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Versions: (draft-dawes-dispatch-logme-reqs) 00 draft-ietf-insipid-logme-reqs

Internet Engineering Task Force                                 P. Dawes
Internet-Draft                                            Vodafone Group
Intended status: Standards Track                        January 16, 2014
Expires: July 20, 2014


           Requirements for Marking SIP Messages to be Logged
                   draft-dawes-insipid-logme-reqs-00

Abstract

   SIP networks use signalling monitoring tools to diagnose user
   reported problem 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 signalling will take between clients, and
   therefore impractical to monitor SIP signalling end-to-end.

   This draft describes requirements for adding an indicator to the SIP
   protocol which can be used to mark signalling as of interest to
   logging.  Such marking will typically be applied as part of network
   testing controlled by the network operator and not used in regular
   client signalling.  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, 2014.

Copyright Notice

   Copyright (c) 2014 IETF Trust and the persons identified as the
   document authors.  All rights reserved.




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   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
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   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.  Requirements Language . . . . . . . . . . . . . . . . . . . .   2
   3.  Motivating Scenario . . . . . . . . . . . . . . . . . . . . .   3
   4.  Skeleton Diagnostic Procedure . . . . . . . . . . . . . . . .   4
   5.  Requirements for a Log Me Marker  . . . . . . . . . . . . . .   5
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .   6
     6.1.  Trust Domain  . . . . . . . . . . . . . . . . . . . . . .   6
     6.2.  Security Threats  . . . . . . . . . . . . . . . . . . . .   6
       6.2.1.  Log-me marking  . . . . . . . . . . . . . . . . . . .   6
       6.2.2.  Sending logged information  . . . . . . . . . . . . .   7
   7.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   7
     7.1.  Normative References  . . . . . . . . . . . . . . . . . .   7
     7.2.  Informative References  . . . . . . . . . . . . . . . . .   7
   Appendix A.  Additional Stuff . . . . . . . . . . . . . . . . . .   8
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .   8

1.  Introduction

   If users experience problems with setting up sessions using SIP,
   their service provider needs to find out why by examining the SIP
   signalling.  Also, if network or client software or hardware is
   upgraded regression testing is needed.  Such diagnostics apply to a
   small proportion of network traffic and can apply end-to-end, even if
   signalling crosses several networks possibly belonging to several
   different network operators.  It may not be possible to predict the
   path through those networks in advance, therefore a mechanism is
   needed to mark a session as being of interest to enable SIP entities
   along the signalling path to provide diagnostic logging.  This draft
   describes the requirements for such a 'log me' marker for SIP
   signalling.

2.  Requirements Language

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



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3.  Motivating Scenario

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

   The figure below shows an example of a signalling path through
   multiple networks.





































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


        Figure 1: Example signalling path through multiple networks

4.  Skeleton Diagnostic Procedure

   The skeleton diagnostic procedure is as follows:

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

   o  All SIP entities that the signalling traverses, from the first
      proxy the terminal connects to at the edge of the network to the
      destination client terminal, can detect that the log me marker is



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      present and can log SIP requests and responses that contain the
      marker if configured to do so.

   o  Subsequent responses and requests in the same dialog are logged.

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

   o  The user's terminal and any other SIP entity that has logged
      signalling sends logs to a server that is co-ordinating
      diagnostics.

5.  Requirements for a Log Me Marker

   o  REQ1: It shall be possible to mark a SIP request or response as of
      interest for logging by inserting a log me marker.  This is known
      as log-me marking.

   o  REQ2: It shall be possible for a log-me marker to cross network
      boundaries.

   o  REQ3: A log-me marker is most effective if it passes 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
      will not use.  A log-me marker should be removed at trust domain
      boundaries.

   o  REQ4: SIP entities should log SIP requests or responses with a
      log-me marker.

   o  REQ5: If a UA receives a request with a log-me marker, it shall
      echo that log-me marker in responses to that request.

   o  REQ6: A SIP proxy may perform log-me marking of requests and
      responses.  Typical cases where a proxy needs to perform log-me
      marking are when a UA has not marked a request and when responses
      received on a dialog of interest for logging do not contain a log-
      me marker.  In these cases, the entity that performs log-me
      marking is stateful inasmuch as it must remember when a dialog is
      of interest for logging.

   o  REQ7: For SIP proxies, logging of SIP requests that contain a log-
      me marker may be stateless.  For example, it is not required for a
      SIP entity to maintain state of which SIP requests contained a
      log-me marker in order to log responses to those requests.
      Echoing a log-me marker in responses is the responsibility of the
      UA that receives a request.



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   o  REQ8: 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 by the diagnostic server to collate all
      logged SIP requests and responses to the initial SIP request in a
      dialog or standalone transaction.  The Session-ID described in I-D
      .ietf-insipid-session-id-reqts [I-D.ietf-insipid-session-id-reqts]
      could be used as the test case identifier but it would be useful
      for the UA to log a human readable name together with this
      Session-ID when it performs log me marking of an initial SIP
      request.

6.  Security Considerations

   All drafts are required to have a security considerations section.
   See RFC 3552 [RFC3552] for a guide.

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 should be
   removed at a trust domain boundary.  If a prior agreement to log
   sessions exists with the net hop network then the log me marker might
   not be removed.

6.2.  Security Threats

6.2.1.  Log-me marking

   The log me marker is not sensitive information, although it will
   sometimes be inserted because a particular device is experiencing
   problems.

   The presence of a log me marker will cause some SIP entities to log
   signalling.  Therefore, this marker must be removed at the earliest
   opportunity if it has been incorrectly inserted.

   Activating a debug mode affects the operation of a terminal,
   therefore it must be supplied by an authorized server to an
   authorized terminal, it must not be altered in transit, and it must
   not be readable by an unauthorized third party.

   Logged signalling is privacy-sensitive data, therefore it must be
   passed to an authorized server, it must not be altered in transit,
   and it must not be readable by an unauthorized third party.






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6.2.2.  Sending logged information

   A SIP entity that has logged information should encrypt it, such that
   it can be decrypted only by the debug server, before sending it to a
   debug server in order to protect the content of logs from a third
   party.

7.  References

7.1.  Normative References

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

7.2.  Informative References

   [I-D.ietf-insipid-session-id-reqts]
              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", draft-ietf-insipid-session-id-reqts-07 (work in
              progress), June 2013.

   [RFC2234]  Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax
              Specifications: ABNF", RFC 2234, November 1997.

   [RFC2629]  Rose, M., "Writing I-Ds and RFCs using XML", RFC 2629,
              June 1999.

   [RFC3261]  Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston,
              A., Peterson, J., Sparks, R., Handley, M., and E.
              Schooler, "SIP: Session Initiation Protocol", RFC 3261,
              June 2002.

   [RFC3311]  Rosenberg, J., "The Session Initiation Protocol (SIP)
              UPDATE Method", RFC 3311, October 2002.

   [RFC3428]  Campbell, B., Rosenberg, J., Schulzrinne, H., Huitema, C.,
              and D. Gurle, "Session Initiation Protocol (SIP) Extension
              for Instant Messaging", RFC 3428, December 2002.

   [RFC3552]  Rescorla, E. and B. Korver, "Guidelines for Writing RFC
              Text on Security Considerations", BCP 72, RFC 3552, July
              2003.

   [RFC3903]  Niemi, A., "Session Initiation Protocol (SIP) Extension
              for Event State Publication", RFC 3903, October 2004.




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   [RFC6086]  Holmberg, C., Burger, E., and H. Kaplan, "Session
              Initiation Protocol (SIP) INFO Method and Package
              Framework", RFC 6086, January 2011.

Appendix A.  Additional Stuff

   This becomes an Appendix.

Author's Address

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

   Phone: +44 7717 275009
   Email: peter.dawes@vodafone.com


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