draft-ietf-sipping-mwi-01.txt   draft-ietf-sipping-mwi-02.txt 
SIPPING WG R. Mahy SIPPING WG R. Mahy
Internet-Draft Cisco Systems, Inc. Internet-Draft Cisco Systems, Inc.
Expires: April 1, 2003 Oct 2002 Expires: September 1, 2003 March 3, 2003
A Message Summary and Message Waiting Indication Event Package for A Message Summary and Message Waiting Indication Event Package for
the Session Initiation Protocol (SIP) the Session Initiation Protocol (SIP)
draft-ietf-sipping-mwi-01.txt draft-ietf-sipping-mwi-02.txt
Status of this Memo Status of this Memo
This document is an Internet-Draft and is in full conformance with This document is an Internet-Draft and is in full conformance with
all provisions of Section 10 of RFC2026. all provisions of Section 10 of RFC2026.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that Task Force (IETF), its areas, and its working groups. Note that other
other groups may also distribute working documents as Internet- groups may also distribute working documents as Internet-Drafts.
Drafts.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
The list of current Internet-Drafts can be accessed at http:// The list of current Internet-Drafts can be accessed at http://
www.ietf.org/ietf/1id-abstracts.txt. www.ietf.org/ietf/1id-abstracts.txt.
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http://www.ietf.org/shadow.html. http://www.ietf.org/shadow.html.
This Internet-Draft will expire on April 1, 2003. This Internet-Draft will expire on September 1, 2003.
Copyright Notice Copyright Notice
Copyright (C) The Internet Society (2002). All Rights Reserved. Copyright (C) The Internet Society (2003). All Rights Reserved.
Abstract Abstract
This draft proposes a SIP event package to carry message waiting This draft proposes a SIP event package to carry message waiting
status and message summaries from a messaging system to an interested status and message summaries from a messaging system to an interested
User Agent. User Agent.
Table of Contents Table of Contents
1. Conventions . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Conventions . . . . . . . . . . . . . . . . . . . . . . . . 3
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8.1 Open Issues . . . . . . . . . . . . . . . . . . . . . . . . 17 8.1 Open Issues . . . . . . . . . . . . . . . . . . . . . . . . 17
8.2 Changes from draft-ietf-sipping-mwi-00 . . . . . . . . . . . 17 8.2 Changes from draft-ietf-sipping-mwi-00 . . . . . . . . . . . 17
8.3 Changes from draft-mahy-sipping-mwi-00 . . . . . . . . . . . 17 8.3 Changes from draft-mahy-sipping-mwi-00 . . . . . . . . . . . 17
8.4 Changes from draft-mahy-sip-mwi-01 . . . . . . . . . . . . . 18 8.4 Changes from draft-mahy-sip-mwi-01 . . . . . . . . . . . . . 18
8.5 Changes from draft-mahy-sip-mwi-00 . . . . . . . . . . . . . 18 8.5 Changes from draft-mahy-sip-mwi-00 . . . . . . . . . . . . . 18
9. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 19 9. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 19
10. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . 19 10. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . 19
Normative References . . . . . . . . . . . . . . . . . . . . 19 Normative References . . . . . . . . . . . . . . . . . . . . 19
Informational References . . . . . . . . . . . . . . . . . . 19 Informational References . . . . . . . . . . . . . . . . . . 19
Author's Address . . . . . . . . . . . . . . . . . . . . . . 20 Author's Address . . . . . . . . . . . . . . . . . . . . . . 20
Full Copyright Statement . . . . . . . . . . . . . . . . . . 21 Intellectual Property and Copyright Statements . . . . . . . 21
1. Conventions 1. Conventions
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC-2119 [3]. document are to be interpreted as described in RFC-2119 [3].
2. Background and Appropriateness 2. Background and Appropriateness
Messaging Waiting Indication is a common feature of telephone Messaging Waiting Indication is a common feature of telephone
networks. It typically involves an audible or visible indication networks. It typically involves an audible or visible indication
that messages are waiting, such as playing a special dial tone that messages are waiting, such as playing a special dial tone
(called message-waiting dial tone), lighting a light or indicator on (called message-waiting dial tone), lighting a light or indicator on
the phone, displaying icons or text, or some combination. Message- the phone, displaying icons or text, or some combination.
waiting dial tone is similar but distinct from stutter dial tone. Message-waiting dial tone is similar but distinct from stutter dial
Both are defined in GR-506 [10]. tone. Both are defined in GR-506 [10].
The methods in the SIP [1] base specification were only designed to The methods in the SIP [1] base specification were only designed to
solve the problem of session initiation for multimedia sessions, and solve the problem of session initiation for multimedia sessions, and
rendezvous. Since Message Waiting Indication is really status rendezvous. Since Message Waiting Indication is really status
information orthogonal to a session, it was not clear how an IP information orthogonal to a session, it was not clear how an IP
telephone acting as a SIP User Agent would implement comparable telephone acting as a SIP User Agent would implement comparable
functionality. Members of the telephony community viewed this as a functionality. Members of the telephony community viewed this as a
shortcoming of SIP. shortcoming of SIP.
Users want the useful parts of the functionality they have using Users want the useful parts of the functionality they have using
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This package does not define any event package parameters. This package does not define any event package parameters.
3.3 SUBSCRIBE Bodies 3.3 SUBSCRIBE Bodies
This package does not define any SUBSCRIBE bodies. This package does not define any SUBSCRIBE bodies.
3.4 Subscription Duration 3.4 Subscription Duration
Subscriptions to this event package MAY range from minutes to weeks. Subscriptions to this event package MAY range from minutes to weeks.
Subscriptions in hours or days are more typical and are RECOMMENDED. Subscriptions in hours or days are more typical and are RECOMMENDED.
The default subscription duration for this event package is one hour.
3.5 NOTIFY Bodies 3.5 NOTIFY Bodies
A simple text-based format is proposed to prevent an undue burden on A simple text-based format is proposed to prevent an undue burden on
low-end user agents, for example, inexpensive IP phones with no low-end user agents, for example, inexpensive IP phones with no
display. Although this format is text-based, it is intended for display. Although this format is text-based, it is intended for
machine consumption only. machine consumption only.
A future extension MAY define other NOTIFY bodies. If no "Accept" A future extension MAY define other NOTIFY bodies. If no "Accept"
header is present in the SUBSCRIBE, the body type defined in this header is present in the SUBSCRIBE, the body type defined in this
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new and old messages is reported in the new and old fields. new and old messages is reported in the new and old fields.
In some cases, detailed message summaries are not available. The In some cases, detailed message summaries are not available. The
status line allows messaging systems or messaging gateways to provide status line allows messaging systems or messaging gateways to provide
the traditional boolean message waiting notification. the traditional boolean message waiting notification.
Messages-Waiting: yes Messages-Waiting: yes
If the Request-URI or To header in a message-summary subscription If the Request-URI or To header in a message-summary subscription
corresponds to a group or collection of individual messaging corresponds to a group or collection of individual messaging
accounts, the notifier MUST specify to which account the message- accounts, the notifier MUST specify to which account the
summary body corresponds. Note that the account URI MUST NOT be message-summary body corresponds. Note that the account URI MUST NOT
delimited with angle brackets ("<" and ">"). be delimited with angle brackets ("<" and ">").
Message-Account: sip:alice@example.com Message-Account: sip:alice@example.com
In the example that follows, more than boolean message summary In the example that follows, more than boolean message summary
information is available to the User Agent. There are two new and information is available to the User Agent. There are two new and
four old fax messages. four old fax messages.
Fax-Message: 2/4 Fax-Message: 2/4
After the summary, the format can optionally list a summary count of After the summary, the format can optionally list a summary count of
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Optionally, after the summary counts, the messaging systems MAY Optionally, after the summary counts, the messaging systems MAY
append RFC 2822 [9]-style message headers, which further describe append RFC 2822 [9]-style message headers, which further describe
newly added messages. Message headers MUST NOT be included in an newly added messages. Message headers MUST NOT be included in an
initial NOTIFY, as new messages could be essentially unbounded in initial NOTIFY, as new messages could be essentially unbounded in
size. Message headers included in subsequent notifications MUST only size. Message headers included in subsequent notifications MUST only
correspond to messages added since the previous notification for that correspond to messages added since the previous notification for that
subscription. A messaging system which includes message headers in a subscription. A messaging system which includes message headers in a
NOTIFY, MUST provide an administrator configurable mechanism for NOTIFY, MUST provide an administrator configurable mechanism for
selecting which headers are sent. Likely headers for inclusion selecting which headers are sent. Likely headers for inclusion
include To, From, Date, Subject, and Message-ID. Note that the include To, From, Date, Subject, and Message-ID. Note that the
formatting of these headers is identical to that of SIP extension- formatting of these headers is identical to that of SIP
headers, not the (similar) format defined in RFC 2822. extension-headers, not the (similar) format defined in RFC 2822.
Implementations which generate large notifications are reminded to Implementations which generate large notifications are reminded to
follow the message size restrictions for unreliable transports follow the message size restrictions for unreliable transports
articulated in Section 18.1.1 of SIP. articulated in Section 18.1.1 of SIP.
Mapping local message state to new/old message status and urgency is Mapping local message state to new/old message status and urgency is
an implementation issue of the messaging system. However, the an implementation issue of the messaging system. However, the
messaging system MUST NOT consider a message "old" merely because it messaging system MUST NOT consider a message "old" merely because it
generated a notification , as this could prevent another subscription generated a notification , as this could prevent another subscription
from accurately receiving message-summary notifications. Likewise, from accurately receiving message-summary notifications. Likewise,
the messaging system MAY use any suitable algorithm to determine that the messaging system MAY use any suitable algorithm to determine that
a message is "urgent". a message is "urgent".
Messaging systems MAY use any algorithm for determining the Messaging systems MAY use any algorithm for determining the
approporiate message-context-class for a specific message. Systems approporiate message-context-class for a specific message. Systems
which use Internet Mail SHOULD use the contents of the Message- which use Internet Mail SHOULD use the contents of the
Context header [6] if present as a hint to make a context Message-Context header [6] (defined in RFC 3458) if present as a hint
determination. Note that a messaging system does not need to support to make a context determination. Note that a messaging system does
a given context in order to generate notifications identified with not need to support a given context in order to generate
that context. notifications identified with that context.
3.6 Subscriber generation of SUBSCRIBE requests 3.6 Subscriber generation of SUBSCRIBE requests
Subscriber User Agents will typically SUBSCRIBE to message summary Subscriber User Agents will typically SUBSCRIBE to message summary
information for a period of hours or days, and automatically attempt information for a period of hours or days, and automatically attempt
to re-SUBSCRIBE well before the subscription is completely expired. to re-SUBSCRIBE well before the subscription is completely expired.
If re-subscription fails, the Subscriber SHOULD periodically retry If re-subscription fails, the Subscriber SHOULD periodically retry
again until a subscription is successful, taking care to backoff to again until a subscription is successful, taking care to backoff to
avoid network congestion. If a subscription has expired, new re- avoid network congestion. If a subscription has expired, new
subscriptions MUST use a new Call-ID. re-subscriptions MUST use a new Call-ID.
The Subscriber SHOULD SUBSCRIBE to that user's message summaries The Subscriber SHOULD SUBSCRIBE to that user's message summaries
whenever a new user becomes associated with the device (a new login). whenever a new user becomes associated with the device (a new login).
The Subscriber MAY also explicitly fetch the current status at any The Subscriber MAY also explicitly fetch the current status at any
time. The subscriber SHOULD renew its subscription immediately after time. The subscriber SHOULD renew its subscription immediately after
a reboot, or when the subscriber's network connectivity has just been a reboot, or when the subscriber's network connectivity has just been
re-established. re-established.
The Subscriber MUST be prepared to receive and process a NOTIFY with The Subscriber MUST be prepared to receive and process a NOTIFY with
new state immediately after sending a new SUBSCRIBE, a SUBSCRIBE, new state immediately after sending a new SUBSCRIBE, a SUBSCRIBE,
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message-summary event-type, it SHOULD authenticate the subscription message-summary event-type, it SHOULD authenticate the subscription
request. If authentication is successful, the Notifier MAY limit the request. If authentication is successful, the Notifier MAY limit the
duration of the subscription to an administrator defined amount of duration of the subscription to an administrator defined amount of
time as described in SIP Events. time as described in SIP Events.
3.8 Notifier generation of NOTIFY requests 3.8 Notifier generation of NOTIFY requests
Immediately after a subscription is accepted, the Notifier MUST send Immediately after a subscription is accepted, the Notifier MUST send
a NOTIFY with the current message summary information. This allows a NOTIFY with the current message summary information. This allows
the Subscriber to resynchronize its state. This initial the Subscriber to resynchronize its state. This initial
synchronization NOTIFY MUST NOT include the optional message headers. synchronization NOTIFY MUST NOT include the optional RFC 2822
[9]-style message headers.
When the status of the messages changes sufficiently for a messaging When the status of the messages changes sufficiently for a messaging
account to change the number of new or old messages, the Notifier account to change the number of new or old messages, the Notifier
SHOULD send a NOTIFY message to all active subscribers to that SHOULD send a NOTIFY message to all active subscribers to that
account. NOTIFY messages sent to subscribers of a group or alias, account. NOTIFY messages sent to subscribers of a group or alias,
MUST contain the message account name in the notification body. MUST contain the message account name in the notification body.
A Messaging System MAY send a NOTIFY with an "Expires" header of "0" A Messaging System MAY send a NOTIFY with an "Expires" header of "0"
and a "Subscription-State" header of "terminated" before a graceful and a "Subscription-State" header of "terminated" before a graceful
shutdown. shutdown.
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package. package.
3.13 Behavior of a Proxy Server 3.13 Behavior of a Proxy Server
There are no additional requirements on a SIP Proxy, other than to There are no additional requirements on a SIP Proxy, other than to
transparently forward the SUBSCRIBE and NOTIFY methods as required in transparently forward the SUBSCRIBE and NOTIFY methods as required in
SIP. However, Proxies SHOULD allow non-SIP URLs. Proxies and SIP. However, Proxies SHOULD allow non-SIP URLs. Proxies and
Redirect servers SHOULD be able to direct the SUBSCRIBE request to an Redirect servers SHOULD be able to direct the SUBSCRIBE request to an
appropriate messaging server User Agent. Proxies are encouraged to appropriate messaging server User Agent. Proxies are encouraged to
support routing to Contacts based on the the method of the request support routing to Contacts based on the the method of the request
and the existence of a feature="voice-mail" parameter in an Accept- and the existence of a feature="voice-mail" parameter in an
Contact header (as specified in the caller preferences Accept-Contact header (as specified in the caller preferences
specification). specification).
4. Examples of Usage 4. Examples of Usage
4.1 Example Message Flow 4.1 Example Message Flow
The examples shown below are for informational purposes only. For a The examples shown below are for informational purposes only. For a
normative description of the event package, please see sections 3 and normative description of the event package, please see sections 3 and
5 of this document. 5 of this document.
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new-urgentmsgs = msgcount new-urgentmsgs = msgcount
old-urgentmsgs = msgcount old-urgentmsgs = msgcount
msgcount = 1*DIGIT ; MUST NOT exceed 2^32-1 msgcount = 1*DIGIT ; MUST NOT exceed 2^32-1
6. Security Considerations 6. Security Considerations
Message Summaries and optional message bodies contain information Message Summaries and optional message bodies contain information
which is typically very privacy sensitive. At minimum, subscriptions which is typically very privacy sensitive. At minimum, subscriptions
to this event package SHOULD be authenticated and properly to this event package SHOULD be authenticated and properly
authorized. Furthermore, notifications SHOULD be encrypted and authorized. Furthermore, notifications SHOULD be encrypted and
integrity protected using either end-to-end mechanisms, or the hop- integrity protected using either end-to-end mechanisms, or the
by-hop protection afforded messages sent to SIPS URIs. hop-by-hop protection afforded messages sent to SIPS URIs.
Additional security considerations are covered in SIP [1] and SIP Additional security considerations are covered in SIP [1] and SIP
Events [2]. Events [2].
7. IANA Considerations 7. IANA Considerations
7.1 SIP Event Package Registration for message-summary 7.1 SIP Event Package Registration for message-summary
Package name: message-summary Package name: message-summary
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8.1 Open Issues 8.1 Open Issues
1. Need to update the caller-preference section to reflect whatever 1. Need to update the caller-preference section to reflect whatever
the replacement will be for feature="voice-mail". the replacement will be for feature="voice-mail".
2. Would be nice to add a pointer to the "collections" work 2. Would be nice to add a pointer to the "collections" work
8.2 Changes from draft-ietf-sipping-mwi-00 8.2 Changes from draft-ietf-sipping-mwi-00
1. Replaced the "media types" concept with message contexts. This 1. Replaced the "media types" concept with message contexts. This is
is a better semantic match than what was in the draft before, and a better semantic match than what was in the draft before, and
also controls extensibility and change control in a single also controls extensibility and change control in a single
document. The list of valid message-context-classes are voice- document. The list of valid message-context-classes are
message, fax-message, pager-message, multimedia-message, text- voice-message, fax-message, pager-message, multimedia-message,
message, and none. text-message, and none.
2. Completely updated the syntax to follow that of SIP instead of 2. Completely updated the syntax to follow that of SIP instead of
the previously more restrictive (and somewhat arbitrary) syntax. the previously more restrictive (and somewhat arbitrary) syntax.
The SIP syntax adds line folding, for example. The optional The SIP syntax adds line folding, for example. The optional
message-headers borrow the "extension-header" syntax and explicit message-headers borrow the "extension-header" syntax and explicit
whitespace separators defined in SIP (ex: HCOLON, SLASH). whitespace separators defined in SIP (ex: HCOLON, SLASH).
3. Added a Message-Account field in the body format to provide the 3. Added a Message-Account field in the body format to provide the
specific account name which corresponds to the notification when specific account name which corresponds to the notification when
forking or state agents are used with group aliases (or forking or state agents are used with group aliases (or
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1. The generic behavior of SUBSCRIBE/NOTIFY is now greatly clarified 1. The generic behavior of SUBSCRIBE/NOTIFY is now greatly clarified
in SIP Events [2] and made consistent with PINT and SIP for in SIP Events [2] and made consistent with PINT and SIP for
presence. This message waiting draft is now consistent with SIP presence. This message waiting draft is now consistent with SIP
Events. Events.
2. The XML format has been removed due to lack of immediate 2. The XML format has been removed due to lack of immediate
interest. At a future date, similar functionality may be added interest. At a future date, similar functionality may be added
as another body definition with an appropriate MIME type. as another body definition with an appropriate MIME type.
3. An IANA Considerations section was added to register the new 3. An IANA Considerations section was added to register the new
"application/simple-message-summary" MIME type and the "simple- "application/simple-message-summary" MIME type and the
message-summary" SIP event package. "simple-message-summary" SIP event package.
4. The "flag-list" was removed due to lack of interest and to 4. The "flag-list" was removed due to lack of interest and to
encourage simplicity. encourage simplicity.
5. Due to synchronization issues, and the recommendation of the VPIM 5. Due to synchronization issues, and the recommendation of the VPIM
Working Group, support for message count "deltas" was removed. Working Group, support for message count "deltas" was removed.
6. The Messages-Waiting line in the body is now mandatory. 6. The Messages-Waiting line in the body is now mandatory.
7. This version of the draft clarifies the role of caller 7. This version of the draft clarifies the role of caller
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9. Contributors 9. Contributors
Ilya Slain came up with the initial format of the text body contained Ilya Slain came up with the initial format of the text body contained
in this document. He was previously listed as a co-author, however, in this document. He was previously listed as a co-author, however,
he is no longer reachable. he is no longer reachable.
10. Acknowledgments 10. Acknowledgments
Thanks to Dan Wing, Dave Oran, Bill Foster, Steve Levy, Denise Thanks to Dan Wing, Dave Oran, Bill Foster, Steve Levy, Denise
Caballero-McCann, Jeff Michel, Priti Patil, Satyender Khatter, Bich Caballero-McCann, Jeff Michel, Priti Patil, Satyender Khatter, Bich
Nguyen, Manoj Bhatia, David Williams, and Bryan Byerly of Cisco; and Nguyen, Manoj Bhatia, David Williams, and Bryan Byerly of Cisco;
Jonathan Rosenberg and Adam Roach of Dynamicsoft. Jonathan Rosenberg and Adam Roach of Dynamicsoft; Eric Burger of
Snowshore; and Eric Tremblay of Mediatrix.
Normative References Normative References
[1] Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston, A., [1] Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston, A.,
Peterson, J., Sparks, R., Handley, M. and E. Schooler, "SIP: Peterson, J., Sparks, R., Handley, M. and E. Schooler, "SIP:
Session Initiation Protocol", RFC 3261, June 2002. Session Initiation Protocol", RFC 3261, June 2002.
[2] Roach, A., "Session Initiation Protocol (SIP)-Specific Event [2] Roach, A., "Session Initiation Protocol (SIP)-Specific Event
Notification", RFC 3265, June 2002. Notification", RFC 3265, June 2002.
[3] Bradner, S., "Key words for use in RFCs to Indicate Requirement [3] Bradner, S., "Key words for use in RFCs to Indicate Requirement
Levels", BCP 14, RFC 2119, March 1997. Levels", BCP 14, RFC 2119, March 1997.
[4] Rosenberg, J. and H. Schulzrinne, "Session Initiation Protocol [4] Rosenberg, J. and H. Schulzrinne, "Session Initiation Protocol
(SIP) Caller Preferences and Callee Capabilities", draft-ietf- (SIP) Caller Preferences and Callee Capabilities",
sip-callerprefs-06 (work in progress), July 2002. draft-ietf-sip-callerprefs-07 (work in progress), November 2002.
[5] Crocker, D. and P. Overell, "Augmented BNF for Syntax [5] Crocker, D. and P. Overell, "Augmented BNF for Syntax
Specifications: ABNF", RFC 2234, November 1997. Specifications: ABNF", RFC 2234, November 1997.
[6] Klyne, G., Burger, E., Candell, E. and C. Eliot, "Message [6] Burger, E., Candell, E., Eliot, C. and G. Klyne, "Message
Context for Internet Mail", draft-ietf-vpim-hint-08 (work in Context for Internet Mail", RFC 3458, January 2003.
progress), June 2002.
Informational References Informational References
[7] Vaudreuil, G. and G. Parsons, "Voice Profile for Internet Mail [7] Vaudreuil, G. and G. Parsons, "Voice Profile for Internet Mail
- version 2", RFC 2421, September 1998. - version 2", RFC 2421, September 1998.
[8] Freed, N. and N. Borenstein, "Multipurpose Internet Mail [8] Freed, N. and N. Borenstein, "Multipurpose Internet Mail
Extensions (MIME) Part Two: Media Types", RFC 2046, November Extensions (MIME) Part Two: Media Types", RFC 2046, November
1996. 1996.
skipping to change at page 21, line 5 skipping to change at page 21, line 5
Author's Address Author's Address
Rohan Mahy Rohan Mahy
Cisco Systems, Inc. Cisco Systems, Inc.
101 Cooper Street 101 Cooper Street
Santa Cruz, CA 95060 Santa Cruz, CA 95060
USA USA
EMail: rohan@cisco.com EMail: rohan@cisco.com
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Acknowledgement Acknowledgement
 End of changes. 

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