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Versions: (draft-clarke-i2rs-traceability) 00 01 02 03 04 05 06 07 08 09 10 11 RFC 7922

I2RS                                                           J. Clarke
Internet-Draft                                              G. Salgueiro
Intended status: Informational                              C. Pignataro
Expires: November 2, 2016                                          Cisco
                                                             May 1, 2016


   Interface to the Routing System (I2RS) Traceability: Framework and
                           Information Model
                    draft-ietf-i2rs-traceability-09

Abstract

   This document describes a framework for traceability in the Interface
   to the Routing System (I2RS) and information model for that
   framework.  It specifies the motivation, requirements, use cases, and
   defines an information model for recording interactions between
   elements implementing the I2RS protocol.  This framework provides a
   consistent tracing interface for components implementing the I2RS
   architecture to record what was done, by which component, and when.
   It aims to improve the management of I2RS implementations, and can be
   used for troubleshooting, auditing, forensics, and accounting
   purposes.

Status of This Memo

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

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

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on November 2, 2016.

Copyright Notice

   Copyright (c) 2016 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents



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   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Terminology and Conventions . . . . . . . . . . . . . . . . .   3
   3.  Motivation  . . . . . . . . . . . . . . . . . . . . . . . . .   3
   4.  Use Cases . . . . . . . . . . . . . . . . . . . . . . . . . .   3
   5.  Information Model . . . . . . . . . . . . . . . . . . . . . .   4
     5.1.  I2RS Traceability Framework . . . . . . . . . . . . . . .   4
     5.2.  I2RS Trace Log Mandatory Fields . . . . . . . . . . . . .   6
     5.3.  End of Message Marker . . . . . . . . . . . . . . . . . .   8
   6.  Examples  . . . . . . . . . . . . . . . . . . . . . . . . . .   9
   7.  Operational Guidance  . . . . . . . . . . . . . . . . . . . .   9
     7.1.  Trace Log Creation  . . . . . . . . . . . . . . . . . . .   9
     7.2.  Trace Log Temporary Storage . . . . . . . . . . . . . . .  10
     7.3.  Trace Log Rotation  . . . . . . . . . . . . . . . . . . .  10
     7.4.  Trace Log Retrieval . . . . . . . . . . . . . . . . . . .  10
       7.4.1.  Retrieval Via Syslog  . . . . . . . . . . . . . . . .  11
       7.4.2.  Retrieval Via I2RS Information Collection . . . . . .  11
       7.4.3.  Retrieval Via I2RS Pub-Sub  . . . . . . . . . . . . .  11
   8.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  12
   9.  Security Considerations . . . . . . . . . . . . . . . . . . .  12
   10. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . .  12
   11. References  . . . . . . . . . . . . . . . . . . . . . . . . .  12
     11.1.  Normative References . . . . . . . . . . . . . . . . . .  13
     11.2.  Informative References . . . . . . . . . . . . . . . . .  13
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  13

1.  Introduction

   The architecture for the Interface to the Routing System
   ([I-D.ietf-i2rs-architecture]) specifies that I2RS Clients wishing to
   retrieve or change routing state on a routing element MUST
   authenticate to an I2RS Agent.  The I2RS Client will have a unique
   identity it provides for authentication, and should provide another,
   opaque identity for applications communicating through it.  The
   programming of routing state will produce a return code containing
   the results of the specified operation and associated reason(s) for
   the result.  All of this is critical information to be used for
   understanding the history of I2RS interactions.




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   This document describes use cases for I2RS traceability.  Based on
   these use cases, the document proposes an information model and
   reporting requirements to provide for effective recording of I2RS
   interactions.  In this context, effective troubleshooting means being
   able to identify what operation was performed by a specific I2RS
   Client, what was the result of the operation, and when that operation
   was performed.

   Discussions about the retention of the data logged as part of I2RS
   traceability, while important, are outside of the scope of this
   document.

2.  Terminology and Conventions

   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].

   The architecture specification for I2RS [I-D.ietf-i2rs-architecture]
   defines additional terms used in this document that are specific to
   the I2RS domain, such as "I2RS Agent", "I2RS Client", etc.  The
   reader is expected to be familiar with the terminology and concepts
   defined in [I-D.ietf-i2rs-architecture].

3.  Motivation

   As networks scale and policy becomes an increasingly important part
   of the control plane that creates and maintains the forwarding state,
   operational complexity increases as well.  I2RS offers more granular
   and coherent control over policy and control plane state, but it also
   removes or reduces the locality of the policy that has been applied
   to the control plane at any individual forwarding device.  The
   ability to automate and abstract even complex policy-based controls
   highlights the need for an equally scalable traceability function to
   provide event-level granularity of the routing system compliant with
   the requirements of I2RS (Section 5 of
   [I-D.ietf-i2rs-problem-statement]).

4.  Use Cases

   An obvious motivation for I2RS traceability is the need to
   troubleshoot and identify root-causes of problems in these
   increasingly complex routing systems.  For example, since I2RS is a
   high-throughput multi-channel, full duplex and highly responsive
   interface, I2RS Clients may be performing a large number of
   operations on I2RS Agents concurrently or at nearly the same time and
   quite possibly in very rapid succession.  As these many changes are
   made, the network reacts accordingly.  These changes might lead to a



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   race condition, performance issues, data loss, or disruption of
   services.  In order to isolate the root cause of these issues it is
   critical that a network operator or administrator has visibility into
   what changes were made via I2RS at a specific time.

   Some network environments have strong auditing requirements for
   configuration and runtime changes.  Other environments have policies
   that require saving logging information for operational or regulatory
   compliance considerations.  These requirements therefore demand that
   I2RS provides an account of changes made to network element routing
   systems.

   As I2RS becomes increasingly pervasive in routing environments, a
   traceability model offers significant advantages and facilitates the
   following use cases:

   o  Automated event correlation, trend analysis, and anomaly
      detection;

   o  Trace log storage for offline (manual or tools) analysis;

   o  Improved accounting of routing system operations;

   o  Standardized structured data format for writing common tools;

   o  Common reference for automated testing and incident reporting;

   o  Real-time monitoring and troubleshooting;

   o  Enhanced network audit, management and forensic analysis
      capabilities.

5.  Information Model

5.1.  I2RS Traceability Framework

   This section describes a framework for I2RS traceability based on the
   I2RS Architecture.  Some notable elements of the architecture are in
   this section.

   The interaction between the optional northbound application, I2RS
   Client, I2RS Agent, the Routing System and the data captured in the
   I2RS trace log is shown in Figure 1.








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         +----------------+
         |Application     |
         |..............  |
         | Application ID |
         +----------------+
                ^
                |   0 .. N
                |
                v
         +-------------+
         |I2RS Client  |
         |.............|
         |  Client ID  |
         +-------------+
                ^
                |  1 .. N
                |
                v
         +-------------+                 +-----------------------------+
         |I2RS Agent   |---------------->|Trace Log                    |
         |             |                 |.............................|
         +-------------+                 |Log Entry  [1 .. N]          |
                ^                        |.............................|
                |                        |Starting Timestamp           |
                |                        |Request State                |
                |                        |Client ID                    |
                |                        |Client Priority              |
                |      ^                 |Secondary ID                 |
    Operation + | Result Code            |Client Address               |
     Op Data    |                        |Requested Operation          |
       v        |                        |Applied Operation            |
                |                        |Operation Data Present       |
                |                        |Requested Operation Data     |
                |                        |Applied Operation Data       |
                |                        |Transaction ID               |
                |                        |Result Code                  |
                |                        |Ending Timestamp             |
                |                        |Timeout Occurred             |
                v                        |End Of Message               |
         +-------------+                 +-----------------------------+
         |Routing      |
         |System       |
         +-------------+

               Figure 1: I2RS Interaction Trace Log Capture






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5.2.  I2RS Trace Log Mandatory Fields

   In order to ensure that each I2RS interaction can be properly traced
   back to the Client that made the request at a specific point in time,
   the following information MUST be collected and stored by the Agent.

   The list below describes the fields captured in the I2RS trace log.

   Entry ID:   This is a unique identifier for each entry in the I2RS
      trace log.  Since multiple operations can occur from the same
      Client at the same time, it is important to have an identifier
      that can be unambiguously associated to a specific entry.

   Starting Timestamp:   The specific time at which the I2RS operation
      entered the specified Request State within the Agent.  The time is
      passed in the [RFC3339] format.  Given that many I2RS operations
      can occur in rapid succession, the use of fractional seconds MUST
      be used to provide adequate granularity.  Fractional seconds
      SHOULD be expressed using human-readable 32-bit second and 32-bit
      microsecond granularity in second.microsecond format.  In the case
      when the trace log entry specifies a Request State of COMPLETED
      this time will reflect when the operation was first received by
      the I2RS Agent.

   Request State:   The state of the given operation within the I2RS
      Agent state machine between the specified Starting and Ending
      Timestamps.  This can be one of the following values:

         PENDING: The request has been receieved and queued for
         processing.

         IN PROCESS: The request is currently being handled by the I2RS
         Agent.

         COMPLETED: The request has reached a terminal point.

      In the case of the COMPLETED state, the Starting and Ending
      Timestamps will cover the entire duration of the operation
      including time spent in the PENDING and IN PROCESS states.

      Every state transition MAY be logged unless doing so will put an
      undue performance burden on the I2RS Agent.  However, an entry
      with Request State set to COMPLETED MUST be logged for all
      operations.

   Client Identity:   The I2RS Client identity used to authenticate the
      Client to the I2RS Agent.




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   Client Priority:   The I2RS Client priority assigned by the access
      control model that authenticates the Client.  For example, this
      can be set by the NETCONF Access Control Model (NACM) as described
      in [RFC6536].

   Secondary Identity:   This is an opaque identity that may be known to
      the Client from a northbound controlling application.  This is
      used to trace the northbound application driving the actions of
      the Client.  The Client may not provide this identity to the Agent
      if there is no external application driving the Client.  However,
      this field MUST be logged even if the Client does not provide a
      Secondary Identity.  In that case, the field will be logged with
      an empty value.

   Client Address:   This is the network address of the Client that
      connected to the Agent.  For example, this may be an IPv4 or IPv6
      address.

   Requested Operation:   This is the I2RS operation that was requested
      to be performed.  For example, this may be an add route operation
      if a route is being inserted into a routing table.  This may not
      be the operation that was actually applied to the Agent.

   Applied Operation:   This is the I2RS operation that was actually
      performed.  This can differ from the Requested Operation in cases
      where the Agent cannot satisfy the Requested Operation.  This
      field may not be logged unless the Request State is COMPLETED.

   Operation Data Present:   This is a Boolean field that indicates
      whether or not addition per-Operation Data is present.

   Requested Operation Data:   This field comprises the data passed to
      the Agent to complete the desired operation.  For example, if the
      operation is a route add operation, the Operation Data would
      include the route prefix, prefix length, and next hop information
      to be inserted as well as the specific routing table to which the
      route will be added.  If Operation Data is provided, then the
      Operation Data Present field MUST be set to TRUE.  Some operations
      may not provide operation data.  In those cases, the Operation
      Data Present field MUST be set to FALSE, and this field MUST be
      empty.  This may not represent the data that was used for the
      operation that was actually applied on the Agent.

   Applied Operation Data:   This field comprises the data that was
      actually applied as part of the Applied Operation.  If the Agent
      cannot satisfy the Requested Operation with the Requested
      Operation Data, then this field can differ from the Requested




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      Operation Data.  This field may not be logged unless the Request
      State is COMPLETED.

   Transaction ID:   The Transaction Identity represents that this
      particular operation is part of a long-running I2RS transaction
      that can consist of multiple, related I2RS operations.  Using this
      value, one can relate multiple log entries together as they are
      part of a single, overall I2RS operation.

   Result Code:   This field holds the result of the operation once the
      Request State is COMPLETED.  In the case of RIB operations, this
      MUST be the return code as specified in Section 4 of
      [I-D.ietf-i2rs-rib-info-model].  The operation may not complete
      with a result code in the case of a timeout.  If the operation
      fails to complete, it MUST still log the attempted operation with
      an appropriate result code.

   Timeout Occurred:   This is a Boolean field that indicates whether or
      not a timeout occurred in the operation.  When this is true, the
      value of the Ending Timestamp MUST be set to the time the Agent
      recorded for the timeout occurrence.  This field may not be logged
      unless the Request State is COMPLETED.

   Ending Timestamp:   The specific time at which the I2RS operation
      exited the specified Request State within the I2RS Agent.  The
      time is passed in the [RFC3339] format.  Given that many I2RS
      operations can occur in rapid succession, the use of fractional
      seconds MUST be used to provide adequate granularity.  Fractional
      seconds SHOULD be expressed using human-readable 32-bit second and
      32-bit microsecond granularity in second.microsecond format.

   End Of Message:   Each log entry SHOULD have an appropriate End Of
      Message (EOM) indicator.  See section Section 5.3 below for more
      details.

5.3.  End of Message Marker

   Because of variability within I2RS trace log fields, implementors
   MUST use a format-appropriate end of message (EOM) indicator in order
   to signify the end of a particular record.  That is, regardless of
   format, the I2RS trace log MUST provide a distinct way of
   distinguishing between the end of one record and the beginning of
   another.  For example, in a linear formated log (similar to syslog)
   the EOM marker may be a newline character.  In an XML formated log,
   the schema would provide for element tags that denote beginning and
   end of records.  In a JSON formated log, the syntax would provide
   record separation (likely by comma-separated array elements).




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6.  Examples

   This section shows a sample of what the fields and values could look
   like.


   Entry ID:                 1
   Starting Timestamp:       2013-09-03T12:00:01.21+00:00
   Request State:            COMPLETED
   Client ID:                5CEF1870-0326-11E2-A21F-0800200C9A66
   Client Priority:          100
   Secondary ID:             com.example.RoutingApp
   Client Address:           2001:db8:c0c0::2
   Requested Operation:      ROUTE_ADD
   Applied Operation:        ROUTE_ADD
   Operation Data Present:   TRUE
   Requested Operation Data: PREFIX 2001:db8:feed:: PREFIX-LEN 64
                             NEXT-HOP 2001:db8:cafe::1
   Applied Operation Data:   PREFIX 2001:db8:feed:: PREFIX-LEN 64
                             NEXT-HOP 2001:db8:cafe::1
   Transaction ID:           2763461
   Result Code:              SUCCESS(0)
   Timeout Occurred:         FALSE
   Ending Timestamp:         2013-09-03T12:00:01.23+00:00

7.  Operational Guidance

   Specific operational procedures regarding temporary log storage,
   rollover, retrieval, and access of I2RS trace logs is out of scope
   for this document.  Organizations employing I2RS trace logging are
   responsible for establishing proper operational procedures that are
   appropriately suited to their specific requirements and operating
   environment.  In this section we only provide fundamental and
   generalized operational guidelines that are implementation-
   independent.

7.1.  Trace Log Creation

   The I2RS Agent interacts with the Routing and Signaling functions of
   the Routing Element.  Since the I2RS Agent is responsible for
   actually making the routing changes on the associated network device,
   it creates and maintains a log of operations that can be retrieved to
   troubleshoot I2RS-related impact to the network.








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7.2.  Trace Log Temporary Storage

   The trace information may be temporarily stored either in an in-
   memory buffer or as a file local to the Agent.  Care should be given
   to the number of I2RS operations expected on a given Agent so that
   the appropriate storage medium is used and to maximize the
   effectiveness of the log while not impacting the performance and
   health of the Agent.  Client requests may not always be processed
   synchronously or within a bounded time period.  Consequently, to
   ensure that trace log fields, such as "Operation" and "Result Code",
   are part of the same trace log record it may require buffering of the
   trace log entries.  This buffering may result in additional resource
   load on the Agent and the network element.

   Section 7.3 discusses rotating the trace log in order to preserve the
   operation history without exhausting Agent or network device
   resources.  It is perfectly acceptable, therefore, to use both an in-
   memory buffer for recent operations while rotating or archiving older
   operations to a local file.

   It is outside the scope of this document to specify the
   implementation details (i.e., size, throughput, data protection,
   privacy, etc.) for the physical storage of the I2RS log file.  Data
   retention policies of the I2RS traceability log is also outside the
   scope of this document.

7.3.  Trace Log Rotation

   In order to prevent the exhaustion of resources on the I2RS Agent or
   its associated network device, it is RECOMMENDED that the I2RS Agent
   implements trace log rotation.  The details on how this is achieved
   are left to the implementation and outside the scope of this
   document.  However, it should be possible to do file rotation based
   on either time or size of the current trace log.  If file rollover is
   supported, multiple archived log files should be supported in order
   to maximize the troubleshooting and accounting benefits of the trace
   log.

7.4.  Trace Log Retrieval

   Implementors are free to provide their own, proprietary interfaces
   and develop custom tools to retrieve and display the I2RS trace log.
   These may include the display of the I2RS trace log as Command Line
   Interface (CLI) output.  However, a key intention of defining this
   information model is to establish a vendor-agnostic and consistent
   interface to collect I2RS trace data.  Correspondingly, retrieval of
   the data should also be made vendor-agnostic.




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   Despite the fact that export of I2RS trace log information could be
   an invaluable diagnostic tool for off-box analysis, exporting this
   information MUST NOT interfere with the ability of the Agent to
   process new incoming operations.

   The following three sections describe potential ways the trace log
   can be accessed.  At least one of these three MUST be used, with the
   I2RS mechanisms being preferred as they are vendor-independent
   approaches to retrieving the data.

7.4.1.  Retrieval Via Syslog

   The syslog protocol [RFC5424] is a standard way of sending event
   notification messages from a host to a collector.  However, the
   protocol does not define any standard format for storing the
   messages, and thus implementors of I2RS tracing would be left to
   define their own format.  So, while the data contained within the
   syslog message would adhere to this information model, and may be
   consumable by a human operator, it would not be easily parseable by a
   machine.  Syslog MAY be employed as a means of retrieving or
   disseminating the I2RS trace log contents.

   If syslog is used for trace log retrieval, then existing logging
   infrastructure and capabilities of syslog [RFC5424] should be
   leveraged without the need to define or extend existing formats.  For
   example, the various fields described in Section 5.2 SHOULD be
   modeled and encoded as Structured Data Elements (referred to as "SD-
   ELEMENT"), as described in Section 6.3.1 of [RFC5424].

7.4.2.  Retrieval Via I2RS Information Collection

   Section 6.7 of the I2RS architecture [I-D.ietf-i2rs-architecture]
   defines a mechanism for information collection.  The information
   collected includes obtaining a snapshot of a large amount of data
   from the network element.  It is the intent of I2RS to make this data
   available in an implementor-agnostic fashion.  Therefore, the I2RS
   trace log SHOULD be made available via the I2RS information
   collection mechanism either as a single snapshot or via a
   subscription stream.

7.4.3.  Retrieval Via I2RS Pub-Sub

   Section 7.6 of the I2RS architecture [I-D.ietf-i2rs-architecture]
   goes on to describe notification mechanisms for a feed of changes
   happening within the I2RS layer.  Specifically, the requirements for
   a publish-subscribe system for I2RS are defined in
   [I-D.ietf-i2rs-pub-sub-requirements].  I2RS Agents SHOULD support
   publishing I2RS trace log information to that feed as described in



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   that document.  Subscribers would then receive a live stream of I2RS
   interactions in trace log format and could flexibly choose to do a
   number of things with the log messages.  For example, the subscribers
   could log the messages to a datastore, aggregate and summarize
   interactions from a single Client, etc.  The full range of potential
   activites is virtually limitless and the details of how they are
   performed are outside the scope of this document, however.

8.  IANA Considerations

   This document makes no request of IANA.

9.  Security Considerations

   The I2RS trace log, like any log file, reveals the state of the
   entity producing it as well as the identifying information elements
   and detailed interactions of the system containing it.  The
   information model described in this document does not itself
   introduce any security issues, but it does define the set of
   attributes that make up an I2RS log file.  These attributes may
   contain sensitive information and thus should adhere to the security,
   privacy and permission policies of the organization making use of the
   I2RS log file.

   It is outside the scope of this document to specify how to protect
   the stored log file, but it is expected that adequate precautions and
   security best practices such as disk encryption, appropriately
   restrictive file/directory permissions, suitable hardening and
   physical security of logging entities, mutual authentication,
   transport encryption, channel confidentiality, and channel integrity
   if transferring log files.  Additionally, the potentially sensitive
   information contained in a log file SHOULD be adequately anonymized
   or obfuscated by operators to ensure its privacy.

10.  Acknowledgments

   The authors would like to thank Alia Atlas for her initial feedback
   and overall support for this work.  Additionally, the authors
   acknowledge Alvaro Retana, Russ White, Matt Birkner, Jeff Haas, Joel
   Halpern, Dean Bogdanovich, Ignas Bagdonas, Nobo Akiya, Kwang-koog
   Lee, Sue Hares, Mach Chen, and Alex Clemm for their reviews,
   contributed text, and suggested improvements to this document.

11.  References







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11.1.  Normative References

   [I-D.ietf-i2rs-architecture]
              Atlas, A., Halpern, J., Hares, S., Ward, D., and T.
              Nadeau, "An Architecture for the Interface to the Routing
              System", draft-ietf-i2rs-architecture-13 (work in
              progress), February 2016.

   [I-D.ietf-i2rs-problem-statement]
              Atlas, A., Nadeau, T., and D. Ward, "Interface to the
              Routing System Problem Statement", draft-ietf-i2rs-
              problem-statement-10 (work in progress), February 2016.

   [I-D.ietf-i2rs-pub-sub-requirements]
              Voit, E., Clemm, A., and A. Prieto, "Requirements for
              Subscription to YANG Datastores", draft-ietf-i2rs-pub-sub-
              requirements-06 (work in progress), April 2016.

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

11.2.  Informative References

   [I-D.ietf-i2rs-rib-info-model]
              Bahadur, N., Kini, S., and J. Medved, "Routing Information
              Base Info Model", draft-ietf-i2rs-rib-info-model-08 (work
              in progress), October 2015.

   [RFC3339]  Klyne, G. and C. Newman, "Date and Time on the Internet:
              Timestamps", RFC 3339, DOI 10.17487/RFC3339, July 2002,
              <http://www.rfc-editor.org/info/rfc3339>.

   [RFC5424]  Gerhards, R., "The Syslog Protocol", RFC 5424,
              DOI 10.17487/RFC5424, March 2009,
              <http://www.rfc-editor.org/info/rfc5424>.

   [RFC6536]  Bierman, A. and M. Bjorklund, "Network Configuration
              Protocol (NETCONF) Access Control Model", RFC 6536,
              DOI 10.17487/RFC6536, March 2012,
              <http://www.rfc-editor.org/info/rfc6536>.

Authors' Addresses







Clarke, et al.          Expires November 2, 2016               [Page 13]


Internet-Draft              I2RS Traceability                   May 2016


   Joe Clarke
   Cisco Systems, Inc.
   7200-12 Kit Creek Road
   Research Triangle Park, NC  27709
   US

   Phone: +1-919-392-2867
   Email: jclarke@cisco.com


   Gonzalo Salgueiro
   Cisco Systems, Inc.
   7200-12 Kit Creek Road
   Research Triangle Park, NC  27709
   US

   Email: gsalguei@cisco.com


   Carlos Pignataro
   Cisco Systems, Inc.
   7200-12 Kit Creek Road
   Research Triangle Park, NC  27709
   US

   Email: cpignata@cisco.com

























Clarke, et al.          Expires November 2, 2016               [Page 14]


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