Internet DRAFT - draft-filsfils-spring-srv6-interop
draft-filsfils-spring-srv6-interop
SPRING C. Filsfils
Internet-Draft F. Clad, Ed.
Intended status: Informational P. Camarillo, Ed.
Expires: September 5, 2019 Cisco Systems, Inc.
A. AbdelSalam
Gran Sasso Science Institute
S. Salsano
Universita di Roma "Tor Vergata"
O. Bonaventure
Universite catholique de Louvain
J. Horn
J. Liste
Cisco
March 4, 2019
SRv6 interoperability report
draft-filsfils-spring-srv6-interop-02
Abstract
Segment Routing (SR) can be applied to the IPv6 data plane by
leveraging a new type of routing extension header, called Segment
Routing Header (SRH). An SRH contains an ordered list, or sequence,
of segments representing topological or service-based instructions,
or any combination of those.
This draft provides an overview of IPv6 Segment Routing (SRv6)
implementations and interoperability. It makes an inventory of the
various pieces of hardware and software that have been demonstrated
to support the processing of an SRH, and details some
interoperability scenarios that have been showcased at a public
event.
Status of This Memo
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Routing platforms supporting SRH processing . . . . . . . . . 3
3. Applications supporting SRH . . . . . . . . . . . . . . . . . 4
4. Interoperability testing . . . . . . . . . . . . . . . . . . 4
4.1. Testbed configuration . . . . . . . . . . . . . . . . . . 4
4.2. Scenarios . . . . . . . . . . . . . . . . . . . . . . . . 5
4.2.1. L3 VPN . . . . . . . . . . . . . . . . . . . . . . . 6
4.2.2. L3 VPN with traffic engineering . . . . . . . . . . . 6
4.2.3. L3 VPN with traffic engineering and service chaining 7
5. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 7
6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 7
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8
8. Security Considerations . . . . . . . . . . . . . . . . . . . 8
9. Informative References . . . . . . . . . . . . . . . . . . . 8
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 9
1. Introduction
Segment Routing (SR), defined in [RFC8402], allows a node to steer
packets through a controlled sequence of instructions, called
segments, by prepending an SR header to the packets. The IPv6
instantiation of Segment Routing (SRv6) leverages the Segment Routing
Header (SRH), a new type of IPv6 routing extension header defined in
[I-D.ietf-6man-segment-routing-header].
As described in [I-D.filsfils-spring-srv6-network-programming], an
SRv6 segment is a network instruction composed of a locator and a
function that is encoded as an IPv6 address. The segment locator is
an IPv6 prefix used by routing devices to steer the packet along the
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shortest IGP path up to the node that advertises this prefix. Since
the active segment is placed in the Destination Address field of the
IPv6 header, steering by intermediate devices only involves plain
IPv6 forwarding and does not require any SR-specific capability.
Once the packet reaches the node indicated by the segment locator,
the segment function is identified and the packet is processed
accordingly. Although the SR functions are locally defined on each
node, a set of general purpose functions have been proposed for
standardization in [I-D.filsfils-spring-srv6-network-programming] in
order to ease interoperability. This set is further extended with
specific purposes functions in [I-D.ietf-dmm-srv6-mobile-uplane] and
[I-D.xuclad-spring-sr-service-programming].
2. Routing platforms supporting SRH processing
The hardware and software platforms listed below have been
demonstrated to support the processing of an SRH as described in
[I-D.ietf-6man-segment-routing-header]. This section also indicates
the supported SRv6 functions and transit behaviors on open-source
software.
Open-source platforms:
o Linux kernel[ref-1][ref-2]: End, End.X, End.T, End.DX2, End.DX6,
End.DX4, End.DT6, End.B6, End.B6.Encaps, T.Insert, T.Encaps,
T.Encaps.L2
o Linux srext module: End, End.X, End.DX2, End.DX6, End.DX4, End.AD,
End.AM
o FD.io VPP: End, End.X, End.DX2, End.DX6, End.DX4, End.DT6,
End.DT4, End.B6, End.B6.Encaps, End.AS, End.AD, End.AM, T.Insert,
T.Encaps, T.Encaps.L2
Cisco:
o Cisco ASR 1000 with IOS XE engineering code
o Cisco ASR 9000 with IOS XR engineering code
o Cisco NCS 5500 with IOS XR engineering code
Barefoot Networks:
o Barefoot Networks Tofino
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3. Applications supporting SRH
In addition to the aforementioned routing platforms, the following
open-source applications have been extended to support the processing
of IPv6 packets containing an SRH. For Wireshark, tcpdump, iptables
and nftables, these extensions have been included in the mainstream
version.
o Wireshark[ref-3]
o tcpdump[ref-4]
o iptables[ref-5][ref-6]
o nftables[ref-7]
o Snort[ref-8]
4. Interoperability testing
The following interoperability testing scenarios were publicly
showcased on August 21-24, 2017 at the SIGCOMM conference.
Five different implementations of SRv6 behaviors were used for this
testing:
o Software implementation in Linux using the srext kernel module
created by University of Rome, Tor Vergata, Italy.
o Software implementation in the FD.io Vector Packet Processor (VPP)
virtual router.
o Hardware implementation in Barefoot Networks Tofino NPU using the
P4 programming language.
o Hardware implementation in Cisco NCS 5500 router using
commercially available NPU.
o Hardware implementation in Cisco ASR 1000 router using custom
ASIC.
4.1. Testbed configuration
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+--------+ +---+ +---+ +---+ +--------+
| Site A +-----+ 1 +--------+ 2 +--------+ 3 +-----+ Site B |
+--------+ +-+-+ +---+ +-+-+ +--------+
| |
| +---+ +---+ |
+-----+ 4 +-----+ 5 +-----+
+-+-+ +-+-+
| |
+-+-+ +-+-+
| 6 | | 7 |
+-+-+ +-+-+
| |
+-+-+ +-+-+
| 8 | | 9 |
+---+ +---+
Figure 1: Testbed topology
As shown in the figure above, the testbed consisted of 9 different
nodes:
o Nodes 1 and 3 are Cisco ASR 1000 routers running IOS XE
engineering code
o Node 2 is a Cisco ASR 9000 router (realizing IPv6 forwarding only)
o Node 4 is a Barefoot Wedge 100BF router
o Node 5 is a Cisco NCS 5500 router running IOS XR engineering code
o Node 6 is a Linux server running the srext kernel module
o Node 7 is a Linux server running the FD.io VPP
o Node 8 is a Linux container running Snort
o Node 9 is a Linux container running iptables
On sites A and B the TRex software is used for traffic generation.
In addition, after every layer 3 operation in the network, Wireshark
traffic analyzer is used to verify proper functionality.
4.2. Scenarios
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4.2.1. L3 VPN
This scenario covers simple L3 VPN functionality for IPv6 traffic
using the SRv6 behaviors T.Encaps and End.DX6 in conjunction with
regular IPv6 routing.
o IPv6 traffic is generated in site A and sent towards a destination
in site B.
o Node 1 performs the T.Encaps operation on the received traffic.
Each packet is encapsulated with an IPv6 header and an SRH
containing 1 segment, owned by node 3, then forwarded along the
shortest path to 3.
o Node 2 performs standard IPv6 forwarding.
o Node 3 performs the End.DX6 function on the received traffic.
Each packet is decapsulated then forwarded on the appropriate
interface towards site B.
o Traffic generator in site B captures and verifies the received
traffic.
4.2.2. L3 VPN with traffic engineering
This scenario covers L3 VPN overlay with underlay optimization in a
single SRv6 encapsulation (IPv6 header + SRH). It leverages the same
T.Encaps and End.DX6 behaviors as the first scenario, combined with
the End and End.X functions.
o IPv6 traffic is generated in site A and sent towards a destination
in site B.
o Node 1 performs the T.Encaps operation on the received traffic.
Each packet is encapsulated with an IPv6 header and an SRH
containing 3 segments, respectively owned by nodes 4, 5 and 3.
The outer IPv6 Destination Address is set to the first segment and
the packets are forwarded accordingly.
o Node 4 performs the End function, forwarding the packets on the
shortest paths towards node 5.
o Node 5 performs the End.X function, forwarding the packets on a
specific interface towards node 3.
o Node 3 performs the End.DX6, decapsulating and then forwarding
each packet on the appropriate interface towards site B.
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o Traffic generator in site B captures and verifies the received
traffic.
4.2.3. L3 VPN with traffic engineering and service chaining
This scenario covers L3 VPN overlay with underlay optimization and
service chaining. Snort and iptables are SR-unaware services in this
situation and accessed via SRv6 dynamic proxy endpoint functions
implemented on nodes 6 and 7.
o IPv6 traffic is generated in site A and sent towards a destination
in site B.
o Node 1 performs the T.Encaps operation on the received traffic.
Each packet is encapsulated with an IPv6 header and an SRH
containing 5 segments, respectively owned by nodes 4, 6, 5, 7 and
3. The outer IPv6 Destination Address is set to the first segment
and the packets are forwarded accordingly.
o Node 4 performs the End.X function, forwarding the packets on a
specific interface towards node 6.
o Node 6 performs the End.AD function, sending the inner IPv6 packet
via 8 (Snort) and restoring the encapsulation on the way back.
o Node 5 performs the End function, forwarding the packets on the
shortest paths towards node 7.
o Node 7 performs the End.AD function, sending the inner IPv6 packet
via 9 (iptables) and restoring the encapsulation on the way back.
o Node 3 performs the End.DX6, decapsulating and then forwarding
each packet on the appropriate interface towards site B.
o Traffic generator in site B captures and verifies the received
traffic.
5. Contributors
David Lebrun, Prem Jonnalagadda and Milad Sharif substantially
contributed to the content of this document.
6. Acknowledgements
TBD
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7. IANA Considerations
This document does not require any action from IANA.
8. Security Considerations
This document does not introduce any security consideration.
9. Informative References
[I-D.filsfils-spring-srv6-network-programming]
Filsfils, C., Camarillo, P., Leddy, J.,
daniel.voyer@bell.ca, d., Matsushima, S., and Z. Li, "SRv6
Network Programming", draft-filsfils-spring-srv6-network-
programming-07 (work in progress), February 2019.
[I-D.ietf-6man-segment-routing-header]
Filsfils, C., Previdi, S., Leddy, J., Matsushima, S., and
d. daniel.voyer@bell.ca, "IPv6 Segment Routing Header
(SRH)", draft-ietf-6man-segment-routing-header-16 (work in
progress), February 2019.
[I-D.ietf-dmm-srv6-mobile-uplane]
Matsushima, S., Filsfils, C., Kohno, M., Camarillo, P.,
daniel.voyer@bell.ca, d., and C. Perkins, "Segment Routing
IPv6 for Mobile User Plane", draft-ietf-dmm-srv6-mobile-
uplane-03 (work in progress), October 2018.
[I-D.xuclad-spring-sr-service-programming]
Clad, F., Xu, X., Filsfils, C., daniel.bernier@bell.ca,
d., Li, C., Decraene, B., Ma, S., Yadlapalli, C.,
Henderickx, W., and S. Salsano, "Service Programming with
Segment Routing", draft-xuclad-spring-sr-service-
programming-01 (work in progress), October 2018.
[ref-1] "Implementing IPv6 Segment Routing in the Linux Kernel",
July 2017, <https://doi.org/10.1145/3106328.3106329>.
[ref-2] "Reaping the Benefits of IPv6 Segment Routing", October
2017, <https://inl.info.ucl.ac.be/publications/
reaping-benefits-ipv6-segment-routing>.
[ref-3] "Add support for Segment Routing (Type 4) Extension
Header", June 2016, <https://code.wireshark.org/review/git
web?p=wireshark.git;a=commit;h=d6e9665872989c5f343fce47484
abe415d77486c>.
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[ref-4] "Add support for IPv6 routing header type 4", December
2017, <https://github.com/the-tcpdump-group/tcpdump/
commit/9c33608cb2fb6a64e1b76745efa530a63de08100>.
[ref-5] "[net-next,v2] netfilter: add segment routing header 'srh'
match", January 2018,
<https://patchwork.ozlabs.org/patch/856578/>.
[ref-6] "[iptables,v2] extensions: add support for 'srh' match",
January 2018,
<https://patchwork.ozlabs.org/patch/859206/>.
[ref-7] "[nft] nftables: Adding support for segment routing header
'srh'", March 2018,
<http://patchwork.ozlabs.org/patch/879061/>.
[ref-8] "IPv6 Segment Routing (SRv6) aware snort", March 2018,
<https://github.com/SRouting/sr-snort>.
[RFC8402] Filsfils, C., Ed., Previdi, S., Ed., Ginsberg, L.,
Decraene, B., Litkowski, S., and R. Shakir, "Segment
Routing Architecture", RFC 8402, DOI 10.17487/RFC8402,
July 2018, <https://www.rfc-editor.org/info/rfc8402>.
Authors' Addresses
Clarence Filsfils
Cisco Systems, Inc.
Belgium
Email: cf@cisco.com
Francois Clad (editor)
Cisco Systems, Inc.
France
Email: fclad@cisco.com
Pablo Camarillo Garvia (editor)
Cisco Systems, Inc.
Spain
Email: pcamaril@cisco.com
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Ahmed AbdelSalam
Gran Sasso Science Institute
Italy
Email: ahmed.abdelsalam@gssi.it
Stefano Salsano
Universita di Roma "Tor Vergata"
Italy
Email: stefano.salsano@uniroma2.it
Olivier Bonaventure
Universite catholique de Louvain
Belgium
Email: olivier.bonaventure@uclouvain.be
Jakub Horn
Cisco
USA
Email: jakuhorn@cisco.com
Jose Liste
Cisco
USA
Email: jliste@cisco.com
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