Network Working Group W. Quan Internet-Draft W. Su Intended status: Standards Track S. Pan Expires: 4 September 2024 Beijing Jiaotong University X. Liang J. Liang China Telecom 3 March 2024 IOAM network awareness for Low Latency, Low Loss, and Scalable Throughput (L4S) draft-quan-l4s-ioam-00 Abstract This specification defines a framework how to update L4S Dual-Queue Coupled AQM with In Situ Operations, Administration, and Maintenance (IOAM). These are designed for consistently very low queuing latency, very low congestion loss, and scaling of perflow throughput by using Explicit Congestion Notification (ECN) using the operational and telemetry information collected by IOAM. Since L4S lacks information about the use of network status and network nodes, which also affect network performance in practice, it is considered to use direct export mode for information collection of L4S-IOAM to strengthen the AQM regulation of L4S. It then gives the normative requirements that are necessary. 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 4 September 2024. Quan, et al. Expires 4 September 2024 [Page 1] Internet-Draft IOAM network awareness for L4S March 2024 Copyright Notice Copyright (c) 2024 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 Revised BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Revised BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 3. IOAM network awareness in L4S framework . . . . . . . . . . . 4 4. Information Details . . . . . . . . . . . . . . . . . . . . . 5 5. UseCases . . . . . . . . . . . . . . . . . . . . . . . . . . 8 6. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 9 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9 8. Security Considerations . . . . . . . . . . . . . . . . . . . 9 9. References . . . . . . . . . . . . . . . . . . . . . . . . . 9 9.1. Normative References . . . . . . . . . . . . . . . . . . 9 9.2. Informative References . . . . . . . . . . . . . . . . . 9 Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 10 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 10 1. Introduction The L4S architecture [RFC9330] allows routers to use a different marking system that can provide early reaction to incipient congestion [RFC9332] and defines a reaction for this feedback when packets are marked with ECN. But congestion still occurs in front of the L4S node. The application of IOAM technology in L4S framework can effectively solve this problem. In Situ Operations, Administration, and Maintenance (IOAM) is used for recording and collecting operational and telemetry information while the packet traverses a path between two points in the network. The IOAM data fields are further updated in [RFC9326] for direct export use cases. This document defines how to use the information collected by the front-end nodes to better update the L4S mechanism. IOAM can collect operational and telemetry information. L4S uses an Explicit Congestion Notification (ECN) scheme at the IP layer with the same set of codepoint transitions as the original (or 'Classic') ECN. Quan, et al. Expires 4 September 2024 [Page 2] Internet-Draft IOAM network awareness for L4S March 2024 The goal of L4S-IOAM is to solve the problem of how to get information awareness between the IOAM network and the L4S site. The basis to achieve this goal is network and computing. Therefore, Network Information Awareness (NIA) system architecture is proposed. As the control plane of the L4S-IOAM framework, NIA introduces the control center component on top of the L4S-IOAM framework to realize the management and comprehensive analysis of network information and encourage L4S site to take action to consider local network awareness. This specification defines how the data collected by IOAM can be used to better update the Low Latency, Low Loss, and Scalable throughput (L4S). The terms "encapsulation" and "decapsulation" are used in this document in the same way as [RFC9197]. An IOAM encapsulating node incorporates one or more IOAM Option-Types into packets that IOAM is enabled for. 2. Terminology L4S: Low Latency, Low Loss, and Scalable Throughput (L4S) as defined in [RFC9330]. L4S Dual-Queue Coupled AQM: A framework for coupling the Active Queue Management (AQM) algorithms in two queues intended for flows with different responses to congestion. IOAM: In situ Operations, Administration, and Maintenance as defined in [RFC9197]. OAM: Operations, Administration, and Maintenance. IOAM Transit Node (IOAM-T): An IOAM transit node updates one or more of the IOAM-Data-Fields. If both the Pre-allocated and the Incremental Trace Option-Types are present in the packet, each IOAM transit node will update at most one of these Option-Types. IOAM Encapsulating Node (IOAM-E): An IOAM encapsulating node incorporates one or more IOAM Option-Types into packets that IOAM is enabled for. If IOAM is enabled for a selected subset of the traffic, the IOAM encapsulating node is responsible for applying the IOAM functionality to the selected subset. IOAM Decapsulating Node (IOAM-DE): An IOAM decapsulating node removes any IOAM Option-Types from packetsand processes and/or exports the associated data. IOAM NODE ID (T-ID): The combination of IOAM node_id and IOAM Namespace-ID should always be unique. Quan, et al. Expires 4 September 2024 [Page 3] Internet-Draft IOAM network awareness for L4S March 2024 Direct Export: Direct Export is an IOAM mode of operation within which IOAM data are to be directly exported to a collector rather than be collected within the data packets. The IOAM Direct Export Option-Type consists of a fixed-size "IOAM direct export option header". Direct Export for IOAM is defined in [RFC9326]. 3. IOAM network awareness in L4S framework The following are system components for the L4S-IOAM. +--------------+ +-----------+ +-------------+ | | L4S | | Monitoring/ | |======>| QUAL-AQM | | Analytics | | | | | IOAM-C |-+ +-----------+ +-------------+ ^ | Processed/interpreted/ | aggregated IOAM data | +--------------+ +-------------+ | | IOAM data | | | processing | | | system(s) |-+ +-------------+ ^ | Raw export of | IOAM data | +--------------+-------+------+--------------+ | | | | | | | | User +---+----+ +---+----+ +---+----+ +---+-----+ packets | IOAM-E | | IOAM-T | | IOAM-T | | IOAM-DE | -------->| Node |====>| Node |====>| Node |====>| Node |--> | | | A | | B | | | +--------+ +--------+ +--------+ +---------+ Figure 1: L4S-IOAM Schematic IOAM Control Center (IOAM-C): Store and manage network information and computing information, and make decisions through a comprehensive analysis of this information. IOAM-C consists of the IOAM Path Calculation Unit I-PCE), IOAM Network Metric Information Base(I-NIB), and IOAM Computing Information Base(I-CIB), and network and computing information is collected through the IOAM-SBI Interface. Quan, et al. Expires 4 September 2024 [Page 4] Internet-Draft IOAM network awareness for L4S March 2024 IOAM Ingress Forwarder (IOAM-E): A network node with a similar SFC Classifier [RFC7665] forwarding function can classify, encapsulate (for example, add a packet header with a service path identifier using the NSH protocol [RFC8300]), and forward incoming traffic. IOAM-E and IOAM-DE have a L4S Network Metric Agent (L-NMA), responsible for collecting network information. In L4S-IOAM, L-NMA reports the collected network information to IOAM-C through the IOAM- SBI Interface. The following are system architecture for the L4S-IOAM. (3) (2) (4) .-------^------..------------^------------------. _________ ,-(1)-----. _____ | IOAM | ; ________ : L4S -------. | | /_ _ _| Monitor | :|Scalable| : _ __\ ||__\_|mark | \ | |_________| :| sender | : __________ / / || / |_____| \ | _________ :|________|\; | |/ -------' ^ \ | |condit'nl| `---------'\_| IP-ECN | Coupling : \_|_|priority |_\ ________ / |Classifier| : / | |scheduler| / |Classic |/ |__________|\ -------. __:__ / | |_________| | sender | \_ __\ || | ||__\_|mark/|/ | |________| / || | || / |drop |/_ _| Classic -------' |_____|\ (1) Scalable sending host (2) Isolation in separate network queues (3) Packet identification protocol (4) Monitor in network queues Figure 2: L4S-IOAM architecture 4. Information Details IOAM for L4S is used to enhance diagnostics of L4S networks. It complements other mechanisms designed to enhance diagnostics of L4S networks, such as the "The Explicit Congestion Notification (ECN) Protocol" described in [RFC9331]. Figure 3 shows awareness information content examples for network aware which is used to provide L4S services. Quan, et al. Expires 4 September 2024 [Page 5] Internet-Draft IOAM network awareness for L4S March 2024 +-------------+----------------------+ | Awareness | Network | | information | information | +-------------+----------------------+ | | IOAM-F location; | | | IOAM-F type; | | Capability | IOAM-F ID; | | parameters | Topology information.| | | | | | | | | | | | | | | | +-------------+----------------------+ | | Service request | | Status | information; | | parameters | Traffic features; | | | Communication | | | information. | +-------------+----------------------+ Figure 3: L4S-IOAM Information Details "IOAM tracing data" is expected to be collected at every IOAM transit node that a packet traverses to ensure visibility into the entire path that a packet takes within an IOAM-Domain. In other words, in a typical deployment, all nodes in an IOAM-Domain would participate in IOAM and, thus, be IOAM transit nodes, IOAM encapsulating nodes, or IOAM decapsulating nodes. If not all nodes within a domain are IOAM capable, IOAM tracing information (i.e., node data, see below) will only be collected on those nodes that are IOAM capable. IOAM tracing can, for example, collect the following types of information: * Identification of the IOAM node. An IOAM node identifier can match to a device identifier or a particular control point or subsystem within a device. * Identification of the interface that a packet was received on, i.e., ingress interface. * Identification of the interface that a packet was sent out on, i.e., egress interface. Quan, et al. Expires 4 September 2024 [Page 6] Internet-Draft IOAM network awareness for L4S March 2024 * Time of day when the packet was processed by the node as well as the transit delay. Different definitions of processing time are feasible and expected, though it is important that all devices of an IOAM-Domain follow the same definition. * Generic data, which is format-free information, where the syntax and semantics of the information are defined by the operator in a specific deployment. For a specific IOAM-Namespace, all IOAM nodes should interpret the generic data the same way. Examples for generic IOAM data include geolocation information (location of the node at the time the packet was processed), buffer queue fill level or cache fill level at the time the packet was processed, or even a battery charge level. * Information to detect whether IOAM trace data was added at every hop or whether certain hops in the domain weren't IOAM transit nodes. * Data that relates to how the packet traversed a node (transit delay, buffer occupancy in case the packet was buffered, and queue depth in case the packet was queued). Export of Export of Export of Export of IOAM data IOAM data IOAM data IOAM data ^ ^ ^ ^ | | | | | | | | User +---+----+ +---+----+ +---+----+ +---+-----+ packets | IOAM-E | | IOAM-T | | IOAM-T | | IOAM-DE | -------->| Node |====>| Node |====>| Node |====>| Node |--> | | | A | | B | | | +--------+ +--------+ +--------+ +---------+ Figure 4: L4S-IOAM Direct Export Mode Consider using Direct Export mode for L4S-IOAM information gathering. OAM information about each IOAM node a packet traverses is collected and immediately exported to a collector. Direct Export could be used in situations where per-hop tracing information is desired, but gathering the information within the packet -- as with per-hop tracing -- is not feasible. Rather than automatically correlating the per-hop tracing information, as done with per-hop tracing, Direct Export requires a collector to correlate the information from the individual nodes. In addition, all nodes enabled for Direct Export need to be capable of exporting the IOAM information to the collector. Quan, et al. Expires 4 September 2024 [Page 7] Internet-Draft IOAM network awareness for L4S March 2024 Those content would allow L4S flows to achieve low latency, low loss and scalable throughput, but would sacrifice the more precise flow balance offered by. 5. UseCases This section gives an example how the application of IOAM technology in L4S framework can effectively solve the problem that the forward node in the network is still congested before the L4S node, so the demand of L4S can also be met in L4S-IOAM, and it is conducive to reducing the overall delay of the network. The following use cases for L4S are being considered by various interested parties: * where the bottleneck is one of various types of access network, e.g., DSL, Passive Optical Networks (PONs), DOCSIS cable, mobile, satellite; or where it's a Wi-Fi link * private networks of heterogeneous data centres, where there is no single administrator that can arrange for all the simultaneous changes to senders, receivers, and networks needed to deploy DCTCP: - a set of private data centres interconnected over a wide area with separate administrations but within the same company - a set of data centres operated by separate companies interconnected by a community of interest network (e.g., for the finance sector) - multi-tenant (cloud) data centres where tenants choose their operating system stack (Infrastructure as a Service (IaaS)) * different types of transport (or application) congestion control: - elastic (TCP/SCTP); - real-time (RTP, RMCAT); and - query-response (DNS/LDAP). * where low delay QoS is required but without inspecting or intervening above the IP layer : - Mobile and other networks have tended to inspect higher layers in order to guess application QoS requirements. However, with growing demand for support of privacy and encryption, L4S Quan, et al. Expires 4 September 2024 [Page 8] Internet-Draft IOAM network awareness for L4S March 2024 offers an alternative. There is no need to select which traffic to favour for queuing when L4S can give favourable queuing to all traffic. * If queuing delay is minimized, applications with a fixed delay budget can communicate over longer distances or via more circuitous paths, e.g., longer chains of service functions [RFC7665] or of onion routers. * If delay jitter is minimized, it is possible to reduce the dejitter buffers on the receiving end of video streaming, which should improve the interactive experience. 6. Contributors Thanks to Xue Zhang, Ziheng Xu and Xuetong Hu for their contributions to this document. 7. IANA Considerations None. 8. Security Considerations For further study. 9. References 9.1. Normative References [RFC8300] Quinn, P., Ed., Elzur, U., Ed., and C. Pignataro, Ed., "Network Service Header (NSH)", RFC 8300, DOI 10.17487/RFC8300, January 2018, . 9.2. Informative References [RFC7665] Halpern, J., Ed. and C. Pignataro, Ed., "Service Function Chaining (SFC) Architecture", RFC 7665, DOI 10.17487/RFC7665, October 2015, . [RFC9197] Brockners, F., Ed., Bhandari, S., Ed., and T. Mizrahi, Ed., "Data Fields for In Situ Operations, Administration, and Maintenance (IOAM)", RFC 9197, DOI 10.17487/RFC9197, May 2022, . Quan, et al. Expires 4 September 2024 [Page 9] Internet-Draft IOAM network awareness for L4S March 2024 [RFC9326] Song, H., Gafni, B., Brockners, F., Bhandari, S., and T. Mizrahi, "In Situ Operations, Administration, and Maintenance (IOAM) Direct Exporting", RFC 9326, DOI 10.17487/RFC9326, November 2022, . [RFC9330] Briscoe, B., Ed., De Schepper, K., Bagnulo, M., and G. White, "Low Latency, Low Loss, and Scalable Throughput (L4S) Internet Service: Architecture", RFC 9330, DOI 10.17487/RFC9330, January 2023, . [RFC9331] De Schepper, K. and B. Briscoe, Ed., "The Explicit Congestion Notification (ECN) Protocol for Low Latency, Low Loss, and Scalable Throughput (L4S)", RFC 9331, DOI 10.17487/RFC9331, January 2023, . [RFC9332] De Schepper, K., Briscoe, B., Ed., and G. White, "Dual- Queue Coupled Active Queue Management (AQM) for Low Latency, Low Loss, and Scalable Throughput (L4S)", RFC 9332, DOI 10.17487/RFC9332, January 2023, . Acknowledgments The authors wish to thank Xue Zhang, Ziheng Xu and Xuetong Hu, for their invaluable comments. Authors' Addresses Wei Quan Beijing Jiaotong University 3 Shangyuan Cun, Haidian District Beijing P.R. China Email: weiquan@bjtu.edu.cn Wei Su Beijing Jiaotong University 3 Shangyuan Cun, Haidian District Beijing P.R. China Email: wsu@bjtu.edu.cn Quan, et al. Expires 4 September 2024 [Page 10] Internet-Draft IOAM network awareness for L4S March 2024 Shuaihao Pan Beijing Jiaotong University 3 Shangyuan Cun, Haidian District Beijing P.R. China Email: 23111016@bjtu.edu.cn Xiaobin Liang China Telecom Research Institute South District of Future Science and Technology, Changping District Beijing P.R. China Email: liangxb2@chinatelecom.cn Jie Liang China Telecom Research Institute South District of Future Science and Technology, Changping District Beijing P.R. China Email: liangjie6@chinatelecom.cn Quan, et al. Expires 4 September 2024 [Page 11]