Link State Routing Working Group Y. Wang Internet-Draft T. Zhou Intended status: Standards Track M. Liu Expires: September 24, 2020 Huawei R. Pang China Unicom March 23, 2020 In-situ Flow Information Telemetry (IFIT) Node Capability Advertisement draft-wang-lsr-ifit-node-capability-advertisement-00 Abstract For advertising In-situ Flow Information Telemetry (IFIT) node capabilities within the entire routing domain, this document extends a new optional TLV to the OSPF RI Opaque LSA, a new optional sub-TLV to the IS-IS Router CAPABILITY TLV, and a new Node Attribute TLV that is encoded in the BGP-LS attribute with Node NLRIs to carry IFIT node capabilities information. Such advertisement allows entities (e.g. a centralized controller) to determine whether a particular IFIT functionality can be supported in a given network. 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 September 24, 2020. Wang, et al. Expires September 24, 2020 [Page 1]
Internet-Dradraft-wang-lsr-ifit-node-capability-advertisemen March 2020 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 the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 3. IFIT Node Capability Advertisement . . . . . . . . . . . . . 3 3.1. IFIT Node Capability Information . . . . . . . . . . . . 3 3.2. OSPF Extension IFIT Node Capability TLV . . . . . . . . . 5 3.3. IS-IS Extension IFIT Node Capability Sub-TLV . . . . . . 6 3.4. BGP-LS Extension IFIT Node Capability TLV . . . . . . . . 6 4. Application . . . . . . . . . . . . . . . . . . . . . . . . . 7 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8 6. Security Considerations . . . . . . . . . . . . . . . . . . . 9 7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 9 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 9 8.1. Normative References . . . . . . . . . . . . . . . . . . 9 8.2. Informative References . . . . . . . . . . . . . . . . . 9 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 10 1. Introduction IFIT provides a complete framework architecture and a reflection-loop working solution for on-path flow telemetry [I-D.song-opsawg-ifit-framework]. At present, there are a family of emerging on-path flow telemetry techniques, including In-situ OAM (IOAM) [I-D.ietf-ippm-ioam-data], Postcard-Based Telemetry (PBT) [I-D.song-ippm-postcard-based-telemetry], IOAM Direct Export (DEX) [I-D.ioamteam-ippm-ioam-direct-export], Enhanced Alternate Marking (EAM) [I-D.zhou-ippm-enhanced-alternate-marking], etc. IFIT is a solution focusing on network domains. The "network domain" consists of a set of network devices or entities within a single Atonomous System (AS). The part of the network which employs IFIT is referred to as the IFIT domain. One network domain may consist of multiple IFIT domains. An IFIT domain may cross multiple network domains. Wang, et al. Expires September 24, 2020 [Page 2]
Internet-Dradraft-wang-lsr-ifit-node-capability-advertisemen March 2020 The family of emerging on-path flow telemetry techniques may be selectively or partially enabled in different vendors' devices as an emerging feature for various use cases of application-aware network operations. So that in order to dynamically enable IFIT functionality in a network domain, it is necessary to advertise the information of IFIT option types supported in each device. BGP-LS defines a way to advertise topology and associated attributes and capabilities of the nodes in that topology to a centralized controller [RFC7752]. Typically, BGP-LS is configured on a small number of nodes that do not necessarily act as head-ends. In order for BGP-LS to signal IFIT node capabilities for all the devices in the network, IFIT node capabilities SHOULD be advertised by every IGP router in the network. Therefore, this document defines extensions to OSPF, IS-IS, and BGP-LS to advertise the IFIT node capabilities. Entities (e.g. centralized controllers) that can use this information to determine whether a particular IFIT functionality can be enabled in a given IFIT domain. An application to this information advertisement is described in detail in Section 4. 2. Terminology OSPF: Open Shortest Path First IS-IS: Intermediate System to Intermediate System RI: Router Information LSA: Link State Advertisement BGP-LS: Advertisement of Link-State and TE Information using Border Gateway Protocol 3. IFIT Node Capability Advertisement 3.1. IFIT Node Capability Information Each IFIT node is configured with a node-id which uniquely identifies a node within the associated IFIT domain. To accommodate the different use cases or requirements of in-situ flow information telemetry, IFIT data fields updated by network nodes fall into different categories which are referred as different IFIT option types, including IOAM Trace Option-Types [I-D.ietf-ippm-ioam-data], IOAM Edge-to-Edge (E2E) Option-Type [I-D.ietf-ippm-ioam-data], IOAM DEX Option-Type [I-D.ioamteam-ippm-ioam-direct-export] and Enhanced Alternate Marking (EAM) Option-Type [I-D.zhou-ippm-enhanced-alternate-marking]. And a subset or all the IFIT-Option-Types and their corresponding IFIT-Data-Fields can be Wang, et al. Expires September 24, 2020 [Page 3]
Internet-Dradraft-wang-lsr-ifit-node-capability-advertisemen March 2020 associated to an IFIT-Namespce. The Namespace identifiers allow devices which are IFIT capable to determine whether IFIT-Option-Types need to be processed. So that IFIT-Option-Types and Namespace-ID SHOULD be carried in IFIT node capability information for advertisement. In this document, the IFIT-Node-Capability information consists of one or more pairs of a 2-octet Namespace-ID and 16-bit Option-Type enabled Flag. 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 +---------------------------------------------------------------+ | Namespace-ID_1 | Option-Type enabled Flag_1 | +---------------------------------------------------------------+ | Namespace-ID_2 | Option-Type enabled Flag_2 | +---------------------------------------------------------------+ | ... | ... | +---------------------------------------------------------------+ Fig. 4 IFIT-Node-Capability Format Where: Namespace-ID: A 16-bit identifier, which MUST be present and populated in all IFIT-Option-Types. The definition is the same as described in [I-D.ietf-ippm-ioam-data]. Option-Type enabled Flag: A 16-bit field, which is defined as: 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 +-------------------------------+ |p|i|d|e|m| Reserved | +-------------------------------+ Where: p-Flag: IOAM Pre-allocated Trace Option Type-enabled flag. If bit p is set (1), the router is capable of IOAM Pre-allocated Trace [I-D.ietf-ippm-ioam-data]. i-Flag: IOAM Incremental Trace Option Type-enabled flag. If bit i is set (1), the router is capable of IOAM Incremental Tracing [I-D.ietf-ippm-ioam-data]. d-Flag: IOAM DEX Option Type-enabled flag. If bit d is set (1), the router is capable of IOAM DEX [I-D.ioamteam-ippm-ioam-direct-export]. Wang, et al. Expires September 24, 2020 [Page 4]
Internet-Dradraft-wang-lsr-ifit-node-capability-advertisemen March 2020 e-Flag: IOAM E2E Option Type-enabled flag. If bit e is set (1), the router is capable of IOAM E2E processing [I-D.ietf-ippm-ioam-data]. m-Flag: Enhanced Alternative Marking enabled flag. If bit m is set (1), then the router is capable of processing Enhanced Alternative Marking packets [I-D.zhou-ippm-enhanced-alternate-marking]. Reserved: Must be set to zero upon transmission and ignored upon receipt. An IFIT node SHALL be capable of more than one IFIT option types. So in this case, Option-Type enabled Flag can has more than one bit being set. 3.2. OSPF Extension IFIT Node Capability TLV Given that OSPF uses the options field in LSAs and hello packets to advertise optional router capabilities [RFC7770], this document defnes a new IFIT Node Capability TLV within the body of the OSPF RI Opaque LSA [RFC7770] to carry the IFIT node capabilities of the router originating the RI LSA. The IFIT Node Capability TLV is composed of three fields, a 2-octet Type field, a 2-octet Length field, and 4-octet Value field. The Type field indicates the type of items in the Value field. The Length field indicates the length of the Value field in octets. The Value field carries the IFIT Node Capability information, which is a multiple of 4 octets field. The IFIT node capability 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 +-------------------------------+-------------------------------+ | Type | Length | +---------------------------------------------------------------+ | IFIT-Node-Capability | ~ ~ +---------------------------------------------------------------+ Fig. 1 OSPF IFIT Node Capability TLV Format Type: To be assigned by IANA Length: A 2-octet field that indicates the length of the value field. IFIT-Node-Capability: A multiple of 4 octets field, which is as defined in Section 3.1. Wang, et al. Expires September 24, 2020 [Page 5]
Internet-Dradraft-wang-lsr-ifit-node-capability-advertisemen March 2020 3.3. IS-IS Extension IFIT Node Capability Sub-TLV The IS-IS Extensions for Advertising Router Information TLV named IS- IS Router CAPABILITY TLV [RFC7981], which allows a router to announce its capabilities within an IS-IS level or the entire routing domain, has been chosen for IFIT node capabilities advertisement. IS-IS Router CAPABILITY TLV is formed of multiple sub-TLVs [RFC5305]. According to the format of IS-IS Router CAPABILITY TLV [RFC7981], the IFIT Node Capability sub-TLV is composed of three fields, a one-octet Type field, a one-octet Length field, and zero or more octets of Value. The Type field indicates the type of items in the Value field. The Length field indicates the length of the Value field in octets. The Value field indicates the IFIT Node Capability, which is a multiple of 4 octets field. The IS-IS IFIT Node-capability Sub-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 +---------------+---------------+ | Type | Length | +---------------+---------------+-------------------------------+ | IFIT-Node-Capability | ~ ~ +---------------------------------------------------------------+ Fig. 2 IS-IS IFIT Node Capability Sub-TLV Format Type: To be assigned by IANA Length: A 8-bit field that indicates the length of the value portion in octets. IFIT-Node-Capability: A multiple of 4 octets field, which is as defined in Section 3.1. 3.4. BGP-LS Extension IFIT Node Capability TLV This document describes extensions enabling BGP-LS speakers to announce the IFIT node capabilities of routers in a network to a BGP- LS consumer (e.g. a centralized controller). The centralized controller can leverage this information in enabling IFIT applications in network domains based on IFIT node capabilities and OAM use cases. IFIT Node-Capability TLV is defined as a new Node Attribute TLV that is encoded in the BGP-LS attribute with Node NLRIs [RFC7752]. The Wang, et al. Expires September 24, 2020 [Page 6]
Internet-Dradraft-wang-lsr-ifit-node-capability-advertisemen March 2020 IFIT Node Capability TLV is defined as a TLV triplet, i.e. a 2-octet Type field, a 2-octet Length field, and 4-octet Value field. The Type field indicates the type of items in the Value field. The Length field indicates the length of the Value field in octets. The Value field indicates the IFIT Node Capability, which is a multiple of 4 octets field. The BGP-LS IFIT Node Capability 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 +-------------------------------+-------------------------------+ | Type | Length | +---------------------------------------------------------------+ | IFIT-Node-Capability | ~ ~ +---------------------------------------------------------------+ Fig. 3 BGP-LS IFIT Node Capability TLV Format Type: To be assigned by IANA Length: A 2-octet field that indicates the length of the value. IFIT-Node-Capability: A multiple of 4 octets field, which is as defined in Section 3.1. 4. Application Within an IFIT domain, one or more IFIT-Option-Types are added into packets at the IFIT-capable head node that is referred to as the IFIT encapsulating node. Then IFIT-Data-Fields may be updated by IFIT transit nodes that the packet traverses. Finally, IFIT-Option-Types are removed at the IFIT-capable end node that is referred to as the IFIT decapsulating node. The role of an IFIT-encapsulating, IFIT- transit or IFIT-decapsulating node is always performed within a specific Namespce. As any packet with IFIT-specific header and metadata MUST not leak out from the IFIT domain, the IFIT decapsulating node MUST be able to capture packets with IFIT-specific header and metadata and recover their format before forwarding them out of the IFIT domain. So that entities (e.g., centralized controllers) can use IFIT node capabilities information to avoid the leak of IFIT-specific header and metadata. Wang, et al. Expires September 24, 2020 [Page 7]
Internet-Dradraft-wang-lsr-ifit-node-capability-advertisemen March 2020 Besides, in order to adapt to different network conditions and different application requirements, a centralized controller needs to switch between different underlying techniques. As different IFIT option types have different encapsulation format in packets and have different processing procedure when packets travers to encapsulating, transit, and decapsulating nodes. For example, for IOAM Trace Option-Types, IOAM tracing data is expected to be collected at every IOAM transit node that a packet traverses to ensure visibility into the entire path a packet takes within an IOAM-domain. If not all nodes within a domain are IOAM Trace Option-Type capable, IOAM-Data- Fields will only be changed on those nodes which are IOAM Trace Option-Type capable and IOAM tracing information will only be collected by those IOAM-capable nodes. For IOAM DEX Option-Type, the requred IOAM data is expected to be exported at every transit node that process a packet with the DEX option. Therefore, this advertisement allows entities (e.g., centralized controllers) to determine whether a specific IFIT functionality can be supported by all devices in a network domain, then enable the IFIT-Data-Fields encapsulation at the head node. 5. IANA Considerations This document makes the following registrations for a TLV type of the new IFIT Node Capability TLV within the body of the OSPF RI Opaque LSA, a Sub-TLV type of the new Sub-TLV proposed from the "Sub-TLVs for TLV 242 (IS-IS Router CAPABILITY TLV)" registry, and a BGP-LS Node Attribute TLV code point for the IFIT Node Capability TLV. +------+-----------------------------------------+ | Type | Description | +------+-----------------------------------------+ | TBD | OSPF Extension IFIT Node Capability TLV | +------+-----------------------------------------+ +------+----------------------------------------------+ | Type | Description | +------+----------------------------------------------+ | TBD | IS-IS Extension IFIT Node Capability Sub-TLV | +------+----------------------------------------------+ +------------+-------------------------------------------+ | Code Point | Description | +------------+-------------------------------------------+ | TBD | BGP-LS Extension IFIT Node Capability TLV | +------------+-------------------------------------------+ Wang, et al. Expires September 24, 2020 [Page 8]
Internet-Dradraft-wang-lsr-ifit-node-capability-advertisemen March 2020 6. Security Considerations This document introduces a new TLV within the existing OSPF RI Opaque LSA, a new sub-TLV for the existing IS-IS Router capability TLV, and a new Node Attribute TLV for the existing Node NLRIs. It does not introduce any new security risks to OSPF, IS-IS and BGP-LS. 7. Acknowledgements TBD. 8. References 8.1. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, <https://www.rfc-editor.org/info/rfc2119>. [RFC5305] "IS-IS Extensions for Traffic Engineering", <https://www.rfc-editor.org/info/rfc5305>. [RFC7752] "North-Bound Distribution of Link-State and Traffic Engineering (TE) Information Using BGP", <https://datatracker.ietf.org/doc/rfc7752/>. [RFC7770] "Extensions to OSPF for Advertising Optional Router Capabilities", <https://www.rfc-editor.org/info/rfc7770>. [RFC7981] "IS-IS Extensions for Advertising Router Information", <https://www.rfc-editor.org/info/rfc7981>. 8.2. Informative References [I-D.ietf-ippm-ioam-data] "Data Fields for In-situ OAM". [I-D.ioamteam-ippm-ioam-direct-export] "In-situ OAM Direct Exporting", <https://datatracker.ietf.org/doc/draft-ioamteam-ippm- ioam-direct-export/>. [I-D.song-ippm-postcard-based-telemetry] "Postcard-based On-Path Flow Data Telemetry", <https://datatracker.ietf.org/doc/draft-song-ippm- postcard-based-telemetry/>. Wang, et al. Expires September 24, 2020 [Page 9]
Internet-Dradraft-wang-lsr-ifit-node-capability-advertisemen March 2020 [I-D.song-opsawg-ifit-framework] "In-situ Flow Information Telemetry Framework", <https://datatracker.ietf.org/doc/draft-song-opsawg-ifit- framework/>. [I-D.zhou-ippm-enhanced-alternate-marking] "Enhanced Alternate Marking Method", <https://datatracker.ietf.org/doc/draft-zhou-ippm- enhanced-alternate-marking/>. Authors' Addresses Yali Wang Huawei 156 Beiqing Rd., Haidian District Beijing China Email: wangyali11@huawei.com Tianran Zhou Huawei 156 Beiqing Rd., Haidian District Beijing China Email: zhoutianran@huawei.com Min Liu Huawei 156 Beiqing Rd., Haidian District Beijing China Email: lucy.liumin@huawei.com Ran Pang China Unicom 9 Shouti South Rd., Haidian District Beijing China Email: pangran@chinaunicom.cn Wang, et al. Expires September 24, 2020 [Page 10]