Network Working Group X. Zhang Internet-Draft F. Yang Intended status: Standards Track W. Cheng Expires: December 18, 2024 China Mobile Z. Fu New H3C Technologies June 18, 2024 Usecases of SRv6 Based Computing Interconnection Network draft-zhang-rtgwg-srv6-computing-connect-usecases-04 Abstract The requirements of computing interconnection are increasingly attracting the attention of service providers. They have been thinking about how to leverage their network advantages to provide integrated networking and computing services. This document describes some scenarios of using SRv6 based network technology which can partially meet the service requirement of computing interconnection. 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. 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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. Zhang, et al. Expires 18 December 2024 [Page 1] Internet-Draft SRv6 Based Computing interconnection Usecases June 2024 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . 2 2. Usage Scenarios of SRv6 based computing interconnection network . 3 2.1. SRv6 based computing interconnection network architecture . . 3 2.2. Path scheduling . . . . . . . . . . . . . . . . . . . . . . 5 2.3. Resource isolation . . . . . . . . . . . . . . . . . . . . . 5 2.4. Multi segment path orchestration . . . . . . . . . . . . . . 5 2.5. Multi Service orchestration . . . . . . . . . . . . . . . . 6 2.6. Network reliability for computing interconnection . . . . . . 6 2.7. Application-aware networking . . . . . . . . . . . . . . . . 6 2.8. Operations, Administration and Maintenance . . . . . . . . . 7 3. Collaboration between computing and network . . . . . . . . . . . 7 4. Best practices. . . . . . . . . . . . . . . . . . . . . . . . . . 8 5. Security Considerations . . . . . . . . . . . . . . . . . . . . . 9 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . . 9 7. Normative References . . . . . . . . . . . . . . . . . . . . . . 9 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . . 9 1. Introduction With the advent of new technology such as cloud computing, big data, artificial intelligence, etc., the demand for computing resource is continuously increasing. More and more data centers, intelligent computing centers, and supercomputing centers have been built to meet the growing demand of computing resource. Usually, these computing centers are centralized(e.g. central cloud). Especially, in some emerging industries, such as self-driving, cloud AR/VR, telemedicine, etc., there are not only requirements for computing resource, but also for quick delivery and guaranteed quality. These requirements are usually related to network factors, such as delay, bandwidth, and jitter, etc. These services can be deployed not only on the central cloud, but also on distributed edge nodes. In order to coordinate computing resource at different levels(center, edge and end) uniformly, and to meet user's requirements for computing power and network, a new type of network is proposed which can combine computing and network information and provide optimal allocation, association and scheduling of computing, storage and network resources. We call it computing interconnection network in this document. The computing interconnection network is a converged architecture with computing and network. The computing interconnection network has attracted the attention of many service providers. Lots of service providers have proposed their own concepts of computing interconnection network, and have also released relevant technical white papers. Different computing resources are interconnected through the network. The goal of computing interconnection network is to achieve "ubiquitous computing resource, computing network symbiosis, intelligent orchestration, and integrated Zhang, et al. Expires 18 December 2024 [Page 2] Internet-Draft SRv6 Based Computing interconnection Usecases June 2024 services", and gradually develop into a infrastructure-level service that can be "once connected, use anywhere" like water and electricity. These goals present some challenges to current network architecture. Segment Routing Architecture [RFC8402] proposes a network paradigm based on a source routing mechanism. The segment routing network has the remarkable characteristics of simplifying the control plane and network state. In addition, segment routing can program the network functions that need to be performed along the way, so that the packets can be transmitted and processed in the desired way. Segment routing can be applied to IPv6 network, which is called SRv6. In addition to inheriting the advantages of source routing, SRv6 has many other advantages. Firstly, IPv6 can provide more addresses to meet the needs of the Internet of Things. Secondly, SRv6 has three levels of programmability that are extremely scalable. Finally, SRv6 also supports in-suit OAM(IOAM), service chain, slicing and other features. SRv6 is the trend in the evolution of IP networks to intelligent IP networks. The network for computing interconnection has attracted the attention of many service providers. They also have deployed new bearer network with SRv6 to provide better connection service. Based on the flexible scalability, programmability, simplicity and other advantages, SRv6 can meet some requirements of computing interconnection network. This document introduces some usage scenarios of SRv6 based computing interconnetion network. 2. Usage Scenarios of SRv6 based computing interconnection network 2.1 SRv6 based computing interconnection network architecture The following figure shows a typical architecture of SRv6 based computing interconnection network. There are two layers here, one is the infrastructure layer and the other is the control layer. *Infrastructure layer: Edge: The network edge device of computing interconnection. In this document, Edge is both the edge device for computing interconnection and the endpoint of the SRv6 path. Computing Resource: The computing resources connected to computing interconnection Edge. It can be cloud, edge or terminal and so on. Client: Clients requesting computing services. *Control layer: Computing and Network Controller: Computing resource scheduling, orchestration and network policy distribution, in this document, CNC is used to represent it. Zhang, et al. Expires 18 December 2024 [Page 3] Internet-Draft SRv6 Based Computing interconnection Usecases June 2024 /-----------------------------------/ / / / Computing and Network Controller / / (CNC) / /-----------:--------:--------:-----/ : : : : : : ...............................: : :............. +----:-----+ : : +----------+ | : : |Computing | | : : |Resource 1|-+ /-----------------------------:-----------------/ : +----+-----+ / +--------------+ / : | / +---------+ | SRv6 | +---------+ / : +--------+--| Edge1 |--|Infrastructure|--| Edge3 |---+---+ : / +---------+ | | +---------+ / | : / | +--------------+ | / | : / | | | / | : / | +----------+ | / +-----+--:-+ / | | Edge 2 | | /+----------+ | / | +----------+ | / |Computing | | / | | | / |Resource 2|-+ /--------------+---------------+--------------+-/ +----------+ | | | +---+--+ +---+--+ +---+--+ +------+ | +------+ | +------+ | |client|-+ |client|-+ |client|-+ +------+ +------+ +------+ Figure 1: SRv6 based computing interconnection network architecture 2.2 Path scheduling when a computing request comes, it is necessary to decide which remote computing node is available to provide the service. Both computing power and network need to be considered for the decision. After the computing node is determined, a SRv6 path fulfilling the SLA requirement can be established to steers the packet to the destination, i.e. the remote computing node. SRv6 is based on source routing mechanism, which can compose the path information at the ingress of the network. The path information is encapsulated in the packet, and identified by a list of SIDs. Then, the packet only need to process the outermost SID downstream. The downstream nodes on the forwarding path can be stateless. SRv6 paths could be established according to default metrics (e.g. cost) or user's policy. These paths can be in loose or strict manner. Zhang, et al. Expires 18 December 2024 [Page 4] Internet-Draft SRv6 Based Computing interconnection Usecases June 2024 2.3 Resource isolation The different services for computing interconnection will be implemented on the same physical network. Some are sensitive to network delay, such as AR/VR. Some are sensitive to packet loss, such as storage services. Therefore, different services share the same physical network, but they need to be isolated from each other. This requires the network with slicing capabilities. Each slice is a logical network. Different slices can provide the services with different SLA requirements which are isolated from each other. SRv6's programmability and protocol simplification could provide slicing capabilities. Using the programmability of SRv6, network devices can assign a specific SID and reserve hardware resources for each slice. The device identifies the network slice based on the specific SID, and steers the packet according to the topology and resources defined by the slice. Then the packets with different SLA requirements can be forwarded in different slices to meet the requirements of business isolation. A head node of the slice network receives the configuration information for indicating resource allocation of network slice from the controller or historical configuration information, then generates a slicing target message, and sends the message to the next-hop intermediate node, which carries information for indicating slice resource allocation for the devices on the path. The configuration information includes the network slice identifier, and the correspondence between the identifier and the target configuration information. The target configuration information includes priority information about resource usage, weight information about resource allocation, the requirement information of bandwidth,computation and storage resource for the network slice, and the like. The contents of the network slice identification indication include the network slice type, network type to which the slice belongs, and the service object of network slice. 2.4 Multi segment path orchestration As described in chapter 1, the computing interconnection network is a converged architecture with computing and network. The computing resources is interconnected through the wide area network. The network may be hierarchical, for example, including access, metro, backbone. For each computing request, CNC needs to learn the state of the network and computing resource comprehensively and make decisions according to the user's constraint. The final selected computing node may cross multiple autonomous domains. Users may want to obtain a link with low delay, high bandwidth, or high reliability. Therefore, it is necessary to consider how to obtain a path that meets SLA when spanning multiple autonomous domains. Zhang, et al. Expires 18 December 2024 [Page 5] Internet-Draft SRv6 Based Computing interconnection Usecases June 2024 The SRv6's BSID realizes the opening of network capabilities. Specifically, the SRv6 network identifies some paths which have specific SLA metrics with a SID, such as low latency. The SID is called BSID, which could be opened to CNC. CNC can select the appropriate BSID according to the user's requirements for network. The BSID hides the complex path information, and only one SID is presented externally. The path represented by the BSID can be a complete path or a certain segment of a complete path. Using SRv6's BSID, underlay and overlay can be combined, and multiple domains can also be connected. SRv6 based computing interconnection network can orchestrate network paths more conveniently and concisely. 2.5 Multi service orchestration In some scenarios, the computing service may need to pass through multiple computing service nodes. For example, in order to meet the requirements of user service's security and stability, when data packets are transmitted in the network, they often need to pass through various service nodes in sequence, such as firewalls, IPS, and application accelerators. This can be achieved through the SRv6 service function chain(SFC for short). SRv6 SFC is realized through the programmability of SRv6. SFC uses specific SIDs to represent the value-added services. The CNC can encode the value-added service functions from the service request in the network path segment list by SIDs, and forward and process the value-added service functions along the path. This maximizes the ability to integrate the computing and network services. 2.6 Network reliability for computing interconnection Different applications hosted on the computing interconnect network have different requirements for network reliability. Network failure usually represents packets loss. However, many interactive multimedia applications (such as cloud gaming) are very sensitive to packet loss, dozens of milliseconds of packet loss will lead to a rapid decline in the quality of service. The traditional fast rerouting mechanism of IP network has some problems, such as complex configuration, worse handover performance, etc. However, the computing interconnect network based on SRv6 can solve these problems. For example, the Topology Independent Loop-Free Alternate(TI-LFA) technology can provide end-to-end local protection mechanism, which complete path switching in a very short period of time after network failure. In addition, SRv6 also provides a micro ring prevention mechanism, which prevent traffic loop in a short time after fault recovery. Therefore, the computing capacity can be continuously and stably transmitted. Another usecase is SRv6 based SD-WAN, which can be aware of the computing resource of applications deployed in the different clouds and can perform the routing policy according to the informations of network and computing resources received. Zhang, et al. Expires 18 December 2024 [Page 6] Internet-Draft SRv6 Based Computing interconnection Usecases June 2024 CPE can receive the detection information of multi clouds from PoP, which can be encapsulated in the Segment Routing Header TLV. And the detection informations include at the least one of the following information: network perfamance indicators, service perfamance indicators, availability detection results and resource location detection results. Based on the detection informations of multi clouds and the quality of network path from CPE to the corresponding cloud, CPE can determine the second cloud as the target node, change the last hop SID of the segment list in the packet from the first SID assigned by the first cloud to the second SID assigned by the second cloud and update the corresponding segment list, then sends the packet to PoP. The first and second SID characterizes a SID assgined to the user. 2.7 Application-aware networking Traditionally, applications and networks are separated, and the network can only identify applications by means of five tuples. This method has a coarser granularity and cannot understand the real needs of applications for computing resource and networks. In computing interconnection network, in order to provide efficient and quality guaranteed computing services, the edge of the network is required to identify different applications and their needs through incoming packets, so as to provide different SLA services. Application-aware networking for IPv6/SRv6 can meet this demand which can carry the application identification and requirements for network and computing, for example by using IPv6 extend head. Then the network edge can perceive these applications and corresponding requirements, so as to steer the packet to the appropriate SRv6 path. 2.8 Operations, Administration and Maintenance As an infrastructure that can serve various industry customers or individual users, the operation, administration and maintenance of computing interconnection network is very important. The network usually changes more frequently. When network quality deteriorates, computing interconnection network needs to respond quickly and provide a better path. Therefore, real-time monitoring of the current network state is required, which can be used as the basis for more accurate and reasonable scheduling decisions and guarantee the SLA requirements. SRv6 supports in-situ OAM(IOAM), which can detect the network quality in real-time and accurate way. Based on the real-time network status, SRv6 based network can better serve computing scheduling and network SLA guarantee. 3. Collaboration between computing and network The core concept of computing interconnection network is collaboration between computing and network. Computing and network are no longer isolated entities, and they need to cooperate with each other. Computing resources and network resources need to be managed and allocated from a global perspective. The reference architecture given Zhang, et al. Expires 18 December 2024 [Page 7] Internet-Draft SRv6 Based Computing interconnection Usecases June 2024 in figure 1 is a possible implementation. In this architecture the centralized CNC can realize the integrated orchestration, control and management of the computing and network. The integrated orchestration of computing and network which is aimed at the diversified and customized requirements of computing and network convergence, could design product and service models based on the flexible combination of the atomic capability of the computing resource and network, and realize the unified orchestration, deployment and guarantee of computing and network services. The collaborative orchestration and scheduling of computing and network provides a new network paradigm to accelerate the digital transformation of society. 4. Best practices Based on the above-mentioned important role of SRv6 in computing interconnection network, as a typical practice, China Mobile has built the infrastructure of SRv6 based DCI network and smart SD-WAN. The SRv6-based DCI network can uniformly access various computing resources and provide computing services. Smart SD-WAN is a new generation of SD-WAN that integrates overlay and underlay networks. SRv6 based DCI network and smart SD-WAN enhance coordination ability between computing and network resource. It enable full connectivity of end, edge, cloud and network, and combine user's intent to achieve collaborative scheduling among application, computing and network, and improve service quality assurance capabilities, to realize end-to-end, differentiated, deterministic, and value-added computing network services. The following is a specific application example. Considering a CDN scheduling system, CDN applications can be regarded as computing services required by users. In the traditional scheduling mode, scheduling system usually allocate CDN node according to the user's geographic location. This will lead to a large number of users in a hotspot area being assigned to the same CDN node, so that some CDN nodes are busy, while others are very idle. This results in low resource utilization, and service quality cannot be guaranteed. In the computing interconnection network, CNC can manage computing resouce and network resources at the same time. It can assign users in the same hotspot area to different CDN nodes according to the nodes computing load obtained in real-time. Corresponding SRv6 paths are established for steering different users's packet to different CDN nodes. Through coordinating computing and network, the problem of unbalanced resource allocation can be solved and user service experience can be improved. Zhang, et al. Expires 18 December 2024 [Page 8] Internet-Draft SRv6 Based Computing interconnection Usecases June 2024 /-----------------------------------/ / / / Computing and Network Controlle / / (CNC) / /--------:-------:--------:---------/ : : : : : : ............................: : :.................. +--:----+ : : +-------+ | : : |CDN | | : : |Node 1 |-+ /-------------------------:------------------------/ : +--+----+ / +----------------+ / : | / +----------+ | Cloud | +----------+ / : +--------+--|SDWAN CPE1|--|Specific Network|--|SDWAN CPE3|--+--+ : / +----------+ | | +----------+ / | : / * +----------------+ * / | : / * | * / | : / * +----------+ * / +----+-:+ / **SRv6 path1**|SDWAN CPE2|**SRv6 path2** /+-------+ | / +----------+ / |CDN | | / | / |Node 2 |-+ /--------------------------------+-----------------/ +-------+ | |-------------|-----+-----|------------| +---+--+ +---+--+ +--+---+ +--+---+ +------+ | +------+ | +------+ | +------+ | |user 1|-+ |user 2|-+ |user 3|-+ |user 4|-+ +------+ +------+ +------+ +------+ Figure 2: CDN system with SRv6 based network Specifically, as shown in figure 2, CDN Node 1 and CDN Node 2 are located at SD-WAN CPE1 and SD-WAN CPE3 respectively. There are a large number of users in the same area accessing to SD-WAN CPE2. It is assumed that CDN Node 1 is closer to this area. In the traditional way, user 1 to user 4 all access CDN Node 1. After the computing interconnection network is deployed, CNC will consider the network and computing load factors at the same time. User 1 and user 2 will access CDN Node 1. User 3 and user 4 will access CDN Node 2. Meanwhile, two SRv6 paths is established on SD-WAN CPE2. Path 1 is to CDN Node 1 and another is to CDN Node 2. User 1 and user 2 will access through path 1, and user 3 and user 4 will access another. In this way, better resource utilization and service experience can be achieved. Zhang, et al. Expires 18 December 2024 [Page 9] Internet-Draft SRv6 Based Computing interconnection Usecases June 2024 5. Security Considerations To be done. 6. IANA Considerations This document does not make any IANA request. 7. Informative References [RFC8402] C. Filsfils, S. Previdi, L. Ginsberg, "Segment Routing Architecture Services", BCP 126, RFC 8402, DOI 10.17487/RFC8402, July 2018, . Authors' Addresses Xiaoqiu Zhang China Mobile Email: zhangxiaoqiu@chinamobile.com Feng Yang China Mobile Email: yangfeng@chinamobile.com Weiqiang Cheng China Mobile Email: chengweiqiang@chinamobile.com Zhihua Fu New H3C Technologies Email: fuzhihua@h3c.com Zhang, et al. Expires 6 December 2024 [Page 9]