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Versions: (draft-mirsky-bier-pmmm-oam) 00 01 02

BIER  Working Group                                            G. Mirsky
Internet-Draft                                                 ZTE Corp.
Intended status: Standards Track                                L. Zheng
Expires: January 19, 2018                                        M. Chen
                                                     Huawei Technologies
                                                             G. Fioccola
                                                          Telecom Italia
                                                           July 18, 2017


 Performance Measurement (PM) with Marking Method in Bit Index Explicit
                        Replication (BIER) Layer
                      draft-ietf-bier-pmmm-oam-02

Abstract

   This document describes a hybrid performance measurement method for
   multicast service over Bit Index Explicit Replication (BIER) domain.

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
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   Drafts is at http://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
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   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on January 19, 2018.

Copyright Notice

   Copyright (c) 2017 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
   (http://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
   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of



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   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 . . . . . . . . . . . . . . . . . . . . . . .   2
     2.2.  Requirements Language . . . . . . . . . . . . . . . . . .   3
   3.  OAM Field in BIER Header  . . . . . . . . . . . . . . . . . .   3
   4.  Theory of Operation . . . . . . . . . . . . . . . . . . . . .   4
     4.1.  Single Mark Enabled Measurement . . . . . . . . . . . . .   4
     4.2.  Double Mark Enabled Measurement . . . . . . . . . . . . .   5
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   6
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .   6
   7.  Acknowledgement . . . . . . . . . . . . . . . . . . . . . . .   6
   8.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   6
     8.1.  Normative References  . . . . . . . . . . . . . . . . . .   6
     8.2.  Informative References  . . . . . . . . . . . . . . . . .   7
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   7

1.  Introduction

   [I-D.ietf-bier-architecture] introduces and explains Bit Index
   Explicit Replication (BIER) architecture and how it supports
   forwarding of multicast data packets.
   [I-D.ietf-bier-mpls-encapsulation] specified that in case of BIER
   encapsulation in MPLS network a BIER-MPLS label, label that is at the
   bottom of the label stack, uniquely identifies the multicast flow.
   [I-D.ietf-ippm-alt-mark] describes hybrid performance measurement
   method, per [RFC7799] classification of measurement methods.  Packet
   Network Performance Monitoring (PNPM), which can be used to measure
   packet loss, latency and jitter on live traffic.  Because this method
   is based on marking consecutive batches of packets the method often
   referred as Marking Method (MM).

   This document defines how marking method can be used on BIER layer to
   measure packet loss and delay metrics of a multicast flow in MPLS
   network.

2.  Conventions used in this document

2.1.  Terminology

   BFR: Bit-Forwarding Router

   BFER: Bit-Forwarding Egress Router




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   BFIR: Bit-Forwarding Ingress Router

   BIER: Bit Index Explicit Replication

   MM: Marking Method

   OAM: Operations, Administration and Maintenance

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 Field in BIER Header

   [I-D.ietf-bier-mpls-encapsulation] defined two bit long field,
   referred as OAM, designated for the marking performance measurement
   method.  The OAM field MUST NOT be used in defining forwarding and/or
   quality of service treatment of a BIER packet.  The OAM field MUST be
   used only for the performance measurement of data traffic in BIER
   layer.  Because setting of the field to any value does not affect
   forwarding and/or quality of service treatment of a packet, the
   marking method in BIER layer can be viewed as example of hybrid
   performance measurement method.

   The Figure 1 displays format of the OAM field

    0
    0   1
   +-+-+-+-+
   | S | D |
   +-+-+-+-+

                 Figure 1: OAM field of BIER Header format

   where:

   o  S- Single mark method;

   o  D - Double mark method.








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4.  Theory of Operation

   The marking method can be successfully used in the multicast
   environment supported by BIER layer.  Without limiting any generality
   consider multicast network presented in Figure 2.  Any combination of
   markings, Loss and/or Delay, can be applied to a multicast flow by
   any Bit Forwarding Router (BFR) at either ingress or egress point to
   perform node, link, segment or end-to-end measurement to detect
   performance degradation defect and localize it efficiently.


                           -----
                         --| D |
                 -----  /  -----
               --| B |--
              /  -----  \  -----
             /           --| E |
   -----    /              -----
   | A |---                -----
   -----    \            --| F |
             \  -----   /  -----
              --| C |--
                -----   \  -----
                         --| G |
                           -----


                        Figure 2: Multicast network

   Using the marking method a BFR creates distinct sub-flows in the
   particular multicast traffic over BIER layer.  Each sub-flow consists
   of consecutive blocks that are unambiguously recognizable by a
   monitoring point at any BFR and can be measured to calculate packet
   loss and/or packet delay metrics.

4.1.  Single Mark Enabled Measurement

   As explained in the [I-D.ietf-ippm-alt-mark], marking can be applied
   to delineate blocks of packets based either on 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.




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   The S flag is used to create alternate flows to measure the packet
   loss by switching value of the S 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:

   o  First/Last Packet Delay calculation: whenever the marking, i.e.
      value of S flag, changes a BFR 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 downstream BFR 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 BFR 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 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 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 an highly optimized implementation of the method.

4.2.  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 S 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 (S 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 the BIER network, so that a BFR can store the
   timestamps of these packets; these timestamps can be compared with
   the timestamps of the same packets on a second BFR 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 useful to have not only
   the average delay but also the minimum and maximum delay values and,




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   in wider terms, to know more about the statistic distribution of
   delay values.

5.  IANA Considerations

   This document requests IANA to register format of the OAM field of
   BIER Header as the following:

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

                     Table 1: OAM field of BIER Header

6.  Security Considerations

   This document list the OAM requirement for BIER-enabled domain and
   does not raise any security concerns or issues in addition to ones
   common to networking.

7.  Acknowledgement

   TBD

8.  References

8.1.  Normative References

   [I-D.ietf-bier-mpls-encapsulation]
              Wijnands, I., Rosen, E., Dolganow, A., Tantsura, J.,
              Aldrin, S., and I. Meilik, "Encapsulation for Bit Index
              Explicit Replication in MPLS and non-MPLS Networks",
              draft-ietf-bier-mpls-encapsulation-07 (work in progress),
              June 2017.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <http://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, <http://www.rfc-editor.org/info/rfc8174>.





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8.2.  Informative References

   [I-D.ietf-bier-architecture]
              Wijnands, I., Rosen, E., Dolganow, A., Przygienda, T., and
              S. Aldrin, "Multicast using Bit Index Explicit
              Replication", draft-ietf-bier-architecture-07 (work in
              progress), June 2017.

   [I-D.ietf-ippm-alt-mark]
              Fioccola, G., Capello, A., Cociglio, M., Castaldelli, L.,
              Chen, M., Zheng, L., Mirsky, G., and T. Mizrahi,
              "Alternate Marking method for passive and hybrid
              performance monitoring", draft-ietf-ippm-alt-mark-05 (work
              in progress), June 2017.

   [RFC7799]  Morton, A., "Active and Passive Metrics and Methods (with
              Hybrid Types In-Between)", RFC 7799, DOI 10.17487/RFC7799,
              May 2016, <http://www.rfc-editor.org/info/rfc7799>.

Authors' Addresses

   Greg Mirsky
   ZTE Corp.

   Email: gregimirsky@gmail.com


   Lianshu Zheng
   Huawei Technologies

   Email: vero.zheng@huawei.com


   Mach Chen
   Huawei Technologies

   Email: mach.chen@huawei.com


   Giuseppe Fioccola
   Telecom Italia

   Email: giuseppe.fioccola@telecomitalia.it








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