Network Working Group D. Lou Internet-Draft L. Iannone Intended status: Experimental Y. Zhou Expires: 27 August 2023 J. Yang C. Zhang Huawei 23 February 2023 Signaling In-Network Computing operations (SINC) deployment considerations draft-zhou-rtgwg-sinc-deployment-considerations-00 Abstract This document is intended to discuss some aspects of the deployment of "Signaling In-Network Computing operations" (SINC). Based on the actual topology of the SINC domain, this document analyzes how each device in the SINC chain undertakes its own functions. This document provides some specific solutions to the use of SINC mechanism. 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 27 August 2023. 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 (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 Lou, et al. Expires 27 August 2023 [Page 1] Internet-Draft SINC deployment considerations February 2023 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 . . . . . . . . . . . . . . . . . . . . . . . . . 2 3. SINC Deployment Considerations . . . . . . . . . . . . . . . 2 4. SINC over SFC Considerations . . . . . . . . . . . . . . . . 4 4.1. SINC NSH encapsulation . . . . . . . . . . . . . . . . . 4 4.2. SINC over SFC Workflow . . . . . . . . . . . . . . . . . 5 5. SINC over MPLS Considerations . . . . . . . . . . . . . . . . 6 5.1. SINC MPLS encapsulation . . . . . . . . . . . . . . . . . 7 5.2. SINC over MPLS Workflow . . . . . . . . . . . . . . . . . 7 6. Security Considerations . . . . . . . . . . . . . . . . . . . 8 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9 Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . 9 References . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Normative References . . . . . . . . . . . . . . . . . . . . . 9 Informative References . . . . . . . . . . . . . . . . . . . . 10 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 10 1. Introduction "Signaling In-Network Computing operations" (SINC) is a mechanism to enable signaling in-network computing operations on data packets in specific scenarios like NetReduce, NetDistributedLock, NetSequencer, etc. This mechanism can effectively reduce the task completion time and improve the system efficiency. The SINC framework design can be found in the draft [I-D.zhou-rtgwg-sinc-00]. 2. Terminology This document uses the terms as defined in [RFC7498], [RFC7665], [RFC8300], [RFC3031], [RFC5036] and [RFC2205]. This document assume that the reader is familiar with the Service Function Chaining architecture and Multi-Protocol Label Switching architecture. 3. SINC Deployment Considerations In order to deploy the SINC solution in the network, the packet from the host needs to be transmitted through a path containing SINC capable switches/routers (SW/R) for data computation. Different from the simplistic experimental network environment used for in network computing verification in research papers, the real network is much more complex, containing multiple SINC SW/Rs with different capabilities and multiple paths between sources and destinations, as Lou, et al. Expires 27 August 2023 [Page 2] Internet-Draft SINC deployment considerations February 2023 shown in Figure 1. The packet traveling between Host A and Host B may pass SINC Node A or B via different paths. It is essential to create a proper route with nodes to support SINC operation and facilitate the packet delivery. The SINC capable SW/Rs should periodically advertise their networking & computing capacities and capabilities, e.g. the operation it can perform, the current work load, the link capacity, etc. Based on those information, the control plane is responsible to create a proper route where the data in the packet will undertake the desired computation before arriving at the destination host. Such a path could be located at layer 2, 3 or 4 dependent of the network context and application environments. For instance, in a telecommunication network where the Multi-Protocol Label Switching (MPLS) [RFC3031] is deployed, we could used the MPLS protocol to encapsulate the SINC header and deliver the packet to a SINC capable SW/R. In a Data Center Network, if the Generic Network Virtualization Encapsulation (GENEVE) [RFC8926] is applied, we may use the GENEVE protocol for encapsulation. Other encapsulation protocols like General Routing Encapsulation (GRE) [RFC2784], Service Function Chaining (SFC) [RFC7665], and so on, could be potential candidates as well. The SINC header is usually copied/moved right after the new encapsulation header, which makes it easier to access the SINC header. +--------+ +--------+ | SINC | | SINC | | Node A | | Node B | +--------+ +--------+ | \/ | \ | / \ | \ | / \ | \ +-------+ +-------+ +-------+ | SW/R | | SW/R | | SW/R | +-------+ +-------+ +-------+ | | | +-------+ +-------+ | | Proxy | | Proxy | | +-------+ +-------+ | | | | +---------+ +---------+ +---------+ | Host A | | Host B | | Host C | +---------+ +---------+ +---------+ Figure 1: SINC In Deployment Topology Lou, et al. Expires 27 August 2023 [Page 3] Internet-Draft SINC deployment considerations February 2023 4. SINC over SFC Considerations In this section, SFC, which is a layer 3.5 protocol, is used as a running example on how to create a tunnel and encapsulate the SINC header, in order to implement the desired in-network computation. Figure 2 shows the architecture of a SFC-based SINC network. In the computing service chain, a host sends out packets containing data operations to be executed in the network. The data operation description should be carried in the packet itself by using a SINC- specific NSH encapsulation. Once the SINC packet enters into the SFC domain, the Service Function Forwarder (SFF) [RFC7665] will forward packets to one or more connected service functions according to information carried in the SFC encapsulation. The Service Function (SF) [RFC7665] is responsible for implementing data operations. +---------+ +---------+ | Host A | | Host B | +---------+ +---------+ | +-----------+ | | | SINC SW/R | | +------------+ +-----+ | +-----+ | +-----+ +-----------+ |SINC Ingress| | | | | | | | | |SINC Egress| | Proxy |-->| SFF |-->| | SFF | |-->| SFF |-->| Proxy | +------------+ +-----+ | +-----+ | +-----+ +-----------+ | | | | +-----+ | | | SF | | | +-----+ | +-----------+ Figure 2: SINC over SFC Architecture. 4.1. SINC NSH encapsulation This section shows how the SINC header can be embedded in the Network Service Header (NSH) [RFC8300] for SFC [RFC7665]. The SINC NSH base header, as shown in Figure 3, is basically another type of NSH Meta Data (MD) header. SINC NSH encapsulation uses the NSH MD fixed-length context headers to carry the data operation information as show in Figure 3. Please refer to the NSH [RFC8300] for a detailed SFC basic header description. Lou, et al. Expires 27 August 2023 [Page 4] Internet-Draft SINC deployment considerations February 2023 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |ver|O|U| TTL | Length |U|U|U|U|MD Type| Next Protocol | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 3: NSH Base Header, where 'MD Type' should contain a code- point assigned by IANA. Following the NSH basic header there is the Service Path Header, show in Figure 4, as defined in [RFC8300]. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Service Path Identifier (SPI) | Service Index | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 4: NSH Service Path Header. The complete SINC NSH header, as shown in Figure 5, stacks the NSH base header, NSH Service Path Header, and the SINC Header all together. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |ver|O|U| TTL | Length |U|U|U|U|MD Type| Next Protocol | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Service Path Identifier (SPI) | Service Index | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Reserved |D|L| Group ID | \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |S | No. of Data Sources | Data Source ID | |I +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |N | SeqNum | |C +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | Data Operation | Data Offset | / +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 5: SINC NSH Header. 4.2. SINC over SFC Workflow For the sake of clarity, a simple example with one sender (Host A) and one receiver (Host B) is used to illustrate the workflow. Packet processing goes through the following steps: 1. Host A transmits a packet containing a SINC header together with data, which will be processed by SFs on SINC capable SW/Rs, to the SINC Ingress Proxy. Lou, et al. Expires 27 August 2023 [Page 5] Internet-Draft SINC deployment considerations February 2023 2. The SINC Ingress Proxy encapsulates the original packet with the SINC header into a SINC NSH header, as the transport protocol indicated by the SFC. 3. The SFF forwards the encapsulated packet to the SINC SW/R. 4. As shown in Figure 2, when the packet reaches the SINC SW/R, the header of the packet will be removed. The SFF looks up the Service Path Identifier (SPI) table and Service Index (SI) table and sends the packet to the SF. 5. The SF performs the computing based on the defined operation in the SINC header after the verification of the Group ID and Data Source ID. The payload will be replaced with the result after computation. The Operation Done flag will be set to 1. The packet is then re-encapsulated with the NSH SINC header. The SI is reduce by 1 while other fields are untouched. Finally, the packet is forwarded to the SINC Egress Proxy. 6. When the packet reaches the SINC Egress Proxy, it looks up the SPI & SI tables and realizes it is the egress. It removes the NSH encapsulation and forwards the inner packet to the final destination. 5. SINC over MPLS Considerations In this section, MPLS, which is a layer 2.5 protocol, is used as a running example on how to create a tunnel and encapsulate the SINC header, in order to implement the desired in-network computation. As shown in the Figure 6, the overall architecture is similar to the SFC solution. In this case, the SINC proxy is also a Label Edge Router. The SW/Rs connecting the SINC proxies and SINC SW/Rs are Label Switching Routers (LSR). Before sending out a SINC packet, the Label Switched Paths (LSP) should be established between the SINC proxies and SINC SW/Rs. The SINC SW/Rs and proxies can identify a SINC packet by the LSPs used. Upon receiving a packet with a SINC header, the SINC Ingress Proxy encapsulates the packet with a MPLS label(s) according to LSP, before forwarding it to the SINC SW/R. The SINC SW/R pops up/pushes the MPLS label before/after the data computation. The results will be forwarded to the SINC Egress Proxy where the MPLS label will be popped up again before the packet is delivered to the destination. Lou, et al. Expires 27 August 2023 [Page 6] Internet-Draft SINC deployment considerations February 2023 +---------+ +---------+ | Host A | | Host B | +---------+ +---------+ | | | | +------------+ +-----+ +-----------+ +-----+ +-----------+ |SINC Ingress| | | | SINC | | | |SINC Egress| | Proxy |-->| LSR |-->| SW/R |-->| LSR |-->| Proxy | +------------+ +-----+ +-----------+ +-----+ +-----------+ Figure 6: SINC over MPLS Architecture. 5.1. SINC MPLS encapsulation As shown in the Figure 7, one or more MPLS labels are added in front of the SINC header. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ \ | Label | TC |S| TTL | |M +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |P ~ ... ~ |L +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |S | Label | TC |S| TTL | / +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Reserved |D|L| Group ID | \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |S | No. of Data Sources | Data Source ID | |I +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |N | SeqNum | |C +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | Data Operation | Data Offset | / +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 7: SINC MPLS Header. 5.2. SINC over MPLS Workflow A simple example with one sender (Host A) and one receiver (Host B) is used to illustrate the workflow. Packet processing goes through the following steps: 1. Host A transmits a packet containing a SINC header together with data to the SINC Ingress Proxy. Lou, et al. Expires 27 August 2023 [Page 7] Internet-Draft SINC deployment considerations February 2023 2. Based on the LSP information obtained from control plane, the SINC Ingress Proxy builds up a SINC MPLS header pre-pended to the original packet. Then, according to the LSP information, the SINC packet is forwarded to the next hop. 3. The LSR forwards the packet based on the LSP information obtained from control plane. 4. As shown in Figure 6, when the packet reaches the SINC node, the LSP tunnel ID indicates that this packet contains a SINC header. The SINC SW/R pops up the label and hands the packet to in- network computing module. It is worth noting that the penultimate hop popping must be disabled. Otherwise, an additional mechanism is needed to signal to the SINC node that there is actually a SINC header in the packet. 5. The in-network computing module verifies the Group ID and Data Source ID in the SINC header, then preforms the required computation defined in the Data Operation field. When it is done, the payload is replaced with the result. The Operation Done flag will be set to 1. The SINC SW/R pushes a MPLS label to the packet. Finally, the packet is forwarded to the SINC egress proxy. 6. When the packet reaches the SINC Egress Proxy, it looks up the LSP information and realizes it is the egress. It pops up the MPLS label, replaces the innner SINC header with the outer SINC header, and forwards the inner packet to the final destination (Host B). 6. Security Considerations In-network computing exposes computing data to network devices, which inevitably raises security and privacy considerations. The security problems faced by in-network computing include, but are not limited to: * Trustworthiness of participating devices * Data hijacking and tampering * Private data exposure This documents assume that the deployment is done in a trusted environment. For example, in a data center network or a private network. Lou, et al. Expires 27 August 2023 [Page 8] Internet-Draft SINC deployment considerations February 2023 A fine security analysis will be provided in future revisions of this memo. 7. IANA Considerations This memo does not contain any request to IANA. Acknowledgements Dirk Trossen's feedbacks were of great help in improving this document. References Normative References [RFC2205] Braden, R., Ed., Zhang, L., Berson, S., Herzog, S., and S. Jamin, "Resource ReSerVation Protocol (RSVP) -- Version 1 Functional Specification", RFC 2205, DOI 10.17487/RFC2205, September 1997, . [RFC2784] Farinacci, D., Li, T., Hanks, S., Meyer, D., and P. Traina, "Generic Routing Encapsulation (GRE)", RFC 2784, DOI 10.17487/RFC2784, March 2000, . [RFC3031] Rosen, E., Viswanathan, A., and R. Callon, "Multiprotocol Label Switching Architecture", RFC 3031, DOI 10.17487/RFC3031, January 2001, . [RFC5036] Andersson, L., Ed., Minei, I., Ed., and B. Thomas, Ed., "LDP Specification", RFC 5036, DOI 10.17487/RFC5036, October 2007, . [RFC7498] Quinn, P., Ed. and T. Nadeau, Ed., "Problem Statement for Service Function Chaining", RFC 7498, DOI 10.17487/RFC7498, April 2015, . [RFC7665] Halpern, J., Ed. and C. Pignataro, Ed., "Service Function Chaining (SFC) Architecture", RFC 7665, DOI 10.17487/RFC7665, October 2015, . Lou, et al. Expires 27 August 2023 [Page 9] Internet-Draft SINC deployment considerations February 2023 [RFC8300] Quinn, P., Ed., Elzur, U., Ed., and C. Pignataro, Ed., "Network Service Header (NSH)", RFC 8300, DOI 10.17487/RFC8300, January 2018, . [RFC8926] Gross, J., Ed., Ganga, I., Ed., and T. Sridhar, Ed., "Geneve: Generic Network Virtualization Encapsulation", RFC 8926, DOI 10.17487/RFC8926, November 2020, . Informative References [I-D.zhou-rtgwg-sinc-00] Lou, Z., Iannone, L., Zhou, Y., Yang, J., and Zhangcuimin, "Signaling In-Network Computing operations (SINC)", Work in Progress, Internet-Draft, draft-zhou-rtgwg-sinc-00, 22 February 2023, . Authors' Addresses Zhe Lou Huawei Technologies Riesstrasse 25 80992 Munich Germany Email: zhe.lou@huawei.com Luigi Iannone Huawei Technologies France S.A.S.U. 18, Quai du Point du Jour 92100 Boulogne-Billancourt France Email: luigi.iannone@huawei.com Yujing Zhou Huawei Technologies Beiqing Road, Haidian District Beijing 100095 China Email: zhouyujing3@huawei.com Lou, et al. Expires 27 August 2023 [Page 10] Internet-Draft SINC deployment considerations February 2023 Jinze Yang Huawei Technologies Beiqing Road, Haidian District Beijing 100095 China Email: yangjinze@huawei.com Cuimin Zhang Huawei Technologies Huawei base in Bantian, Longgang District Shenzhen China Email: zhangcuimin@huawei.com Lou, et al. Expires 27 August 2023 [Page 11]