| 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
This document illustrates the SRv6 "micro segment" (SRv6 uSID or uSID for short) instruction.
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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.
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.
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
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:
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.
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:
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:
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:
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.
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 Semco, Bertrand Duvivier, Frederic Trate, Kris Michielsen, Eyal Dagan, Eli Stein, Ofer Iny, Elad Naor, Aviad Behar, Joseph Chin.
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
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
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
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
| [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", Internet-Draft draft-filsfils-spring-net-pgm-extension-srv6-usid-03, 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", Internet-Draft draft-filsfils-spring-srv6-net-pgm-illustration-01, August 2019. |
| [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)", Internet-Draft draft-ietf-6man-segment-routing-header-26, 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", Internet-Draft draft-ietf-spring-srv6-network-programming-09, February 2020. |