Internet Engineering Task Force Internet Draft Koetter draft-koetter-cpl-network-00.txt February 17, 2002 Expires: August 16, 2002 CPL Extensions for Network Operators 1. STATUS OF THIS MEMO This document is an Internet-Draft and is in full conformance with all provisions of Section 10 of RFC2026. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at anytime. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress". The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt To view the list Internet-Draft Shadow Directories, see http://www.ietf.org/shadow.html. 2. Abstract The Call Processing Language (CPL) can be used to describe and control Internet telephony services. The original CPL specification focuses on call handling on network servers. The extensions of CPL in this document are designed to add capabilities to describe network-operator-related services. These services are essential for providing services on a network. Further networks features have to be definded before network operators have got a sufficient toolset. Here two features will be introduced. These are televote and lawful interception. 3. Introduction The current CPL [1] specification focuses on the server side call handling. It does not support network-operator related services. We can either create a new language or extend CPL to provide such support. Extending CPL is a better choice for two reasons. First, many existing CPL components can be re-used. Second, the network-operator features can influence call handling which has been defined in the current CPL specification. Koetter [Page 1] Internet Draft CPL-Network February 17, 2002 The CPL extensions for network-operators are not tied to any particular protocol. 4. Conventions of This Document In this document, the key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALLNOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" are to be interpreted as described in RFC 2119 [2] and indicate requirement levels for compliant CPL implementations. In examples, non-XML strings such as -action1- and so forth, are sometimes used. These represent further parts of the script which are not relevant to the example in question. Some paragraphs are indented, like this; they give motivations of design choices, or questions for future discussion in the development of the CPL extensions, and are not essential to the specification of the language. 5. Overview of the Extensions We define two kinds of extensions. These are all sub-level actions. The actions provide benefit for network operators. The actions are namely "televote" and "lawful interception". In the case the owner of an IP network can interconnect with other networks as well as not doing so and offering gateways to traditional telephony networks. For these different infrastructures the network provider needs tools in order to offer different services to different users. Network operators need more features in order to offer telephony over IP networks and being able to do billing, restrictions or new services. It should also be assured that the user MUST NOT be able to overcome restrictions of the network operators. Further features for network operators can be CLIP (Call Line Identification Restriction) and CLIR (Call Line Identification Presentation) as well as the limitation of numbers and services. Completely new services may also be the authentification by password at the server when calling or called, location based services, and message services to other networks like SMS (short message service). 6. Namespace of CPL extensions for network-operators The namespace of the CPL extensions for network-operators will be "http://www.rfc-editor.org/rfc/rfcxxxx.txt" and will be declared as xmlns:network. Figure 1 shows the example of Koetter [Page 2] Internet Draft CPL-Network February 17, 2002 using namespace declaration of CPL extensions for network- operators. 7. New sub-level actions We still keep 'incoming' and 'outgoing' as the top-level actions. We create a new kind of actions named sub-level actions to hold the CPL extensions. The sub-level action defines a lower-level tag of the top-level action. We add two sub-level actions for CPL extensions for network- operators. Figure 1: Namespace declaration of CPL extensions for network-operators Tag: cpl Parameters: None Sub-tags: ancillary See CPL Section 10 subaction See CPL Section 9 network:lawfulintercept sub level action for lawful call interception. network:televote sub level action for televote outgoing Top-level actions to take on outgoing calls incoming Top-level actions to take on incoming calls Figure 2: Syntax of the extended CPL node 8. New network operator features Here only two new features are introduces. As mentioned for a complete network tool set more features are needed. They should be defined in later version of this Koetter [Page 3] Internet Draft CPL-Network February 17, 2002 8.1 Lawful interception The feature network:lawfulintercept, the action performed when the network operator wants to intercept the conversation. The operator may define how he wants the interception to happen and what device will be used. Node: lawfulintercept Outputs: None Parameters: method method to intercept the call destination address of intercepting device Figure 3: Syntax of lawful interception node 8.2 Syntax of the extended CPL node Televote The second subaction is network:televote, the action performed when a network operator wants to do a televoting. Televoting contains a number of parameters that specify the usage. In the CPL engine the televote action should be realised with as little use of resources as possible. Televoting processes in traditional telephony may cause an avalanche of calls in a short period of time. The CPL server should be enabled to be able to cope with those. The network:televote subaction has got the parameter endmode that specifies when the current cpl script should be read again. Node: televote Outputs: None Parameters: starttime start time of televote process stoptime stop time of televote process duration duration of televote process endmode defines the end mode mode defines the selection mode n defines probability or nth submissionmode defines mode of submission submissionaddress address for result submission winnermode direction mode for successful winneraddress address if successful Figure 4: Syntax of the televote node 9. Examples The examples should show how the features could be used. 9.1 Lawful interception The script in Figure 5 is a script that provides a lawful call interception for all incoming calls. Koetter [Page 4] Internet Draft CPL-Network February 17, 2002 method="IP" destination= "129.130.131.132"> Figure 5: Example script: Lawful interception 9.2 Televote The script in Figure 6 is a script that does a televoting session. The session starts on the 31st of October 2002 at 13:30 and has the duration of one hour. The calls should be counted and the 1000th caller will be redirected to sip:winnerphone@destination.com. The result of televote will be submitted by electronic mail to customer@destinastion.com. The result should contain at least the number of incoming calls but could include more depending on CPL engine realisation. Figure 6: Example script: Televote Koetter [Page 5] Internet Draft CPL-Network February 17, 2002 10. The XML DTD of the CPL extensions for network oprators The XML DTD of the CPL extensions for network-operators follows the XML DTD of CPL with some modifications on the sub-level actions. We avoid repeating the parts that are the same as those in XML DTD for CPL in this document. Only the new added definitions are listed here. Figure 7: DTD lawful interception Figure 8: DTD televote 11. ESSENTIAL REMARK FOR FURTHER USE This paper was written during in the circumstances of a final degree thesis at the University of Stuttgart in the IND. It means that I will most probably not be working on this subject in the future. Due to this the paper is open for modifications. If changed please submit one copy to my mentioned email address. If parts of this document are kept in further versions please keep the names in the authors list. An implementation of the features televote and lawful interception does exist at Siemens AG, ICN WN CC NA A 19, Hofmannstr. 51, 81559 Munich, Germany. Koetter [Page 6] Internet Draft CPL-Network February 17, 2002 12. Authors' Addresses Stephan Koetter electronic mail: stephan.koetter@web.de 13. Bibliography [1] J. Lennox and H. Schulzrinne, "CPL: a language for user control of internet telephony services," Internet Draft, Internet Engineering Task Force, July 2000. Work in progress. [2] S. Bradner, "Key words for use in RFCs to indicate requirement levels," Request for Comments 2119, Internet Engineering Task Force, Mar. 1997. [3] M. Handley, H. Schulzrinne, E. Schooler, and J. Rosenberg, "SIP: session initiation protocol," Request for Comments 2543, Internet Engineering Task Force, Mar. 1999. [4] R. Sparks, "SIP call control," Internet Draft, Internet Engineering Task Force, Feb. 2001. Work in progress. Full Copyright Statement Copyright (c) The Internet Society (2001). All Rights Reserved. This document and translations of it may be copied and furnished to others, and derivative works that comment on or otherwise explain it or assist in its implementation may be prepared, copied, published and distributed, in whole or in part, without restriction of any kind, provided that the above copyright notice and this paragraph are included on all such copies and derivative works. However, this document itself may not be modified in any way, such as by removing the copyright notice or references to the Internet Society or other Internet organizations, except as needed for the purpose of developing Internet standards in which case the procedures for copyrights defined in the Internet Standards process must be followed, or as required to translate it into languages other than English. The limited permissions granted above are perpetual and will not be revoked by the Internet Society or its successors or assigns. This document and the information contained herein is provided on an "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. Koetter [Page 7] Internet Draft CPL-Network February 17, 2002 Table of Contents 1. STATUS OF THIS MEMO 1 2. ABSTRACT 1 3. INTRODUCTION 1 4. CONVENTIONS OF THIS DOCUMENT 2 5. OVERVIEW OF THE EXTENSIONS 2 6. NAMESPACE OF CPL EXTENSIONS FOR NETWORK-OPERATORS 2 7. NEW SUB-LEVEL ACTIONS 3 8. NEW NETWORK OPERATOR FEATURES 3 8.1 LAWFUL INTERCEPTION 4 8.2 SYNTAX OF THE EXTENDED CPL NODE TELEVOTE 4 9. EXAMPLES 4 9.1 LAWFUL INTERCEPTION 4 9.2 TELEVOTE 5 10. THE XML DTD OF THE CPL EXTENSIONS FOR NETWORK OPRATORS 6 11. ESSENTIAL REMARK FOR FURTHER USE 6 12. AUTHORS' ADDRESSES 7 13. BIBLIOGRAPHY 7 Koetter [Page 8]