draft-ietf-sipbrandy-osrtp-10.txt		rfc8643.txt
	SIPBRANDY Working Group A. Johnston		Internet Engineering Task Force (IETF) A. Johnston
	Internet-Draft Villanova University		Request for Comments: 8643 Villanova University
	Intended status: Informational B. Aboba		Category: Informational B. Aboba
	Expires: December 19, 2019 Microsoft		ISSN: 2070-1721 Microsoft
	A. Hutton		A. Hutton
	Atos		Atos
	R. Jesske		R. Jesske
	Deutsche Telekom		Deutsche Telekom
	T. Stach		T. Stach
	Unaffiliated		Unaffiliated
	June 17, 2019		August 2019
	An Opportunistic Approach for Secure Real-time Transport Protocol		An Opportunistic Approach for Secure Real-time Transport Protocol
	(OSRTP)		(OSRTP)
	draft-ietf-sipbrandy-osrtp-10
	Abstract		Abstract
	Opportunistic Secure Real-time Transport Protocol (OSRTP) is an		Opportunistic Secure Real-time Transport Protocol (OSRTP) is an
	implementation of the Opportunistic Security mechanism, as defined in		implementation of the Opportunistic Security mechanism, as defined in
	RFC 7435, applied to the Real-time Transport Protocol (RTP). OSRTP		RFC 7435, applied to the Real-time Transport Protocol (RTP). OSRTP
	allows encrypted media to be used in environments where support for		allows encrypted media to be used in environments where support for
	encryption is not known in advance, and not required. OSRTP does not		encryption is not known in advance and is not required. OSRTP does
	require Session Description Protocol (SDP) extensions or features and		not require Session Description Protocol (SDP) extensions or features
	is fully backwards compatible with existing implementations using		and is fully backwards compatible with existing implementations using
	encrypted and authenticated media and implementations that do not		encrypted and authenticated media and implementations that do not
	encrypt or authenticate media packets. OSRTP is not specific to any		encrypt or authenticate media packets. OSRTP is not specific to any
	key management technique for Secure RTP (SRTP). OSRTP is a		key management technique for Secure RTP (SRTP). OSRTP is a
	transitional approach useful for migrating existing deployments of		transitional approach useful for migrating existing deployments of
	real-time communications to a fully encrypted and authenticated		real-time communications to a fully encrypted and authenticated
	state.		state.
	Status of This Memo		Status of This Memo
	This Internet-Draft is submitted in full conformance with the		This document is not an Internet Standards Track specification; it is
	provisions of BCP 78 and BCP 79.		published for informational purposes.
	Internet-Drafts are working documents of the Internet Engineering		This document is a product of the Internet Engineering Task Force
	Task Force (IETF). Note that other groups may also distribute		(IETF). It represents the consensus of the IETF community. It has
	working documents as Internet-Drafts. The list of current Internet-		received public review and has been approved for publication by the
	Drafts is at https://datatracker.ietf.org/drafts/current/.		Internet Engineering Steering Group (IESG). Not all documents
			approved by the IESG are candidates for any level of Internet
			Standard; see Section 2 of RFC 7841.
	Internet-Drafts are draft documents valid for a maximum of six months		Information about the current status of this document, any errata,
	and may be updated, replaced, or obsoleted by other documents at any		and how to provide feedback on it may be obtained at
	time. It is inappropriate to use Internet-Drafts as reference		https://www.rfc-editor.org/info/rfc8643.
	material or to cite them other than as "work in progress."
	This Internet-Draft will expire on December 19, 2019.
	Copyright Notice		Copyright Notice
	Copyright (c) 2019 IETF Trust and the persons identified as the		Copyright (c) 2019 IETF Trust and the persons identified as the
	document authors. All rights reserved.		document authors. All rights reserved.
	This document is subject to BCP 78 and the IETF Trust's Legal		This document is subject to BCP 78 and the IETF Trust's Legal
	Provisions Relating to IETF Documents		Provisions Relating to IETF Documents
	(https://trustee.ietf.org/license-info) in effect on the date of		(https://trustee.ietf.org/license-info) in effect on the date of
	publication of this document. Please review these documents		publication of this document. Please review these documents
	skipping to change at page 2, line 33 ¶		skipping to change at page 2, line 32 ¶
	1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2		1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
	1.1. Applicability Statement . . . . . . . . . . . . . . . . . 3		1.1. Applicability Statement . . . . . . . . . . . . . . . . . 3
	2. Requirements Language . . . . . . . . . . . . . . . . . . . . 3		2. Requirements Language . . . . . . . . . . . . . . . . . . . . 3
	3. SDP Offer/Answer Considerations . . . . . . . . . . . . . . . 3		3. SDP Offer/Answer Considerations . . . . . . . . . . . . . . . 3
	3.1. Generating the Initial OSRTP Offer . . . . . . . . . . . 4		3.1. Generating the Initial OSRTP Offer . . . . . . . . . . . 4
	3.2. Generating the Answer . . . . . . . . . . . . . . . . . . 4		3.2. Generating the Answer . . . . . . . . . . . . . . . . . . 4
	3.3. Offerer Processing the Answer . . . . . . . . . . . . . . 4		3.3. Offerer Processing the Answer . . . . . . . . . . . . . . 4
	3.4. Modifying the Session . . . . . . . . . . . . . . . . . . 5		3.4. Modifying the Session . . . . . . . . . . . . . . . . . . 5
	4. Security Considerations . . . . . . . . . . . . . . . . . . . 5		4. Security Considerations . . . . . . . . . . . . . . . . . . . 5
	5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6		5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6
	6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 6		6. References . . . . . . . . . . . . . . . . . . . . . . . . . 6
	7. References . . . . . . . . . . . . . . . . . . . . . . . . . 6		6.1. Normative References . . . . . . . . . . . . . . . . . . 6
	7.1. Normative References . . . . . . . . . . . . . . . . . . 6		6.2. Informative References . . . . . . . . . . . . . . . . . 7
	7.2. Informative References . . . . . . . . . . . . . . . . . 7		Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . 7
	Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 8		Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 8
	1. Introduction		1. Introduction
	Opportunistic Security [RFC7435] (OS) is an approach to security that		Opportunistic Security (OS) [RFC7435] is an approach to security that
	defines a third mode for security between "cleartext" and		defines a third mode for security between "cleartext" and
	"comprehensive protection" that allows encryption and authentication		"comprehensive protection" that allows encryption and authentication
	of media to be used if supported but will not result in failures if		of media to be used if supported but will not result in failures if
	it is not supported. In the context of the transport of secure media		it is not supported. In the context of the transport of secure media
	streams using RTP and is secured derivatives, cleartext is		streams using RTP and its secured derivatives, cleartext is
	represented by an RTP [RFC3550] media stream which is negotiated with		represented by an RTP [RFC3550] media stream that is negotiated with
	the RTP/AVP (Audio Video Profile) [RFC3551] or the RTP/AVPF profile		the RTP/AVP (Audio-Visual Profile) [RFC3551] or the RTP/AVPF profile
	[RFC4585], whereas, comprehensive protection is represented by a		[RFC4585], whereas comprehensive protection is represented by a
	Secure RTP [RFC3711] stream, negotiated with a secure profile, such		Secure RTP [RFC3711] stream negotiated with a secure profile, such as
	as SAVP or SAVPF [RFC5124]. OSRTP allows SRTP to be negotiated with		SAVP or SAVPF [RFC5124]. OSRTP allows SRTP to be negotiated with the
	the RTP/AVP profile, with fallback to RTP if SRTP is not supported.		RTP/AVP profile, with fallback to RTP if SRTP is not supported.
	There have been some extensions to SDP to allow profiles to be		There have been some extensions to SDP to allow profiles to be
	negotiated such as SDP Capabilities Negotiation (capneg) [RFC5939].		negotiated, such as SDP Capabilities Negotiation (SDPCapNeg)
	However, these approaches are complex and have very limited		[RFC5939]. However, these approaches are complex and have very
	deployment in communication systems. Other key management protocols		limited deployment in communication systems. Other key management
	for SRTP have been developed which by design use OS, such as ZRTP		protocols for SRTP that have been developed, such as ZRTP [RFC6189],
	[RFC6189]. This approach for OSRTP is based on		use OS by design. This approach for OSRTP is based on [Kaplan06]
	[I-D.kaplan-mmusic-best-effort-srtp] where it was called "best effort		where it was called "best effort SRTP". [Kaplan06] has a full
	SRTP". [I-D.kaplan-mmusic-best-effort-srtp] has a full discussion of		discussion of the motivation and requirements for opportunistic
	the motivation and requirements for opportunistic secure media.		secure media.
	OSRTP uses the presence of SRTP keying-related attributes in an SDP		OSRTP uses the presence of SRTP keying-related attributes in an SDP
	offer to indicate support for opportunistic secure media. The		offer to indicate support for opportunistic secure media. The
	presence of SRTP keying-related attributes in the SDP answer		presence of SRTP keying-related attributes in the SDP answer
	indicates that the other party also supports OSRTP and encrypted and		indicates that the other party also supports OSRTP and that encrypted
	authenticated media will be used. OSRTP requires no additional		and authenticated media will be used. OSRTP requires no additional
	extensions to SDP or new attributes and is defined independently of		extensions to SDP or new attributes and is defined independently of
	the key agreement mechanism used. OSRTP is only usable when media is		the key agreement mechanism used. OSRTP is only usable when media is
	negotiated using the Offer/Answer protocol [RFC3264].		negotiated using the Offer/Answer protocol [RFC3264].
	1.1. Applicability Statement		1.1. Applicability Statement
	OSRTP is a transitional approach that provides a migration path from		OSRTP is a transitional approach that provides a migration path from
	unencrypted communication (RTP) to fully encrypted communication		unencrypted communication (RTP) to fully encrypted communication
	(SRTP). It is only to be used in existing deployments which are		(SRTP). It is only to be used in existing deployments that are
	attempting to transition to fully secure communications. New		attempting to transition to fully secure communications. New
	applications and new deployments will not use OSRTP.		applications and new deployments will not use OSRTP.
	2. Requirements Language		2. Requirements Language
	The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",		The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
	"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and		"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
	"OPTIONAL" in this document are to be interpreted as described in BCP		"OPTIONAL" in this document are to be interpreted as described in
	14 [RFC2119] [RFC8174] when, and only when, they appear in all		BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
	capitals, as shown here.		capitals, as shown here.
	3. SDP Offer/Answer Considerations		3. SDP Offer/Answer Considerations
	This section defines the SDP offer/answer considerations for		This section defines the SDP offer/answer considerations for
	opportunistic security.		opportunistic security.
	The procedures are for a specific m= section describing RTP-based		The procedures are for a specific "m=" section describing RTP-based
	media. If an SDP offer or answer contains multiple such m= sections,		media. If an SDP offer or answer contains multiple such "m="
	the procedures are applied to each m= section individually.		sections, the procedures are applied to each "m=" section
			individually.
	"Initial OSRTP offer" refers to the offer in which oportunistic		"Initial OSRTP offer" refers to the offer in which opportunistic
	security is offered for an m= section for the first time within an		security is offered for an "m=" section for the first time within an
	SDP session.		SDP session.
	It is important to note that OSRTP makes no changes, and has no		It is important to note that OSRTP makes no changes to and has no
	effect on media sessions in which the offer contains a secure profile		effect on media sessions in which the offer contains a secure profile
	of RTP, such as SAVP or SAVPF. As discussed in [RFC7435], that is		of RTP, such as SAVP or SAVPF. As discussed in [RFC7435], that is
	the "comprehensive protection" for media mode.		the "comprehensive protection" for media mode.
	3.1. Generating the Initial OSRTP Offer		3.1. Generating the Initial OSRTP Offer
	To indicate support for OSRTP in an SDP offer, the offerer uses the		To indicate support for OSRTP in an SDP offer, the offerer uses the
	RTP/AVP profile [RFC3551] or the RTP/AVPF profile [RFC4585] but		RTP/AVP profile [RFC3551] or the RTP/AVPF profile [RFC4585] but
	includes SRTP keying attributes. OSRTP is not specific to any key		includes SRTP keying attributes. OSRTP is not specific to any key
	management technique for SRTP and multiple key management techniques		management technique for SRTP, and multiple key management techniques
	can be included on the SDP offer. For example:		can be included on the SDP offer. For example:
	If the offerer supports DTLS-SRTP key agreement [RFC5763], then an		If the offerer supports DTLS-SRTP key agreement [RFC5763], then an
	a=fingerprint attribute will be present, or		"a=fingerprint" attribute will be present. Or:
	If the offerer supports SDP Security Descriptions key agreement		If the offerer supports SDP Security Descriptions key agreement
	[RFC4568], then an a=crypto attribute will be present, or		[RFC4568], then an "a=crypto" attribute will be present. Or:
	If the offerer supports ZRTP key agreement [RFC6189], then an		If the offerer supports ZRTP key agreement [RFC6189], then an
	a=zrtp-hash attribute will be present.		"a=zrtp-hash" attribute will be present.
	3.2. Generating the Answer		3.2. Generating the Answer
	To accept OSRTP, an answerer receiving an offer indicating support		To accept OSRTP, an answerer receiving an offer indicating support
	for OSRTP generates an SDP answer containing SRTP keying attributes		for OSRTP generates an SDP answer containing SRTP keying attributes
	which match one of the keying methods in the offer. The answer MUST		that match one of the keying methods in the offer. The answer MUST
	NOT contain attributes from more than one keying method, even if the		NOT contain attributes from more than one keying method, even if the
	offer contained multiple keying method attributes. The selected SRTP		offer contained multiple keying method attributes. The selected SRTP
	key management approach is followed and SRTP media is used for this		key management approach is followed, and SRTP media is used for this
	session. If the SRTP key management fails for any reason, the media		session. If the SRTP key management fails for any reason, the media
	session MUST fail. To decline OSRTP, the answerer generates an SDP		session MUST fail. To decline OSRTP, the answerer generates an SDP
	answer omitting SRTP keying attributes, and the media session		answer omitting SRTP keying attributes, and the media session
	proceeds with RTP with no encryption or authentication used.		proceeds with RTP with no encryption or authentication used.
	3.3. Offerer Processing the Answer		3.3. Offerer Processing the Answer
	If the offerer of OSRTP receives an SDP answer which does not contain		If the offerer of OSRTP receives an SDP answer that does not contain
	SRTP keying attributes, then the media session proceeds with RTP. If		SRTP keying attributes, then the media session proceeds with RTP. If
	the SDP answer contains SRTP keying attributes then the associated		the SDP answer contains SRTP keying attributes, then the associated
	SRTP key management approach is followed and SRTP media is used for		SRTP key management approach is followed and SRTP media is used for
	this session. If the SRTP key management fails, the media session		this session. If the SRTP key management fails, the media session
	MUST fail.		MUST fail.
	3.4. Modifying the Session		3.4. Modifying the Session
	When an offerer generates a subsequent SDP offer it should do so		When an offerer generates a subsequent SDP offer, it should do so
	following the principles of [RFC6337] meaning that the decision to		following the principles of [RFC6337], meaning that the decision to
	create the new SDP offer should not be influenced by what was		create the new SDP offer should not be influenced by what was
	previously negotiated. For example if a previous OSRTP offer did not		previously negotiated. For example, if a previous OSRTP offer did
	result in SRTP being established the offerer may try again and		not result in SRTP being established, the offerer may try again and
	generate a new OSRTP offer as specified in section 3.1.		generate a new OSRTP offer as specified in Section 3.1.
	4. Security Considerations		4. Security Considerations
	The security considerations of [RFC4568] apply to OSRTP, as well as		The security considerations of [RFC4568] apply to OSRTP, as well as
	the security considerations of the particular SRTP key agreement		the security considerations of the particular SRTP key agreement
	approach used. However, the authentication requirements of a		approach used. However, the authentication requirements of a
	particular SRTP key agreement approach are relaxed when that key		particular SRTP key agreement approach are relaxed when that key
	agreement is used with OSRTP, which is consistent with the		agreement is used with OSRTP, which is consistent with the
	Opportunistic Security approach described [RFC7435]. For example:		Opportunistic Security approach described in [RFC7435]. For example:
	For DTLS-SRTP key agreement [RFC5763], an authenticated signaling		For DTLS-SRTP key agreement [RFC5763], an authenticated signaling
	channel does not need to be used with OSRTP if it is not		channel does not need to be used with OSRTP if it is not
	available.		available.
	For SDP Security Descriptions key agreement [RFC4568], an		For SDP Security Descriptions key agreement [RFC4568], an
	authenticated signaling channel does not need to be used with		authenticated signaling channel does not need to be used with
	OSRTP if it is not available, although an encrypted signaling		OSRTP if it is not available, although an encrypted signaling
	channel MUST still be used.		channel MUST still be used.
	For ZRTP key agreement [RFC6189], the security considerations are		For ZRTP key agreement [RFC6189], the security considerations are
	unchanged, since ZRTP does not rely on the security of the		unchanged, since ZRTP does not rely on the security of the
	signaling channel.		signaling channel.
	While OSRTP does not require authentication of the key-agreement		While OSRTP does not require authentication of the key agreement
	mechanism, it does need to avoid exposing SRTP keys to eavesdroppers,		mechanism, it does need to avoid exposing SRTP keys to eavesdroppers,
	since this could enable passive attacks against SRTP. Section 8.3 of		since this could enable passive attacks against SRTP. Section 8.3 of
	[RFC4568] requires that any messages that contain SRTP keys be		[RFC4568] requires that any messages that contain SRTP keys be
	encrypted, and further says that encryption "SHOULD" provide end-to-		encrypted, and further says that encryption SHOULD provide end-to-end
	end confidentiality protection if intermediaries that could inspect		confidentiality protection if intermediaries that could inspect the
	the SDP message are present. At the time of this writing, it is		SDP message are present. At the time of this writing, it is
	understood that the [RFC4568] requirement for end-to-end		understood that the requirement in [RFC4568] for end-to-end
	confidentiality protection is commonly ignored. Therefore, if OSRTP		confidentiality protection is commonly ignored. Therefore, if OSRTP
	is used with SDP Security Descriptions, any such intermediaries		is used with SDP Security Descriptions, any such intermediaries
	(e.g., SIP proxies) must be assumed to have access to the SRTP keys.		(e.g., SIP proxies) must be assumed to have access to the SRTP keys.
	As discussed in [RFC7435], OSRTP is used in cases where support for		As discussed in [RFC7435], OSRTP is used in cases where support for
	encryption by the other party is not known in advance, and not		encryption by the other party is not known in advance and is not
	required. For cases where it is known that the other party supports		required. For cases where it is known that the other party supports
	SRTP or SRTP needs to be used, OSRTP MUST NOT be used. Instead, a		SRTP or SRTP needs to be used, OSRTP MUST NOT be used. Instead, a
	secure profile of RTP is used in the offer.		secure profile of RTP is used in the offer.
	5. IANA Considerations		5. IANA Considerations
	This document has no actions for IANA.		This document has no actions for IANA.
	6. Acknowledgements		6. References
	This document is dedicated to our friend and colleague Francois Audet
	who is greatly missed in our community. His work on improving
	security in SIP and RTP provided the foundation for this work.
	Thanks to Eric Rescorla, Martin Thomson, Christer Holmberg, and
	Richard Barnes for their comments.
	7. References
	7.1. Normative References		6.1. Normative References
	[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate		[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
	Requirement Levels", BCP 14, RFC 2119,		Requirement Levels", BCP 14, RFC 2119,
	DOI 10.17487/RFC2119, March 1997,		DOI 10.17487/RFC2119, March 1997,
	<https://www.rfc-editor.org/info/rfc2119>.		<https://www.rfc-editor.org/info/rfc2119>.
	[RFC3264] Rosenberg, J. and H. Schulzrinne, "An Offer/Answer Model		[RFC3264] Rosenberg, J. and H. Schulzrinne, "An Offer/Answer Model
	with Session Description Protocol (SDP)", RFC 3264,		with Session Description Protocol (SDP)", RFC 3264,
	DOI 10.17487/RFC3264, June 2002,		DOI 10.17487/RFC3264, June 2002,
	<https://www.rfc-editor.org/info/rfc3264>.		<https://www.rfc-editor.org/info/rfc3264>.
	skipping to change at page 7, line 35 ¶		skipping to change at page 7, line 24 ¶
	<https://www.rfc-editor.org/info/rfc6189>.		<https://www.rfc-editor.org/info/rfc6189>.
	[RFC7435] Dukhovni, V., "Opportunistic Security: Some Protection		[RFC7435] Dukhovni, V., "Opportunistic Security: Some Protection
	Most of the Time", RFC 7435, DOI 10.17487/RFC7435,		Most of the Time", RFC 7435, DOI 10.17487/RFC7435,
	December 2014, <https://www.rfc-editor.org/info/rfc7435>.		December 2014, <https://www.rfc-editor.org/info/rfc7435>.
	[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC		[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
	2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,		2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
	May 2017, <https://www.rfc-editor.org/info/rfc8174>.		May 2017, <https://www.rfc-editor.org/info/rfc8174>.
	7.2. Informative References		6.2. Informative References
	[I-D.kaplan-mmusic-best-effort-srtp]		[Kaplan06] Kaplan, H. and F. Audet, "Session Description Protocol
	Audet, F. and H. Kaplan, "Session Description Protocol
	(SDP) Offer/Answer Negotiation For Best-Effort Secure		(SDP) Offer/Answer Negotiation For Best-Effort Secure
	Real-Time Transport Protocol", draft-kaplan-mmusic-best-		Real-Time Transport Protocol", Work in Progress,
	effort-srtp-01 (work in progress), October 2006.		draft-kaplan-mmusic-best-effort-srtp-01, October 2006.
	[RFC5939] Andreasen, F., "Session Description Protocol (SDP)		[RFC5939] Andreasen, F., "Session Description Protocol (SDP)
	Capability Negotiation", RFC 5939, DOI 10.17487/RFC5939,		Capability Negotiation", RFC 5939, DOI 10.17487/RFC5939,
	September 2010, <https://www.rfc-editor.org/info/rfc5939>.		September 2010, <https://www.rfc-editor.org/info/rfc5939>.
	[RFC6337] Okumura, S., Sawada, T., and P. Kyzivat, "Session		[RFC6337] Okumura, S., Sawada, T., and P. Kyzivat, "Session
	Initiation Protocol (SIP) Usage of the Offer/Answer		Initiation Protocol (SIP) Usage of the Offer/Answer
	Model", RFC 6337, DOI 10.17487/RFC6337, August 2011,		Model", RFC 6337, DOI 10.17487/RFC6337, August 2011,
	<https://www.rfc-editor.org/info/rfc6337>.		<https://www.rfc-editor.org/info/rfc6337>.
			Acknowledgements
			This document is dedicated to our friend and colleague Francois Audet
			who is greatly missed in our community. His work on improving
			security in SIP and RTP provided the foundation for this work.
			Thanks to Eric Rescorla, Martin Thomson, Christer Holmberg, and
			Richard Barnes for their comments.
	Authors' Addresses		Authors' Addresses
	Alan Johnston		Alan Johnston
	Villanova University		Villanova University
	Villanova, PA		Villanova, PA
	USA		United States of America
	Email: alan.b.johnston@gmail.com		Email: alan.b.johnston@gmail.com
	Bernard Aboba		Bernard Aboba
	Microsoft		Microsoft
	One Microsoft Way		One Microsoft Way
	Redmond, WA 98052		Redmond, WA 98052
	USA		United States of America
	Email: bernard.aboba@gmail.com		Email: bernard.aboba@gmail.com
	Andrew Hutton		Andrew Hutton
	Atos		Atos
	Mid City Place		Mid City Place
	London WC1V 6EA		London WC1V 6EA
	UK		United Kingdom
	Email: andrew.hutton@atos.net		Email: andrew.hutton@atos.net
	Roland Jesske		Roland Jesske
	Deutsche Telekom		Deutsche Telekom
	Heinrich-Hertz-Strasse 3-7		Heinrich-Hertz-Strasse 3-7
	Darmstadt 64295		Darmstadt 64295
	Germany		Germany
	Email: R.Jesske@telekom.de		Email: R.Jesske@telekom.de
End of changes. 40 change blocks.
	90 lines changed or deleted		89 lines changed or added
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