Internet DRAFT - draft-ietf-insipid-logme-reqs
draft-ietf-insipid-logme-reqs
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.
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This Internet-Draft will expire on July 20, 2017.
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Copyright Notice
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document authors. All rights reserved.
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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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