SPRING C. Filsfils, Ed. Internet-Draft P. Camarillo, Ed. Intended status: Informational Cisco Systems, Inc. Expires: August 28, 2020 D. Cai Alibaba D. Voyer Bell Canada I. Meilik Broadcom K. Patel Arrcus, Inc. W. Henderickx Nokia P. Jonnalagadda Barefoot Networks D. Melman Marvell February 25, 2020 NET-PGM extension: SRv6 uSID illustration draft-filsfils-spring-net-pgm-srv6-usid-illus-00 Abstract This document illustrates the SRv6 "micro segment" (SRv6 uSID or uSID for short) instruction. 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/. 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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 2. Illustration . . . . . . . . . . . . . . . . . . . . . . . . 2 2.1. Reference diagram . . . . . . . . . . . . . . . . . . . . 3 2.2. SRv6 overlay with underlay optimization . . . . . . . . . 3 3. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 4 4. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 5 5. References . . . . . . . . . . . . . . . . . . . . . . . . . 8 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 9 1. Introduction SRv6 Network Programming [I-D.ietf-spring-srv6-network-programming] defines a mechanism to build a network program with topological and service segments. It leverages the SRH [I-D.ietf-6man-segment-routing-header] to encode a network program together with optional metadata shared among the different SIDs. [I-D.filsfils-spring-net-pgm-extension-srv6-usid] draft extends SRv6 Network Programming with a new type of SRv6 SID behavior: SRv6 uN. This document illustrates it. 2. Illustration This section extends the illustrations for SRv6 Network Programming [I-D.filsfils-spring-srv6-net-pgm-illustration] to cover uSID. The reference topology is the same with the addition of link 6-8. Filsfils, et al. Expires August 28, 2020 [Page 2] Internet-Draft NET-PGM extension: SRv6 uSID illustration February 2020 2.1. Reference diagram Nodes 1 to 8 are considered within the network domain. Nodes X and Y are outside the domain. Nodes 1 and 8 act as PE respectively to nodes X and Y. All the links within the domain have the same IGP metric. The IGP- metric shortest-path from 1 to 8 is 1-2-7-8 while the latency-metric shortest-path from 1 to 8 is 1-2-3-4-5-6-7-8. 3------4---5 | \ / | 6 | / \ 1--- 2------7---8 / \ X Y Tenant100 Tenant100 with IPv4 20/8 Figure 1: Reference topology 2.2. SRv6 overlay with underlay optimization Let us illustrate a low-latency SR-L3VPN service delivered to a packet (X,Y). PE 1 encapsulates (X, Y) in an outer IPv6 header with DA = 2001:db8:0300:0500:0700:: and SRH (B:8:D0::; SL=1; NH=4). Leveraging the illustration conventions from SRv6 network programming, the following resulting packet leaves node 1 in the direction of node 3: (A1::, 2001:db8:0300:0500:0700::)(B:8:D0::; SL=1; NH=4)(X, Y) 2001:db8:0300:0500:0700:: is a uSID carrier encoding a source routed stateless path via node 3 then 5 then 7. B:8:D0:: is an End.DT4 SID instantiated at node 8. 1 sends this packet to 2, as 2 is on the shortest-path to 2001:db8:0300::/48 advertised by 3. When 2 receives the packet, 2 performs a regular IPv6 FIB lookup. It finds a FIB entry for 2001:db8:0300::/48 and forwards along the shortest path to 3. Filsfils, et al. Expires August 28, 2020 [Page 3] Internet-Draft NET-PGM extension: SRv6 uSID illustration February 2020 When 3 receives the packet, 3 matches 2001:db8:0300::/48 in its "My SID Table" and executes the uN behavior. The updated DA becomes 2001:db8:0500:0700::. Node 3 then performs a lookup on the updated DA and forwards the packet to 5 along the shortest path to 2001:db8:0500::/48. The following packet leaves node 3: (A1::, 2001:db8:0500:0700::)(B:8:D0::; SL=1; NH=4)(X, Y) 4 forwards along the shortest path to 2001:db8:0500::/48. When 5 receives the packet, 5 matches 2001:db8:0500::/48 in its "My SID Table" and executes the uN behavior. The updated DA becomes 2001:db8:0700::. 5 performs a lookup on the updated DA and forwards the packet to 7 along the shortest path to 2001:db8:0700::/48. The following packet leaves node 5: (A1::, 2001:db8:0700::)(B:8:D0::; SL=1; NH=4)(X, Y) 6 forwards along the shortest path to 2001:db8:0700::/48. When 7 receives the packet, 7 matches 2001:db8:0700::/48 in its "My SID Table" and finds the bound function uN. As a result, Node 7 executes the "End with PSP and USD support" pseudocode, decrementing the SL value in the SRH, and updating the DA with the next SID B:8:D0::. Since the SL value is zero the SRH is removed. Node 7 performs a lookup on the updated DA and forwards along the shortest path. The following packet leaves node 7: (A1::, B:8:D0::)(X, Y) 8 receives it, performs the End.DT4 function and sends the IP packet (X, Y) towards its VPN destination. This example illustrates the benefits highlighted in the next section. 3. Acknowledgements The authors would like to acknowledge Francois Clad, Peter Psenak, Ketan Talaulikar, Jakub Horn, Swadesh Agrawal, Zafar Ali, Darren Dukes, Kiran Sadshiran, Junaid Israr, Lakshmanan Srikanth, Asif Islam, Saleem Hafeez, Michael MacKenzie, Sushek Shekar, YuanChao Su, Alexander Preusche, Alberto Donzelli, Miya Kohno, David Smith, Ianik Filsfils, et al. Expires August 28, 2020 [Page 4] Internet-Draft NET-PGM extension: SRv6 uSID illustration February 2020 Semco, Bertrand Duvivier, Frederic Trate, Kris Michielsen, Eyal Dagan, Eli Stein, Ofer Iny, Elad Naor, Aviad Behar, Joseph Chin. 4. Contributors Jisu Bhattacharyaa Cisco Systems, Inc. United States of America Email: jisu@cisco.com Kamran Raza Cisco Systems, Inc. Canada Email: skraza@cisco.com John Bettink Cisco Systems, Inc. United States of America Email: jbettink@cisco.com Tomonobu Niwa KDDI Japan Email: to-niwa@kddi.com Luay Jalil Verizon United States of America Email: luay.jalil@one.verizon.com Zhichun Jiang Tencent China Filsfils, et al. Expires August 28, 2020 [Page 5] Internet-Draft NET-PGM extension: SRv6 uSID illustration February 2020 Email: zcjiang@tencent.com Ahmed Shawky Saudi Telecom Company Saudi Arabia Email: ashawky@stc.com.sa Nic Leymann Deutsche Telekom Germany Email: N.Leymann@telekom.de Dirk Steinberg Lapishills Consulting Limited Cyprus Email: dirk@lapishills.com Shawn Zandi LinkedIn United States of America Email: szandi@linkedin.com Gaurav Dawra LinkedIn United States of America Email: gdawra@linkedin.com Jim Uttaro AT&T United States of America Filsfils, et al. Expires August 28, 2020 [Page 6] Internet-Draft NET-PGM extension: SRv6 uSID illustration February 2020 Email: ju1738@att.com Ning So Reliance United States of America Email: Ning.So@ril.com Michael Fiumano Sprint United States of America Email: michael.f.fiumano@sprint.com Mazen Khaddam Cox United States of America Email: Mazen.Khaddam@cox.com Jichun Ma China Unicom China Email: majc16@chinaunicom.cn Satoru Matsushima Softbank Japan Email: satoru.matsushima@g.softbank.co.jp Francis Ferguson CenturyLink United States of America Filsfils, et al. Expires August 28, 2020 [Page 7] Internet-Draft NET-PGM extension: SRv6 uSID illustration February 2020 Email: Francis.Ferguson@centurylink.com Takuya Miyasaka KDDI Japan Email: ta-miyasaka@kddi.com Kentaro Ebisawa Toyota Motor Corporation Japan Email: ebisawa@toyota-tokyo.tech Yukito Ueno NTT Communications Corporation Japan Email: yukito.ueno@ntt.com 5. References [I-D.filsfils-spring-net-pgm-extension-srv6-usid] Filsfils, C., Camarillo, P., Cai, D., Voyer, D., Meilik, I., Patel, K., Henderickx, W., Jonnalagadda, P., and D. Melman, "Network Programming extension: SRv6 uSID instruction", draft-filsfils-spring-net-pgm-extension- srv6-usid-03 (work in progress), February 2020. [I-D.filsfils-spring-srv6-net-pgm-illustration] Filsfils, C., Camarillo, P., Li, Z., Matsushima, S., Decraene, B., Steinberg, D., Lebrun, D., Raszuk, R., and J. Leddy, "Illustrations for SRv6 Network Programming", draft-filsfils-spring-srv6-net-pgm-illustration-01 (work in progress), August 2019. Filsfils, et al. Expires August 28, 2020 [Page 8] Internet-Draft NET-PGM extension: SRv6 uSID illustration February 2020 [I-D.ietf-6man-segment-routing-header] Filsfils, C., Dukes, D., Previdi, S., Leddy, J., Matsushima, S., and D. Voyer, "IPv6 Segment Routing Header (SRH)", draft-ietf-6man-segment-routing-header-26 (work in progress), October 2019. [I-D.ietf-spring-srv6-network-programming] Filsfils, C., Camarillo, P., Leddy, J., Voyer, D., Matsushima, S., and Z. Li, "SRv6 Network Programming", draft-ietf-spring-srv6-network-programming-10 (work in progress), February 2020. Authors' Addresses Clarence Filsfils (editor) Cisco Systems, Inc. Belgium Email: cf@cisco.com Pablo Camarillo Garvia (editor) Cisco Systems, Inc. Spain Email: pcamaril@cisco.com Dennis Cai Alibaba China Email: d.cai@alibaba-inc.com Daniel Voyer Bell Canada Canada Email: daniel.voyer@bell.ca Israel Meilik Broadcom Israel Email: israel.meilik@broadcom.com Filsfils, et al. Expires August 28, 2020 [Page 9] Internet-Draft NET-PGM extension: SRv6 uSID illustration February 2020 Keyur Patel Arrcus, Inc. United States of America Email: keyur@arrcus.com Wim Henderickx Nokia Belgium Email: wim.henderickx@nokia.com Prem Jonnalagadda Barefoot Networks United States of America Email: prem@barefootnetworks.com David Melman Marvell Israel Email: davidme@marvell.com Filsfils, et al. Expires August 28, 2020 [Page 10]