IPPM Working Group                                          S. Niccolini
Internet-Draft                                             S. Tartarelli
Intended status: Standards Track                              J. Quittek
Expires: August 28, 2008                                             NEC
                                                                M. Swany
                                                                    UDel
                                                       February 25, 2008


    Information Model and XML Data Model for Traceroute Measurements
                  draft-ietf-ippm-storetraceroutes-08

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Copyright Notice

   Copyright (C) The IETF Trust (2008).

Abstract

   This document describes a standard way to store the configuration and
   the results of traceroute measurements.  This document first of all
   describes the tool itself; afterwards, the common information model
   is defined dividing the information elements in two semantically
   separated groups (configuration elements and results ones).  Moreover



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   an additional element is defined to relate configuration elements and
   results ones by means of a common unique identifier.  On the basis of
   the information model a data model based on XML is defined to store
   the results of traceroute measurements.


Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  3
   2.  Terminology used in this document  . . . . . . . . . . . . . .  3
   3.  The Traceroute tool and its operations . . . . . . . . . . . .  4
   4.  Results of traceroute measurements . . . . . . . . . . . . . .  4
   5.  Information Model for Traceroute Measurements  . . . . . . . .  5
     5.1.  Data Types . . . . . . . . . . . . . . . . . . . . . . . .  6
     5.2.  Information Elements . . . . . . . . . . . . . . . . . . .  7
       5.2.1.  Relationship between the Information Elements  . . . .  7
       5.2.2.  Configuration Information Elements . . . . . . . . . .  9
       5.2.3.  Results Information Elements . . . . . . . . . . . . . 13
       5.2.4.  Information Element Correlating Configuration and
               Results Elements . . . . . . . . . . . . . . . . . . . 16
       5.2.5.  Information Elements to compare traceroute
               measurements results one with each other . . . . . . . 16
   6.  Data Model for Storing Traceroute Measurements . . . . . . . . 17
   7.  XML Schema for traceroute Measurements . . . . . . . . . . . . 19
   8.  Security Considerations  . . . . . . . . . . . . . . . . . . . 36
     8.1.  Conducting Traceroute Measurements . . . . . . . . . . . . 36
     8.2.  Securing Traceroute Measurements Information . . . . . . . 37
   9.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . . 37
   10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 37
     10.1. Normative References . . . . . . . . . . . . . . . . . . . 37
     10.2. Informative References . . . . . . . . . . . . . . . . . . 38
   Appendix A.  Traceroute Default Configuration Parameters . . . . . 39
     A.1.  Alternative Traceroute Implementations . . . . . . . . . . 42
   Appendix B.  Known Problems with Traceroute  . . . . . . . . . . . 43
     B.1.  Compatibility between traceroute measurements results
           and IPPM metrics . . . . . . . . . . . . . . . . . . . . . 43
   Appendix C.  Differences to DISMAN-TRACEROUTE-MIB  . . . . . . . . 43
     C.1.  Naming . . . . . . . . . . . . . . . . . . . . . . . . . . 44
     C.2.  Semantics  . . . . . . . . . . . . . . . . . . . . . . . . 45
     C.3.  Additional Information Elements  . . . . . . . . . . . . . 45
   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 45
   Intellectual Property and Copyright Statements . . . . . . . . . . 47









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1.  Introduction

   Traceroutes are being used by lots of measurement efforts, either as
   an independent measurement or to get path information to support
   other measurement efforts.  That is why there is the need to
   standardize the way the configuration and the results of traceroute
   measurements are stored.  The standard metrics defined by IPPM
   working group in matter of delay, connectivity and losses do not
   apply to the metrics returned by the traceroute tool; therefore, in
   order to compare results of traceroute measurements, the only
   possibility is to add to the stored results a specification of the
   operating system and version for the traceroute tool used.  This
   document, in order to store results of traceroute measurements and
   allow comparison of them, defines a standard way to store them using
   a XML schema.  The document is organized as follows: Section 2
   defines the terminology used in this document, Section 3 describes
   the traceroute tool, Section 4 describes the results of a traceroute
   measurement as displayed to the screen from which the traceroute tool
   was launched.  Section 5 and Section 6 respectively describe the
   information model and data model for storing configuration and
   results of the traceroute measurements.  The document ends with
   security considerations and IANA considerations in Section 8 and
   Section 9 respectively.

   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 [RFC2119].


2.  Terminology used in this document

   The terminology used in this document is defined as follow:
   o  traceroute tool: a software tool for network diagnostic behaving
      like described in Section 3;
   o  traceroute measurement: an instance of the traceroute tool
      launched, with specific configuration parameters (traceroute
      measurement configuration parameters), from a specific host
      (initiator of the traceroute measurement) giving as output
      specific traceroute measurement results;
   o  traceroute probe: one of many IP packets send out by the
      traceroute tool during a traceroute measurement;
   o  traceroute measurement configuration parameters: the configuration
      parameters of a traceroute measurement;
   o  traceroute measurement results: the results of a traceroute
      measurement;
   o  traceroute measurement information: both the results and the
      configuration parameters of a traceroute measurement;




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   o  traceroute measurement path: a sequence of hosts transited in
      order by traceroute probes during a traceroute measurement;


3.  The Traceroute tool and its operations

   Traceroute is a network diagnostic tool used to determine the hop by
   hop path from a source to a destination and the Round Trip Time (RTT)
   from the source to each hop.  Traceroute can be therefore used to
   discover some information (hop counts, delays, etc.) about the path
   between the initiator of the traceroute measurement and other hosts.

   Typically, the traceroute tool attempts to discover the path to a
   destination by sending UDP probes with specific time-to-live (TTL)
   values in the IP packet header and trying to elicit an ICMP
   TIME_EXCEEDED response from each gateway along the path to some host.

   More in detail, a first set of probes with TTL equal to 1 are sent by
   the traceroute tool from the host initiating the traceroute
   measurement (some tool implementations allow setting the initial TTL
   to a value equal to "n" different from 1, so that the first "n-1"
   hops are skipped and the first hop that will be traced is the "n-th"
   in the path).  Upon receiving a probe, the first hop host decreases
   the TTL value (by one or more).  By observing a TTL value equal to
   zero, the host rejects the probe and typically returns an ICMP
   message with a TIME_EXCEEDED value.  The traceroute tool can
   therefore derive the IP address of the first hop from the header of
   the ICMP message and evaluate the RTT between the host initiating the
   traceroute measurement and the first hop.  The next hops are
   discovered following the same procedure, taking care of increasing at
   each step the TTL value of the probes by one.  The TTL value is
   increased until either an ICMP PORT_UNREACHABLE message is received,
   meaning that the destination host has been reached, or the maximum
   configured number of hops has been hit.

   Some implementations, use ICMP Echos, instead of UDP datagrams.
   However, many routers do not return ICMP messages about ICMP
   messages, i.e. no ICMP TIME_EXCEEDED is returned for an ICMP Echo.
   Therefore, this document recommends to base implementations on UDP
   datagrams.  Considerations on TCP-based implementations of the
   traceroute tool are reported in Appendix A.1.


4.  Results of traceroute measurements

   The following list reports the information fields provided as results
   by all traceroute tool implementations considered.  The order in
   which they are reported here is not relevant and it changes in



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   different implementations.  For each hop the information reported is:
   o  the hop index;
   o  the host symbolic address, provided that at least one of the
      probes received a response, the symbolic address could be resolved
      at the corresponding host and that the option to display only
      numerical addresses was not set;
   o  the host IP address, provided that at least one of the probes
      received a response;
   o  the RTT for each response to a probe.
   Depending on the traceroute tool implementation, additional
   information might be displayed in the output (for instance MPLS-
   related information).

   It might happen that some probes do not receive a response within the
   configured time-out (for instance if the probe is filtered out by a
   firewall).  In this case, an "*" is displayed in place of the RTT.
   The information model reflects this using a string with the value of
   "RoundTripTimeNotAvailable" meaning either the probe was lost because
   of a time-out or it was not possible to transmit a probe.  It may
   also happen that some implementations print the same line multiple
   times when a router decreases the TTL by more than one looking like
   multiple hops, the information model is not impacted by this since
   each line is handled separately and it is left to the applications
   handling the XML file how to deal with it.  Moreover, for delays
   below 1 ms, some implementations reports 0 ms (e.g.  UNIX and LINUX)
   while WINDOWS tracert reports "< 1 ms".


5.  Information Model for Traceroute Measurements

   The information model is composed of information elements; for
   defining these information elements, a template is used.  Such
   template is specified in the list below:

   o  name - A unique and meaningful name for the information element.
      The preferred spelling for the name is to use mixed case if the
      name is compound, with an initial lower case letter, e.g.,
      "sourceIpAddress".
   o  description - The semantics of this information element.
   o  dataType - One of the types listed in Section 5.1 of this document
      or in an extension of the information model.  The type space for
      attributes is constrained to facilitate implementation.
   o  units - If the element is a measure of some kind, the units
      identify what the measure is.







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5.1.  Data Types

   This section describes the set of valid data types of the information
   model.

   o  String - The type "String" represents a finite length string of
      valid characters from the Unicode character encoding set.  Unicode
      allows for ASCII and many other international character sets to be
      used.  It is expected that strings will be encoded in UTF-8
      format, which is identical in encoding for USASCII characters, but
      also accommodates other Unicode multi-byte characters.
   o  InetAddressType - The type "InetAddressType" represents a type of
      Internet address.  The allowed values are to be intended as
      imported from [RFC4001] (where the intent was to import only some
      of the values); additional allowed value are "asnumber" and
      "noSpecification".
   o  InetAddress - The type "InetAddress" denotes a generic Internet
      address.  The allowed values are to be intended as imported from
      [RFC4001], where the intent was to import only some of the values;
      an additional allowed value is the AS number to be indicated as
      the actual number plus the indication how the mapping from IP
      address to AS number was performed.
   o  ipASNumberMappingType - The type "ipASNumberMappingType"
      represents a type of mapping from IP to AS number, it indicated
      the method that was used to do get the mapping (allowed values are
      "bgptables", "routingregistries", "nslookup", "others" or
      "unknown".
   o  TruthValue - The type "TruthValue" represents a Boolean value.
      The allowed values are to be intended as imported from [RFC2579].
   o  Unsigned32 - The type "Unsigned32" represents a value in the range
      (0..4294967295).
   o  Unsigned16 - The type "Unsigned16" represents a value in the range
      (0..65535).
   o  Unsigned8 - The type "Unsigned8" represents a value in the range
      (0..255).
   o  InterfaceIndexOrZero - The type "InterfaceIndexOrZero" is an
      extension of the InterfaceIndex convention.  The latter defines a
      greater than zero value used to identify an interface or interface
      sub-layer in the system.  This extension permits the additional
      value of zero.  Examples of the usage of zero might include
      situations where interface was unknown, or when none or all
      interfaces need to be referenced.  The allowed values are to be
      intended as imported from [RFC2863].
   o  ProbesType - The type "ProbesType" represents a way of indicating
      the protocol used for the traceroute probes.  Allowed values are
      UDP, TCP, ICMP.





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   o  DateAndTime - The type "DateAndTime" represents a date-time
      specification.  The allowed values are to be intended as imported
      from [RFC2579] apart from the fact that in this document there is
      the need to use a millisecond resolution instead a decisecond one.
   o  OperationResponseStatus - The type "OperationResponseStatus" is
      used to report the result of an operation.  The allowed values are
      to be intended as imported from [RFC4560].

5.2.  Information Elements

   This section describes the elements related to the storing of a
   traceroute measurement.  The elements are grouped in two groups
   (Configuration and Results) according to their semantics.  In order
   to relate configuration and results elements by means of a common
   unique identifier, an additional element is defined belonging to both
   the two groups.

5.2.1.  Relationship between the Information Elements

   Every traceroute measurement is represented by an instance of the
   "traceRoute" element.  This class provides a standardized
   representation for traceroute measurement data.  The "traceroute"
   element is an element that can be composed of (depending on the
   nature of the traceroute measurement):

   o  1 "Request" element - containing the traceroute measurement
      configuration parameters;
   o  1 "MeasurementMetadata" element - containing the traceroute
      measurement parameters actually used;
   o  1 "Measurement" element - containing the traceroute measurement
      results;
   o  1 "Request" element and 1 "MeasurementMetadata" element;
   o  1 "Request" element and 1 "Measurement" element;
   o  1 "Measurement" element and 1 "MeasurementMetadata" element;
   o  1 "Request" element, 1 "MeasurementMetadata" element and 1
      "Measurement" element;

   The "Request" element (as well as the "MeasurementMetadata" element,
   since they are of the same "_Metadata" type) is a sequence that
   contains:

   o  1 "TestName" element;
   o  1 optional "OSName" element;
   o  1 optional "OSVersion" element;
   o  1 optional "ToolVersion" element;
   o  1 optional "ToolName" element;





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   o  1 "CtlTargetAddressType" element;
   o  1 "CtlTargetAddress" element;
   o  1 "CtlBypassRouteTable" element;
   o  1 "CtlProbeDataSize" element;
   o  1 "CtlTimeOut" element;
   o  1 "CtlProbesPerHop" element;
   o  1 "CtlPort" element;
   o  1 "CtlMaxTtl" element;
   o  1 "CtlDSField" element;
   o  1 "CtlSourceAddressType" element;
   o  1 "CtlSourceAddress" element;
   o  1 optional "CtlIfIndex" element;
   o  1 optional "CtlMiscOptions" element;
   o  1 optional "CtlMaxFailures" element;
   o  1 "CtlDontFragment" element;
   o  1 "CtlInitialTtl" element;
   o  1 optional "CtlDescr" element;
   o  1 "CtlType" element;

   Configuration Information Elements (both "Request" and
   "MeasurementMetadata" elements) can describe not just traceroute
   measurements that have already happened ("MeasurementMetadata"
   elements), but also configuration to be used when requesting a
   measurement to be made ("Request" element).  This is quite different
   semantically, even if the individual information elements are the
   same since the elements contained are exactly the same.

   The "Measurement" element ("_Measurement" type) is a sequence that
   contains:

   o  1 "TestName" element;
   o  1 "ResultsStartDateAndTime" element;
   o  1 "ResultsIpTgtAddrType" element;
   o  1 "ResultsIpTgtAddr" element;
   o  1..2550 "ResultsProbe" elements;
   o  0..255 "ResultsHopRawOutputData" elements;
   o  1 "ResultsEndDateAndTime" element;

   Additionally it is important to say that each "ResultsProbe" element
   is a sequence that ontains:

   o  1 "Index" element;
   o  1 "HopIndex" element;
   o  1 "IndexPerHop" element;
   o  1 "HopAddrType" element;
   o  1 "HopAddr" element;





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   o  1 optional "HopGeoLocation" element;
   o  1..255 optional "MPLSLabelStackEntry" elements;
   o  1 "RoundTripTime" element;
   o  1 "ResponseStatus" element;
   o  1 "Time" element;

5.2.2.  Configuration Information Elements

   This section describes the elements specific to the configuration of
   the traceroute measurement.

5.2.2.1.  CtlTargetAddressType

   o  name - CtlTargetAddressType
   o  description - Specifies the type of destination address used in
      the traceroute measurement.
   o  dataType - InetAddressType
   o  units - N/A

5.2.2.2.  CtlTargetAddress

   o  name - CtlTargetAddress
   o  description - Specifies the host address used in the traceroute
      measurement.  The host address type can be determined by the
      examining the value of the corresponding CtlTargetAddressType.
   o  dataType - InetAddress
   o  units - N/A

5.2.2.3.  CtlBypassRouteTable

   o  name - CtlBypassRouteTable
   o  description - Specifies if the optional bypassing of the route
      table was enabled or not.  If enabled, the normal routing tables
      will be bypassed and the probes will be sent directly to a host on
      an attached network.  If the host is not on a directly-attached
      network, an error is returned.  This option can be used to perform
      the traceroute measurement to a local host through an interface
      that has no route defined.  Please refer to "SO_DONTROUTE" for
      more explanations regarding this.
   o  dataType - TruthValue
   o  units - N/A

5.2.2.4.  CtlProbeDataSize

   o  name - CtlProbeDataSize
   o  description - Specifies the size of the probes of a traceroute
      measurement in octets.  If UDP datagrams are used as probes, then
      the value contained in this object is exact.  If another protocol



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      is used to transmit probes (i.e.  TCP or ICMP) for which the
      specified size is not appropriate, then the implementation can use
      whatever size (appropriate to the method) is closest to the
      specified size.  The maximum value for this object was computed by
      subtracting the smallest possible IP header size of 20 octets
      (IPv4 header with no options) and the UDP header size of 8 octets
      from the maximum IP packet size.  An IP packet has a maximum size
      of 65535 octets (excluding IPv6 Jumbograms).
   o  dataType - Unsigned32
   o  units - octets

5.2.2.5.  CtlTimeOut

   o  name - CtlTimeOut
   o  description - Specifies the time-out value, in seconds, for each
      probe of a traceroute measurement.
   o  dataType - Unsigned32
   o  units - seconds

5.2.2.6.  CtlProbesPerHop

   o  name - CtlProbesPerHop
   o  description - Specifies the number of probes with the same time-
      to-live (TTL) value that are sent for each host.
   o  dataType - Unsigned32
   o  units - probes

5.2.2.7.  CtlPort

   o  name - CtlPort
   o  description - Specifies the base port used by the traceroute
      measurement.
   o  dataType - Unsigned16
   o  units - Port number

5.2.2.8.  CtlMaxTtl

   o  name - CtlMaxTtl
   o  description - Specifies the maximum TTL value for the traceroute
      measurement.
   o  dataType - Unsigned8
   o  units - time-to-live value

5.2.2.9.  CtlDSField

   o  name - CtlDSField





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   o  description - Specifies the value that was stored in the
      Differentiated Services (DS) field in the traceroute probe.  The
      DS Field is defined as the Type of Service (TOS) octet in a IPv4
      header or as the Traffic Class octet in a IPv6 header.  The value
      of this object must be a decimal integer in the range from 0 to
      255.  This option can be used to determine what effect an explicit
      DS field setting has on a traceroute measurement and its probes.
      Not all values are legal or meaningful.  Useful TOS octet values
      are probably '16' (low delay) and '8' (high throughput).  Further
      references can be found in [RFC2474] for the definition of the
      Differentiated Services (DS) field and to [RFC1812] Section 5.3.2
      for Type of Service (TOS).
   o  dataType - Unsigned8
   o  units - N/A

5.2.2.10.  CtlSourceAddressType

   o  name - CtlSourceAddressType
   o  description - Specifies the type of the source address,
      CtlSourceAddress, used in the traceroute measurement.
   o  dataType - InetAddressType
   o  units - N/A

5.2.2.11.  CtlSourceAddress

   o  name - CtlSourceAddress
   o  description - Specifies the IP address (which has to be given as
      an IP number, not a hostname) as the source address used in
      traceroute probes.  On hosts with more than one IP address, this
      option can be used to force the source address to be something
      other than the primary IP address of the interface the probe is
      sent on.  A zero length octet string value for this object means
      that source address specification was disabled.  The address type
      (InetAddressType) that relates to this object is specified by the
      corresponding value of CtlSourceAddressType.
   o  dataType - InetAddress
   o  units - N/A

5.2.2.12.  CtlIfIndex

   o  name - CtlIfIndex
   o  description - Specifies the interface index used in the traceroute
      measurement for sending the traceroute probes.  A value of zero
      for this object implies that the interface was unknown.
   o  dataType - InterfaceIndexOrZero
   o  units - N/A





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5.2.2.13.  CtlMiscOptions

   o  name - CtlMiscOptions
   o  description - Specifies implementation dependent options.
   o  dataType - String
   o  units - N/A

5.2.2.14.  CtlMaxFailures

   o  name - CtlMaxFailures
   o  description - Specifies the maximum number of consecutive timeouts
      allowed before terminating a traceroute measurement.  A value of
      either 255 (maximum hop count/possible TTL value) or a 0 indicates
      that the function of terminating a remote traceroute measurement
      when a specific number of consecutive timeouts are detected was
      disabled.  This element is included to give full compatibility
      with [RFC4560].  No known implementation of traceroute currently
      supports it.
   o  dataType - Unsigned8
   o  units - timeouts

5.2.2.15.  CtlDontFragment

   o  name - CtlDontFragment
   o  description - Specifies if the don't fragment flag (DF) in the IP
      header for a probe was enabled or not.  Setting the DF flag can be
      used for performing a manual PATH MTU test.
   o  dataType - TruthValue
   o  units - N/A

5.2.2.16.  CtlInitialTtl

   o  name - CtlInitialTtl
   o  description - Specifies the initial TTL value used in a traceroute
      measurement.  Such TTL setting is intended to bypass the initial
      (often well known) portion of a path.
   o  dataType - Unsigned8
   o  units - N/A

5.2.2.17.  CtlDescr

   o  name - CtlDescr
   o  description - The purpose of this element is to provide a
      description of the traceroute measurement.
   o  dataType - String
   o  units - N/A





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5.2.2.18.  CtlType

   o  name - CtlType
   o  description - Specifies the implementation method used for the
      traceroute measurement.  It specifies if the traceroute is using
      TCP, UDP, ICMP or others type of probes.
   o  dataType - ProbesType
   o  units - N/A

5.2.3.  Results Information Elements

   This section describes the elements specific to the results of the
   traceroute measurement.

5.2.3.1.  ResultsStartDateAndTime

   o  name - ResultsStartDateAndTime
   o  description - Specifies the date and start time of the traceroute
      measurement.  This is the time when the first probe was seen at
      the sending interface.
   o  dataType - DateAndTime
   o  units - N/A

5.2.3.2.  ResultsIpTgtAddrType

   o  name - ResultsIpTgtAddrType
   o  description - Specifies the type of address stored in the
      corresponding ResultsIpTgtAddr element.
   o  dataType - InetAddressType
   o  units - N/A

5.2.3.3.  ResultsIpTgtAddr

   o  name - ResultsIpTgtAddr
   o  description - Specifies the IP address associated with a
      CtlTargetAddress value when the destination address is specified
      as a DNS name.  The value of this object should be a zero length
      octet string when a DNS name is not specified or when a specified
      DNS name fails to resolve.
   o  dataType - InetAddress
   o  units - N/A

5.2.3.4.  Index

   o  name - Index
   o  description - Specifies an index that consecutively numbers all
      probes for which a reply was received in the sequential order in
      which the replies were received.  The maximum value for this



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      object is CtlMaxTtl*CtlProbesPerHop.
   o  dataType - Unsigned32
   o  units - N/A

5.2.3.5.  HopIndex

   o  name - HopIndex
   o  description - Specifies which hop in a traceroute measurement path
      the probe's results are for.
   o  dataType - Unsigned8
   o  units - N/A

5.2.3.6.  IndexPerHop

   o  name - IndexPerHop
   o  description - Specifies the index of a probe for a particular hop
      in a traceroute measurement path.  The number of probes per hop is
      determined by the value of the corresponding CtlProbesPerHop
      element.
   o  dataType - Unsigned8
   o  units - N/A

5.2.3.7.  HopAddrType

   o  name - HopAddrType
   o  description - Specifies the type of address stored in the
      corresponding HopAddr element.
   o  dataType - InetAddressType
   o  units - N/A

5.2.3.8.  HopAddr

   o  name - HopAddr
   o  description - Specifies the address of a hop in the traceroute
      measurement path.  This object is not allowed to be a DNS name.
      The value of the corresponding object, HopAddrType, indicates this
      object's IP address type.
   o  dataType - InetAddress
   o  units - N/A

5.2.3.9.  HopGeoLocation

   o  name - HopGeoLocation
   o  description - Specifies the geo location of a hop in the
      traceroute measurement path represented according to [RFC3825].
   o  dataType - String





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   o  units - N/A

5.2.3.10.  MPLSLabelStackEntry

   o  name - MPLSLabelStackEntry
   o  description - Specifies entries of the MPLS label stack of a probe
      observed when the probe arrived at the hop that replied to the
      probe.  This object contains one MPLS label stack entry as 32 bit
      value as it is observed on the MPLS label stack.  Contained in
      this single number are the MPLS label, the Exp field, the S flag,
      and the MPLS TTL value as specified in RFC 3032.  If more than one
      MPLS label stack antry is reported then multiple instances of
      elements of this type are used.  They must be ordered in the same
      order as on the label stack with the top label stack entry being
      reported first.
   o  dataType - Unsigned32
   o  units - N/A

5.2.3.11.  RoundTripTime

   o  name - RoundTripTime
   o  description - Specifies the amount of time measured in
      milliseconds from when a probe was sent to when its response was
      received or when it timed out.  The value of this element is
      reported as the truncation of the number reported by the
      traceroute tool (the output "< 1 ms" is therefore encoded as 0
      ms).  A string with the value of "RoundTripTimeNotAvailable" means
      either the probe was lost because of a timeout or it was not
      possible to transmit a probe.
   o  dataType - Unsigned32 or String
   o  units - milliseconds or N/A

5.2.3.12.  ResponseStatus

   o  name - ResponseStatus
   o  description - Specifies the result of a traceroute measurement
      made by the host for a particular probe.
   o  dataType - OperationResponseStatus
   o  units - N/A

5.2.3.13.  Time

   o  name - Time
   o  description - Specifies the timestamp for when the response to the
      probe was received at the interface.
   o  dataType - DateAndTime





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   o  units - N/A

5.2.3.14.  ResultsHopRawOutputData

   o  name - ResultsHopRawOutputData
   o  description - Specifies the raw output data returned by the
      traceroute measurement for a certain hop in a traceroute
      measurement path.  It is an implementation-dependant printable
      string, expected to be useful for a human interpreting the
      traceroute results.
   o  dataType - String
   o  units - N/A

5.2.3.15.  ResultsEndDateAndTime

   o  name - ResultsEndDateAndTime
   o  description - Specifies the date and end time of the traceroute
      measurement.  It is either the time when the response to the last
      probe of the traceroute measurement was received or the time when
      the last probe of the traceroute measurement was sent plus the
      relative timeout (in case of missing response).
   o  dataType - DateAndTime
   o  units - N/A

5.2.4.  Information Element Correlating Configuration and Results
        Elements

   This section defines an additional element belonging to both the two
   previous groups (configuration elements and result elements) named
   TestName.  This element is defined in order to relate configuration
   elements and results ones by means of a common unique identifier (to
   be considered unique within the scope of a specific host, initiator
   of the traceroute measurement).

5.2.4.1.  TestName

   o  name - TestName
   o  description - Specifies the name of a traceroute measurement.
      This is locally unique, within the scope of a specific host,
      initiator of the traceroute measurement.
   o  dataType - String
   o  units - N/A

5.2.5.  Information Elements to compare traceroute measurements results
        one with each other

   This section defines additional elements belonging to both the two
   previous groups (configuration elements and result elements); these



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   elements were defined in order to allow traceroute measurements
   results comparison among different traceroute measurements.

5.2.5.1.  OSName

   o  name - OSName
   o  description - Specifies the name of the operating system on which
      the traceroute measurement was launched.
   o  dataType - String
   o  units - N/A

5.2.5.2.  OSVersion

   o  name - OSVersion
   o  description - Specifies the OS version on which the traceroute
      measurement was launched.
   o  dataType - String
   o  units - N/A

5.2.5.3.  ToolVersion

   o  name - ToolVersion
   o  description - Specifies the version of the traceroute tool used.
   o  dataType - String
   o  units - N/A

5.2.5.4.  ToolName

   o  name - ToolName
   o  description - Specifies the name of the traceroute tool used.
   o  dataType - String
   o  units - N/A


6.  Data Model for Storing Traceroute Measurements

   For storing and transmitting information according to the information
   model defined in the previous section, a data model is required that
   specifies how to encode the elements of the information model.

   There are several design choices for a data model.  It can use a
   binary or textual representation and it can be defined from scratch
   or use already existing frameworks and data models.  In general, the
   use of already existing frameworks and models should be preferred.

   Binary and textual representation both have advantages and
   disadvantages.  Textual representations are (with some limitations)
   human readable while a binary representation consumes less resources



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   for storing, transmitting and parsing data.

   An already existing and closely related data model is the DISMAN-
   TRACEROUTE-MIB module [RFC4560], that specifies a BER encoding
   [RFC3417] used by the Simple Network Management Protocol (SNMP)
   [RFC3410] for transmitting traceroute measurement information
   (configuration and results).  This data model is well suited and
   supported within network management systems, but as a general format
   for storing and transmitting traceroute results it is not easily
   applicable.

   Another binary representation would be an extension of traffic flow
   information encodings as specified for the IPFIX protocol [RFC5101],
   [RFC5102].  The IPFIX protocol is extensible.  However, the
   architecture behind this protocol [I-D.ietf-ipfix-architecture] is
   targeted at exporting passively measured flow information.
   Therefore, some obstacles are expected when trying to use it for
   transmitting traceroute measurements information.

   For textual representations, using the eXtensible Markup Language
   (XML) [XML] is an obvious choice.  XML supports clean structuring of
   data and syntax checking of records.  With some limitations it is
   human readable.  It is supported well by a huge pool of tools and
   standards for generating, transmitting, parsing and converting it to
   other data formats.  Its disadvantages is the resource consumption
   for processing, storing, and transmitting information.  Since the
   expected data volumes related to traceroute measurements in network
   operation and maintenance is not expected to be extremely high, the
   inefficient usage of resources is not a significant disadvantage.
   Therefore, XML was chosen as basis for the traceroute measurements
   information model that is specified in this section.

   Section 7 contains the XML schema to be used as a template for
   storing and/or exchanging traceroute measurements information.  The
   schema was designed in order to use an extensible approach based on
   templates (pretty similar to how IPFIX protocol is designed) where
   the traceroute configuration elements (both the requested parameters,
   Request, and the actual parameters used, MeasurementMetadata) are
   metadata to be referenced by results information elements (data) by
   means of the TestName element (used as unique identifier, within the
   scope of a specific host, initiator of the traceroute measurement).
   Currently Open Grid Forum (OGF) is also using this approach and
   cross-requirements have been analyzed.  As a result of this analysis
   the XML schema contained in Section 7 is compatible with OGF schema
   since it was designed in a way that both limits the unnecessary
   redundancy and a simple one-to-one transformation between the two
   exist.




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7.  XML Schema for traceroute Measurements

   <?xml version="1.0" encoding="UTF-8"?>
   <xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"
              targetNamespace="urn:ietf:params:xml:ns:traceroute-1.0">

     <xs:simpleType name="inetAddressType">
       <xs:restriction base="xs:string">
         <xs:enumeration value="unknown"/>
         <xs:enumeration value="ipv4"/>
         <xs:enumeration value="ipv6"/>
         <xs:enumeration value="dns"/>
         <xs:enumeration value="asnumber"/>
         <xs:enumeration value="noSpecification"/>
       </xs:restriction>
     </xs:simpleType>

     <xs:simpleType name="inetAddressTypeWithoutDns">
       <xs:restriction base="xs:string">
         <xs:enumeration value="unknown"/>
         <xs:enumeration value="ipv4"/>
         <xs:enumeration value="ipv6"/>
         <xs:enumeration value="asnumber"/>
         <xs:enumeration value="noSpecification"/>
       </xs:restriction>
     </xs:simpleType>

     <xs:simpleType name="_zeroLengthString">
       <xs:restriction base="xs:string">
         <xs:maxLength value="0"/>
       </xs:restriction>
     </xs:simpleType>

     <xs:simpleType name="_inetAddressIpv4">
       <xs:restriction base="xs:string">
         <xs:pattern value="(([1-9]?[0-9]|1[0-9][0-9]|
         2[0-4][0-9]|25[0-5]).){3}([1-9]?[0-9]|1[0-9]
         [0-9]|2[0-4][0-9]|25[0-5])"/>
       </xs:restriction>
     </xs:simpleType>

     <xs:simpleType name="_inetAddressIpv6">
       <xs:restriction base="xs:string">
         <xs:pattern value="(([\dA-Fa-f]{1,4}:){7}[\dA-Fa-f]{1,4})
         (:([\d]{1,3}.){3}[\d]{1,3})?"/>
       </xs:restriction>
     </xs:simpleType>




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     <xs:simpleType name="_inetAddressDns">
       <xs:restriction base="xs:string">
         <xs:maxLength value="256"/>
       </xs:restriction>
     </xs:simpleType>

     <xs:simpleType name="_asNumber">
       <xs:restriction base="xs:unsignedInt"/>
     </xs:simpleType>

     <xs:simpleType name="_ipASNumberMappingType">
       <xs:restriction base="xs:string">
         <xs:enumeration value="bgptables"/>
         <xs:enumeration value="routingregistries"/>
         <xs:enumeration value="nslookup"/>
         <xs:enumeration value="others"/>
         <xs:enumeration value="unknown"/>
       </xs:restriction>
     </xs:simpleType>

     <xs:simpleType name="operationResponseStatus">
       <xs:restriction base="xs:string">
         <xs:enumeration value="responseReceived"/>
         <xs:enumeration value="unknown"/>
         <xs:enumeration value="internalError"/>
         <xs:enumeration value="requestTimedOut"/>
         <xs:enumeration value="unknownDestinationAddress"/>
         <xs:enumeration value="noRouteToTarget"/>
         <xs:enumeration value="interfaceInactiveToTarget"/>
         <xs:enumeration value="arpFailure"/>
         <xs:enumeration value="maxConcurrentLimitReached"/>
         <xs:enumeration value="unableToResolveDnsName"/>
         <xs:enumeration value="invalidHostAddress"/>
       </xs:restriction>
     </xs:simpleType>

     <xs:simpleType name="_dateAndTime">
       <xs:restriction base="xs:dateTime"/>
     </xs:simpleType>

     <xs:simpleType name="_TestName">
       <xs:annotation>
         <xs:documentation>Specifies the name of a
         traceroute measurement. This is locally unique,
         within the scope of a specific host, initiator of
         the traceroute measurement.
         </xs:documentation>
       </xs:annotation>



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       <xs:restriction base="xs:string">
         <xs:maxLength value="255"/>
       </xs:restriction>
     </xs:simpleType>

     <xs:simpleType name="_OSName">
       <xs:annotation>
         <xs:documentation>Specifies the name of the operating
         system on which the traceroute measurement was
         launched.
         </xs:documentation>
       </xs:annotation>
       <xs:restriction base="xs:string">
         <xs:maxLength value="255"/>
       </xs:restriction>
     </xs:simpleType>

     <xs:simpleType name="_OSVersion">
       <xs:annotation>
         <xs:documentation>Specifies the OS version on which the
         traceroute measurement was launched.
         </xs:documentation>
       </xs:annotation>
       <xs:restriction base="xs:string">
         <xs:maxLength value="255"/>
       </xs:restriction>
     </xs:simpleType>

     <xs:simpleType name="_ToolVersion">
       <xs:annotation>
         <xs:documentation>Specifies the version of the traceroute
         tool used.
         </xs:documentation>
       </xs:annotation>
       <xs:restriction base="xs:string">
         <xs:maxLength value="255"/>
       </xs:restriction>
     </xs:simpleType>

     <xs:simpleType name="_ToolName">
       <xs:annotation>
         <xs:documentation>Specifies the name of the traceroute
         tool used.
         </xs:documentation>
       </xs:annotation>
       <xs:restriction base="xs:string">
         <xs:maxLength value="255"/>
       </xs:restriction>



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     </xs:simpleType>

     <xs:simpleType name="_CtlBypassRouteTable">
       <xs:annotation>
         <xs:documentation>Specifies if the optional bypassing
         of the route table was enabled or not. If enabled,
         the normal routing tables will be bypassed and the
         probes will be sent directly to a host on an attached
         network. If the host is not on a directly-attached
         network, an error is returned.  This option can be
         used to perform the traceroute measurement to a
         local host through an interface that has no route
         defined. Please refer to SO_DONTROUTE for
         more explanations regarding this.
         </xs:documentation>
       </xs:annotation>
       <xs:restriction base="xs:boolean"/>
     </xs:simpleType>

     <xs:simpleType name="_CtlProbeDataSize">
       <xs:annotation>
         <xs:documentation>Specifies the size of the probes
         of a traceroute measurement in octets. If UDP
         datagrams are used as probes, then the value
         contained in this object is exact. If another
         protocol is used to transmit probes (i.e. TCP or
         ICMP) for which the specified size is not
         appropriate, then the implementation can use
         whatever size (appropriate to the method) is
         closest to the specified size. The maximum value
         for this object was computed by subtracting the
         smallest possible IP header size of 20 octets (IPv4
         header with no options) and the UDP header size of
         8 octets from the maximum IP packet size. An IP
         packet has a maximum size of 65535 octets (excluding
         IPv6 Jumbograms).
         </xs:documentation>
       </xs:annotation>
       <xs:restriction base="xs:unsignedShort">
         <xs:maxExclusive value="65508"/>
       </xs:restriction>
     </xs:simpleType>

     <xs:simpleType name="_CtlTimeOut">
       <xs:annotation>
         <xs:documentation>Specifies the time-out value, in
         seconds, for each probe of a traceroute measurement.
         </xs:documentation>



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       </xs:annotation>
       <xs:restriction base="xs:unsignedByte">
         <xs:minExclusive value="0"/>
         <xs:maxExclusive value="61"/>
       </xs:restriction>
     </xs:simpleType>

     <xs:simpleType name="_CtlProbesPerHop">
       <xs:annotation>
         <xs:documentation>Specifies the number of probes
         with the same time-to-live (TTL) value that are
         sent for each host.
         </xs:documentation>
       </xs:annotation>
       <xs:restriction base="xs:unsignedByte">
         <xs:minExclusive value="0"/>
         <xs:maxExclusive value="11"/>
       </xs:restriction>
     </xs:simpleType>

     <xs:simpleType name="_CtlPort">
       <xs:annotation>
         <xs:documentation>Specifies the base port used
         by the traceroute measurement.
         </xs:documentation>
       </xs:annotation>
       <xs:restriction base="xs:unsignedByte">
         <xs:minExclusive value="0"/>
       </xs:restriction>
     </xs:simpleType>

     <xs:simpleType name="_CtlMaxTtl">
       <xs:annotation>
         <xs:documentation>Specifies the maximum TTL value
         for the traceroute measurement.
         </xs:documentation>
       </xs:annotation>
       <xs:restriction base="xs:unsignedByte">
         <xs:minExclusive value="0"/>
       </xs:restriction>
     </xs:simpleType>

     <xs:simpleType name="_CtlDSField">
       <xs:annotation>
         <xs:documentation>Specifies the value that was
         stored in the Differentiated Services (DS) field
         in the traceroute probe. The DS Field is defined
         as the Type of Service (TOS) octet in a IPv4 header



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         or as the Traffic Class octet in a IPv6 header.
         The value of this object must be a decimal integer
         in the range from 0 to 255. This option can be
         used to determine what effect an explicit DS field
         setting has on a traceroute measurement and its
         probes. Not all values are legal or meaningful.
         Useful TOS octet values are probably '16' (low
         delay) and '8' (high throughput). Further references
         can be found in RFC 2474 for the definition of the
         Differentiated Services (DS) field and to RFC 1812
         Section 5.3.2 for Type of Service (TOS).
         </xs:documentation>
       </xs:annotation>
       <xs:restriction base="xs:unsignedByte"/>
     </xs:simpleType>

     <xs:simpleType name="_CtlIfIndex">
       <xs:annotation>
         <xs:documentation>Specifies the interface index
         used in the traceroute measurement for sending
         the traceroute probes. A value of zero for this
         object implies that the interface was unknown.
         </xs:documentation>
       </xs:annotation>
       <xs:restriction base="xs:unsignedByte"/>
     </xs:simpleType>

     <xs:simpleType name="_CtlMiscOptions">
       <xs:annotation>
         <xs:documentation>Specifies implementation dependent
         options.</xs:documentation>
       </xs:annotation>
       <xs:restriction base="xs:string">
         <xs:maxLength value="255"/>
       </xs:restriction>
     </xs:simpleType>

     <xs:simpleType name="_CtlMaxFailures">
       <xs:annotation>
         <xs:documentation>Specifies the maximum number
         of consecutive timeouts allowed before terminating
         a traceroute measurement. A value of either 255
         (maximum hop count/possible TTL value) or a 0
         indicates that the function of terminating a
         remote traceroute measurement when a specific
         number of consecutive timeouts are detected was
         disabled. This element is included to give full
         compatibility with RFC 4560. No known implementation



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         of traceroute currently supports it.
         </xs:documentation>
       </xs:annotation>
       <xs:restriction base="xs:unsignedByte"/>
     </xs:simpleType>

     <xs:simpleType name="_CtlDontFragment">
       <xs:annotation>
         <xs:documentation>Specifies if the don't fragment
         flag (DF) in the IP header for a probe was enabled
         or not. Setting the DF flag can be used for
         performing a manual PATH MTU test.
         </xs:documentation>
       </xs:annotation>
       <xs:restriction base="xs:boolean"/>
     </xs:simpleType>

     <xs:simpleType name="_CtlInitialTtl">
       <xs:annotation>
         <xs:documentation>Specifies the initial TTL
         value used in a traceroute measurement. Such
         TTL setting is intended to bypass the initial
         (often well known) portion of a path.
         </xs:documentation>
       </xs:annotation>
       <xs:restriction base="xs:unsignedByte">
         <xs:minExclusive value="0"/>
       </xs:restriction>
     </xs:simpleType>

     <xs:simpleType name="_CtlDescr">
       <xs:annotation>
         <xs:documentation>The purpose of this element
         is to provide a description of the traceroute
         measurement.
         </xs:documentation>
       </xs:annotation>
       <xs:restriction base="xs:string">
         <xs:maxLength value="255"/>
       </xs:restriction>
     </xs:simpleType>

     <xs:simpleType name="_CtlType">
       <xs:annotation>
         <xs:documentation>Specifies the implementation
         method used for the traceroute measurement.
         It specifies if the traceroute is using TCP,
         UDP, ICMP or others type of probes.



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         </xs:documentation>
       </xs:annotation>
       <xs:restriction base="xs:string">
         <xs:enumeration value="TCP"/>
         <xs:enumeration value="UDP"/>
         <xs:enumeration value="ICMP"/>
         <xs:enumeration value="others"/>
       </xs:restriction>
     </xs:simpleType>

     <xs:simpleType name="_Index">
       <xs:annotation>
         <xs:documentation>Specifies an index that
         consecutively numbers all probes for which
         a reply was received in the sequential order
         in which the replies were received. The
         maximum value for this object is
         CtlMaxTtl*CtlProbesPerHop.
         </xs:documentation>
       </xs:annotation>
       <xs:restriction base="xs:unsignedShort">
         <xs:minExclusive value="0"/>
         <xs:maxExclusive value="2551"/>
       </xs:restriction>
     </xs:simpleType>

     <xs:simpleType name="_HopIndex">
       <xs:annotation>
         <xs:documentation>Specifies which hop in a
         traceroute measurement path the probe's
         results are for.
         </xs:documentation>
       </xs:annotation>
       <xs:restriction base="xs:unsignedByte">
         <xs:minExclusive value="0"/>
       </xs:restriction>
     </xs:simpleType>

     <xs:simpleType name="_IndexPerHop">
       <xs:annotation>
         <xs:documentation>Specifies the index of a
         probe for a particular hop in a traceroute
         measurement path. The number of probes per hop
         is determined by the value of the corresponding
         CtlProbesPerHop element.
         </xs:documentation>
       </xs:annotation>
       <xs:restriction base="xs:unsignedByte">



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         <xs:minExclusive value="0"/>
         <xs:maxExclusive value="11"/>
       </xs:restriction>
     </xs:simpleType>

     <xs:simpleType name="_HopGeoLocation">
       <xs:annotation>
         <xs:documentation>Specifies the geo location of a
         hop in the traceroute measurement path represented
         according to RFC 3825.
         </xs:documentation>
       </xs:annotation>
       <xs:restriction base="xs:string">
         <xs:maxLength value="255"/>
       </xs:restriction>
     </xs:simpleType>

    <xs:simpleType name="_MPLSLabelStackEntry">
       <xs:annotation>
         <xs:documentation>Specifies entries of the
         MPLS label stack of a probe observed when the probe
         arrived at the hop that replied to the probe. This
         object contains one MPLS label stack entry as 32 bit
         value as it is observed on the MPLS label stack.
         Contained in this single number are the MPLS label,
         the Exp field, the S flag, and the MPLS TTL value as
         specified in RFC 3032.
         If more than one MPLS label stack antry is reported
         then multiple instances of elements of this type are
         used. They must be ordered in the same order as on
         the label stack with the top label stack entry being
         reported first.
         </xs:documentation>
       </xs:annotation>
       <xs:restriction base="xs:unsignedInt">
         <xs:maxInclusive value="4294967295"/>
       </xs:restriction>
     </xs:simpleType>

     <xs:simpleType name="_probeRoundTripTime">
       <xs:restriction base="xs:unsignedShort">
         <xs:maxExclusive value="60001"/>
       </xs:restriction>
     </xs:simpleType>

     <xs:simpleType name="_probeRoundTripTimeNotAvailable">
       <xs:restriction base="xs:string">
         <xs:enumeration value="NotAvailable"/>



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       </xs:restriction>
     </xs:simpleType>

     <xs:simpleType name="_ResultsHopRawOutputData">
       <xs:annotation>
         <xs:documentation>Specifies the raw output data
         returned by the traceroute measurement for a certain
         hop in a traceroute measurement path. It is
         an implementation-dependant printable string,
         expected to be useful for a human interpreting the
         traceroute results.
         </xs:documentation>
       </xs:annotation>
       <xs:restriction base="xs:string">
         <xs:maxLength value="200"/>
       </xs:restriction>
     </xs:simpleType>

     <xs:complexType name="_inetAddressASNumber">
       <xs:annotation>
         <xs:documentation>Specifies the AS number of a hop in the
         traceroute path as a 32 bit number and the indication how
         the mapping from IP address to AS number was performed.
         </xs:documentation>
       </xs:annotation>
       <xs:sequence>
         <xs:element name="asNumber"
                     type="_asNumber"/>
         <xs:element name="ipASNumberMappingType"
                     type="_ipASNumberMappingType"/>
       </xs:sequence>
     </xs:complexType>

     <xs:complexType name="_inetAddress">
       <xs:choice>
         <xs:element name="inetAddressUnknown"
                     type="_zeroLengthString"/>
         <xs:element name="inetAddressIpv4"
                     type="_inetAddressIpv4"/>
         <xs:element name="inetAddressIpv6"
                     type="_inetAddressIpv6"/>
         <xs:element name="inetAddressDns"
                     type="_inetAddressDns"/>
         <xs:element name="inetAddressASNumber"
                     type="_inetAddressASNumber"/>
       </xs:choice>
     </xs:complexType>




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     <xs:complexType name="_inetAddressWithoutDns">
       <xs:choice>
         <xs:element name="inetAddressUnknown"
                     type="_zeroLengthString"/>
         <xs:element name="inetAddressIpv4"
                     type="_inetAddressIpv4"/>
         <xs:element name="inetAddressIpv6"
                     type="_inetAddressIpv6"/>
         <xs:element name="inetAddressASNumber"
                     type="_inetAddressASNumber"/>
         <xs:element name="zeroLengthString"
                     type="_zeroLengthString"/>
       </xs:choice>
     </xs:complexType>

     <xs:complexType name="_CtlTargetAddressType">
       <xs:annotation>
         <xs:documentation>Specifies the type of destination
         address used in the traceroute measurement.
         </xs:documentation>
       </xs:annotation>
       <xs:sequence>
         <xs:element name="targetAddressType"
                     type="inetAddressType"/>
       </xs:sequence>
     </xs:complexType>

     <xs:complexType name="_CtlTargetAddress">
       <xs:annotation>
         <xs:documentation>Specifies the host address
         used in the traceroute measurement. The host
         address type can be determined by the examining
         the value of the corresponding CtlTargetAddressType.
         </xs:documentation>
       </xs:annotation>
       <xs:sequence>
         <xs:element name="targetAddress" type="_inetAddress"/>
       </xs:sequence>
     </xs:complexType>

     <xs:complexType name="_CtlSourceAddressType">
       <xs:annotation>
         <xs:documentation>Specifies the type of the source
         address, CtlSourceAddress, used in the traceroute
         measurement.
         </xs:documentation>
       </xs:annotation>
       <xs:sequence>



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         <xs:element name="sourceAddressType"
                     type="inetAddressTypeWithoutDns"/>
       </xs:sequence>
     </xs:complexType>

     <xs:complexType name="_CtlSourceAddress">
       <xs:annotation>
         <xs:documentation>Specifies the IP address (which
         has to be given as an IP number, not a hostname)
         as the source address used in traceroute probes.
         On hosts with more than one IP address, this option
         can be used to force the source address to be
         something other than the primary IP address of the
         interface the probe is sent on. A zero length
         octet string value for this object means that
         source address specification was disabled. The
         address type (InetAddressType) that relates to
         this object is specified by the corresponding
         value of CtlSourceAddressType.
         </xs:documentation>
       </xs:annotation>
       <xs:sequence>
         <xs:element name="sourceAddress"
                     type="_inetAddressWithoutDns"/>
       </xs:sequence>
     </xs:complexType>

     <xs:complexType name="_ResultsStartDateAndTime">
       <xs:annotation>
         <xs:documentation>Specifies the date and start
         time of the traceroute measurement. This is the
         time when the first probe was seen at the sending
         interface.
         </xs:documentation>
       </xs:annotation>
       <xs:sequence>
         <xs:element name="dateAndTime" type="_dateAndTime"/>
       </xs:sequence>
     </xs:complexType>

     <xs:complexType name="_ResultsIpTgtAddrType">
       <xs:annotation>
         <xs:documentation>Specifies the type of address stored
         in the corresponding ResultsIpTgtAddr element.
         </xs:documentation>
       </xs:annotation>
       <xs:sequence>
         <xs:element name="ipTgtAddrType"



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                     type="inetAddressTypeWithoutDns"/>
       </xs:sequence>
     </xs:complexType>

     <xs:complexType name="_ResultsIpTgtAddr">
       <xs:annotation>
         <xs:documentation>Specifies the IP address associated
         with a CtlTargetAddress value when the destination
         address is specified as a DNS name. The value of
         this object should be a zero length octet string
         when a DNS name is not specified or when a specified
         DNS name fails to resolve.
         </xs:documentation>
       </xs:annotation>
       <xs:sequence>
         <xs:element name="ipTgtAddr"
                     type="_inetAddressWithoutDns"/>
       </xs:sequence>
     </xs:complexType>

     <xs:complexType name="_HopAddrType">
       <xs:annotation>
         <xs:documentation>Specifies the type of address stored
         in the corresponding HopAddr element.
         </xs:documentation>
       </xs:annotation>
       <xs:sequence>
         <xs:element name="probeHopAddrType"
                     type="inetAddressTypeWithoutDns"/>
       </xs:sequence>
     </xs:complexType>

     <xs:complexType name="_HopAddr">
       <xs:annotation>
         <xs:documentation>Specifies the address of a
         hop in the traceroute measurement path. This
         object is not allowed to be a DNS name. The
         value of the corresponding object, HopAddrType,
         indicates this object's IP address type.
         </xs:documentation>
       </xs:annotation>
       <xs:sequence>
         <xs:element name="probeHopAddr"
                     type="_inetAddressWithoutDns"/>
       </xs:sequence>
     </xs:complexType>

     <xs:complexType name="_RoundTripTime">



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       <xs:annotation>
         <xs:documentation>Specifies the amount of
         time measured in milliseconds from when a
         probe was sent to when its response was
         received or when it timed out. The value of
         this element is reported as the truncation
         of the number reported by the traceroute
         tool (the output "&lt; 1 ms" is therefore
         encoded as 0 ms). A string with the value of
         "RoundTripTimeNotAvailable" means either the
         probe was lost because of a timeout or it
         was not possible to transmit a probe.
         </xs:documentation>
       </xs:annotation>
       <xs:choice>
           <xs:element name="probeRoundTripTime"
                       type="_probeRoundTripTime"/>
           <xs:element name="probeRoundTripTimeNotAvailable"
                       type="_probeRoundTripTime"/>
       </xs:choice>
     </xs:complexType>

     <xs:complexType name="_ResponseStatus">
       <xs:annotation>
         <xs:documentation>Specifies the result of a traceroute
         measurement made by the host for a particular probe.
         </xs:documentation>
       </xs:annotation>
       <xs:sequence>
         <xs:element name="probeResponseStatus"
                     type="operationResponseStatus"/>
       </xs:sequence>
     </xs:complexType>

     <xs:complexType name="_Time">
       <xs:annotation>
         <xs:documentation>Specifies the timestamp for
         when the response to the probe was received at the
         interface.
         </xs:documentation>
       </xs:annotation>
       <xs:sequence>
         <xs:element name="dateAndTime" type="_dateAndTime"/>
       </xs:sequence>
     </xs:complexType>

     <xs:complexType name="_ResultsProbe">
       <xs:sequence>



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         <xs:element name="Index"
                     type="_Index"/>
         <xs:element name="HopIndex"
                     type="_HopIndex"/>
         <xs:element name="IndexPerHop"
                     type="_IndexPerHop"/>
         <xs:element name="HopAddrType"
                     type="_HopAddrType"/>
         <xs:element name="HopAddr"
                     type="_HopAddr"/>
         <xs:element name="HopGeoLocation"
                     type="_HopGeoLocation"
                     minOccurs="0" maxOccurs="1"/>
         <xs:element name="MPLSLabelStackEntry"
                     type="_MPLSLabelStackEntry"
                     minOccurs="0" maxOccurs="255"/>
         <xs:element name="RoundTripTime"
                     type="_RoundTripTime"/>
         <xs:element name="ResponseStatus"
                     type="_ResponseStatus"/>
         <xs:element name="Time"
                     type="_Time"/>
       </xs:sequence>
     </xs:complexType>

     <xs:complexType name="_ResultsEndDateAndTime">
       <xs:annotation>
         <xs:documentation>Specifies the date and end time
         of the traceroute measurement. It is either the
         time when the response to the last probe of the
         traceroute measurement was received or the time
         when the last probe of the traceroute measurement
         was sent plus the relative timeout (in case of
         missing response).
         </xs:documentation>
       </xs:annotation>
       <xs:sequence>
         <xs:element name="dateAndTime" type="_dateAndTime"/>
       </xs:sequence>
     </xs:complexType>

     <xs:complexType name="_Metadata">
       <xs:annotation>
         <xs:documentation>Specifies the metadata for a
         traceroute operation. In a request, these are the
         requested parameters. In a response, they are the
         actual parameters used.
         </xs:documentation>



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       </xs:annotation>
       <xs:sequence>
         <xs:element name="TestName"
                     type="_TestName"/>
         <xs:element name="OSName"
                     type="_OSName"
                     minOccurs="0" maxOccurs="1"/>
         <xs:element name="OSVersion"
                     type="_OSVersion"
                     minOccurs="0" maxOccurs="1"/>
         <xs:element name="ToolVersion"
                     type="_ToolVersion"
                     minOccurs="0" maxOccurs="1"/>
         <xs:element name="ToolName"
                     type="_ToolName"
                     minOccurs="0" maxOccurs="1"/>
         <xs:element name="CtlTargetAddressType"
                     type="_CtlTargetAddressType"/>
         <xs:element name="CtlTargetAddress"
                     type="_CtlTargetAddress"/>
         <xs:element name="CtlBypassRouteTable"
                     type="_CtlBypassRouteTable"
                     />
         <xs:element name="CtlProbeDataSize"
                     type="_CtlProbeDataSize"/>
         <xs:element name="CtlTimeOut"
                     type="_CtlTimeOut"/>
         <xs:element name="CtlProbesPerHop"
                     type="_CtlProbesPerHop"/>
         <xs:element name="CtlPort"
                     type="_CtlPort"/>
         <xs:element name="CtlMaxTtl"
                     type="_CtlMaxTtl"/>
         <xs:element name="CtlDSField"
                     type="_CtlDSField"/>
         <xs:element name="CtlSourceAddressType"
                     type="_CtlSourceAddressType"/>
         <xs:element name="CtlSourceAddress"
                     type="_CtlSourceAddress"/>
         <xs:element name="CtlIfIndex"
                     type="_CtlIfIndex" minOccurs="0"
                     maxOccurs="1"/>
         <xs:element name="CtlMiscOptions"
                     type="_CtlMiscOptions" minOccurs="0"
                     maxOccurs="1"/>
         <xs:element name="CtlMaxFailures"
                     type="_CtlMaxFailures" minOccurs="0"
                     maxOccurs="1"/>



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         <xs:element name="CtlDontFragment"
                     type="_CtlDontFragment"/>
         <xs:element name="CtlInitialTtl"
                     type="_CtlInitialTtl"/>
         <xs:element name="CtlDescr"
                     type="_CtlDescr" minOccurs="0"
                     maxOccurs="1"/>
         <xs:element name="CtlType"
                     type="_CtlType"/>
       </xs:sequence>
     </xs:complexType>

     <xs:complexType name="_Measurement">
       <xs:annotation>
         <xs:documentation>
           Contains the actual traceroute measurement
           results.
         </xs:documentation>
       </xs:annotation>
       <xs:sequence>
         <xs:element name="TestName"
                     type="_TestName"/>
         <xs:element name="ResultsStartDateAndTime"
                     type="_ResultsStartDateAndTime"/>
         <xs:element name="ResultsIpTgtAddrType"
                     type="_ResultsIpTgtAddrType"/>
         <xs:element name="ResultsIpTgtAddr"
                     type="_ResultsIpTgtAddr"/>
         <xs:element name="ResultsProbe"
                     type="_ResultsProbe"
                     minOccurs="1" maxOccurs="2550"/>
         <xs:element name="ResultsHopRawOutputData"
                     type="_ResultsHopRawOutputData"
                     minOccurs="0" maxOccurs="255"/>
         <xs:element name="ResultsEndDateAndTime"
                     type="_ResultsEndDateAndTime"/>
       </xs:sequence>
     </xs:complexType>

     <xs:complexType name="_traceRoute">
       <xs:sequence minOccurs="1">
         <xs:element name="Request"
                   type="_Metadata" minOccurs="0" />
         <xs:element name="MeasurementMetadata"
                   type="_Metadata" minOccurs="0" />
         <xs:element name="Measurement"
                   type="_Measurement" minOccurs="0" />
       </xs:sequence>



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     </xs:complexType>

     <!--Reference to "traceRoute" element-->
     <xs:element
      xmlns="urn:ietf:params:xml:ns:traceroute-1.0"
      name="traceRoute" type="_traceRoute"/>

   </xs:schema>



8.  Security Considerations

   Security considerations in this section discuss are grouped into
   considerations related to conducting traceroute measurements and
   considerations related to storing and transmitting traceroute
   measurements information.

   This memo does not specify an implementation of a traceroute tool.
   Neither does it specify a certain procedure for storing traceroute
   measurements information.  Still it is considered desirable to
   discuss related security issues below.

8.1.  Conducting Traceroute Measurements

   Conducting Internet measurements can raise both security and privacy
   concerns.  Traceroute measurements, in which traffic is injected into
   the network, can be abused for denial-of-service attacks disguised as
   legitimate measurement activity.

   Measurement parameters MUST be carefully selected so that the
   measurements inject trivial amounts of additional traffic into the
   networks they measure.  If they inject "too much" traffic, they can
   skew the results of the measurement, and in extreme cases cause
   congestion and denial of service.

   The measurements themselves could be harmed by routers giving
   measurement traffic a different priority than "normal" traffic, or by
   an attacker injecting artificial measurement traffic.  If routers can
   recognize measurement traffic and treat it separately, the
   measurements will not reflect actual user traffic.  If an attacker
   injects artificial traffic that is accepted as legitimate, the loss
   rate will be artificially lowered.  Therefore, the measurement
   methodologies SHOULD include appropriate techniques to reduce the
   probability measurement traffic can be distinguished from "normal"
   traffic.

   Authentication techniques, such as digital signatures, may be used



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   where appropriate to guard against injected traffic attacks.

8.2.  Securing Traceroute Measurements Information

   Traceroute measurement information are not considered highly
   sensitive.  Still, they may contain sensitive information on network
   paths, routing states, use IP addresses, and roundtrip times, that
   the operator a networks may want to detect for business or security
   reasons.

   It is thus important to control access to Information acquired by
   conducting traceroute measurements, particularly when transmitting it
   over a networks but also when storing it.  It is RECOMMENDED that
   transmission of traceroute measurement information over a network
   uses appropriate protection mechanisms for preserving privacy,
   integrity and authenticity.  It is further RECOMMENDED that secure
   authentication and authorization are used for protecting stored
   traceroute measurement information.


9.  IANA Considerations

   This document uses URNs to describe an XML namespace and an XML
   schema for traceroute measurements information storing and
   transmission conforming to a registry mechanism described in
   [RFC3688].  Two URI assignments are requested.
   1.  Registration request for the IPPM traceroute measurements
       namespace
       *  URI: urn:ietf:params:xml:ns:traceroute-1.0
       *  Registrant Contact: IESG
       *  XML: None.  Namespace URIs do not represent an XML
   2.  Registration request for the IPPM traceroute measurements schema
       *  URI: urn:ietf:params:xml:schema:traceroute-1.0
       *  Registrant Contact: IESG
       *  XML: See the section Section 7 of this document.


10.  References

10.1.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC2579]  McCloghrie, K., Ed., Perkins, D., Ed., and J.
              Schoenwaelder, Ed., "Textual Conventions for SMIv2",
              STD 58, RFC 2579, April 1999.




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   [RFC2863]  McCloghrie, K. and F. Kastenholz, "The Interfaces Group
              MIB", RFC 2863, June 2000.

   [RFC3825]  Polk, J., Schnizlein, J., and M. Linsner, "Dynamic Host
              Configuration Protocol Option for Coordinate-based
              Location Configuration Information", RFC 3825, July 2004.

   [RFC4001]  Daniele, M., Haberman, B., Routhier, S., and J.
              Schoenwaelder, "Textual Conventions for Internet Network
              Addresses", RFC 4001, February 2005.

   [RFC4560]  Quittek, J. and K. White, "Definitions of Managed Objects
              for Remote Ping, Traceroute, and Lookup Operations",
              RFC 4560, June 2006.

10.2.  Informative References

   [I-D.ietf-ipfix-architecture]
              Sadasivan, G., "Architecture for IP Flow Information
              Export", draft-ietf-ipfix-architecture-12 (work in
              progress), September 2006.

   [RFC1812]  Baker, F., "Requirements for IP Version 4 Routers",
              RFC 1812, June 1995.

   [RFC2474]  Nichols, K., Blake, S., Baker, F., and D. Black,
              "Definition of the Differentiated Services Field (DS
              Field) in the IPv4 and IPv6 Headers", RFC 2474,
              December 1998.

   [RFC2578]  McCloghrie, K., Ed., Perkins, D., Ed., and J.
              Schoenwaelder, Ed., "Structure of Management Information
              Version 2 (SMIv2)", STD 58, RFC 2578, April 1999.

   [RFC3410]  Case, J., Mundy, R., Partain, D., and B. Stewart,
              "Introduction and Applicability Statements for Internet-
              Standard Management Framework", RFC 3410, December 2002.

   [RFC3417]  Presuhn, R., "Transport Mappings for the Simple Network
              Management Protocol (SNMP)", STD 62, RFC 3417,
              December 2002.

   [RFC3688]  Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
              January 2004.

   [RFC5101]  Claise, B., "Specification of the IP Flow Information
              Export (IPFIX) Protocol for the Exchange of IP Traffic
              Flow Information", RFC 5101, January 2008.



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   [RFC5102]  Quittek, J., Bryant, S., Claise, B., Aitken, P., and J.
              Meyer, "Information Model for IP Flow Information Export",
              RFC 5102, January 2008.

   [XML]      Yergeau et al., F., "Extensible Markup Language (XML) 1.0
              (Third Edition)", W3C Recommendation, February 2004.


Appendix A.  Traceroute Default Configuration Parameters

   This section lists traceroute measurement configuration parameters as
   well as their defaults on various platforms and illustrates how
   widely they may vary.  This document considered four major traceroute
   tool implementations and compared them based on configurable
   parameters and default values.  The LINUX (SUSE 9.1), BSD (FreeBSD
   7.0) and UNIX (SunOS 5.9) implementations are based on UDP datagrams,
   while the WINDOWS (XP SP2) one uses ICMP Echos.  The comparison is
   summarized in the following table, where an N/A in the option column,
   means that such parameter is not configurable for the specific
   implementation.  A comprehensive comparison of available
   implementations is outside the scope of this document; however,
   already by sampling a few different implementations, it can be
   observed that they can differ quite significantly in terms of
   configurable parameters and also default values.Note that in the
   following table only those options which are available in at least
   two of the considered implementations are reported.

             +---------------------------------------------------------+
             |  OS    |Option|           Description         | Default |
             +--------+------+-------------------------------+---------+
             | LINUX  | -m   |Specify the maximum TTL used   |   30    |
             |--------+------|in traceroute probes.          |---------|
             | FreeBSD| -m   |                               |  OS var |
             |--------+------|                               |---------|
             | UNIX   | -m   |                               |   30    |
             |--------+------|                               |---------|
             | WINDOWS| -h   |                               |   30    |
             +--------+------+-------------------------------+---------+
             | LINUX  | -n   |Display hop addresses          |    -    |
             |--------+------|numerically rather than        |---------|
             | FreeBSD| -n   |symbolically.                  |    -    |
             |--------+------|                               |---------|
             | UNIX   | -n   |                               |    -    |
             |--------+------|                               |---------|
             | WINDOWS| -d   |                               |    -    |
             +--------+------+-------------------------------+---------+
             | LINUX  | -w   |Set the time to wait for a     |  3 sec  |
             |--------+------|response to a probe.           |---------|



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             | FreeBSD| -w   |                               |  5 sec  |
             |--------+------|                               |---------|
             | UNIX   | -w   |                               |  5 sec  |
             |--------+------|                               |---------|
             | WINDOWS| -w   |                               |  4 sec  |
             +--------+------+-------------------------------+---------+
             | LINUX  | N/A  |Specify a loose source route   |    -    |
             |--------+------|gateway (to direct the         |---------|
             | FreeBSD| -g   |traceroute probes through      |    -    |
             |--------+------|routers not necessarily in     |---------|
             | UNIX   | -g   | the path).                    |    -    |
             |--------+------|                               |---------|
             | WINDOWS| -g   |                               |    -    |
             +--------+------+-------------------------------+---------+
             | LINUX  | -p   |Set the base UDP port number   |  33434  |
             |------- +------|used in traceroute probes      |---------|
             | FreeBSD| -p   |(UDP port = base + nhops - 1). |  33434  |
             |--------+------|                               |---------|
             | UNIX   | -p   |                               |  33434  |
             |--------+------|                               |---------|
             | WINDOWS| N/A  |                               |    -    |
             +--------+------+-------------------------------+---------+
             | LINUX  | -q   |Set the number of probes per   |    3    |
             |--------+------|TTL.                           |---------|
             | FreeBSD| -q   |                               |    3    |
             |--------+------|                               |---------|
             | UNIX   | -q   |                               |    3    |
             |--------+------|                               |---------|
             | WINDOWS| N/A  |                               |    3    |
             +--------+------+-------------------------------+---------+
             | LINUX  | -S   |Set the IP source address in   |IP       |
             |--------+------|outgoing probes to the         |address  |
             | FreeBSD| -s   |specified value.               |of the   |
             |--------+------|                               |out      |
             | UNIX   | -s   |                               |interface|
             |--------+------|                               |         |
             | WINDOWS| N/A  |                               |         |
             +--------+------+-------------------------------+---------+
             | LINUX  | -t   |Set the type-of-service (TOS)  |    0    |
             |--------+------|in the probes to the specified |---------|
             | FreeBSD| -t   |value.                         |    0    |
             |--------+------|                               |---------|
             | UNIX   | -t   |                               |    0    |
             |--------+------|                               |---------|
             | WINDOWS| N/A  |                               |    0    |
             +--------+------+-------------------------------+---------+
             | LINUX  | -v   |Verbose output: received ICMP  |    -    |
             |--------+------|packets other than             |---------|



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             | FreeBSD| -v   |TIME_EXCEEDED and              |    -    |
             |--------+------|UNREACHABLE are listed.        |---------|
             | UNIX   | -v   |                               |    -    |
             |--------+------|                               |---------|
             | WINDOWS| N/A  |                               |    -    |
             +--------+------+-------------------------------+---------+
             | LINUX  | N/A  |Set  the time (in msec) to     |    -    |
             |--------+------|pause between probes.          |---------|
             | FreeBSD| -z   |                               |    0    |
             |--------+------|                               |---------|
             | UNIX   | -P   |                               |    0    |
             |--------+------|                               |---------|
             | WINDOWS| N/A  |                               |    -    |
             +--------+------+-------------------------------+---------+
             | LINUX  | -r   |Bypass the normal routing      |    -    |
             |--------+------|tables and send directly to a  |---------|
             | FreeBSD| -r   |host on attached network.      |    -    |
             |--------+------|                               |---------|
             | UNIX   | -r   |                               |    -    |
             |--------+------|                               |---------|
             | WINDOWS| N/A  |                               |    -    |
             +--------+------+-------------------------------+---------+
             | LINUX  | -f   |Set the initial TTL for the    |    1    |
             |--------+------|first probe.                   |---------|
             | FreeBSD| -f   |                               |    1    |
             |--------+------|                               |---------|
             | UNIX   | -f   |                               |    1    |
             |--------+------|                               |---------|
             | WINDOWS| N/A  |                               |    1    |
             +--------+------+-------------------------------+---------+
             | LINUX  | -F   |Set the "don't fragment" bit.  |    -    |
             |--------+------|                               |---------|
             | FreeBSD| -F   |                               |    -    |
             |--------+------|                               |---------|
             | UNIX   | -F   |                               |    -    |
             |--------+------|                               |---------|
             | WINDOWS| N/A  |                               |    -    |
             +--------+------+-------------------------------+---------+
             | LINUX  | N/A  |Enables socket level debugging.|    -    |
             |--------+------|                               |---------|
             | FreeBSD| -d   |                               |    -    |
             |--------+------|                               |---------|
             | UNIX   | -d   |                               |    -    |
             |--------+------|                               |---------|
             | WINDOWS| N/A  |                               |    -    |
             +--------+------+-------------------------------+---------+
             | LINUX  | N/A  |Use ICMP ECHO instead of UDP   |    -    |
             |--------+------|datagrams.                     |---------|



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             | FreeBSD| -I   |                               |    -    |
             |--------+------|                               |---------|
             | UNIX   | -I   |                               |    -    |
             |--------+------|                               |---------|
             | WINDOWS| N/A  |                               |    -    |
             +--------+------+-------------------------------+---------+
             | LINUX  | -I   |Specify a network interface to |    -    |
             |--------+------|obtain the IP address for      |---------|
             | FreeBSD| -i   |outgoing IP packets            |    -    |
             |--------+------|(alternative to option -s).    |---------|
             | UNIX   | -i   |                               |    -    |
             |--------+------|                               |---------|
             | WINDOWS| N/A  |                               |    -    |
             +--------+------+-------------------------------+---------+
             | LINUX  | N/A  |Toggle checksum.               |    -    |
             |--------+------|                               |---------|
             | FreeBSD| -x   |                               |    -    |
             |--------+------|                               |---------|
             | UNIX   | -x   |                               |    -    |
             |--------+------|                               |---------|
             | WINDOWS| N/A  |                               |    -    |
             +--------+------+-------------------------------+---------+
             | LINUX  |  -   |As optional last parameter,    |Depends  |
             |--------+------|LINUX, FreeBSD and UNIX        |on       |
             | FreeBSD|  -   |implementations allow          |implement|
             |--------+------|specifying the probe datagram  |ation.   |
             | UNIX   |  -   |length for outgoing probes.    |         |
             |--------+------|                               |         |
             | WINDOWS| N/A  |                               |         |
             +--------+------+-------------------------------+---------+

A.1.  Alternative Traceroute Implementations

   As stated above, the widespread use of firewalls might prevent UDP or
   ICMP based traceroutes to completely trace the path to a destination,
   since traceroute probes might end up being filtered.  In some cases,
   such limitation might be overcome by sending instead TCP packets to
   specific ports that hosts located behind the firewall are listening
   for connections on.  TCP based implementations use TCP SYN or FIN
   probes and listen for TIME_EXCEEDED messages, TCP RESET and other
   messages from firewalls and gateways on the path.  On the other hand,
   some firewalls filter out TCP SYN packets to prevent denial of
   service attacks, therefore the actual advantage of using TCP instead
   of UDP traceroute depends mainly on firewall configurations, which
   are not known in advance.  A detailed analysis of TCP-based
   traceroute tools and measurements was outside the scope of this
   document, anyway for completeness reasons the information model
   supports the storing of TCP-based traceroute measurements, too.



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Appendix B.  Known Problems with Traceroute

B.1.  Compatibility between traceroute measurements results and IPPM
      metrics

   Because of implementation choices, a known inconsistency exists
   between the round-trip delay metric defined by the IPPM working group
   in RFC 2681 and the results returned by the current traceroute tool
   implementations.  Unfortunately, it is unlikely that the traceroute
   tool implementations will implement the standard definition in the
   near future.  The only possibility is therefore to compare results of
   different traceroute measurements one with each other; in order to do
   this, specifications both of the operating system (name and version)
   and of the traceroute tool version used were added to the metadata
   elements in order to help in comparing metrics between two different
   traceroute measurements results (if run using the same operating
   system and the same version of the tool).  Moreover, the traceroute
   tool has built-in configurable mechanisms like time-outs and can
   experience problems related to the crossing of firewalls; therefore
   some of the packets that traceroute sends out end up being time-out
   or filtered.  As a consequence, it might not be possible to trace the
   path to a node or there might not be a complete set of probes
   describing the RTT to reach it.


Appendix C.  Differences to DISMAN-TRACEROUTE-MIB

   For performing remote traceroute operations at managed node, the IETF
   has standardized the DISMAN-TRACEROUTE-MIB module in [RFC4560].  This
   module allows:

   o  retrieving capability information of the traceroute tool
      implementation at the managed node,
   o  configuring traceroute measurements to be performed,
   o  retrieving information about ongoing and completed traceroute
      measurements,
   o  retrieving traceroute measurement statistics.

   The traceroute storage format described in this document has
   significant overlaps with this MIB module.  Particularly, the models
   for the traceroute measurement configuration and for the result from
   completed measurements are almost identical.  But for other pats of
   the DISMAN-TRACEROUTE MIB module there is no need to model them in a
   traceroute measurements storage format.  Particularly, the capability
   information, information about ongoing measurements and measurement
   statistics are not covered by the DISMAN traceroute storage model.

   Concerning traceroute measurements and their results, there are



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   structural differences between the two models caused by the different
   choices for the encoding of the specification.  For DISMAN-
   TRACEROUTE-MIB, the Structure of Management Information (SMIv2, STD
   58, RFC 2578 [RFC2578]) was used, while the IPPM traceroute
   measurements data model is encoded using XML.

   This difference in structure implies that the DISMAN-TRACEROUTE-MIB
   module contains SMI-specific information element (managed objects)
   that concern tables of managed objects (specification, entry creation
   and deletion, status retrieval) that are not required for the XML-
   encoded traceroute measurements data model.

   But for most of the remaining information elements that concern
   configuration of traceroute measurements and results of completed
   measurements, the semantics is identical between the DISMAN-
   TRACEROUTE-MIB module and the traceroute measurements data model.
   There are very few exceptions to this which are listed below.  Also
   naming of information elements is identical between both models with
   a few exceptions.  For the traceroute measurements data model, a few
   information elements have been added, some because of the different
   structure and some to provide additional information on completed
   measurements.

C.1.  Naming

   Basically, names in both models are chosen using the same naming
   conventions.

   For the traceroute measurement configuration information all names,
   such as CtlProbesPerHop, are identical in both models except for the
   traceRoute prefix that was removed to avoid unnecessary redundancy in
   the XML file and for CtlDataSize which was renamed to
   CtlProbeDataSize for clarification in the traceroute measurements
   data model.

   Results of measurements in the DISMAN-TRACEROUTE-MIB modules are
   distributed over two tables, the traceRouteResultsTable containing
   mainly information about ongoing measurements and the
   traceRouteProbeHistoryTable containing only information about
   completed measurements.  According to the SMIv2 naming conventions
   names of information elements in these tables have different prefixes
   (traceRouteResults and traceRouteProbeHistory).  Since the traceroute
   measurements data model only reports on completed measurements, this
   separation is not needed anymore and the prefix "Results" is used for
   all related information elements.

   Beyond that, there are only a few changes in element names.  The
   renaming actions include:



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   o  traceRouteProbeHistoryProbeIndex to IndexPerHop,
   o  traceRouteProbeHistoryResponse to RoundTripTime,
   o  traceRouteProbeHistoryTime to ResultsEndDateAndTime,
   o  traceRouteProbeHistoryLastRC to ResultsHopRawOutputData.

C.2.  Semantics

   The semantics was changed for two information elements only.

   For traceRouteProbeHistoryResponse in the DISMAN-TRACEROUTE-MIB, a
   value of 0 indicated, that it was not possible to transmit a probe.
   For the traceroute measurements data model, a value of 0 for element
   RoundTripTime indicates that the measured time was less than one
   millisecond, while for the case that it was not possible to transmit
   a probe a string is used that indicates the problem.

   For traceRouteCtlIfIndex in the DISMAN-TRACEROUTE-MIB, a value of 0
   indicated, that it the option to set the index is not available.
   This was translated to the traceroute measurements data model, such
   that a value of 0 for this element indicates that the used interface
   is unknown.

   The element traceRouteProbeHistoryLastRC in the DISMAN-TRACEROUTE-MIB
   was replaced by element ResultsHopRawOutputData.  While
   traceRouteProbeHistoryLastRC just reports a reply code,
   ResultsHopRawOutputData reports the full raw output data (per hop)
   produced by the traceroute measurements that was used.

C.3.  Additional Information Elements

   Only a few information elements have been added to the model of the
   DISMAN-TRACEROUTE-MIB module.

   o  For providing geographical information about hops in the
      traceroute measurement path, HopGeoLocation was added.
   o  For providing information on the MPLS label stack entries of a
      probe in the traceroute measurement path MPLSLabelStackEntry was
      added.
   o  For providing additional timestamp beyond ResultsEndDateAndTime,
      ResultsStartDateAndTime and Time were added.











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Authors' Addresses

   Saverio Niccolini
   NEC Laboratories Europe, NEC Europe Ltd.
   Kurfuersten-Anlage 36
   Heidelberg  69115
   Germany

   Phone: +49 (0) 6221 4342 118
   Email: saverio.niccolini@netlab.nec.de
   URI:   http://www.netlab.nec.de


   Sandra Tartarelli
   NEC Laboratories Europe, NEC Europe Ltd.
   Kurfuersten-Anlage 36
   Heidelberg  69115
   Germany

   Phone: +49 (0) 6221 4342 132
   Email: sandra.tartarelli@netlab.nec.de
   URI:   http://www.netlab.nec.de


   Juergen Quittek
   NEC Laboratories Europe, NEC Europe Ltd.
   Kurfuersten-Anlage 36
   Heidelberg  69115
   Germany

   Phone: +49 (0) 6221 4342 115
   Email: quittek@netlab.nec.de
   URI:   http://www.netlab.nec.de


   Martin Swany
   Dept. of Computer and Information Sciences, University of Delaware
   Newark  DE 19716
   U.S.A.

   Email: swany@UDel.Edu










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