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Versions: (draft-dawes-insipid-logme-reqs) 00 01 02 03 04 05 06 07 08 09 10 11 12 RFC 8123

Internet Engineering Task Force                                 P. Dawes
Internet-Draft                                            Vodafone Group
Intended status: Informational                            C. Arunachalam
Expires: July 20, 2017                                     Cisco Systems
                                                        January 16, 2017


           Requirements for Marking SIP Messages to be Logged
                    draft-ietf-insipid-logme-reqs-12

Abstract

   SIP networks use signaling monitoring tools to debug customer
   reported problems and for regression testing if network or client
   software is upgraded.  As networks grow and become interconnected,
   including connection via transit networks, it becomes impractical to
   predict the path that SIP signaling will take between clients, and
   therefore impractical to monitor SIP signaling end-to-end.

   This draft describes requirements for adding an indicator to the SIP
   protocol data unit (PDU, or a SIP message) that marks the PDU as a
   candidate for logging.  Such marking will typically be applied as
   part of network testing controlled by the network operator and not
   used in regular client signaling.  However, such marking can be
   carried end-to-end including the SIP terminals, even if a session
   originates and terminates in different networks.

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 July 20, 2017.








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Copyright Notice

   Copyright (c) 2017 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
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   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Conventions Used in this Document . . . . . . . . . . . . . .   3
   3.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   3
     3.1.  Network Boundary  . . . . . . . . . . . . . . . . . . . .   3
     3.2.  Trust Domain  . . . . . . . . . . . . . . . . . . . . . .   4
     3.3.  Intermediary  . . . . . . . . . . . . . . . . . . . . . .   4
   4.  Motivating Scenario . . . . . . . . . . . . . . . . . . . . .   4
     4.1.  Introduction  . . . . . . . . . . . . . . . . . . . . . .   4
     4.2.  Example Network Arrangement . . . . . . . . . . . . . . .   4
     4.3.  Example Debugging Procedure . . . . . . . . . . . . . . .   5
   5.  Logme Marking Requirements  . . . . . . . . . . . . . . . . .   6
     5.1.  Message Logs  . . . . . . . . . . . . . . . . . . . . . .   6
     5.2.  "Log Me" Marking  . . . . . . . . . . . . . . . . . . . .   6
     5.3.  Processing the "Log Me" Marker  . . . . . . . . . . . . .   7
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .   8
     6.1.  Trust Domain  . . . . . . . . . . . . . . . . . . . . . .   8
     6.2.  Security Threats  . . . . . . . . . . . . . . . . . . . .   8
       6.2.1.  "Log Me" Marking  . . . . . . . . . . . . . . . . . .   8
       6.2.2.  Logged Information  . . . . . . . . . . . . . . . . .   9
   7.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   9
   8.  Acknowledgments . . . . . . . . . . . . . . . . . . . . . . .   9
   9.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   9
     9.1.  Normative References  . . . . . . . . . . . . . . . . . .   9
     9.2.  Informative References  . . . . . . . . . . . . . . . . .   9
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  10

1.  Introduction

   Service providers, enterprises, and others who operate networks that
   use SIP (see [RFC3261]) need the ability to debug end user reported
   problems and also to run regression tests if SIP client software/



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   hardware is upgraded.  Such debugging and tests might be confined to
   a single service provider or network, or may occur between the
   administrative domains of different network operators, including
   domains in different countries that are interconnected through
   networks belonging to one or more third parties.

   A mechanism is needed to mark particular SIP sessions, i.e. those
   related to debugging or regression testing, as candidates for logging
   and this marking must be carried within the candidate SIP messages as
   they are routed across networks (and geographies) to enable logging
   at each SIP entity without having to know in advance the list of SIP
   entities through which the SIP signaling messages will traverse.
   Such marking must take into account that SIP messages might traverse
   different network operators, different countries, regions with
   different privacy requirements, and different trust domains.  This
   draft describes the requirements for such a "log me" marker for SIP
   signaling.

2.  Conventions Used in this Document

   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], except that
   rather than describing interoperability requirements, they are used
   to describe requirements to be satisfied by the "log-me" marker
   solution.

3.  Terminology

3.1.  Network Boundary

   A network boundary is the part of a signaling path where messages
   pass between entities that are under different administrative
   control.  [RFC5853] Figure 2 shows a network boundary between GW-A1
   in operator A's network and the Session Border Controller (SBC) in
   operator B's network.  A network boundary is significant in this
   document because manipulation of signaling at the boundary could
   prevent end-to-end testing or troubleshooting.

   Topology hiding and protocol repair (see [RFC5853]) are two common
   functions that manipulate signaling at the network boundary.  These
   functions are performed by SIP device types (see [RFC7092]) such as
   Session Border Controller and Interconnection Border Control Function
   (IBCF).







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3.2.  Trust Domain

   In this document a trust domain is the set of entities that have been
   identified, by prior agreement, as participating elements in logging,
   typically for the purpose of debugging or regression testing.  A
   trust domain contains all SIP entities under configuration control of
   the network operator that is performing regression testing plus all
   SIP entities that are under configuration control of peer network
   operators who have agreed to participate in that regression testing.
   The purpose of trust domain requirements is to prevent network
   operators inadvertently triggering logging in networks that are not
   part of any testing or troubleshooting.

3.3.  Intermediary

   The term "intermediary" is defined in [RFC7989] section 2 and refers
   to any entity along the call signaling path.

4.  Motivating Scenario

4.1.  Introduction

   Signaling for SIP session setup can cross several networks, and these
   networks may not have common ownership and also may be in different
   countries.  If a single operator wishes to perform regression testing
   or fault debugging end-to-end, the separate ownership of networks
   that carry the signaling and the explosion in the number of possible
   signaling paths through SIP entities from the originating to the
   terminating user make it impractical to pre-configure logging of an
   end-to-end SIP signaling of a session of interest.

4.2.  Example Network Arrangement

   The figure below gives an example of a signaling path through
   multiple networks.
















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              +------------------+          +------------------+
              | COUNTRY W        |          | COUNTRY X        |
              | Operator A       |          | Operator A       |
              |                  |          |                  |
              | SIP Phones       |          | SIP Phones       |
              |                  |        //|                  |
              +------------------+       // +------------------+
                             |                  //
                             |                 //
                      ,'```',             //    +------------------+
              .`',.'        `..'``',<==//   | COUNTRY X        |
              ,'  Operator A         `',    | Operator A       |
              ;    Backbone Network    ..'--|                  |
              ',            ,.,    .'`      | PSTN phones      |
              '.,.`'.,,,.`   `''`           |                  |
                             ||                     +------------------+
                             ||
                             \/
              +------------------+
              |                  |
              |  Transit Network |
              |                  |
              |                  |\\
              +------------------+ \\
                              |             \\
                              |              \\
              +------------------+    \\    +------------------+
              | COUNTRY Z        |     \\   | COUNTRY Y        |
              | Operator C       |      \\=>| Operator B       |
              |                  |          |                  |
              | SIP Phones       |          | SIP Phones       |
              |                  |          |                  |
              +------------------+          +------------------+


        Figure 1: Example signaling path through multiple networks

4.3.  Example Debugging Procedure

   One possible set of steps is outlined below to illustrate the
   debugging procedure.

   o  The user's terminal is placed in debug mode.  The terminal logs
      its own signaling and inserts a "log me" marker into SIP requests
      for session setup.

   o  All SIP entities that the signaling traverses, from the first
      proxy the terminal connects to at the edge of the network to the



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      destination client terminal, detect that the "log me" marker is
      present and log SIP requests and responses that contain the marker
      if configured to do so.

   o  Subsequent responses and requests in the same dialog are also
      marked with a "log me" marker.  For some scenarios, such as call
      transfer, related dialogs may also be marked with "log me" marker.

   o  Logging stops, either because the dialog has ended or because a
      'stop event', typically expiry of a certain amount of time,
      occurred.

   o  Logs are retrieved, for example by logging on to the SIP entity or
      entities that contain the logs.

5.  Logme Marking Requirements

5.1.  Message Logs

   o  REQ1: If a SIP message is logged then the entire SIP message (SIP
      headers and message body) MUST be logged using standard logging
      format such as SIP CLF defined in [RFC6873].

   o  REQ2: Header fields SHOULD be logged in the form in which they
      appear in the message, they SHOULD NOT be converted between long
      and compact forms described in [RFC3261] clause 7.3.3.

   When and how signaling logs are retrieved is out of scope of this
   document.  Logs might be retrieved by logging on to the SIP entity
   that contains the logs, by sending logs to a central server that is
   co-ordinating debugging, by storing them on removable media for later
   manual collection, or by some other method.  All log retrieval
   mechanisms MUST adhere to authorization and privacy protection
   policies set forth by the network administrator.

5.2.  "Log Me" Marking

   o  REQ3: It MUST be possible to mark a SIP request or response to be
      considered for logging by inserting a "log me" marker.  This is
      known as "log me" marking.

   o  REQ4: It MUST be possible for a "log me" marker to cross network
      boundaries.

   o  REQ5: A "log me" marker MAY include an identifier that indicates
      the test case that caused it to be inserted, known as a test case
      identifier.  The test case identifier does not have any impact on
      session setup, it is used to collate all logged SIP requests and



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      responses to the initial SIP request in a dialog or standalone
      transaction.  The local UUID portion of Session-ID described in
      [RFC7206] and [RFC7989] could be used as a random test case
      identifier.

5.3.  Processing the "Log Me" Marker

   o  REQ6: A "log me" marker is most effective if all networks on the
      signaling path agree to pass it end-to-end.  However, source
      networks should behave responsibly and not leave it to a
      downstream network to detect and remove a marker that it is not
      expecting.

   o  REQ7: The presence of a "log me" marker indicates that a request
      or response is part of debugging or regression testing.

   o  REQ8: It MUST be possible to insert a "log me" marker in SIP
      responses that correspond to SIP requests with a "log me" marker
      in order to ensure that the complete SIP transaction is logged.
      This requirement applies to endpoints, SIP/PSTN gateways and
      B2BUAs.

   o  REQ9: The "log me" marker mechanism SHOULD allow a SIP
      intermediary to request logging SIP requests and responses on
      behalf of the originating endpoint.  The typical use case for this
      requirement is for compatibility with User Agents (UA) that have
      not implemented "log me" marking, i.e. when a UA has not marked a
      request or when responses received on a dialog of interest for
      logging do not contain an echoed "log me" marker.  Another use
      case is when the session origination UA that inserted log me
      marker is no longer participating in the session (e.g., call
      transfer scenarios) and the intermediary adds "log me" marker in
      related sessions to enable end-to-end signaling analysis.

   o  REQ10: The mechanism MUST allow stateless processing of SIP
      requests that contain a "log me" marker by SIP intermediaries.
      This requirement enables the SIP intermediaries to base the
      decision to log a SIP request or response solely on the presence
      of the "log me" marker.

   o  REQ11: The scope of SIP message logging request includes all
      requests and responses within a given dialog.  The scope can be
      extended to related dialogs that correspond to an end-to-end
      session for scenarios discussed in REQ9.  The "log me" request
      MUST be indicated at the beginning of the dialog of interest and
      SHOULD continue to the dialog end without any stop and restart
      during the duration of the dialog.




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   o  REQ12: The presence of a "log me" marker might cause some SIP
      entities to log signaling.  Therefore, this marker MUST be removed
      at the earliest opportunity if it has been incorrectly inserted
      (e.g. mid-dialog or outside the configured start and stop of "log
      me" marking).

   The definition of types of events that cause logging to stop and
   configuring SIP entities to detect such "stop events" is outside the
   scope of this document.

6.  Security Considerations

   In order to prevent any security implications of a "log me" marker,
   the marker itself MUST NOT contain any sensitive information,
   detecting its presence or absence MUST NOT reveal sensitive
   information, and maliciously adding a "log me" marker MUST NOT
   adversely affect a network.  This section analyses how to meet these
   requirements.

6.1.  Trust Domain

   Since a "log me" marker may cause a SIP entity to log the SIP header
   and body of a request or response, the "log me" marker MUST be
   removed at a trust domain boundary.  If a prior agreement to log
   sessions exists with the next hop network then the "log me" marker
   SHOULD NOT be removed.

6.2.  Security Threats

6.2.1.  "Log Me" Marking

   The "log me" marker MUST NOT convey any sensitive information,
   although the "log me" marker will sometimes be inserted because a
   particular device is experiencing problems.  The "log me" marker MUST
   NOT reveal any information related to any SIP user or device.

   The insertion of "log me" marker at the endpoint MUST be approved by
   the end user or by the network administrator.  Similarly, network
   administrator authorization is required for a SIP intermediary to
   insert a "log me" marker on behalf of an UA that does not support
   "log me" marking.

   Activating a debug mode affects the operation of a terminal,
   therefore debugging configuration MUST be supplied by an authorized
   party to an authorized terminal through a secure communication
   channel.





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6.2.2.  Logged Information

   Logged signaling is privacy-sensitive data, therefore signaling logs
   MUST NOT be readable by an unauthorized third party.

7.  IANA Considerations

   There are no IANA considerations associated with this document.

8.  Acknowledgments

   The authors wish to thank Jorgen Axell, Ben Campbell, Keith Drage,
   Vijay Gurbani, Christer Holmberg, Hadriel Kaplan, Paul Kyzivat, James
   Polk, Gonzalo Salgueiro, Alberto Llamas, Brett Tate, Paul Giralt,
   Stewart Bryant, Sean Turner, and Dan Romascanu for their constructive
   comments and guidance while developing this document.

9.  References

9.1.  Normative References

   [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>.

   [RFC6873]  Salgueiro, G., Gurbani, V., and A. Roach, "Format for the
              Session Initiation Protocol (SIP) Common Log Format
              (CLF)", RFC 6873, DOI 10.17487/RFC6873, February 2013,
              <http://www.rfc-editor.org/info/rfc6873>.

9.2.  Informative References

   [RFC3261]  Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston,
              A., Peterson, J., Sparks, R., Handley, M., and E.
              Schooler, "SIP: Session Initiation Protocol", RFC 3261,
              DOI 10.17487/RFC3261, June 2002,
              <http://www.rfc-editor.org/info/rfc3261>.

   [RFC5853]  Hautakorpi, J., Ed., Camarillo, G., Penfield, R.,
              Hawrylyshen, A., and M. Bhatia, "Requirements from Session
              Initiation Protocol (SIP) Session Border Control (SBC)
              Deployments", RFC 5853, DOI 10.17487/RFC5853, April 2010,
              <http://www.rfc-editor.org/info/rfc5853>.







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   [RFC7092]  Kaplan, H. and V. Pascual, "A Taxonomy of Session
              Initiation Protocol (SIP) Back-to-Back User Agents",
              RFC 7092, DOI 10.17487/RFC7092, December 2013,
              <http://www.rfc-editor.org/info/rfc7092>.

   [RFC7206]  Jones, P., Salgueiro, G., Polk, J., Liess, L., and H.
              Kaplan, "Requirements for an End-to-End Session
              Identification in IP-Based Multimedia Communication
              Networks", RFC 7206, DOI 10.17487/RFC7206, May 2014,
              <http://www.rfc-editor.org/info/rfc7206>.

   [RFC7989]  Jones, P., Salgueiro, G., Pearce, C., and P. Giralt, "End-
              to-End Session Identification in IP-Based Multimedia
              Communication Networks", RFC 7989, DOI 10.17487/RFC7989,
              October 2016, <http://www.rfc-editor.org/info/rfc7989>.

Authors' Addresses

   Peter Dawes
   Vodafone Group
   The Connection
   Newbury, Berkshire  RG14 2FN
   UK

   Email: peter.dawes@vodafone.com


   Chidambaram Arunachalam
   Cisco Systems
   7200-12 Kit Creek Road
   Research Triangle Park, NC, NC  27709
   US

   Email: carunach@cisco.com

















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