DISPATCH Ranjit. Avasarala Internet-Draft Motorola Solutions Inc Intended status: Informational R. Jesske Expires: May 26, 2011 Deutsche Telekom November 22, 2010 A Session Initiation Protocol (SIP) Event Package for Communication Barring Notification Information in support of the Dynamic Incoming Communication Barring (ICB) service draft-avasarala-dispatch-comm-barring-notification-01.txt Abstract 3GPP is defining the protocol specification for the Communication Barring (CB) service using IP Multimedia (IM) Core Network (CN) subsystem supplementary service and more particularly the dynamic incoming communication barring service. As part of dynamic incoming communication barring (ICB) service, a SIP based Event package framework is used for notifying users about communication barrings (dynamic and rule based) of their incoming communication sessions. This document proposes a new SIP event package for allowing users to subscribe to and receive such notifications. Users can further define filters to control the rate and content of such notifications. The proposed event package is applicable to the ICB supplementary service in IMS and may not be applicable to the general internet.. 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 May 26, 2011. Copyright Notice Copyright (c) 2010 IETF Trust and the persons identified as the Avasarala & Jesske Expires May 26, 2011 [Page 1] Internet-Draft SIP Communication Barring Notification November 2010 document authors. All rights reserved. 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 to this document. Code Components extracted from this document must 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. Avasarala & Jesske Expires May 26, 2011 [Page 2] Internet-Draft SIP Communication Barring Notification November 2010 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4 3. Applicability Statement . . . . . . . . . . . . . . . . . . . 4 4. Abbreviations and Definitions . . . . . . . . . . . . . . . . 5 4.1. Abbreviations . . . . . . . . . . . . . . . . . . . . . . 5 4.2. Definitions . . . . . . . . . . . . . . . . . . . . . . . 5 5. Requirements . . . . . . . . . . . . . . . . . . . . . . . . . 5 6. Package Definition . . . . . . . . . . . . . . . . . . . . . . 5 6.1. Event Package Name . . . . . . . . . . . . . . . . . . . . 5 6.2. Event Package Parameters . . . . . . . . . . . . . . . . . 6 6.3. SUBSCRIBE bodies . . . . . . . . . . . . . . . . . . . . . 6 6.4. Subscription Duration . . . . . . . . . . . . . . . . . . 6 6.5. Notify bodies . . . . . . . . . . . . . . . . . . . . . . 6 6.6. Notifier Processing of SUBSCRIBE requests . . . . . . . . 7 6.6.1. Authentication . . . . . . . . . . . . . . . . . . . . 7 6.6.2. Authorization . . . . . . . . . . . . . . . . . . . . 7 6.7. Notifier Generation of NOTIFY requests . . . . . . . . . . 8 6.8. Subscriber Processing of NOTIFY Requests . . . . . . . . . 9 6.9. Handling of Forked Requests . . . . . . . . . . . . . . . 9 6.10. Rate of Notifications . . . . . . . . . . . . . . . . . . 9 6.11. State Agents . . . . . . . . . . . . . . . . . . . . . . . 9 7. Comm_barring-info Document . . . . . . . . . . . . . . . . . . 9 8. Structure of Comm_barring-info Format . . . . . . . . . . . . 10 8.1. Comm_barring-info Element . . . . . . . . . . . . . . . . 10 8.1.1. comm-barring-subs-info Element . . . . . . . . . . . . 10 8.1.2. Comm-barring-ntfy-info Element . . . . . . . . . . . . 12 8.1.3. Comm_barring-info-selection-criteria . . . . . . . . . 13 8.2. Sample Notification body . . . . . . . . . . . . . . . . . 14 8.2.1. Instance of communication barring subscription filter document . . . . . . . . . . . . . . . . . . . 14 8.2.2. Instance of communication barring notification document . . . . . . . . . . . . . . . . . . . . . . . 15 8.3. Schema . . . . . . . . . . . . . . . . . . . . . . . . . . 15 9. Security Considerations . . . . . . . . . . . . . . . . . . . 20 10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 20 10.1. Communication Barring Information Event Package Registration . . . . . . . . . . . . . . . . . . . . . . . 20 11. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 21 12. References . . . . . . . . . . . . . . . . . . . . . . . . . . 21 12.1. Normative References . . . . . . . . . . . . . . . . . . . 21 12.2. Informative References . . . . . . . . . . . . . . . . . . 21 Appendix A. Change log . . . . . . . . . . . . . . . . . . . . . 22 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 22 Avasarala & Jesske Expires May 26, 2011 [Page 3] Internet-Draft SIP Communication Barring Notification November 2010 1. Introduction 3GPP is currently maintaining and specifying incoming communication barring mechanisms which allow users to dynamically block incoming communications from callers whom they consider as unwanted or unsolicited. The intention of such mechanisms is to provide users with sufficient flexibility to manage their incoming communications in a better way. The most common example is the Anonymous Communication Rejection (ACR) where in the incoming communications from senders whose identity is marked as "Anonymous" is rejected. Similarly other variants of ICB include dynamically blocking a particular caller by the subscribers, called the dynamic ICB which is specified in 3GPP specification [1]. However, However, with the increasing number of unwanted calls and increased usage of incoming communication barring services, users may have lot of callers being blocked from time to time and for different periods based on temporary or permanent block. For instance, a user may have blocked a particular caller for a temporary period and specified the period as 1 year. Though there are ways by which users can keep track of their communication barrings, there is no efficient mechanism for the users to get information of their communication barrings that get enacted in the network. This information would help them to verify their rules and rectify if required This document defines a SIP event package that allows a SIP User Agents to subscribe to and be notified of communication barrings enacted on their behalf 2. Terminology In this document, the key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" are to be interpreted as described in RFC 2119 [2] and indicate requirement levels for compliant implementations. 3. Applicability Statement It is believed that the SIP event package defined here is not applicable to the general Internet and has been designed to serve the architecture of the Dynamic ICB service defined for IMS core networks. The aim of this memo is to follow the procedure indicated in RFC 5727 [3] and to register a new event package with event name "comm-barring-info" with IANA. Avasarala & Jesske Expires May 26, 2011 [Page 4] Internet-Draft SIP Communication Barring Notification November 2010 4. Abbreviations and Definitions 4.1. Abbreviations CB: Communication Barring. CBN: Communication Barring Notification. ICB: Incoming Communication Barring. 4.2. Definitions Subscriber - The User Agent who has subscribed to the Communication Barring notification service. User - Another term for the subscriber. Barring User - The User Agent who has configured a Communication Barring. This could be the User Agent who has configured the Incoming Communication Barring service rules in the network. Originating User - The User Agent who is the originator of the incoming communication, The Originating User is also referred to as the Caller. IMS Core Network - This refers to the IMS based SIP based network that conforms to the [7] and not the general SIP network as defined in [4]. 5. Requirements The Communication Barring Notification (CBN) service enables a user to receive notification about the barring of any of his/her incoming communications, which were addressed to the user's address. A comprehensive description of all the requirements that affect the CBN service developed by 3GPP and is found in and [5] and [1] 6. Package Definition This section fills in the details needed for an event package as defined in Section 4.4 of [6]. 6.1. Event Package Name The SIP Events specification requires package definitions to specify the name of their package or template-package. Avasarala & Jesske Expires May 26, 2011 [Page 5] Internet-Draft SIP Communication Barring Notification November 2010 The name of this package is "comm-barring-info". As specified in [6], this value appears in the Event header present in SUBSCRIBE and NOTIFY requests. 6.2. Event Package Parameters The SIP Events specification [6] allows packages to define additional parameters. This event package "comm-barring-info" does not define additional parameters. . 6.3. SUBSCRIBE bodies The SIP Events specification requires package or template-package definitions to define the usage, if any, of bodies in SUBSCRIBE requests. A SUBSCRIBE for Communication Barring event MAY contain a body. The purpose of the body depends on its type. Subscriptions to the Comm_barring-info event package SHALL only include a body of MIME type "application/comm-barring-info+xml". A body of the SUBSCRIBE request with content type set to MIME type "application/comm-barring-info+xml" contains information about the communication barring notification information filter criteria and notification trigger criteria. The subscriber SHALL also verify that this information conforms to a valid XML document as defined in [8]. The subscriber SHALL also verify that the information contained in the XML document contains elements defined in Section 8.1.1 only. 6.4. Subscription Duration The default expiration time for subscriptions within this package is 3600 seconds. As per [6], the subscriber MAY specify an alternate expiration in the Expires header field. 6.5. Notify bodies The SIP Events specification requires package definitions to define a default value for subscription durations, and to discuss reasonable choices for durations when they are explicitly specified. The NOTIFY message contains bodies. This body is a format listed in the Accept header field of the SUBSCRIBE request or a package specific default format if the Accept header field was omitted from the SUBSCRIBE request. In this event package, the body of the notification contains the communication barring information pertaining to the barring that Avasarala & Jesske Expires May 26, 2011 [Page 6] Internet-Draft SIP Communication Barring Notification November 2010 occurred in the network on behalf of the subscriber. The format of the communication barring information is an XML document as per elements defined in Section 8.1.2. All subscribers and notifiers of the "comm-barring-info" event package MUST support the "application/comm-barring-info+xml" data format described in Section 8. The SUBSCRIBE request MAY contain an Accept header field. If no such header field is present, it has a default value of "application/comm-barring-info+xml" (assuming Event header has a value of "comm-barring-info"). If the Accept header field is present, it MUST contain the value "application/ comm-barring-info+xml". 6.6. Notifier Processing of SUBSCRIBE requests The contents of a document containing comm-barring-info information can contain sensitive information that can reveal some privacy information. Therefore, such comm-barring-info documents MUST only be sent to authorized subscribers. In order to determine if a subscription originates in an authorized user, the subscriber MUST be authenticated as described in Section 6.6.1 and then the user MUST be authorized to be a subscriber as described in Section 6.6.2. The Notifier MUST look into the SUBSCRIBE request body for a comm- barring-info document containing filter criteria. If the filter criteria is present, it should check if the filter criteria conforms to the format described in Section 8.1.1. If the received criteria is valid, then the NOTIFIER MUST use that for generating notifications about communication barrings that occur on behalf of the user. 6.6.1. Authentication Notifiers MUST authenticate all subscription requests. This authentication can be done using any of the mechanisms defined in [4] and other authentication extensions. 6.6.2. Authorization Once authenticated, the notifier makes an authorization decision. A notifier MUST NOT accept a subscription unless authorization has been provided by the user. The means by which authorization are provided are outside the scope of this document. Authorization may have been provided ahead of time through access lists, perhaps specified in a web page. Authorization may have been provided by means of uploading some kind of standardized access control list document Avasarala & Jesske Expires May 26, 2011 [Page 7] Internet-Draft SIP Communication Barring Notification November 2010 6.7. Notifier Generation of NOTIFY requests The SIP Events specification details the formatting and structure of NOTIFY messages. However, packages are mandated to provide detailed information on when to send a NOTIFY, how to compute the state of the resource, how to generate neutral or fake state information, and whether state information is complete or partial. This section describes those details for the "comm-barring-info" event package. A notifier MUST send a NOTIFY when a communication barring is enacted on behalf of the user. If there is a stored filter criteria for the user, then the notifier MUST look into the filter criteria before generating the NOTIFY request towards the user. If the filter criteria matches, then the notifier generates the NOTIFY request and sends the NOTIFY request to the user. If the filter criteria does not match the enacted communication barring, then the notifier just increments the communication barring count and does not send any NOTIFY request towards the user. The body of the NOTIFY MUST be sent using the type "application/ comm-barring-info+xml" and must contain the elements defined in Section 8.1.2 only. The Content-Type header field MUST be set to "application/comm-barring-info+xml". It is RECOMMENDED that the notifiers do maintain the history of last N communication barrings that occurred, where the value N >=1 as part of state information for that server and include it in the communication barring notification information sent to the user. in addition to this it is also RECOMMENDED that the notifiers maintain the list of last M communication barring notifications sent to the user, where M equal to or less than N. M equals N if notifications are sent for all communication barrings that occurred. The value M is decremented whenever a communication barring notification is sent to the user. The notifiers check the value of M as being greater than 0 prior to generating the notification information. The value of N could be configured and is left to server policy to determine appropriate value. The state information is retained even after the notification for those barrings are sent to the subscriber and changes when new barring occurs and whenever a notification is sent. So every time a new barring occurs and a notification is sent, the state information changes to reflect the latest barring removing the oldest barring information and to reflect the latest notification information sent. Avasarala & Jesske Expires May 26, 2011 [Page 8] Internet-Draft SIP Communication Barring Notification November 2010 6.8. Subscriber Processing of NOTIFY Requests The SIP Events specification expects event packages to describe the process followed by the subscriber upon receipt of a NOTIFY request. In this specification, each NOTIFY request contains a comm-barring- info document 6.9. Handling of Forked Requests The SIP Events specification requires each package to describe handling of forked Requests. Though the incoming SUBSCRIBE request could be forked, this specification only allows a single dialog to be constructed as a result of emitting an initial SUBSCRIBE request, This guarantees that only a single notifier is generating notifications for a particular subscription to a particular user. 6.10. Rate of Notifications The SIP Events specification requires each package to specify maximum rate at which notifications can be sent . Comm_barring-info notifiers SHOULD NOT generate notifications for a single subscription at a rate of more than once every five seconds. 6.11. State Agents The notifiers maintain the state of last N communication barrings and last M communication barring notification sent, where N (N>=1) is the number of communication barrings that occurred in the network on behalf of the subscriber and M is the number of communication barring notifications sent to the user. If notifications are sent for every communication barring that occurred, then M will be equal to N, else M will be less than N if filter criteria comes into play. Thus at any point of time a subscriber MAY know the state of communication barrings enacted on his or her behalf and number of notifications sent by the server. 7. Comm_barring-info Document Comm_barring-info document is an XML document [8] that MUST be well- formed and SHOULD be valid. Communication Barring Information documents MUST be based on XML 1.0 and MUST be encoded using UTF-8 [9]. Avasarala & Jesske Expires May 26, 2011 [Page 9] Internet-Draft SIP Communication Barring Notification November 2010 8. Structure of Comm_barring-info Format A Communications Barring Information document starts with a "comm- barring-info" element. The comm-barring-info element has a series of elements describing the particular communication barring or the filter criteria for receiving the communication barring information. 8.1. Comm_barring-info Element The comm-barring-info element gives information about the specific communication barring or it could give information about a particular selection criteria for the user receiving the communication barring information. 8.1.1. comm-barring-subs-info Element The comm-barring-subs-info element is used by the subscribing user to specify the communication barring information selection criteria and the communication barring notification trigger criteria. It contains the following elements: 8.1.1.1. comm-barring-selection-criteria This element contains information about communication barring information selection criteria. It contains following sub-elements for specifying the selection criteria. 8.1.1.1.1. originating-user-selection-criteria This element specifies the originating user information for the communication i.e. the caller. This is specified in the form of "user-name" and "user-uri". E.g. sip:Alice@domain.com. The Username as well as User-URI specified will be compared with the originating user information of the current user and if there is a match, then information about the barring of this specific communication would be selected for notification to the Subscriber. It consists of the following sub-elements. 8.1.1.1.1.1. user-info This element gives user details like username and URI. This element has further sub-elements for describing username and user URI 8.1.1.1.1.1.1. User-name This element gives Username. "Alice". Avasarala & Jesske Expires May 26, 2011 [Page 10] Internet-Draft SIP Communication Barring Notification November 2010 8.1.1.1.1.1.2. User-URI This element gives User URI. E.g "sip:Alice@domain.com". It takes the form of any URI scheme like sip. sips, tel or any other URI scheme 8.1.1.1.2. barring-time-selection-criteria This element specifies the time range for receiving notifications. It contains following additional elements . 8.1.1.1.2.1. time-range This element specifies the time range at which notifications for communication barrings can be sent to the subscriber. This could be specified in the form of a time-interval to enable periodic triggering of notifications of communication barrings which took place in that time-interval. NOTE: If the time-range element is not specified, then notifications about every communication barring that occurs is sent to the subscriber. 8.1.1.1.2.1.1. start-time This element specifies the start time for receiving notifications. Its value is expressed in YYYY:MM:DDTHH:MM:SSZ format. 8.1.1.1.2.1.2. end-time This element specifies the end time for receiving notifications. Its value is expressed in YYYY:MM:DDTHH:MM:SSZ format. 8.1.1.1.3. barring-reason-selection-criteria This element contains the reason for communication barring. It contains following sub-element: 8.1.1.1.3.1. barring-reason-info This element gives the actual reason for the communication barring. E.g. "Call Forward on Busy". 8.1.1.1.4. number-of-barrings-selection-criteria This element contains the total number of barrings that occurred in network on behalf of the user till then. Avasarala & Jesske Expires May 26, 2011 [Page 11] Internet-Draft SIP Communication Barring Notification November 2010 8.1.1.1.5. number-of-notifications-selection-criteria This element contains the total number of communication barring notifications sent by the network to user till then. 8.1.1.2. comm-barring-ntfy-trigger-criteria 8.1.1.2.1. notification-time-selection-criteria This element informs the server about the time at which the notification should be triggered. 8.1.1.2.2. presence-status-selection-criteria This element gives the presence status of the subscriber, based on which the decision can be made, whether the subscriber wishes to receive notification information or not. 8.1.1.2.2.1. presence-selection-info This element specifies the presence status of the subscriber within which the subscriber expects to receive notifications about communication barrings. 8.1.2. Comm-barring-ntfy-info Element This element gives the notification information. This element has following sub-elements: 8.1.2.1. originating-user-info Refer to Section 8.1.1.1.1 for details of this element. 8.1.2.2. barring-time-info This element gives the time of communication barring. Its value is expressed in YYYY:MM:DDTHH:MM:SS format. 8.1.2.3. barring-reason-info This element contains the reason for the communication barring which could be because of the standard rules like ICB or ACR or any other custom rule defined by the subscriber. 8.1.2.4. num-barrings This element gives the number of communication barrings that occurred in the network on behalf of the user till date. Avasarala & Jesske Expires May 26, 2011 [Page 12] Internet-Draft SIP Communication Barring Notification November 2010 8.1.2.5. num-notifications This element gives the number of communication barring notifications sent till date to the user. 8.1.3. Comm_barring-info-selection-criteria This element gives the subscriber various to select communication barring information. This element has following sub-elements. 8.1.3.1. disable-originating-user-info This element gives the subscriber option of adding originating user information to the notification information. The default value is false which means the subscriber wants the originating-user-info element to be present in the notification information. 8.1.3.2. disable-barring-time-info This element gives the subscriber option of adding barring-time information to the notification information. The default value is false which means the subscriber wants the barring-time-info to be present in the notification information. 8.1.3.3. disable-barring-reason This element gives the subscriber option of adding barring-reason information to the notification information. The default value is false which means the subscriber wants the barring-reason information to be present in the notification information. 8.1.3.4. disable-barring-rule This element gives the subscriber option of adding barring-rule information to the notification information. The default value is false which means the subscriber wants the barring-rule information to be present in the notification information. 8.1.3.5. disable-number-of-barrings This element gives the subscriber option of adding number of barrings that occurred till date to the notification information. The default value is false which means the subscriber wants the number of barrings that occurred till date information to be present in the notification information Avasarala & Jesske Expires May 26, 2011 [Page 13] Internet-Draft SIP Communication Barring Notification November 2010 8.1.3.6. disable-number-of-notifications This element gives the subscriber option of adding number of communication barring notifications sent to the user till date to the notification information. The default value is false which means the subscriber wants the number of notifications that were sent to the user till date information to be present in the notification information. 8.2. Sample Notification body 8.2.1. Instance of communication barring subscription filter document Boss sip:boss@office.com 1999-05-31T13:20:00-05:00Z 2006-05-06T13:20:00-05:00Z 404 302 1999-05-31T13:20:00-05:00Z 2006-05-06T13:20:00-05:00Z Avasarala & Jesske Expires May 26, 2011 [Page 14] Internet-Draft SIP Communication Barring Notification November 2010 8.2.2. Instance of communication barring notification document Boss sip:boss@office.com 1999-06-01T13:20:00-05:00Z 404 1 1 8.3. Schema Avasarala & Jesske Expires May 26, 2011 [Page 16] Internet-Draft SIP Communication Barring Notification November 2010 Avasarala & Jesske Expires May 26, 2011 [Page 17] Internet-Draft SIP Communication Barring Notification November 2010 Avasarala & Jesske Expires May 26, 2011 [Page 18] Internet-Draft SIP Communication Barring Notification November 2010 Avasarala & Jesske Expires May 26, 2011 [Page 19] Internet-Draft SIP Communication Barring Notification November 2010 9. Security Considerations Authentication and authorization of subscriptions have been discussed in Section 6.6. Lack of authentication or authorization may provide comm-barring-info information to unauthorized parties and can reveal sensitive information with regards to the user's call receiving patterns. For example, who calls the user and at what time, etc. Integrity protection and confidentiality of notifications are also discussed in Section 6.7. If a notifier does not encrypt bodies of NOTIFY requests, an eavesdropper could learn the status of a SIP user agent and use it to create malicious sessions. If the notifier does not integrity protect the bodies of NOTIFY requests, a man-in- the- middle attacker or malicious SIP proxy could modify the contents of the comm-barring-info event package notification. Although this does not cause harm, it can create annoyances. 10. IANA Considerations This document registers the new SIP Event Package. 10.1. Communication Barring Information Event Package Registration Package Name: Comm_barring-info Type: Package Contact: Jon Merdith, Published Specification: RFC XXXX (Note to RFC Editor) Avasarala & Jesske Expires May 26, 2011 [Page 20] Internet-Draft SIP Communication Barring Notification November 2010 11. Acknowledgements The authors would like to thank Samir Saklikar, Subir Saha, Ban Al- Bakri, John Elwell, Paul Kyzivat and Mary Barnes for their useful suggestions. 12. References 12.1. Normative References [1] 3GPP, "Anonymous Communication Rejection (ACR) and Communication Barring (CB) using IP Multimedia (IM) Core Network (CN) subsystem; Protocol specification", 3GPP TS 24.611 8.2.0, December 2008. [2] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [3] Peterson, J., Jennings, C., and R. Sparks, "Change Process for the Session Initiation Protocol (SIP) and the Real-time Applications and Infrastructure Area", BCP 67, RFC 5727, March 2010. [4] 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. [5] 3GPP, "IP Multimedia Core Network Subsystem (IMS) Multimedia Telephony Service and supplementary services; Stage 1", 3GPP TS 22.173 10.2.0, March 2010. [6] Roach, A., "Session Initiation Protocol (SIP)-Specific Event Notification", RFC 3265, June 2002. 12.2. Informative References [7] 3GPP, "IP multimedia call control protocol based on Session Initiation Protocol (SIP) and Session Description Protocol (SDP); Stage 3", 3GPP TS 24.229 10.1.0, September 2010. [8] Bray, T., Sperberg-McQueen, C., Paoli, J., and E. Maler, "Extensible Markup Language (XML) 1.0 (Second Edition)", World Wide Web Consortium FirstEdition REC-xml-20001006, October 2000, . [9] Schulzrinne, H., Tschofenig, H., Morris, J., Cuellar, J., Polk, J., and J. Rosenberg, "Common Policy: A Document Format for Avasarala & Jesske Expires May 26, 2011 [Page 21] Internet-Draft SIP Communication Barring Notification November 2010 Expressing Privacy Preferences", RFC 4745, February 2007. Appendix A. Change log [RFC EDITOR NOTE: Please remove this section when publishing] Changes from draft-avasarala-sipping-comm-barring-notification-00 o Moved from SIPPING to DISPATCH WG. o Incorporated review comments. o Re-submitting since -00 expired Authors' Addresses Ranjit Avasarala Motorola Solutions India Pvt Ltd Bagamane Tech Park, C V Raman Nagar Bangalore 560093 India Email: ranjit@motorolasolutions.com Roland Jesske Deutsche Telekom Heinrich-Hertz-Strasse 3-7 Darmstadt 64307 Germany Email: r.jesske@telekom.de Avasarala & Jesske Expires May 26, 2011 [Page 22]