rtgwg R. Chen Internet-Draft ZTE Corporation Intended status: Informational K. Yao Expires: 9 January 2025 China Mobile C. Gao ZTE Corporation 8 July 2024 A Framework and Definition for Collective Communication Offloading draft-chen-rtgwg-cco-framework-and-definition-00 Abstract This document provides a definition of the term "Collective Communication Offloading" for use within the IETF and specifically as a reference for other IETF documents that describe or use aspects of Collective Communication Offloading. The document also describes the characteristics of an IETF Collective Communication Offloading, related terms and their meanings, and discusses the general framework for Collective Communication Offloading, the necessary system components and interfaces. 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 9 January 2025. Copyright Notice Copyright (c) 2024 IETF Trust and the persons identified as the document authors. All rights reserved. Chen, et al. Expires 9 January 2025 [Page 1] Internet-Draft A Framework and Definition for CCO July 2024 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 1.1. Requirements Language . . . . . . . . . . . . . . . . . . 3 2. Terms and Abbreviations . . . . . . . . . . . . . . . . . . . 3 3. Definition of CCO . . . . . . . . . . . . . . . . . . . . . . 3 4. Framework . . . . . . . . . . . . . . . . . . . . . . . . . . 4 4.1. CCOM . . . . . . . . . . . . . . . . . . . . . . . . . . 5 4.2. Infrastructure Layer . . . . . . . . . . . . . . . . . . 6 4.3. CCOM Southbound Interface . . . . . . . . . . . . . . . . 6 4.3.1. Interface between the CCO-member and CCOM . . . . . . 6 4.3.2. IInterface between the CCO-switch and CCOM . . . . . 7 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7 6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 7 7. Informative References . . . . . . . . . . . . . . . . . . . 7 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 8 1. Introduction Collective Communication Offloading(CCO) feature allows the offloading of collective operations to the switches. Distributed applications that might benefit from the CCO include but not limited to: * Artificial intelligence (AI). * High performance computing (HPC). In Network Computing(INC) is a relatively common technology. Both AI and HPC networks, the specific usage of INC is Collective Communication Offloading(CCO). The use cases and characteristics of each use case are further described in [I-D.yao-tsvwg-cco-problem-statement-and-usecases]. This document provides a definition of the term " Collective Communication Offloading " for use within the IETF and specifically as a reference for other IETF documents that describe or use aspects of Collective Communication Offloading. Chen, et al. Expires 9 January 2025 [Page 2] Internet-Draft A Framework and Definition for CCO July 2024 The document also describes the characteristics of an IETF Collective Communication Offloading, related terms and their meanings, and discusses the general framework for Collective Communication Offloading, the necessary system components and interfaces. 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. Terms and Abbreviations The terms and abbreviations used in this document are listed below. INC:In Network Computing CCO: Collective Communication Offloading CCOM: Collective Communication Offloading Manager CCO-switch: A device in a network that performs collective operations CCO-member: A member of a collective group. CCO-tree: A tree of CCO-switches used for collective offload for a Collective Group. Collective Group: A set of works that participate in a collective operation. 3. Definition of CCO The definition of CCO in IETF context is as follows: The Collective Communication Offloading (CCO) can efficiently and controllably utilize the storage and computing resources of network equipment without affecting the normal functions of network equipment. CCO feature takes the approach of offloading collective operations to the CCO switch to achieve the ultimate network performance, such as reduced latency, increased throughput, and so on. The type of collective operations referred to in this draft is as follows, they can benefit from CCO: Chen, et al. Expires 9 January 2025 [Page 3] Internet-Draft A Framework and Definition for CCO July 2024 * Broadcast:distribute data from one member to all other members. * AllGather:collect and distribute data from all members. * Reduce:combine data from all members and distribute the results to one member. * AllReduce:combine data from all members and distribute the results to all members. * ReduceScatter:combine data from all members but scatter the results to all members. * Barrier:synchronize across all members. 4. Framework An IETF CCO and its realization involves the following stakeholders and it is relevant to define them for consistent terminology(see Figure 1). * CCOM: The CCOM can be used to discover CCO-switch capability and manages CCO-switch resources. It is mainly responsible for establishes collective groups and configuration of resources allocated to a group for collective offload. * Infrastructure Layer: It includes CCO-switch and CCO-member. * CCOM Southbound Interface:It includesInterface between the CCO- member and CCOM and Interface between the CCO-switch and CCOM. Chen, et al. Expires 9 January 2025 [Page 4] Internet-Draft A Framework and Definition for CCO July 2024 +-----------------------------------------------------------------------+ | +----------------+ +-------------------+ +----------------------+ | | |Group Management| |Topology Management| |CCO-switch capability | | | +----------------+ +-------------------+ | Management | | | CCOM +----------------------+ | +-----------------+-------------------------------+---------------------+ | | Interface between the CCO-member and CCOM Interface between the CCO-switch and CCOM | | +------------+-------------------------------+------------------+ | | | | | +------+-----+ +-----+------+ | | | CCO-member | | CCO-switch | | | +------------+ +------------+ | | Infrastructure Layer | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 1: Figure 1: The framework of the CCO 4.1. CCOM The CCOM is mainly responsible for establish collective groups and allocates the necessary CCO resources for the collective group. The CCOM is reachable by the CCO-switch and by the group CCO-member, possibly through different networks. When a set of members decide to form a group, The CCOM determines an CCO-tree to assign to the group for collective offload. The CCOM then configures each individual switch via Interface between CCO-switches and CCOM, and finally returns to the CCO-member all information required to communicate with their neighboring CCO-switch. The CCOM has the following functional modules: * Group Management: It includes group creation/destruction, group status query, and allocates and de-allocate the necessary CCO resources for the collective group. * Topology Management: The CCOM obtains or computes an CCO-tree between CCO-member and CCO-switch for the group after receiving requests from all members. The CCO-tree is determined using the underlay topology and CCO-switch resource information. * CCO-switch capability management: The CCOM MUST obtain the CCO- switch capability and manages CCO-switch resources. Chen, et al. Expires 9 January 2025 [Page 5] Internet-Draft A Framework and Definition for CCO July 2024 4.2. Infrastructure Layer It includes CCO-switch and CCO-member. * CCO-switch: A device in a network that performs collective operations. It receives input data from CCO-member and performs a reduction operation to produce a single result, and then distribute the output data to one or more members depending on the collective group configuration and particular collective operation. * CCO-member: A member of a collective group. It provides input data and accepts output data, the initiator of collective operations. 4.3. CCOM Southbound Interface The interworking and interoperability between the CCOM and the CCO- switch and the CCO-member to provide common means of provisioning, operating and monitoring the CCO is enabled by the following communication interfaces (see Figure 1). 4.3.1. Interface between the CCO-member and CCOM It is an interface between CCOM and CCO-member. The CCOM can use this interface to communicate with CCO-member about group information, including requests from CCO-member to join the group, creation and destruction of the group, group status query, etc. The main interactive information is as follows: * CCO-member registers with CCOM: CCO-member need to register with CCOM to let CCOM know the existence of the current member and maintain the connection with the CCO-member. CCO-member register with CCOM through this interface. Registration request parameters include: the CCO-member's addressing information and MTU supported by CCO-member. * Group setup: CCO-member joins a group by providing a set of required capabilities to the CCOM. A group is established after all members have attempted to join. Group creation MUST fail if the required network resources or capabilities are not provided. * Group destruction: If the topology changes during the life time of the group or Once any member has left, the group is no longer usable, the CCOM must tear down the group, and build a new CCO- tree. Chen, et al. Expires 9 January 2025 [Page 6] Internet-Draft A Framework and Definition for CCO July 2024 4.3.2. IInterface between the CCO-switch and CCOM It is an interface between CCOM and CCO-switch. The CCOM discover CCO-switch capability and manages CCO-switch resources. The main interactive information is as follows: * Discover CCO-switch capability: The CCOM queries the CCO-switch to obtain their capabilities. The capabilities of the CCO-switch mainly include: whether it supports network computing, supported types of collective operations, supported group numbers, number of trees, supported MTU, etc. * Allocate and de-allocate switch resources for a group: To allocate resources for the Collective Group, the CCOM first needs to know the type of collective operations the group intends to perform. Because, a deployment can have different types of CCO-switch, e.g., some switches can have reduction support while others can support only data transfer offload. So, the CCOM queries the CCO- switch to obtain their capabilities. In this way, the CCOM can allocate appropriate resources when different Collective Groups might perform different types of collective operations. 5. IANA Considerations There are no requests to IANA in this framework document. 6. Acknowledgements TBD. 7. Informative References [I-D.yao-tsvwg-cco-problem-statement-and-usecases] Yao, K., Shiping, X., Li, Y., Huang, H., and D. KUTSCHER, "Collective Communication Optimization: Problem Statement and Use cases", Work in Progress, Internet-Draft, draft- yao-tsvwg-cco-problem-statement-and-usecases-00, 23 October 2023, . [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017, . Chen, et al. Expires 9 January 2025 [Page 7] Internet-Draft A Framework and Definition for CCO July 2024 Authors' Addresses Ran Chen ZTE Corporation Nanjing China Email: chen.ran@zte.com.cn Kehan Yao China Mobile Beijing China Email: yaokehan@chinamobile.com Chenqiang Gao ZTE Corporation Nanjing China Email: gao.chenqiang@zte.com.cn Chen, et al. Expires 9 January 2025 [Page 8]