Network Working Group
Internet Engineering Task Force (IETF)                        M. Bagnulo
Internet-Draft
Request for Comments: 7398                                          UC3M
Intended status:
Category: Informational                                     T. Burbridge
Expires: April 10, 2015
ISSN: 2070-1721                                                       BT
                                                             S. Crawford
                                                                SamKnows
                                                              P. Eardley
                                                                      BT
                                                               A. Morton
                                                               AT&T Labs
                                                         October 7, 2014
                                                            January 2015

 A Reference Path and Measurement Points for Large-Scale Measurement of
                         Broadband Performance
                      draft-ietf-ippm-lmap-path-07

Abstract

   This document defines a reference path for Large-scale Measurement of
   Broadband Access Performance (LMAP) and measurement points for
   commonly used performance metrics.  Other similar measurement
   projects may also be able to use the extensions described here for
   measurement point location.  The purpose is to create an efficient
   way to describe the location of the measurement point(s) used to
   conduct a particular measurement.

Status of This Memo

   This Internet-Draft document is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents not an Internet Standards Track specification; it is
   published for informational purposes.

   This document is a product of the Internet Engineering Task Force
   (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list  It represents the consensus of current Internet-
   Drafts is at http://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid the IETF community.  It has
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   Internet Engineering Steering Group (IESG).  Not all documents
   approved by the IESG are a maximum candidate for any level of Internet
   Standard; see Section 2 of RFC 5741.

   Information about the current status of six months this document, any errata,
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   This Internet-Draft will expire on April 10, 2015.
   http://www.rfc-editor.org/info/rfc7398.

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  Requirements Language . . . . . . . . . . . . . . . . . .   3
   2.  Purpose and Scope . . . . . . . . . . . . . . . . . . . . . .   3
   3.  Terms and Definitions . . . . . . . . . . . . . . . . . . . .   4
     3.1.  Reference Path  . . . . . . . . . . . . . . . . . . . . .   4
     3.2.  Subscriber  . . . . . . . . . . . . . . . . . . . . . . .   4
     3.3.  Dedicated Component (Links or Nodes)  . . . . . . . . . .   5   4
     3.4.  Shared Component (Links or Nodes) . . . . . . . . . . . .   5
     3.5.  Resource Transition Point . . . . . . . . . . . . . . . .   5
     3.6.  Service Demarcation Point . . . . . . . . . . . . . . . .   5
     3.7.  Managed and Un-Managed Unmanaged Sub-paths . . . . . . . . . . . . .   5
   4.  Reference Path  . . . . . . . . . . . . . . . . . . . . . . .   6   5
   5.  Measurement Points  . . . . . . . . . . . . . . . . . . . . .   7
   6.  Translation Between  Examples of Reference Path and Paths with Various Technologies . . . .  11
   7.  Example of Reference Path with Resource Transition  . . . . . . . . . . . . . . . . .  12  13
   8.  Security considerations . . . . . . . . . . . . . . . . . . .  13
   9.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  14
   10. Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  14
   11.
   9.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  14
     11.1.
     9.1.  Normative References  . . . . . . . . . . . . . . . . . .  14
     11.2.
     9.2.  Informative References  . . . . . . . . . . . . . . . . .  14
   Authors' Addresses  . . . . .  15
   Appendix A.  Acknowledgments  . . . . . . . . . . . . . . . . . .  15  16

1.  Introduction

   This document defines a reference path for Large-scale Measurement of
   Broadband Access Performance (LMAP) or similar measurement projects.
   The series of IP Performance Metrics (IPPM) RFCs have developed terms
   that are generally useful for path description (section (see Section 5 of
   [RFC2330]).  There are a limited number of additional terms needing
   definition here, and they will be defined
   in this memo.

   The reference path (See section (see Section 3.1 and Figure 1 of [Y.1541],
   including the accompanying discussion) is usually needed when
   attempting to communicate precisely about the components that
   comprise the path, and is often expressed in terms of their number
   (hops) and geographic location.  This memo takes the path definition further,
   further by establishing a set of measurement points along the path
   and ascribing a unique designation to each point.  This topic has
   been previously developed in section Section 5.1 of [RFC3432], [RFC3432] and as part of
   the updated framework for composition and aggregation, section aggregation in Section 4 of
   [RFC5835].  Section 4.1 of [RFC5835] defines the term "measurement
   point".

   Measurement points and the paths they inhabit are often described in
   general terms, like "end-to-end", "user-to-user", or "access".  These
   terms alone are insufficient for the scientific method: method, since we need
   to clarify issues such as: What is an end?  Where is a user located?
   Is the home network included?

   As an illustrative example, consider a measurement agent in an LMAP
   system.  When it reports its measurement results, rather than
   detailing its IP address and that of its measurement peer, it may
   prefer to describe the measured path segment abstractly (perhaps for
   privacy reasons).  For instance "from reasons), e.g., 'from a measurement agent at a home gateway
   to a measurement peer at a DSLAM". DSLAM.'  This memo provides the definition
   for such abstract 'measurement points' and therefore and, therefore, the portion of
   'reference path' between them.

   The motivation for this memo is to provide an unambiguous framework
   to describe measurement coverage, coverage or scope of the reference path.
   This is an essential part of the meta-data metadata to describe measurement
   results.  Measurements conducted over different path scopes are not a
   valid basis for performance comparisons.  We note that additional
   measurement context information may be necessary to support a valid
   comparison of results.

1.1.  Requirements Language

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in RFC 2119 [RFC2119].

2.  Purpose and Scope

   The scope of this memo is to define a reference path for LMAP
   activities with a sufficient level of detail to determine the
   location of different measurement points along a path without
   ambiguity.  These conventions are likely to be useful in other
   measurement projects as well, and in describing to describe the applicable measurement scope
   for some metrics.

   The connection between the reference path and specific network
   technologies (with differing underlying architectures) is within the
   scope of this method, memo, and examples are provided.  Both wired and
   wireless technologies are in-scope. in scope.

   The purpose is to create an efficient way to describe the location of
   the measurement point(s) used to conduct a particular measurement so
   that the measurement result will be adequately described in terms of
   scope or coverage.  This should serve many measurement uses,
   including:

   diagnostic:

   o  diagnostic, where the same metric would be measured on different
      sub-paths bounded by measurement points (see Section 4.10
      of[RFC5835]), of
      [RFC5835]), for example example, to isolate the sub-path contributing the
      majority of impairment levels observed on a path.

   comparison:

   o  comparison, where the same metric may be measured on equivalent
      portions of different network infrastructures, for example example, to
      compare the performance of wired and wireless home network
      technologies.

3.  Terms and Definitions

   This section defines key terms and concepts for the purposes of this memo.

3.1.  Reference Path

   A reference path is a serial combination of hosts, routers, switches,
   links, radios, and processing elements that comprise all the network
   elements traversed by each packet in a flow between the source and
   destination hosts.  A reference path also indicates the various
   boundaries present, such as administrative boundaries.  A reference
   path is intended to be equally applicable to all IP and link-layer
   networking technologies.  Therefore, the components are generically
   defined
   defined, but their functions should have a clear counterpart or be
   obviously omitted in any network architecture.

3.2.  Subscriber

   An

   A subscriber is an entity (associated with one or more users) that is
   engaged in a subscription with a service provider.  The subscriber is
   allowed to subscribe and un-subscribe unsubscribe to services, services and to register a
   user or a list of users authorized to enjoy these services.  [Q1741]  [Q.1741]

   Both the subscriber and service provider are allowed to set the
   limits relative to the use that associated users make of subscribed
   services.

3.3.  Dedicated Component (Links or Nodes)

   All resources of a Dedicated Component dedicated component (typically a link or node on
   the Reference Path) reference path) are allocated to serving the traffic of an
   individual Subscriber. subscriber.  Resources include transmission time-slots,
   queue space, processing for encapsulation and address/port
   translation, and others.  A Dedicated Component dedicated component can affect the
   performance of the Reference Path, reference path or the performance of any sub-path
   where the component is involved.

3.4.  Shared Component (Links or Nodes)

   A component on the Reference Path reference path is designated a Shared Component "shared component"
   when the traffic associated with multiple Subscribers subscribers is served by
   common resources.

3.5.  Resource Transition Point

   A

   This is a point between Dedicated dedicated and Shared Components shared components on a Reference Path
   reference path that may be a point of significance, significance and is identified
   as a transition between two types of resources.

3.6.  Service Demarcation Point

   This is the point where a service managed by the service provider
   begins (or ends), ends) and varies by technology.  For example, this point
   is usually defined as the Ethernet interface on a residential gateway
   or modem where the scope of a packet transfer service begins and
   ends.  In the case of a WiFi Service, service, this would be an Air Interface air interface
   within the intended service boundary (e.g., walls of the coffee
   shop).  The Demarcation Point demarcation point may be within an integrated endpoint
   using an Air Interface air interface (e.g., Long-Term Evolution User Equipment, LTE
   UE). Equipment (LTE
   UE)).  Ownership does not necessarily affect the demarcation point; a
   Subscriber
   subscriber may own all equipment on their premises, but it is likely
   that the service provider will certify such equipment for connection
   to their network, network or that a third-party will certify standards
   compliance.

3.7.  Managed and Un-Managed Unmanaged Sub-paths

   Service providers are responsible for the portion of the path they
   manage.  However, most paths involve a sub-path which that is beyond the
   management of the subscriber's service provider.  This means that
   private networks, wireless networks using unlicensed frequencies, and
   the networks of other service providers are designated as Un-managed unmanaged
   sub-paths.  The Service Demarcation Point service demarcation point always divides Managed managed and Un-managed
   unmanaged sub-paths.

4.  Reference Path

   This section defines a reference path for Internet communication.

Subsc. -- Private -- Private -- Service-- Intra IP -- GRA -- Transit ...
device     Net #1     Net #2    Demarc.    Access     GW     GRA GW

... Transit -- GRA -- Service -- Private -- Private -- Destination
    GRA GW     GW     Demarc.    Net #n     Net #n+1   Host

                GRA = Globally Routable Address, Address
                 GW = Gateway

                         Figure 1: Reference Path

   The following are descriptions of reference path components that may
   not be clear from their name alone.

   o  Subsc.  (Subscriber) device - This is a host that normally
      originates and terminates communications conducted over the IP
      packet transfer service.

   o  Private Net #x - This is a network of devices owned and operated
      by the Internet Service Subscriber. service subscriber.  In some configurations, one
      or more private networks and the device that provides the Service
      Demarcation service
      demarcation point are collapsed in a single device (and ownership (ownership may
      shift to the service provider), and provider); this should be noted as part of
      the path description.

   o  Intra IP Access - This is the first point in the access
      architecture
      architecture, beyond the Service Demarc. service demarcation, where a globally
      routable IP address is exposed and used for routing.  In
      architectures that use tunneling, this point may be equivalent to
      the Globally Routable Address Gateway (GRA GW).  This point could
      also collapse to the device providing the Service Demarc., service demarcation, in
      principle.  Only one Intra IP Access point is shown, but they can
      be identified in any access network.

   o  GRA GW - This is the point of interconnection between a Service Provider's service
      provider's administrative domain and the rest of the Internet,
      where routing will depend on the GRAs in the IP header.

   o  Transit GRA GW - If one or more networks intervene between the
      Service Provider's
      service provider's access networks of the Subscriber subscriber and of the
      Destination Host,
      destination host, then such networks are designated "transit" and
      are bounded by two Transit transit GRA GW. GWs.

   Use of multiple IP address families in the measurement path must be
   noted, as the conversions between IPv4 and IPv6 certainly influence
   the visibility of a GRA for each family.

   In the case that a private address space is used throughout an access
   architecture, then the Intra IP Access points must use the same
   address space as the Service Demarcation service demarcation point, and the Intra IP
   Access points must be selected such that a test between these points
   produces a useful assessment of access performance (e.g., includes
   both shared and dedicated access link infrastructure).

5.  Measurement Points

   A key aspect of measurement points, beyond the definition in section
   Section 4.1 of [RFC5835], is that the innermost IP header and higher higher-
   layer information must be accessible through some means.  This is
   essential to measure IP metrics.  There may be tunnels and/or other
   layers
   which that encapsulate the innermost IP header, even adding another
   IP header of their own.

   In general, measurement points cannot always be located exactly where
   desired.  However, the definition in [RFC5835] and the discussion in
   section
   Section 5.1 of [RFC3432] indicate that allowances can be made: made; for
   example, it is nearly ideal when there are deterministic errors that
   can be quantified between desired and actual measurement point. points.

   The Figure figure below illustrates the assignment of measurement points to
   selected components of the reference path.

Subsc. -- Private -- Private -- Service-- Intra IP -- GRA -- Transit ...
device     Net #1     Net #2    Demarc.    Access     GW     GRA GW
mp000                            mp100      mp150    mp190    mp200

... Transit -- GRA -- Service -- Private -- Private -- Destination
    GRA GW     GW     Demarc.    Net #n     Net #n+1   Host
    mpX90     mp890   mp800                            mp900

                GRA = Globally Routable Address, Address
                 GW = Gateway

       Figure 1 2: Reference Path with Measurement Point Designations

   Each measurement point on a specific reference path MUST be assigned
   a unique number.  To facilitate interpretation of the results, the
   measuring organisation organization (and whoever it shares results with) MUST have
   an unambiguous understanding of what path or point was measured.  In
   order to achieve this, a set of numbering recommendations follow.

   When communicating the results of measurements, the measuring
   organization SHOULD supply a diagram similar to Figure 1 2 (with the
   technology-specific information in examples that follow), follow) and MUST
   supply it when additional measurement point numbers have been defined
   and used, with used (with sufficient detail to identify measurement locations in
   the path. path).

   Ideally, the consumer of measurement results would know the location
   of a measurement point on the reference path from the measurement
   point number alone, and alone; the recommendations below provide a way to
   accomplish this goal.  Although the initial numbering may be fully
   compliant with this system, network growth, consolidation, and re-
   arrangement, or changing circumstances such as ownership changes, could cause could, over time,
   lead to gaps in network numbers or non-monotonic measurement point
   number assignments along the path over time. path.  Such circumstances could include
   growth, consolidation, re-arrangement, and change of ownership of the
   network.  These are examples of reasonable causes for numbering
   deviations which that must be identified on the reference path diagram, as
   required above.

   Whilst

   While the numbering of a measurement point is in the context of a
   particular path, for simplicity simplicity, the measuring organisation organization SHOULD
   use the same numbering for a device (playing the same role) on all
   the measurement paths through it.  Similarly, whilst the measurement
   point numbering is in the context of a particular measuring
   organisation,
   organization, organizations with similar technologies and
   architectures are encouraged to coordinate on local numbering and
   diagrams.

   The measurement point numbering system, mpXnn, has two independent
   parts:

   1.  The X in mpXnn indicates the network number.  The network with
       the Subscriber's subscriber's device is network 0.  The network of a different
       organization (administrative or ownership domains) SHOULD be
       assigned a different number.  Each successive network number
       SHOULD be one greater than the previous network's number.  Two
       circumstances make it necessary to designate X=9 in the
       Destination Host's
       destination host's network and X=8 for the Service Provider service provider
       network at the Destination: destination:

       A.  The number of Transit transit networks is unknown.

       B.  The number of Transit transit networks varies over time.

   2.  The nn in mpXnn indicates the measurement point and is locally- locally
       assigned by network X.  The following conventions are suggested:

       A.  00 SHOULD be used for a measurement point at the Subscriber's subscriber's
           device and at the Service Demarcation service demarcation point or GW nearest to
           the Subscriber's subscriber's device for Transit Networks. transit networks.

       B.  90 SHOULD be used for a measurement point at the GW of a
           network (opposite from the Subscriber's subscriber's device or Service
           Demarc.). service
           demarcation).

       C.  In most networks, measurement point numbers SHOULD
           monotonically increase from the point nearest the
           Subscriber's
           subscriber's device to the opposite network boundary on the
           path (see below). (but see item D for an exception).

       D.  When a Destination destination host is part of the path, 00 SHOULD be
           used for a measurement point at the Destination destination host and at
           the Destination's Service Demarcation destination's service demarcation point.  Measurement
           point numbers SHOULD monotonically increase from the point
           nearest the Destination's destination's host to the opposite network
           boundary on the path ONLY in these networks.  This
           directional numbering reversal allows consistent 00
           designation for end hosts and Service Demarcs. service demarcation.

       E.  50 MAY be used for an intermediate measurement point of
           significance, such as a Network Address Translator (NAT).

       F.  20 MAY be used for a traffic aggregation point point, such as a
           DSLAM
           Digital Subscriber Line Access Multiplexer (DSLAM) within a
           network.

       G.  Any other measurement points SHOULD be assigned unused
           integers between 01 and 99.  The assignment SHOULD be stable
           for at least the duration of a particular measurement study, study
           and SHOULD avoid numbers that have been assigned to other
           locations within network X (unless the assignment is
           considered sufficiently stale).  Sub-networks  Subnetworks or domains
           within a network are useful locations for measurement points.

   When supplying a diagram of the reference path and measurement
   points, the operator of the measurement system MUST indicate: indicate the
   reference path, the numbers (mpXnn) of the measurement points, and
   the technology-specific definition of any measurement point other
   than X00 and X90 with sufficient detail to clearly define its
   location (similar to the technology-specific examples in Section 6 of
   this document).

   If the number of intermediate networks (between the source and
   destination) is not known or is unstable, then this SHOULD be
   indicated on the diagram diagram, and results from measurement points within
   those networks need to be treated with caution.

   Notes:

   o  The terminology "on-net" and "off-net" is sometimes used when
      referring to the Subscriber's subscriber's Internet Service Provider (ISP)
      measurement coverage.  With respect to the reference path, tests
      between mp100 and mp190 are "on-net".

   o  Widely deployed broadband Internet access measurements have used
      pass-through devices[SK] devices [SK] (at the subscriber's location) directly
      connected to the service demarcation point: point; this would be located
      at mp100.

   o  The networking technology must be indicated for the measurement
      points used, especially the interface standard and configured
      speed (because the measurement connectivity itself can be a
      limiting factor for the results).

   o  If it can be shown that a link connecting to a measurement point
      has reliably deterministic performance or negligible impairments,
      then the remote end of the connecting link is an equivalent point
      for some methods of measurement (although those methods should
      describe this possibility in detail; detail, it is not in-scope in scope to provide
      such methods here).  In any case, the presence of a link and
      claimed equivalent measurement point must be reported.

   o  Some access network architectures may have an additional traffic
      aggregation device between mp100 and mp150.  Use of a measurement
      point at this location would require a local number and diagram.

   o  A Carrier Grade NAT (CGN) deployed in the Service Provider's service provider's
      access network would be positioned between mp100 and mp190, and
      the egress side of the CGN may be designated mp150.  mp150 is
      generally an intermediate measurement point in the same address
      space as mp190.

   o  In the case that private address space is used in an access
      architecture, then mp100 may need to use the same address space as its
      "on-net" measurement point counterpart, counterpart so that a test between
      these points produces a useful assessment of network performance.
      Tests between mp000 and mp100 could use a different private
      address space, and when the globally-routable globally routable side of a CGN is at
      mp150, then the private address side of the CGN could be designated
      mp149 for tests with mp100.

   o  Measurement points at Transit transit GRA GWs are numbered mpX00 and
      mpX90, where X is the lowest positive integer not already used in
      the path.  The GW of the first transit network is shown, shown with point
      mp200 and the last transit network GW with mpX90.

6.  Translation Between  Examples of Reference Path and Paths with Various Technologies

   This section and those that follow are intended to provide example
   mappings between particular network technologies and the reference
   path.

   We provide an example for 3G Cellular cellular access below.

   Subscriber -- Private ---  Service ------------- GRA --- Transit ...
   device         Net #1      Demarc.                GW     GRA GW
   mp000                       mp100                mp190    mp200

   |_____________UE______________|___RAN+Core____|___GGSN__|
   |_____Un-managed
   |_____Unmanaged sub-path_____|____Managed sub-path_____|

      GRA = Globally Routable Address, Address
       GW = Gateway, Gateway
       UE = User Equipment, Equipment
      RAN = Radio Access Network, Network
     GGSN = Gateway GPRS General Packet Radio Service (GPRS) Support Node.

   We next Node

        Figure 3: Example of Reference Path with 3G Cellular Access

   Next, we provide an example of DSL access.  Consider the case where:

   o  The Customer Premises Equipment (CPE) has a NAT device that is
      configured with a public IP address.

   o  The CPE is consists of a wired residential GW and modem internally
      connected (via Private Net #2) to an embedded home router that has also an incorporated a and WiFi
      access point and this is the only networking device in the home
      network, all endpoints (Private Net #1).  All subscriber devices (UE) attach directly
      to the CPE though through the WiFi access. mp100 is on the modem side of
      Private Net #2.

   We believe this is a fairly common configuration in some parts of the
   world and is fairly simple as well.

   This case would map into the defined reference measurement points as
   follows:

Subsc. -- Private -- Private -- Service-- Intra IP -- GRA -- Transit ...
device     Net #1     Net #2    Demarc.    Access     GW     GRA GW
mp000                            mp100      mp150    mp190    mp200
|--UE--|------------CPE/NAT--------|------|-BRAS-|------|
                                   |------DSL Network---|
|_______Un-managed
|________Unmanaged sub-path________|__Managed sub-path__|

                GRA = Globally Routable Address, Address
                 GW = Gateway, Gateway
               BRAS = Broadband Remote Access Server

            Figure 4: Example of Reference Path with DSL Access

   Consider next another access network case where:

   o  The Customer Premises Equipment (CPE) CPE is a NAT device that is configured with a private IP
      address.

   o  There is a Carrier Grade NAT (CGN) CGN located deep in the Access access ISP network.

   o  The CPE is a home router that has also an incorporated a WiFi
      access point and this is the only networking device in the home
      network, all endpoints attach directly to the CPE though through the WiFi
      access.

   We believe this is becoming a fairly common configuration in some
   parts of the world.

   This case would map into the defined reference measurement points as
   follows:

Subsc. -- Private ------------- Service-- Intra IP -- GRA -- Transit ...
device     Net #1               Demarc.    Access     GW     GRA GW
mp000                            mp100      mp150    mp190    mp200
|--UE--|------------CPE/NAT--------|------|-CGN-|------|
                                   |--Access Network---|
|_______Un-managed
|________Unmanaged sub-path________|_Managed sub-path__|

                GRA = Globally Routable Address, Address
                 GW = Gateway
                CGN = Carrier Grade NAT

               Figure 5: Example of Reference Path with CGN

7.  Example of Reference Path with Resource Transition

   This section gives an example of Shared shared and Dedicated dedicated portions with
   the reference path.  This example shows two Resource Transition
   Points. resource transition
   points.

   Consider the case where:

   o  The CPE consists of a wired Residential residential GW and modem (Private
      Net#2) Net
      #2) connected to a WiFi access point (Private Net#1). Net #1).  The
      Subscriber
      subscriber device (UE) attaches to the CPE though through the WiFi
      access.

   o  The WiFi subnetwork (Private Net#1) Net #1) shares unlicensed radio
      channel resources with other WiFi access networks (and potentially
      other sources of interference), thus interference); thus, this is a Shared shared portion of
      the path.

   o  The wired subnetwork (Private Net#2) Net #2) and a portion of the Service
      Provider's Network service
      provider's network are Dedicated Resources dedicated resources (for a single
      Subscriber), thus
      subscriber); thus, there is a Resource Transition Point resource transition point between
      (Private Net#1)
      Private Net #1 and (Private Net#2). Private Net #2.

   o  Subscriber traffic shares common resources with other subscribers
      upon reaching the Carrier Grade NAT (CGN), thus CGN; thus, there is a
      Resource Transition Point resource transition point
      and further network components are designated as Shared Resources. shared resources.

   We believe this is a fairly common configuration in parts of the
   world.

   This case would map into the defined reference measurement points as
   follows:

Subsc. -- Private -- Private -- Access -- Intra IP -- GRA -- Transit ...
device     Net #1     Net #2    Demarc.    Access     GW     GRA GW
mp000                            mp100      mp150    mp190    mp200
|--UE--|------------CPE/NAT--------|------|-CGN-|------|
       |   WiFi   |  1000Base-T    |--Access Network---|

       |-Shared--|RT|------Dedicated------| RT  |-----Shared------...
|_______Un-managed
|_______Unmanaged sub-path________|_Managed sub-path__|

                GRA = Globally Routable Address, Address
                 GW = Gateway, Gateway
                 RT = Resource Transition Point

     Figure 6: Example of Reference Path with Two Reference Transition
                                  Points

8.  Security considerations Considerations

   Specification of a Reference Path reference path and identification of measurement
   points on the path represent agreements among interested parties, and
   they parties.
   They present no threat to the implementors of this memo, or to the
   Internet resulting from implementation of the guidelines provided
   here.

   Attacks at end hosts or identified measurement points are possible.
   However, there is no requirement to include IP addresses of hosts or
   other network devices in a reference path with measurement points
   that is compliant with this memo.  As a result, the path diagrams
   with measurement point designation numbers do not aid such attacks.

   Most network operators' diagrams of reference paths will bear a close
   resemblance to similar diagrams in relevant standards or other
   publicly available documents.  However, when an operator must include
   atypical network details in their diagram, e.g., to explain why a
   longer latency measurement is expected, then the diagram reveals some
   topological details and should be marked as confidential and shared
   with others under a specific agreement.

   When considering privacy of those involved in measurement or those
   whose traffic is measured, there may be sensitive information
   communicated to recipients of the network diagrams illustrating paths
   and measurement points described above.  We refer the reader to the
   privacy considerations described in the Large Scale Measurement of
   Broadband Performance (LMAP) Framework [I-D.ietf-lmap-framework], [LMAP-FRAMEWORK], which covers
   active and passive measurement techniques and supporting material on
   measurement context.  For example, the value of sensitive information
   can be further diluted by summarising summarizing measurement results over many
   individuals or areas served by the provider.  There is an opportunity
   enabled by forming anonymity sets described in [RFC6973] based on the
   reference path and measurement points in this memo.  For example, all
   measurements from the Subscriber subscriber device can be identified as "mp000",
   instead of using the IP address or other device information.  The
   same anonymisation anonymization applies to the Internet
   Service Provider, service provider, where
   their Internet gateway would be referred to as "mp190".

9.  IANA Considerations

   This memo makes no requests for IANA consideration.

10.  Acknowledgements

   Thanks to Matt Mathis, Charles Cook, Dan Romascanu, Lingli Deng, and
   Spencer Dawkins for review and comments.

11.  References

11.1.

9.1.  Normative References

   [RFC2330]  Paxson, V., Almes, G., Mahdavi, J., and M. Mathis,
              "Framework for IP Performance Metrics", RFC 2330, May
              1998.

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

   [RFC2330]  Paxson, V., Almes, G., Mahdavi, J., and M. Mathis,
              "Framework for IP Performance Metrics", RFC 2330, May
              1998, <http://www.rfc-editor.org/info/rfc2330>.

   [RFC3432]  Raisanen, V., Grotefeld, G., and A. Morton, "Network
              performance measurement with periodic streams", RFC 3432,
              November 2002. 2002, <http://www.rfc-editor.org/info/rfc3432>.

   [RFC5835]  Morton, A. and S. Van den Berghe, "Framework for Metric
              Composition", RFC 5835, April 2010.

11.2. 2010,
              <http://www.rfc-editor.org/info/rfc5835>.

9.2.  Informative References
   [I-D.ietf-lmap-framework]

   [LMAP-FRAMEWORK]
              Eardley, P., Morton, A., Bagnulo, M., Burbridge, T.,
              Aitken, P., and A. Akhter, "A framework for large-scale
              measurement platforms (LMAP)", draft-ietf-lmap-
              framework-08 (work Work in progress), Progress, draft-
              ietf-lmap-framework-08, August 2014.

   [Q.1741]   International Telecommunications Union, "IMT-2000
              references to Release 9 of GSM-evolved UMTS core network",
              ITU-T Recommendation Q.1741.7, November 2011,
              <http://www.itu.int/rec/T-REC-Q.1741.7/en>.

   [RFC6973]  Cooper, A., Tschofenig, H., Aboba, B., Peterson, J.,
              Morris, J., Hansen, M., and R. Smith, "Privacy
              Considerations for Internet Protocols", RFC 6973, July
              2013.
              2013, <http://www.rfc-editor.org/info/rfc6973>.

   [SK]       Crawford, Sam., S., "Test Methodology White Paper", SamKnows
              Whitebox Briefing Note
              http://www.samknows.com/broadband/index.php, July 2011.

   [Q1741]    Q.1741.7, , "IMT-2000 references to Release 9 of GSM-
              evolved UMTS core network",
              http://www.itu.int/rec/T-REC-Q.1741.7/en, November 2011. July 2011,
              <http://www.samknows.com/broadband/index.php>.

   [Y.1541]   Y.1541, ,   International Telecommunications Union, "Network
              performance objectives for IP-based services", http://www.itu.int/rec/T-REC-Y.1541/en, ITU-T
              Recommendation Y.1541, November 2011. 2011,
              <http://www.itu.int/rec/T-REC-Y.1541/en>.

Appendix A.  Acknowledgments

   Thanks to Matt Mathis, Charles Cook, Dan Romascanu, Lingli Deng, and
   Spencer Dawkins for review and comments.

Authors' Addresses

   Marcelo Bagnulo
   Universidad Carlos III de Madrid
   Av. Universidad 30
   Leganes, Madrid  28911
   SPAIN
   Spain

   Phone: 34 91 6249500
   Email:
   EMail: marcelo@it.uc3m.es
   URI:   http://www.it.uc3m.es

   Trevor Burbridge
   BT
   Adastral Park, Martlesham Heath
   Ipswich
   ENGLAND

   Email:
   United Kingdom

   EMail: trevor.burbridge@bt.com

   Sam Crawford
   SamKnows

   Email:

   EMail: sam@samknows.com

   Phil

   Philip Eardley
   BT
   Adastral Park, Martlesham Heath
   Ipswich
   ENGLAND

   Email:
   United Kingdom

   EMail: philip.eardley@bt.com
   Al Morton
   AT&T Labs
   200 Laurel Avenue South
   Middletown, NJ
   USA

   Email:
   United States

   EMail: acmorton@att.com