SPRING                                                     D. Dukes, Ed.
Internet-Draft                                               C. Filsfils
Intended status: Informational                              P. Camarillo
Expires: January 9, 2020                             Cisco Systems, Inc.
                                                            July 8, 2019

     Comparative Analysis of MTU overhead in the context of SPRING


   This document provides an apples-to-apples comparative analysis of
   MTU overhead in the context of SPRING.

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  Stateless IPv6 Encapsulation Within a VPN Context . . . .   2
       1.1.1.  Analysis of MTU overhead  . . . . . . . . . . . . . .   2
   2.  Informative References  . . . . . . . . . . . . . . . . . . .   3
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   3

1.  Introduction

   This document provides an apples-to-apples comparative analysis of
   MTU overhead in the context of SPRING.

   The first version of this document concentrates on stateless IPv6
   encapsulation within a VPN context.

1.1.  Stateless IPv6 Encapsulation Within a VPN Context

   A VPN context provides routing and forwarding isolation at interface
   granularity on a Provider Edge (PE) node.

   Encapsulation between PE nodes is used to forward traffic between the
   VPN contexts of remote nodes.  Typically, this encapsulation encodes
   the remote node address and VPN context.

   Stateless encapsulation requires no additional state be propagated
   between PE and provider (P) nodes.

1.1.1.  Analysis of MTU overhead

   VXLAN [RFC7348], LISP [RFC6830], GTP and SRv6
   [I-D.filsfils-spring-srv6-network-programming] encapsulations are
   considered as they provide stateless encapsulation while supporting
   VPN contexts.

   VXLAN, LISP, and GTP encapsulate all add VPN context via UDP.

   o  VXLAN: 56 bytes : IPv6(40) + UDP(8) + VXLAN(8)

   o  LISP: 56 bytes : IPv6(40) + UDP(8) + LISP(8)

   o  GTP: 56 bytes : IPv6(40) + UDP(8) + GTP(8)

   SRv6 encapsulates and includes the VPN context with the destination

   o  SRv6: 40 bytes : IPv6(40)

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   The SRv6 VPN SID encodes location and VPN context so IPv6
   encapsulation is all that's required for the SRv6 case, i.e. there is
   no Segment Routing Extension Header (SRH)
   [I-D.ietf-6man-segment-routing-header] required.

   SRv6 results in a lower overhead than VXLAN, LISP, and GTP for
   stateless encapsulation within a VPN context.

2.  Informative References

              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.

              Filsfils, C., Dukes, D., Previdi, S., Leddy, J.,
              Matsushima, S., and d. daniel.voyer@bell.ca, "IPv6 Segment
              Routing Header (SRH)", draft-ietf-6man-segment-routing-
              header-21 (work in progress), June 2019.

   [RFC6830]  Farinacci, D., Fuller, V., Meyer, D., and D. Lewis, "The
              Locator/ID Separation Protocol (LISP)", RFC 6830,
              DOI 10.17487/RFC6830, January 2013,

   [RFC7348]  Mahalingam, M., Dutt, D., Duda, K., Agarwal, P., Kreeger,
              L., Sridhar, T., Bursell, M., and C. Wright, "Virtual
              eXtensible Local Area Network (VXLAN): A Framework for
              Overlaying Virtualized Layer 2 Networks over Layer 3
              Networks", RFC 7348, DOI 10.17487/RFC7348, August 2014,

Authors' Addresses

   Darren Dukes (editor)
   Cisco Systems, Inc.

   Email: ddukes@cisco.com

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   Clarence Filsfils
   Cisco Systems, Inc.

   Email: cfilsfil@cisco.com

   Pablo Camarillo
   Cisco Systems, Inc.

   Email: pcamaril@cisco.com

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