Network Working Group Y. Liu Internet Draft R. Pang Intended status: Standards Track China Unicom Expires: January 4, 2025 July 4, 2024 Use Cases and Requirements of Massive Data Transmission（MDT） in High Bandwidth-delay Product (BDP) Network draft-liu-rtgwg-mdt-in-high-bdp-01 Abstract This document describes the use cases and related requirements of Massive Data Transmission（MDT）in High Bandwidth-delay Product (BDP) Network. To achieve MDT, it is necessary to implement service identification and traffic record, network layer load balancing, transmission protocol optimization, etc. 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), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. 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." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html This Internet-Draft will expire on January 4, 2025. Liu, et al. Expire January 4, 2025 [Page 1] Internet-Draft MDT in High BDP Network June 2024 Copyright Notice Copyright (c) 2023 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..................................................2 1.1. Requirements Language.......................................3 2. Massive data transmission in high BDP network.................3 3. Use Cases and Requirements....................................4 3.1. Service Identification and Traffic Record...................4 3.2. Load Balancing at Network Level.............................5 3.3. Optimization of Transmission Protocols......................5 3.4. Collaboration Requirements..................................5 3.4.1. Collaboration Between Terminal APP and Controller.........6 3.4.2. Collaboration Between Network Device and Controller.......6 3.4.3. Collaboration Between Network Device and Terminal APP.....6 3.4.4. Interface Requirements....................................6 4. Security Considerations.......................................6 5. IANA Considerations...........................................6 6. References....................................................7 6.1. Normative References........................................7 6.2. Informational References....................................7 Authors' Addresses...............................................8 1. Introduction With the continuous development of industries such as autonomous driving, AI intelligent computing, and enterprise cloud, the demand for massive data transmission across wide area networks from edge data centers/enterprises to core data centers has become increasingly common, and higher requirements have been put forward for existing carrier network architectures. Taking the scenarios of supercomputing and intelligent computing as example, data transmission usually includes two requirements: Liu, et al. Expire January 4, 2025 [Page 2] Internet-Draft MDT in High BDP Network June 2024 1) The transmission of training data between intelligent computing centers, supercomputing centers, and between intelligent computing centers and supercomputing centers is usually carried by optical networks due to high bandwidth requirements and high connection stability. 2) sThe transmission of training data and result feedback between users and intelligent computing centers/supercomputing centers can be carried through IP networks due to their strong suddenness and cost sensitivity. The MDT can be achieved by traditional high-speed private lines, providing users with efficient and reliable data transmission. However, traditional private lines usually use billing methods such as daily or monthly rent, with fixed bandwidth resources and expensive prices. The long-distance transmission of massive data requires flexible transmission tasks based on user data characteristics, completion time, and security requirements, utilizing the idle bandwidth resources of existing private lines and networks to reduce transmission costs and improve transmission efficiency. This draft mainly describes the overall architecture of feasible solutions for MDT in high BDP network, typical problems that may be encountered, and proposes potential solutions, including but not limited to how to perform load balancing scheduling at the global level of the network to avoid the impact of massive data transmission on existing network services; how to identify MDT services for traffic record and billing purposes; how to optimize the congestion control algorithm of the transport layer protocol to ensure that the throughput of TCP protocol can be improved in long-distance lossy networks. 1.1. 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. 2. Massive data transmission in high BDP network Figure 1 show schematic diagram of the network architecture of MDT in high BDP network, where key functional units include: DC/User APP：APP can be deployed on DC/personal terminal devices, which can be traditional file transfer tools or customized apps Liu, et al. Expire January 4, 2025 [Page 3] Internet-Draft MDT in High BDP Network June 2024 developed for MDT scenarios, which implements enhanced functions such as intelligent data compression, intelligent partitioning, encryption, etc. Network：existing service carrier networks of current operators, such as metropolitan area networks, backbone networks, etc. Controller：existing network management system includes controllers, collaborators, orchestrators, etc. +-----+ +-----------+ +------+ | DC |<--------------------------->| | |Center| | APP | |---->|Controller |<-----| | DC2 | +-----+ | +-----------| | |->+------+ | | ^ | | | +------+ | | | | | | Edge | V V V | |--->| DC1 |-\ +-------+ +-------+ +-------+ / +------+ \-> | Edge | | Core | | Edge |/ | |-->| |-->| | /------> |Network| |Network| |Network| / +-------+ +-------+ +-------+\ +------+ / \ +------+ | User1|--/ \-> | User2| | APP | | APP | +------+ +------+ Figure 1: Architecture of MDT in high BDP network 3. Use Cases and Requirements MDT service is a predictable time-efficient service that requires data transmission to be completed within a specified time, not sensitive to transmission delay, but requires a considerable amount of network resources. Compared with traditional Internet and private line services, how to improve transmission efficiency, achieve service identification, complete scheduling and billing for services are key issues to be considered. 3.1. Service Identification and Traffic Record Before starting transmission, the APP will notify the controller of the required data size and expected completion time for the task. The controller will dynamically adjust the network path calculation and private line bandwidth based on transmission requirements and the current available link resources of the network, and distribute the configuration to network nodes. Liu, et al. Expire January 4, 2025 [Page 4] Internet-Draft MDT in High BDP Network June 2024 After the transmission task is initiated, network devices need to be able to identify MDT services and corresponding account information based on certain identifiers, perform traffic record, and report the statistical results to the controller. The controller can get the overall MDT usage of the network, as well as the specific resource completion status for a particular user, and make corresponding strategy adjustments. From the above use cases, it can be seen that the billing of MDT services and the scheduling and allocation of available bandwidth resources in the current network require network devices to recognize the current MDT services. APNID defined in [I-D.li-apn- problem-statement-usecases] may be a potential solution to meet the identification requirements of MDT service. 3.2. Load Balancing at Network Level The bandwidth requirement for MDT service is generally between 500M- 10G, and the launch of each service requires a huge consumption of network resources. With the continuous increase of service launching, how to make reasonable use of network idle resources, allocate global network resources and data express tasks, and minimize the impact on existing services have become necessary issues to consider. The controller notifies the APP of available network resource information, and the APP dynamically adjusts the data sending strategy based on the available network bandwidth, and cooperates with network devices to improve the overall resource utilization of the network. When the controller discovers a shortage of available network resources or predicts a rapid growth in future network traffic, it should notify the APP side in advance to make policy adjustments. 3.3. Optimization of Transmission Protocols In most scenarios, the two ends of MDT services need to cross a wide area network, with a distance of over 1000 km. RTT is in the tens of MS range, and there is a small amount of packet loss in the network, which poses new challenges to the traditional TCP [RFC7805]. Based on current test results, the traditional TCP congestion control algorithm [RFC2581] may not achieve the expected transmission rate for MDT. Therefore, an efficient, secure transmission protocol that can adapt to the current network state and resource status is needed to solve these problems. The current network satae, including bandwidth, congestion state, path, etc, can be measured by ippm and other network state measurement technologies. The network state can be carried by the ack of Liu, et al. Expire January 4, 2025 [Page 5] Internet-Draft MDT in High BDP Network June 2024 transmission protocols (TCP or QUIC) and also processed in reciever. By using the network state information, the transmission protocols can achieve congestion control and traffic control to optimize the network throughput. 3.4. Collaboration Requirements To meet the resource requirements of MDT business while not affecting existing network services, efficient collaboration between controllers, terminal APPs, and network devices is required. 3.4.1. Collaboration Between Terminal APP and Controller The terminal APP needs to authenticate and authorize the controller to accept scheduling. The APP reports the request for transmission tasks to the controller, such as the size of the data to be transmitted, the transmission completion time, the service priority, etc. The controller formulates a scheduling strategy based on the transmission request and network resource, and issues it to the APP for execution. 3.4.2. Collaboration Between Network Device and Controller The controller needs to get the real-time status of the network devices and the available bandwidth resources of all links, perform global routing and bandwidth configuration changes based on the service demands reported by the APP, and distribute the configuration to network devices. Network devices report their operational status, available resource information, and specific MDT service information to the controller, and receive policy information provided by the controller. 3.4.3. Collaboration Between Network Device and Terminal APP The host-network coordination scheme has been increasingly widely discussed. In this scheme, the network side needs to use some status information of network nodes, such as CIR, MTU, Link Usage (defined in RFC 9473), status information of Segment list, etc., to guide the host(APP) to adjust the sending strategy. The overall principle is that in the scenario of massive data transmission, the host can select the idle network paths and the most economical transmission mode flexibly based on the information provided by the network side, then improve the load utilization of the network. Liu, et al. Expire January 4, 2025 [Page 6] Internet-Draft MDT in High BDP Network June 2024 At the same time, the host needs to notify the network side through some identification to indicate the APP status , and the key demands for the network node. The network devices can adjust the strategy based on this information. For example, in order to reduce the impact on the existing services of the current network, the priority of some less important service messages should be marked as not very important. Thus, when congestion occurs, the network equipment will preferentially discard these messages. 3.4.4. Interface Requirements TBD. 4. Security Considerations TBD. 5. IANA Considerations TBD. 6. References 6.1. Normative References [RFC7805] Zimmermann, A., Eddy, W., and L. Eggert, "Moving Outdated TCP Extensions and TCP-Related Documents to Historic or Informational Status", RFC 7805, DOI 10.17487/RFC7805, April 2016, . [RFC2581] Allman, M., Paxson, V., and W. Stevens, "TCP Congestion Control", RFC 2581, DOI 10.17487/RFC2581, April 1999, . [RFC 9526] Filsfils, C., Talaulikar, K., Ed., Voyer, D., Bogdanov, A., and P. Mattes, "Segment Routing Policy Architecture", RFC 9256, DOI 10.17487/RFC9256, July 2022, . Liu, et al. Expire January 4, 2025 [Page 7] Internet-Draft MDT in High BDP Network June 2024 6.2. Informational References [I-D.li-apn-problem-statement-usecases] Li, Z., Peng, S., Voyer, D., Xie, C., Liu, P., Qin, Z., and G. S. Mishra, "Problem Statement and Use Cases of Application-aware Networking (APN)", Work in Progress, Internet-Draft, draft-li-apn- problem-statement-usecases-08, 3 April 2023, . [I-D.li-apn-header] Li, Z., Peng, S., and S. Zhang, "Application- aware Networking (APN) Header", Work in Progress, Internet-Draft, draft-li-apn-header-04, 12 April 2023, . Liu, et al. Expire January 4, 2025 [Page 8] Internet-Draft MDT in High BDP Network June 2024 Authors' Addresses Ying Liu China Unicom China Email: liuy619@chinaunicom.cn Mengyao Han China Unicom China Email: hanmy12@chinaunicom.cn Zheng Ruan China Unicom China Email: ruanz6@chinaunicom.cn Liu, et al. Expire September 4, 2024 [Page 9]