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NVO3  Working Group                                          G. Fioccola
Internet-Draft                                            Telecom Italia
Intended status: Standards Track                               G. Mirsky
Expires: December 27, 2018                                     ZTE Corp.
                                                              T. Mizrahi
                                                                 Marvell
                                                           June 25, 2018


     Performance Measurement (PM) with Alternate Marking in Network
                     Virtualization Overlays (NVO3)
                     draft-fmm-nvo3-pm-alt-mark-02

Abstract

   This document describes how the alternate marking method can be used
   for performance measurement method in a Network Virtualization
   Overlays (NVO3) Domain.  The description aims to be general for NVO3
   encapsulations, but is focused to Geneve, recommended by the NVO3
   design team [I-D.ietf-nvo3-encap].

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
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   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on December 27, 2018.

Copyright Notice

   Copyright (c) 2018 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



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   to this document.  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.  Conventions used in this document . . . . . . . . . . . . . .   2
     2.1.  Terminology . . . . . . . . . . . . . . . . . . . . . . .   3
     2.2.  Requirements Language . . . . . . . . . . . . . . . . . .   3
   3.  OAM Performance Measurement in a NVO3 Domain  . . . . . . . .   3
   4.  The Mark Field in the NVO3 Header . . . . . . . . . . . . . .   5
   5.  Theory of Operation . . . . . . . . . . . . . . . . . . . . .   6
     5.1.  Single Mark Enabled Measurement . . . . . . . . . . . . .   6
     5.2.  Double Mark Enabled Measurement . . . . . . . . . . . . .   7
     5.3.  Multiplexed Mark Enabled Measurement  . . . . . . . . . .   8
   6.  Multipoint Measurement Considerations . . . . . . . . . . . .   8
   7.  The Mark Field in Geneve  . . . . . . . . . . . . . . . . . .   8
   8.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   9
     8.1.  Mark Field in Geneve Header . . . . . . . . . . . . . . .   9
   9.  Security Considerations . . . . . . . . . . . . . . . . . . .   9
   10. Acknowledgement . . . . . . . . . . . . . . . . . . . . . . .   9
   11. References  . . . . . . . . . . . . . . . . . . . . . . . . .   9
     11.1.  Normative References . . . . . . . . . . . . . . . . . .   9
     11.2.  Informative References . . . . . . . . . . . . . . . . .  10
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  11

1.  Introduction

   [RFC7365] provides a framework for Data Center (DC) Network
   Virtualization over Layer 3 (NVO3) tunnels.  It is intended to aid in
   standardizing protocols and mechanisms to support large-scale network
   virtualization for data centers.

   [RFC8321] describes a performance measurement method, which can be
   used to measure packet loss, latency, and jitter on live traffic.
   Since this method is based on marking consecutive batches of packets
   the method often referred to as the Alternate Marking Method (AMM).

   This document defines how the alternate marking method can be used to
   measure packet loss and delay metrics of an NVO3 Domain.

2.  Conventions used in this document







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2.1.  Terminology

   AMM: Alternate Marking Method

   OAM: Operations, Administration and Maintenance

   NVO3: Network Virtualization Overlays

   NVE: Network Virtualization Edge

   VNI: Virtual Network Instance

   DC: Data Center

   NVA: Network Virtualization Authority

   Geneve: Generic Network Virtualization Encapsulation

   VXLAN: Virtual Extensible LAN

   GUE: Generic UDP Encapsulation

2.2.  Requirements Language

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
   "OPTIONAL" in this document are to be interpreted as described in BCP
   14 [RFC2119] [RFC8174] when, and only when, they appear in all
   capitals, as shown here.

3.  OAM Performance Measurement in a NVO3 Domain

   Figure 1 shows the generic reference model for a DC network
   virtualization over an L3 infrastructure while Figure 2 shows the
   generic reference model for the Network Virtualization Edge (NVE).
   Both Figures are taken from [RFC7365] and [RFC8014].















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            +--------+                                    +--------+
            | Tenant +--+                            +----| Tenant |
            | System |  |                           (')   | System |
            +--------+  |    .................     (   )  +--------+
                        |  +---+           +---+    (_)
                        +--|NVE|---+   +---|NVE|-----+
                           +---+   |   |   +---+
                           / .    +-----+      .
                          /  . +--| NVA |--+   .
                         /   . |  +-----+   \  .
                        |    . |             \ .
                        |    . |   Overlay   +--+--++--------+
            +--------+  |    . |   Network   | NVE || Tenant |
            | Tenant +--+    . |             |     || System |
            | System |       .  \ +---+      +--+--++--------+
            +--------+       .....|NVE|.........
                                  +---+
                                    |
                                    |
                          =====================
                            |               |
                        +--------+      +--------+
                        | Tenant |      | Tenant |
                        | System |      | System |
                        +--------+      +--------+

      Figure 1: Generic Reference Model for DC Network Virtualization
                            Overlays (RFC7365)

                        +-------- L3 Network -------+
                        |                           |
                        |        Tunnel Overlay     |
            +------------+---------+       +---------+------------+
            | +----------+-------+ |       | +---------+--------+ |
            | |  Overlay Module  | |       | |  Overlay Module  | |
            | +---------+--------+ |       | +---------+--------+ |
            |           |VN Context|       | VN Context|          |
            |           |          |       |           |          |
            |  +--------+-------+  |       |  +--------+-------+  |
            |  | |VNI|   .  |VNI|  |       |  | |VNI|   .  |VNI|  |
       NVE1 |  +-+------------+-+  |       |  +-+-----------+--+  | NVE2
            |    |   VAPs     |    |       |    |    VAPs   |     |
            +----+------------+----+       +----+-----------+-----+
                 |            |                 |           |
                 |            |                 |           |
                Tenant Systems                 Tenant Systems

              Figure 2: Generic NVE Reference Model (RFC7365)



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   L3 networks provide transport for an emulated Layer 2 created by NVE
   devices.  The connectivity between the NVE devices is achieved with
   unicast and multicast tunneling methods.  Then, the NVE devices
   present an emulated Layer 2 network to the Tenant End Systems at a
   Virtual Network Instance (VNI) through Virtual Access Points (VAPs).
   The NVE devices map Layer 2 unicast to Layer 3 unicast point-to-point
   tunnels and may either map Layer 2 multicast to Layer 3 multicast
   tunnels or may replicate packets onto multiple Layer 3 unicast
   tunnels.

   The emulated Layer 2 network is provided by the NVE devices to which
   the Tenant End Systems are connected.  This network of NVE can be
   operated by a single service provider or can span across multiple
   administrative domains.  Likewise, the L3 Overlay Network can be
   operated by a single service provider or span across multiple
   administrative domains.

   Each of the layers is responsible for its own OAM.  Complex OAM
   relationships exist as a result of the hierarchical layering, but
   this is out of scope here.

   When we refer to an OAM domain considered in this document we refer
   to a set of NVEs and the tunnels which interconnect them.

   It is commonly agreed that NVO3 OAM Performance Management supports
   measurements (packet loss, latency, and jitter) per VNI between two
   NVE devices that support the same VNI within a given NVO3 domain.

4.  The Mark Field in the NVO3 Header

   This document defines a two-bit long field, referred to as Mark field
   (M), as part of the NVO3 Header and designated for the alternate
   marking performance measurement method [RFC8321].  The Mark field
   MUST NOT be used in defining forwarding and/or quality of service
   treatment of an NVO3 packet.  The Mark field MUST be used only for
   the performance measurement of data traffic in the NVO3 layer.  Since
   the field does not affect forwarding and/or quality of service
   treatment of packets, the alternate marking method in the NVO3 layer
   can be viewed as nearly-passive performance measurement method.

   Figure 3 displays the format of the Mark field.










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    0
    0   1
   +-+-+-+-+
   | L | D |
   +-+-+-+-+

                      Figure 3: Mark field (M) format

   where:

   o  L - Loss bit;

   o  D - Delay bit.

5.  Theory of Operation

   The marking method can be used in NVO3.  For example, one can
   consider the NVO3 reference model presented in Figure 1.  AMM can be
   applied at either ingress or egress NVE to detect performance
   degradation defect and localize it efficiently.

   Using AMM, NVE1 creates distinct sub-flows.  Each sub-flow consists
   of consecutive blocks that are unambiguously recognizable by a
   monitoring point at any component of the NVO3, e.g.  NVE2 or NVE3,
   and can be measured to calculate packet loss and/or packet delay
   metrics.

   Every NVO3 Header [I-D.ietf-nvo3-geneve], [I-D.ietf-nvo3-vxlan-gpe]
   and [I-D.ietf-nvo3-gue] can be considered for the application of AMM.

5.1.  Single Mark Enabled Measurement

   As explained in the [RFC8321], marking can be applied to delineate
   blocks of packets based either on the equal number of packets in a
   block or based on equal time interval.  The latter method offers
   better control as it allows better account for capabilities of
   downstream nodes to report statistics related to batches of packets
   and, at the same time, time resolution that affects defect detection
   interval.

   If the Single Mark measurement used, then the D flag MUST be set to
   zero on transmit and ignored by monitoring point.

   The L flag is used to create alternate flows to measure the packet
   loss by switching the value of the L flag every N-th packet or at
   certain time intervals.  Delay metrics MAY be calculated with the
   alternate flow using any of the following methods:




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   o  First/Last Packet Delay calculation: whenever the marking, i.e.
      the value of L flag, changes a component of the NVO3 can store the
      timestamp of the first/last packet of the block.  The timestamp
      can be compared with the timestamp of the packet that arrived in
      the same order through a monitoring point at a downstream
      component of the NVO3 to compute packet delay.  Because timestamps
      collected based on order of arrival this method is sensitive to
      packet loss and re-ordering of packets

   o  Average Packet Delay calculation: an average delay is calculated
      by considering the average arrival time of the packets within a
      single block.  A component of the NVO3 may collect timestamps for
      each packet received within a single block.  Average of the
      timestamp is the sum of all the timestamps divided by the total
      number of packets received.  Then the difference between averages
      calculated at two monitoring points is the average packet delay on
      that segment.  This method is robust to out of order packets and
      also to packet loss (only a small error is introduced).  This
      method only provides a single metric for the duration of the block
      and it doesn't give the minimum and maximum delay values.  This
      limitation could be overcome by reducing the duration of the block
      by means of a highly optimized implementation of the method.

5.2.  Double Mark Enabled Measurement

   Double Mark method allows measurement of minimum and maximum delays
   for the monitored flow but it requires more nodal and network
   resources.  If the Double Mark method used, then the L flag MUST be
   used to create the alternate flow, i.e. mark larger batches of
   packets.  The D flag MUST be used to mark single packets to measure
   delay jitter.

   The first marking (L flag alternation) is needed for packet loss and
   also for average delay measurement.  The second marking (D flag is
   put to one) creates a new set of marked packets that are fully
   identified over NVO3, so that a component can store the timestamps of
   these packets; these timestamps can be compared with the timestamps
   of the same packets on another component of the NVO3 to compute
   packet delay values for each packet.  The number of measurements can
   be easily increased by changing the frequency of the second marking.
   But the frequency of the second marking must be not too high in order
   to avoid out of order issues.  This method is suitable to have not
   only the average delay but also the minimum and maximum delay values
   and, in wider terms, to know more about the statistic distribution of
   delay values.






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5.3.  Multiplexed Mark Enabled Measurement

   There is also a scheme that provides the benefits of Double Mark
   method, but uses only one bit like Single Mark.  This methodology is
   described in [I-D.mizrahi-ippm-compact-alternate-marking].  The
   concept is that in the middle of each block of packets with a certain
   value of the L flag, a single packet has the L flag inverted.  So, by
   examining the stream, the packets with the inverted bit can be easily
   identified and employed for delay measurement.  This Alternate
   Marking variation is advantageous because it requires only one bit
   from each packet, and such bits are always in short supply.

6.  Multipoint Measurement Considerations

   The Multipoint characteristics of the traffic within a given NVO3
   Domain could be considered a valuable Use Case of
   [I-D.fioccola-ippm-multipoint-alt-mark].

7.  The Mark Field in Geneve

   [I-D.ietf-nvo3-geneve] defines the format of the Geneve Header.

   The design team recommendations in [I-D.ietf-nvo3-encap] section 7
   concluded that Geneve is most suitable as a starting point for the
   proposed standard for network virtualization.

   In addition, the design team recommended addressing requirements for
   OAM considerations for alternate marking and for performance
   measurements that need 2 bits in the header.  This document clarifies
   the need for the current OAM bit in the Geneve Header.

     Geneve Header:
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |Ver|  Opt Len  |O|C| M | Rsvd. |          Protocol Type        |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |        Virtual Network Identifier (VNI)       |    Reserved   |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                    Variable Length Options                    |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                          Figure 4: Geneve Header

   This document defines a two-bit long field, referred to as the Mark
   field (M in Figure 4, as part of Geneve and designated for the
   alternate marking performance measurement method [RFC8321].  The Mark
   field MUST NOT be used in defining forwarding and/or quality of
   service treatment of a NVO3 packet.  The Mark field MUST be used only
   for the performance measurement of data traffic in the NVO3 layer.



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   Since the field does not affect forwarding and/or quality of service
   treatment of packets, the alternate marking method in the NVO3 layer
   can be viewed as nearly-passive performance measurement method.

8.  IANA Considerations

8.1.  Mark Field in Geneve Header

   This document requests IANA to allocate Mark field as two bits-long
   field from Geneve Header Reserved Bits [I-D.ietf-nvo3-geneve].

   This document requests IANA to register values of the Mark field of
   Geneve as the following:

   +--------------+---------+--------------------------+---------------+
   | Bit Position | Marking | Description              | Reference     |
   +--------------+---------+--------------------------+---------------+
   |      0       |    L    | Single Mark Measurement  | This document |
   |      1       |    D    | Double Mark Measurement  | This document |
   +--------------+---------+--------------------------+---------------+

                       Table 1: Mark field of Geneve

9.  Security Considerations

   This document lists the OAM requirement for the NVO3 domain and does
   not raise any security concerns or issues in addition to ones common
   to networking and NVO3.

10.  Acknowledgement

   The authors would like to thank Dale R.  Worley for the contribution.

11.  References

11.1.  Normative References

   [I-D.ietf-nvo3-encap]
              Boutros, S., Ganga, I., Garg, P., Manur, R., Mizrahi, T.,
              Mozes, D., Nordmark, E., Smith, M., Aldrin, S., and I.
              Bagdonas, "NVO3 Encapsulation Considerations", draft-ietf-
              nvo3-encap-01 (work in progress), October 2017.

   [I-D.ietf-nvo3-geneve]
              Gross, J., Ganga, I., and T. Sridhar, "Geneve: Generic
              Network Virtualization Encapsulation", draft-ietf-
              nvo3-geneve-06 (work in progress), March 2018.




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   [I-D.ietf-nvo3-gue]
              Herbert, T., Yong, L., and O. Zia, "Generic UDP
              Encapsulation", draft-ietf-nvo3-gue-05 (work in progress),
              October 2016.

   [I-D.ietf-nvo3-vxlan-gpe]
              Maino, F., Kreeger, L., and U. Elzur, "Generic Protocol
              Extension for VXLAN", draft-ietf-nvo3-vxlan-gpe-06 (work
              in progress), April 2018.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <https://www.rfc-editor.org/info/rfc2119>.

   [RFC8174]  Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
              2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
              May 2017, <https://www.rfc-editor.org/info/rfc8174>.

11.2.  Informative References

   [I-D.fioccola-ippm-multipoint-alt-mark]
              Fioccola, G., Cociglio, M., Sapio, A., and R. Sisto,
              "Multipoint Alternate Marking method for passive and
              hybrid performance monitoring", draft-fioccola-ippm-
              multipoint-alt-mark-03 (work in progress), June 2018.

   [I-D.mizrahi-ippm-compact-alternate-marking]
              Mizrahi, T., Arad, C., Fioccola, G., Cociglio, M., Chen,
              M., Zheng, L., and G. Mirsky, "Compact Alternate Marking
              Methods for Passive and Hybrid Performance Monitoring",
              draft-mizrahi-ippm-compact-alternate-marking-01 (work in
              progress), March 2018.

   [RFC7365]  Lasserre, M., Balus, F., Morin, T., Bitar, N., and Y.
              Rekhter, "Framework for Data Center (DC) Network
              Virtualization", RFC 7365, DOI 10.17487/RFC7365, October
              2014, <https://www.rfc-editor.org/info/rfc7365>.

   [RFC8014]  Black, D., Hudson, J., Kreeger, L., Lasserre, M., and T.
              Narten, "An Architecture for Data-Center Network
              Virtualization over Layer 3 (NVO3)", RFC 8014,
              DOI 10.17487/RFC8014, December 2016,
              <https://www.rfc-editor.org/info/rfc8014>.







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   [RFC8321]  Fioccola, G., Ed., Capello, A., Cociglio, M., Castaldelli,
              L., Chen, M., Zheng, L., Mirsky, G., and T. Mizrahi,
              "Alternate-Marking Method for Passive and Hybrid
              Performance Monitoring", RFC 8321, DOI 10.17487/RFC8321,
              January 2018, <https://www.rfc-editor.org/info/rfc8321>.

Authors' Addresses

   Giuseppe Fioccola
   Telecom Italia
   Via Reiss Romoli, 274
   Torino  10148
   Italy

   Email: giuseppe.fioccola@telecomitalia.it


   Greg Mirsky
   ZTE Corp.

   Email: gregimirsky@gmail.com


   Tal Mizrahi
   Marvell
   6 Hamada St.
   Yokneam
   Israel

   Email: talmi@marvell.com





















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