zch-lsr-isis-network-slicing]). The following format is defined for this sub-TLV: 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 2 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type=TBD4 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Flags | Weight | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | AII | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | SID/Index/Label(Variable) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 3 where: Type:TBD4(Suggested value to be assigned by IANA) Length: Variable. Depending on the size of the SID. Weight: Variable. 1 octet carrying the weight used for load-balancing purposes. The use of weight is described in section 3.4 of [RFC8402]. AII: Identifies the TN-slice (AII) information corresponding to the Adjacency-SID. The "Flags" and "SID/Index/Label" fields are the same as the Adjacency-SID sub-TLV [RFC8667]. 3.2.4. LAN-Adj-SID for TN-slice Identifier TLV In LAN subnetworks, [RFC8667] defines the LAN-Adj-SID sub-TLV for a router to advertise the Adj-SID of each of its neighbors. LAN-Adj-SID for TN-slice Identifier TLV is used to distinguish forwarding behavior of different virtual networks, Adjacency-SID need to be allocated per TN-slice Identifier. This information is derived from the LAN-Adj-SID for TN-slice Identifier sub-TLV of IS-IS (section 8 of I-D. [I-D.zch-lsr-isis-network-slicing]). chen & Peng Expires March 6, 2021 [Page 6] Internet-Draft BGP-LS Extensions for TS September 2020 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 2 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type=TBD5 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Flags | Weight | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Neighbor System-ID (ID length octets) | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | AII | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | SID/Label/Index (variable) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 4 where: Type:TBD5 (Suggested value to be assigned by IANA) Length: Variable. Depending on the size of the SID. The "Flags" and "SID/Index/Label" fields are the same as the Adjacency-SID sub-TLV [RFC8667]. AII: Identifies the TN-slice (AII) information corresponding to the Adjacency-SID. 3.3. Prefix Attribute TLVs Prefix-SID for TN-slice Identifier TLV should only be added to the BGP-LS Attribute associated with the Prefix NLRI describing the prefix of the IGP node. This TLV is used to distinguish forwarding behavior of different virtual networks.This information is derived from TN-slice identifier Participation sub-TLV of IS-IS (section 6 of [I-D.zch-lsr-isis-network-slicing]). The Prefix-SID for TN-slice Identifier TLV has the following format: chen & Peng Expires March 6, 2021 [Page 7] Internet-Draft BGP-LS Extensions for TS September 2020 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 2 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type=TBD6 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Flag | Algorithm | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | AII | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | SID/Index/Label(Variable) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 5 where: Type:TBD6 (Suggested value to be assigned by IANA) Length: Variable. Depending on the size of the SID. The "Flags" and "SID/Index/Label" fields are the same as the Prefix- SID sub-TLV [RFC8667]. Algorithm: Accoridng to section "3.2. SR-Algorithm Sub-TLV" of [RFC8667], two values can be set in this field. o 0: Shortest Path First (SPF) algorithm based on link metric. o 1: Strict Shortest Path First (SPF) algorithm based on link metric. Note that[I-D.ietf-lsr-flex-algo] also allows user to define other algorithm values, i.e., FA-id within [128, 255], for the purpose of constraint based path computation. However, an FA-id algorithm value MUST not be set in this field, the reason is that FA-id has not semantic local within AII. AII: Identifies the TN-slice (AII) information corresponding to the Prefix-SID. 4. IANA Considerations This document does not define any new protocol or any extension to an existing protocol. chen & Peng Expires March 6, 2021 [Page 8] Internet-Draft BGP-LS Extensions for TS September 2020 5. Acknowledgements TBD 6. Normative References [I-D.ietf-idr-bgpls-inter-as-topology-ext] Wang, A., Chen, H., Talaulikar, K., and S. Zhuang, "BGP-LS Extension for Inter-AS Topology Retrieval", draft-ietf- idr-bgpls-inter-as-topology-ext-08 (work in progress), April 2020. [I-D.ietf-lsr-flex-algo] Psenak, P., Hegde, S., Filsfils, C., Talaulikar, K., and A. Gulko, "IGP Flexible Algorithm", draft-ietf-lsr-flex- algo-10 (work in progress), August 2020. [I-D.peng-teas-network-slicing] Peng, S., Chen, R., Mirsky, G., and F. Qin, "Packet Network Slicing using Segment Routing", draft-peng-teas- network-slicing-03 (work in progress), February 2020. [I-D.zch-lsr-isis-network-slicing] Zhu, Y., Chen, R., Peng, S., and F. Qin, "IS-IS Extensions to Support Transport Network Slices using Segment Routing", draft-zch-lsr-isis-network-slicing-05 (work in progress), July 2020. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . [RFC4915] Psenak, P., Mirtorabi, S., Roy, A., Nguyen, L., and P. Pillay-Esnault, "Multi-Topology (MT) Routing in OSPF", RFC 4915, DOI 10.17487/RFC4915, June 2007, . [RFC5120] Przygienda, T., Shen, N., and N. Sheth, "M-ISIS: Multi Topology (MT) Routing in Intermediate System to Intermediate Systems (IS-ISs)", RFC 5120, DOI 10.17487/RFC5120, February 2008, . [RFC5340] Coltun, R., Ferguson, D., Moy, J., and A. Lindem, "OSPF for IPv6", RFC 5340, DOI 10.17487/RFC5340, July 2008, . chen & Peng Expires March 6, 2021 [Page 9] Internet-Draft BGP-LS Extensions for TS September 2020 [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, . [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017, . [RFC8402] Filsfils, C., Ed., Previdi, S., Ed., Ginsberg, L., Decraene, B., Litkowski, S., and R. Shakir, "Segment Routing Architecture", RFC 8402, DOI 10.17487/RFC8402, July 2018, . [RFC8667] Previdi, S., Ed., Ginsberg, L., Ed., Filsfils, C., Bashandy, A., Gredler, H., and B. Decraene, "IS-IS Extensions for Segment Routing", RFC 8667, DOI 10.17487/RFC8667, December 2019, . Authors' Addresses Ran Chen ZTE Corporation No.50 Software Avenue, Yuhuatai District Nanjing China Email: chen.ran@zte.com.cn Shaofu ZTE Corporation No.68 Zijinghua Road, Yuhuatai District Nanjing China Email: peng.shaofu@zte.com.cn chen & Peng Expires March 6, 2021 [Page 10]