SIPPING E. Burger Internet-Draft Brooktrout Technology, Inc. Expires: April 1, 2005 M. Dolly AT&T Labs October 1, 2004 A Session Initiation Protocol (SIP) Event Package for Key Press Stimulus (KPML) draft-ietf-sipping-kpml-06 Status of this Memo This document is an Internet-Draft and is subject to all provisions of section 3 of RFC 3667. By submitting this Internet-Draft, each author represents that any applicable patent or other IPR claims of which he or she is aware have been or will be disclosed, and any of which he or she become aware will be disclosed, in accordance with RFC 3668. 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 any time. 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. The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. This Internet-Draft will expire on April 1, 2005. Copyright Notice Copyright (C) The Internet Society (2004). Abstract This document describes a SIP Event Package "kpml" that enables monitoring of DTMF signals and uses XML documents referred to as Key Press Markup Language (KPML). The kpml Event Package may be used to support applications consistent with the principles defined in the document titled "A Framework for Application Interaction in the Burger & Dolly Expires April 1, 2005 [Page 1] Internet-Draft KPML October 2004 Session Initiation Protocol (SIP)". The event package uses SUBSCRIBE messages and allows for XML documents that define and describe filter specifications for capturing key presses (DTMF Tones) entered at a presentation-free User Interface SIP User Agent (UA). The event package uses NOTIFY messages and allows for XML documents to report the captured key presses (DTMF tones), consistent with the filter specifications, to an Application Server. The scope of this package is for collecting supplemental key presses or mid-call key presses (triggers). Conventions used in this document RFC2119 [1] provides the interpretations for the key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" found in this document. The Application Interaction Framework document [23] provides the interpretations for the terms "User Device", "SIP Application", and "User Input". This document uses the term "Application" and "Requesting Application" interchangeably with "SIP Application". Additionally, the Application Interaction Framework document discusses User Device Proxies. A common instantiation of a User Device Proxy is a Public Switched Telephone Network (PSTN) gateway. Because the normative behavior of a presentation free User Interface is identical for a presentation free SIP User Agent and a presentation free User Device Proxy, this document uses "User Device" for both cases. Burger & Dolly Expires April 1, 2005 [Page 2] Internet-Draft KPML October 2004 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 5 2. Protocol Overview . . . . . . . . . . . . . . . . . . . . . . 6 3. Key Concepts . . . . . . . . . . . . . . . . . . . . . . . . . 7 3.1 Subscription Duration . . . . . . . . . . . . . . . . . . 7 3.2 Timers . . . . . . . . . . . . . . . . . . . . . . . . . . 8 3.3 Pattern Matches . . . . . . . . . . . . . . . . . . . . . 9 3.4 Digit Suppression . . . . . . . . . . . . . . . . . . . . 12 3.5 User Input Buffer Behavior . . . . . . . . . . . . . . . . 14 3.6 DRegex . . . . . . . . . . . . . . . . . . . . . . . . . . 16 3.6.1 Overview . . . . . . . . . . . . . . . . . . . . . . . 16 3.6.2 Operation . . . . . . . . . . . . . . . . . . . . . . 17 3.7 Monitoring Direction . . . . . . . . . . . . . . . . . . . 18 3.8 Multiple Simultaneous Subcriptions . . . . . . . . . . . . 19 4. KPML Behavior . . . . . . . . . . . . . . . . . . . . . . . . 20 4.1 Constructing Event Requests . . . . . . . . . . . . . . . 20 4.2 Receiving Event Requests . . . . . . . . . . . . . . . . . 20 4.3 Constructing Event Responses . . . . . . . . . . . . . . . 22 4.3.1 Rate of Notifications . . . . . . . . . . . . . . . . 24 4.4 Receiving Event Responses . . . . . . . . . . . . . . . . 25 5. Formal Syntax . . . . . . . . . . . . . . . . . . . . . . . . 25 5.1 DRegex . . . . . . . . . . . . . . . . . . . . . . . . . . 25 5.2 KPML Request . . . . . . . . . . . . . . . . . . . . . . . 26 5.3 KPML Response . . . . . . . . . . . . . . . . . . . . . . 29 6. Enumeration of KPML Status Codes . . . . . . . . . . . . . . . 30 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 30 7.1 SIP Event Package Registration . . . . . . . . . . . . . . 30 7.2 MIME Media Type application/kpml-request+xml . . . . . . . 31 7.3 MIME Media Type application/kpml-response+xml . . . . . . 32 7.4 URN Sub-Namespace Registration for urn:ietf:xml:ns:kpml-request . . . . . . . . . . . . . . . 32 7.5 URN Sub-Namespace Registration for urn:ietf:xml:ns:kpml-response . . . . . . . . . . . . . . 33 7.6 KPML Request Schema Registration . . . . . . . . . . . . . 34 7.7 KPML Response Schema Registration . . . . . . . . . . . . 34 8. Security Considerations . . . . . . . . . . . . . . . . . . . 34 9. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 9.1 Monitoring for Octothorpe . . . . . . . . . . . . . . . . 35 9.2 Dial String Collection . . . . . . . . . . . . . . . . . . 35 10. Call Flow Examples . . . . . . . . . . . . . . . . . . . . . 36 10.1 Supplemental Digits . . . . . . . . . . . . . . . . . . . 36 10.2 Multiple Applications . . . . . . . . . . . . . . . . . . 40 11. References . . . . . . . . . . . . . . . . . . . . . . . . . 48 11.1 Normative References . . . . . . . . . . . . . . . . . . . . 48 11.2 Informative References . . . . . . . . . . . . . . . . . . . 49 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . 50 A. Contributors . . . . . . . . . . . . . . . . . . . . . . . . . 51 Burger & Dolly Expires April 1, 2005 [Page 3] Internet-Draft KPML October 2004 B. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 51 Intellectual Property and Copyright Statements . . . . . . . . 53 Burger & Dolly Expires April 1, 2005 [Page 4] Internet-Draft KPML October 2004 1. Introduction This document describes a SIP Event Package "kpml" that enables monitoring of DTMF signals and utilizes XML documents referred to as Key Press Markup Language (KPML). KPML is a markup [21] that enables presentation-free User Interfaces as described in the Application Interaction Framework [23]. The Key Press Stimulus Package is a SIP Event Notification Package [5] that uses the SUBSCRIBE and NOTIFY methods of SIP. The subscription filter and notification report bodies use the Keypad Markup Language, KPML. The "kpml" event package requires the definition of two new MIME types, two new URN Sub-Namespaces, and two Schema for the KPML Request and the KPML Response. The scope of this package is for collecting supplemental key presses or mid-call key presses (triggers). This capability allows an Application Server service provider to monitor (filter) for a set of DTMF patterns at a SIP User Agent located either in an end user device or a gateway. In particular, the "kpml" event package enables "dumb phones" and "gateways" which receive signals from dumb phones to report user key-press events. Colloquially, this mechanism provides for "digit reporting" or "Dual-Tone Multi-Frequency (DTMF) reporting." The capability eliminates the need for hairpinning through a Media Server or duplicating all the DTMF events, when an Application Server needs to trigger mid-call service processing on DTMF digit patterns. A goal of KPML is to fit in an extremely small memory and processing footprint. The name of the XML document, KPML, reflects its legacy support role. The public switched telephony network (PSTN) accomplished signaling by transporting DTMF tones in the bearer channel from the user terminal to the local exchange. This is in-band signaling. Voice-over-IP networks transport in-band signals with actual DTMF waveforms or RFC2833 [12] packets. In RFC2833, the signaling application inserts RFC2833 named signal packets as well as, or instead of, generating tones in the media path. The receiving application receives the signal information in the media stream. RFC2833 tones are ideal for conveying telephone-events point-to-point in an RTP stream, as in the context of straightforward sessions like a 2-party call or simple, centrally mixed conference. However, there are other environments where additional or alternative requirements are needed. These other environments include protocol translation and complex call control. Burger & Dolly Expires April 1, 2005 [Page 5] Internet-Draft KPML October 2004 An interested application could request notifications of every key press. However, many of the use cases for such signaling show that many applications are interested in only one or a few keystrokes. Thus a mechanism is needed for specifying to the user's interface what stimuli the application requires. 2. Protocol Overview The "kpml" event package uses explicit subscription notification requests, using SUBSCRIBE/NOTIFY. The User Device MUST return a Contact URI that has GRUU [26] properties in the Contact header of a SIP INVITE, 1xx, or 2xx response. Following the semantics of SUBSCRIBE, if the User Interface receives a second subscription for the same dialog, including id, if present, the user inferface/device MUST terminate the existing KPML subscription and replace it with the new subscription. An Application MAY register multiple User Input patterns in a single KPML subscription. If the User Interface supports multiple, simultaneous KPML subscriptions, the Application installs the subscriptions either in a new SUBSCRIBE-initiated dialog or on an existing SUBSCRIBE-initiated dialog with a new event id tag. If the User Interface does not support multiple, simultaneous KPML subscriptions, the User Interface MUST respond with a KPML status code. A KPML subscription can be persistent or one-shot. Persistent requests are active until either the dialog terminates, including normal subscription expiration, the Application replaces them, the Application deletes them by sending a null document on the dialog, or the Application deletes the subscription by sending a SUBCRIBE with an expires value of zero (0). Standard SUBSCRIBE processing dictates the User Device sends a NOTIFY response if it receives a SUBSCRIBE with an expires of zero. One-shot requests terminate the subscription upon the receipt of DTMF values which provde a match. The "persist" KPML element specifies whether the subscription remains active for the duration specified in the SUBSCRIBE message or if it automatically terminates upon a pattern match. Burger & Dolly Expires April 1, 2005 [Page 6] Internet-Draft KPML October 2004 SIP SUBSCRIBE messages are routed to the User Interface using standard SIP request routing. A KPML subscription contained in the SUBCRIBE message identifies the media stream by referencing its dialog identifiers. NOTIFY messages MAY contain XML documents. If the User Interface matches a digitmap, the NOTIFY message (response) contains an XML document that indicates the User Input detected and whether the User Interface suppressed the representation of User Input, such as tones, or RFC2833, from the media stream. If the User Interface encountered an an error condition, such as a timeout, this will also be reported. 3. Key Concepts 3.1 Subscription Duration The subscription lifetime MUST NOT be longer than the negotiated expires time, per RFC3265 [5]. The subscription lifetime should be longer than the expected call time. The default subscription lifetime (Expires value) MUST be 7200 seconds. Subscribers MUST be able to handle the User Interface returning an Expires value smaller than the requested value. Per RFC3265 [5], the subscription duration is the value returned by the User Interface in the 200 OK Expires header. There are two types of subscriptions: one-shot and persistent. Persistent subscriptions have two sub-types: continuous notify and single-notify. One-shot subscriptions terminate after a pattern match occurs and a report is issued in a NOTIFY message. If the User Interface detects a key press stimulus that triggers a one-shot KPML event, then the User Interface (notifier) MUST set the "Subscription-State" in the NOTIFY message to "terminated". At this point the User Interface MUST consider the subscription expired. Persistent subscriptions remain active at the User Interface, even after a match. For continuous notify persistent subscriptions, the User Interface will emit a NOTIFY message whenever the User Input matches a subscribed pattern. For single-notify persistent subscriptions, the user device will emit a NOTIFY message at the first match, but will not emit further NOTIFY messages until the Application issues a new subscription request on the subscription dialog. Burger & Dolly Expires April 1, 2005 [Page 7] Internet-Draft KPML October 2004 NOTE: The single-notify persistent subscription enables lock-step (race-free) quarantining of User Input between different digit maps. The "persist" attribute to the tag in the KPML subscription body affects the lifetime of the subscription. If the persist attribute is "one-shot", then once there is a match (or no match is possible), the subscription ends after the User Interface notifies the Application. If the persist attribute is "persist" or "single-notify", then the subscription ends when the Application explicitly ends it or the User Interface terminates the subscription. If the User Interface does not support persistent subscriptions, it returns a NOTIFY message with the KPML status code set to 531. If there are digits in the buffer and the digits match an expression in the SUBSCRIBE filter, the User Interface prepares the appropriate NOTIFY response message. Note the values of the persistent attribute are case sensitive. 3.2 Timers To address the various key press collection scenarios, three timers are defined. They are the extra, critical, and inter-digit timers. o The extra timer is the time to wait after the longest match has occurred (presumably for the Enter key). o The critical timer is the time to wait for another digit if the collected digits can match a pattern. o The inter-digit timer is the maximum time to wait between digits. Note: there is no start timer, as that concept does not apply in the KPML context. The User Interface MAY support an extra-digit timeout value. This is the amount of time the User Interface will wait for another key press when it already has a matched . The application can specify the extra-digit timeout as an integer number of milliseconds by using the "extradigittimer" attribute to the tag. The default is 500 milliseconds. The User Interface MAY support a critical-digit timeout value. This is the amount of time the User Interface will wait for another key press when it already has a matched but there is another, longer that may also match the pattern. The application can specify the critical-digit timeout as an integer number of milliseconds by using the "criticaldigittimer" attribute to the Burger & Dolly Expires April 1, 2005 [Page 8] Internet-Draft KPML October 2004 tag. The default is 1000 milliseconds. The User Interface MAY support an inter-digit timeout value. This is the amount of time the User Interface will wait for User Input before returning a timeout error result on a partially matched pattern. The application can specify the inter-digit timeout as an integer number of milliseconds by using the "interdigittimer" attribute to the tag. The default is 4000 milliseconds. If the User Interface does not support the specification of an inter-digit timeout, the User Interface MUST silently ignore the specification. If the User Interface supports the specification of an inter-digit timeout, but not to the granularity specified by the value presented, the User Interface MUST round up the requested value to the closest value it can support. 3.3 Pattern Matches During the subscription lifetime, the User Interface may detect a key press stimulus that triggers a KPML event. In this case, the User Interface (notifier) MUST return the appropriate KPML document. The pattern matching logic works as follows. KPML User Interfaces MUST follow the logic presented in this section so that different implementations will perform deterministically on the same KPML document given the same User Input. The pattern match algorithm matches the longest regular expression. This is the same mode as H.248.1 [16] and not the mode presented by MGCP [15]. The pattern match algorithm choice has an impact on determining when a pattern matches. Consider the following KPML document. Burger & Dolly Expires April 1, 2005 [Page 9] Internet-Draft KPML October 2004 0 011 Figure 1: Greedy Matching In Figure 1, if we were to match on the first found pattern, the string "011" would never match. This happens because the "0" rule would match first. While this behavior is what most applications desire, it does come at a cost. Consider the following KPML document snippet. x{7} x{10} Figure 2: Timeout Matching Figure 2 shows a typical North American dial plan. From an application perspective, users expect a seven-digit number to respond quickly, not waiting the typical inter-digit critical timer (usually four seconds). Conversely, the User does not want the system to cut off their ten-digit number at seven digits because they did not enter the number fast enough. One approach to this problem is to have an explicit dial string terminator. Typically, it is the pound key (#). Now, consider the following snippet. x{7}# x{10}# Figure 3: Timeout Matching with Enter The problem with the approach in Figure 3 is that the digit collector will still look for a digit after the "#" in the seven-digit case. Worse yet, the "#" will appear in the returned dial string. The approach used in KPML is to have an explicit "Enter Key", as shown in the following snippet. Burger & Dolly Expires April 1, 2005 [Page 10] Internet-Draft KPML October 2004 x{7} x{10} Figure 4: Timeout Matching with Enter Key In Figure 4, the enterkey attribute to the tag specifies a string that terminates a pattern. In this situation, if the user enters seven digits followed by the "#" key, the pattern matches (or fails) immediately. KPML indicates a terminated nomatch with a KPML status code 402. NOTE: The enterkey is a string. The enterkey can be a sequence of key presses, such as "**". Some patterns look for long duration key presses. For example, some applications look for long "#" or long "*". KPML uses the "L" modifier to characters to indicate long key presses. The following KPML document looks for a long pound of at least 3 seconds. L# The request can specify what constitutes "long" by setting the long attribute to the . This attribute is an integer representing the number of milliseconds. If the user presses a key for longer than "long" milliseconds, the Long modifier is true. The default length of the long attribute is 2500 milliseconds. User Interfaces MUST distinguish between long and short input when the KPML document specifies both in a document. However, if there is not a corresponding long key press pattern in a document, the User Interface MUST match the key press pattern irrespective of the length of time the user presses the key. An an example, in the following snippet in Figure 6, the User Interface discriminates between a long "*" and a normal "*", but any length "#" will match the pattern. Burger & Dolly Expires April 1, 2005 [Page 11] Internet-Draft KPML October 2004 * L* # Figure 6: Long and Short Matching Some User Interfaces are unable to present long key presses. An example is an old private branch exchange (PBX) phone set that emits fixed-length tones when the user presses a key. To address this issue, the User Interface MAY interpret a success of a single key press to be equivalent to a long key press of the same key. The Application indicates it wants this behavior by setting the "longrepeat" attribute to the to "true". The KPML document specifies if the patterns are to be persistent by setting the "persist" attribute to the tag to "persist" or "single-notify". Any other value, including "one-shot", indicates the request is a one-shot subscription. If the User Interface does not support persistent subscriptions, it returns a KPML document with the KPML status code set to 531. If there are digits in the buffer and the digits match an expression in the KPML document, the User Interface emits the appropriate kpml notification. Note the values of the persistent attribute are case sensitive. Some User Interfaces may support multiple regular expressions in a given pattern request. In this situation, the application may wish to know which pattern triggered the event. KPML provides a "tag" attribute to the tag. The "tag" is an opaque string that the User Interface sends back in the notification report upon a match in the digit map. In the case of multiple matches, the User Interface MUST chose the longest match in the KPML document. If multiple matches match the same length, the User Interface MUST chose the first expression listed in the subscription KPML document based on KPML document order. If the User Interface does not support multiple regular expressions in a pattern request, the User Interface MUST return a KPML document with the KPML status code set to 532. 3.4 Digit Suppression Under basic operation, a KPML User Interface will transmit in-band tones (RFC2833 [12] or actual tone) in parallel with User Input reporting. Burger & Dolly Expires April 1, 2005 [Page 12] Internet-Draft KPML October 2004 NOTE: If KPML did not have this behavior, then a User Interface executing KPML could easily break called applications. For example, take a personal assistant that uses "*9" for attention. If the user presses the "*" key, KPML will hold the digit, looking for the "9". What if the user just enters a "*" key, possibly because they accessed an IVR system that looks for "*"? In this case, the "*" would get held by the User Interface, because it is looking for the "*9" pattern. The user would probably press the "*" key again, hoping that the called IVR system just did not hear the key press. At that point, the User Interface would send both "*" entries, as "**" does not match "*9". However, that would not have the effect the user intended when they pressed "*". On the other hand, there are situations where passing through tones in-band is not desirable. Such situations include call centers that use in-band tone spills to effect a transfer. For those situations, KPML adds a suppression tag, "pre", to the tag. There MUST NOT be more than one 
 in any given
   .

   If there is only a single  and a single , suppression
   processing is straightforward.  The end-point passes User Input until
   the stream matches the regular expression 
.  At that point, the
   User Interface will continue collecting User Input, but will suppress
   the generation or pass-through of any in-band User Input.

   If the User Interface suppressed stimulus, it MUST indicate this by
   including the attribute "suppressed" with a value of "true" in the
   notification.

   Clearly, if the User Interface is processing the KPML document
   against buffered User Input, it is too late to suppress the
   transmission of the User Input, as the User Interface has long sent
   the stimulus.  This is a situation where there is a 
   specification, but the "suppressed" attribute will not be "true" in
   the notification.  If there is a 
 tag that the User Interface
   matched and the User Interface is unable to suppress the User Input,
   it MUST set the "suppressed" attribute to "false".

   A KPML User Interface MAY perform suppression.  If it is not capable
   of suppression, it ignores the suppression attribute.  It MUST set
   the "suppressed" attribute to "false".  In this case, the pattern to
   match is the concatenated pattern of pre+value.

   At some point in time, the User Interface will collect enough User
   Input to the point it matches a 
 pattern.  The interdigittimer
   attribute indicates how long to wait once the user enters stimulus



Burger & Dolly           Expires April 1, 2005                 [Page 13]

Internet-Draft                    KPML                      October 2004


   before reporting a time-out error.  If the interdigittimer expires,
   the User Interface MUST issue a time-out report, transmit the
   suppressed User Input on the media stream, and stop suppression.

   Once the User Interface detects a match and it sends a NOTIFY request
   to report the User Input, the User Interface MUST stop suppression.
   Clearly, if subsequent User Input matches another 
 expression,
   then the User Interface MUST start suppression.

   After suppression begins, it may become clear that a match will not
   occur.  For example, take the expression
   
*8
xxx[2-9]xxxxxx
   At the point the User Interface receives "*8", it will stop
   forwarding stimulus.  Let us say that the next three digits are
   "408".  If the next digit is a zero or one, the pattern will not
   match.

      NOTE: It is critically important for the User Interface to have a
      sensible inter-digit timer.  This is because an errant dot (".")
      may suppress digit sending forever.

   Applications should be very careful to indicate suppression only when
   they are fairly sure the user will enter a digit string that will
   match the regular expression.  In addition, applications should deal
   with situations such as no-match or time-out.  This is because the
   User Interface will hold digits, which will have obvious User
   Interface issues in the case of a failure.

3.5  User Input Buffer Behavior

   User Interfaces MUST buffer User Input upon receipt of an
   authenticated and accepted subscription.  Subsequent KPML documents
   apply their patterns against the buffered User Input.  Some
   applications use modal interfaces where the first few key presses
   determine what the following key presses mean.  For a novice user,
   the application may play a prompt describing what mode the
   application is in.  However, "power users" often barge through the
   prompt.

   KPML provides a  tag in the  element.  The default is
   not to flush User Input.  Flushing User Input has the effect of
   ignoring key presses entered before the installation of the KPML
   subscription.  To flush User Input, include the tag
   yes
   in the KPML subscription document.  Note that this directive affects
   only the current subscription dialog/id combination.

   Lock-step processing of User Input is where the User Interface issues



Burger & Dolly           Expires April 1, 2005                 [Page 14]

Internet-Draft                    KPML                      October 2004


   a notification, the Application processes the notification while the
   User Interface buffers additional User Input, the Application
   requests more User Input, and only then does the User Interface
   notify the Application based on the collected User Input.  To direct
   the User Interface to operate in lock-step mode, set the 
   attribute persist="single-notify".

   The User Interface MUST be able to process no.  This
   directive is effectively a no-op.

   Other string values for  may be defined in the future.  If the
   User Interface receives a string it does not understand, it MUST
   treat the string as a no-op.

   If the user presses a key that cannot match any pattern within a
    tag, the User Interface MUST discard all buffered key presses
   up to and including the current key press from consideration against
   the current or future KPML documents on a given dialog.  However, as
   described above, once there is a match, the User Interface buffers
   any key presses the user entered subsequent to the match.

      NOTE:  This behavior allows for applications to only receive User
      Input that is of interest to them.  For example, a pre-paid
      application only wishes to monitor for a long pound.  If the user
      enters other stimulus, presumably for other applications, the
      pre-paid application does not want notification of that User
      Input.  This feature is fundamentally different than the behavior
      of TDM-based equipment where every application receives every key
      press.

   To limit reports to only complete matches, set the "nopartial"
   attribute to the  tag to "true".  In this case, the User
   Interface attempts to match a rolling window over the collected User
   input.

   KPML subscriptions are independent.  Thus it is not possible for the
   current document to know if a following document will enable barging
   or want User Input flushed.  Therefore, the User Interface MUST
   buffer all User Input, subject to the forced_flush caveat described
   below.

   On a given SUBSCRIBE dialog with a given id, the User Interface MUST
   buffer all User Input detected between the time of the report and the
   receipt of the next document, if any.  If the next document indicates
   a buffer flush, then the interpreter MUST flush all collected User
   Input from consideration from KPML documents received on that dialog
   with the given event id.  If the next document does not indicate
   flushing the buffered User Input, then the interpreter MUST apply the



Burger & Dolly           Expires April 1, 2005                 [Page 15]

Internet-Draft                    KPML                      October 2004


   collected User Input (if possible) against the digit maps presented
   by the script's  tags.  If there is a match, the interpreter
   MUST follow the procedures in Section 5.3.  If there is no match, the
   interpreter MUST flush all of the collected User Input.

   Given the potential for needing an infinite buffer for User Input,
   the User Interface MAY discard the oldest User Input from the buffer.
   If the User Interface discards digits, when the User Interface issues
   a KPML notification, it MUST set the forced_flush attribute of the
    tag to "true".  For future use, the Application MUST
   consider any non-null value, other than "false" that it does not
   understand, to be the same as "true".
      NOTE:  The requirement to buffer all User Input for the entire
      length of the session is not really onerous under normal
      operation.  For example, if one has a gateway with 8,000 sessions,
      and the gateway buffers 50 key presses on each session, the
      requirement is only 400,000 bytes, assuming one byte per key
      press.

   Unless there is a suppress indicator in the digit map, it is not
   possible to know if the User Input is for local KPML processing or
   for other recipients of the media stream.  Thus, in the absence of a
   suppression indicator, the User Interface transmits the User Input to
   the far end in real time, using either RFC2833, generating the
   appropriate tones, or both.

3.6  DRegex

3.6.1  Overview

   This subsection is informative in nature.

   The Digit REGular EXpression (DRegex) syntax is a telephony-oriented
   mapping of POSIX Extended Regular Expressions (ERE) [17].

   KPML does not use full POSIX ERE for the following reasons.
   o  KPML will often run on high density or extremely low power and
      memory footprint devices.
   o  Telephony application convention uses the star symbol ("*") for
      the star key and "x" for any digit 0-9.  Requiring the developer
      to escape the star ("\*") and expand the "x" ("[0-9]") is error
      prone.  This also leads DRegex to using the dot (".") to indicate
      repetition, which was the function of the unadorned star in POSIX
      ERE.
   o  POSIX ERE has clear, unambiguous rules for the precedence of the
      alternation operator ("|").  However, a few people in the SIPPING
      Work Group thought we should not allow them.  This was due to
      implementers not getting precedence right in MGCP [15] and H.248.1



Burger & Dolly           Expires April 1, 2005                 [Page 16]

Internet-Draft                    KPML                      October 2004


      [16].

   The following table shows the mapping from DRegex to POSIX ERE.

                         +--------+-----------+
                         | DRegex | POSIX ERE |
                         +--------+-----------+
                         | *      | \*        |
                         | .      | *         |
                         | x      | [0-9]     |
                         | [xc]   | [0-9c]    |
                         +--------+-----------+

                  Table 1: DRegex to POSIX ERE Mapping

   The first substitution, which replaces a star for an escaped star, is
   because telephony application designers are used to using the star
   for the (very common) star key.  Requiring an escape sequence for
   this common pattern would be error prone.  In addition, the usage
   found in DRegex is the same as found in MGCP [15] and H.248.1 [16].

   Likewise, the use of the dot instead of star is common usage from
   MGCP and H.248.1, and reusing the star in this context would also be
   confusing and error prone.

   The "x" character is a common indicator of a dialed digit.  We use it
   here, continuing the convention.

   Users need to take care not to confuse the DRegex syntax with POSIX
   EREs.  They are NOT identical.  In particular there are many features
   of POSIX EREs that DRegex does not support.

   As an implementation note, if one makes the substitutions described
   in the above table, then a standard POSIX ERE engine can parse the
   digit string.  However, the mapping does not work in the reverse
   (POSIX ERE to DRegex) direction.  DRegex only implements the
   Normative behavior described below.

3.6.2  Operation

   White space is removed before parsing DRegex.  This enables sensible
   pretty printing in XML without affecting the meaning of the DRegex
   string.

   The following rules demonstrate the use of DRegex in KPML.






Burger & Dolly           Expires April 1, 2005                 [Page 17]

Internet-Draft                    KPML                      October 2004


   +---------------------------------+---------------------------------+
   | Entity                          | Matches                         |
   +---------------------------------+---------------------------------+
   | character                       | digits 0-9 and A-D (case        |
   |                                 | insensitive)                    |
   | *                               | *                               |
   | #                               | #                               |
   | [character selector]            | Any character in selector       |
   | [^digit selector]               | Any digit (0-9) NOT in selector |
   | [range1-range2]                 | Any digit (0-9) in range from   |
   |                                 | range1 to range2, inclusive     |
   | x                               | Any digit 0-9                   |
   | {m}                             | m repetitions of previous       |
   |                                 | pattern                         |
   | {m,}                            | m or more repetitions of        |
   |                                 | previous pattern                |
   | {,n}                            | At most n (including zero)      |
   |                                 | repetitions of previous pattern |
   | {m,n}                           | at least m and at most n        |
   |                                 | repetitions of previous pattern |
   | Lc                              | Match the character c if it is  |
   |                                 | "long"; c is a digit 0-9 and    |
   |                                 | A-D, #, or *.                   |
   +---------------------------------+---------------------------------+

        +------------+-----------------------------------------+
        | Example    | Description                             |
        +------------+-----------------------------------------+
        | 1          | Matches the digit 1                     |
        | [179]      | Matches 1, 7, or 9                      |
        | [^01]      | Matches 2, 3, 4, 5, 6, 7, 8, 9          |
        | [2-9]      | Matches 2, 3, 4, 5, 6, 7, 8, 9          |
        | x          | Matches 0, 1, 2, 3, 4, 5, 6, 7, 8, 9    |
        | *6[179#]   | Matches *61, *67, *69, or *6#           |
        | x{10}      | Ten digits (0-9)                        |
        | 011x{7,15} | 011 followed by seven to fifteen digits |
        | L*         | Long star                               |
        +------------+-----------------------------------------+


3.7  Monitoring Direction

   SIP identifies dialogs by their dialog identifier.  The dialog
   identifier is the remote-tag, local-tag, and Call-ID entities defined
   in RFC3261 [4].

   One method of determining the dialog identifier, particularly for
   third-party applications, is the SIP Dialog Package [27].



Burger & Dolly           Expires April 1, 2005                 [Page 18]

Internet-Draft                    KPML                      October 2004


   For most situations, such as a monaural point-to-point call with a
   single codec, the stream to monitor is obvious.  In such situations
   the Application need not specify which stream to monitor.

   But there may be ambiguity in specifying only the SIP dialog to
   monitor.  The dialog may specify multiple SDP streams that could
   carry key press events.  For example, a dialog may have multiple
   audio streams.  Wherever possible, the User Interface MAY apply local
   policy to disambiguate which stream or streams to monitor.  In order
   to have an extensible mechanism for identifying streams, the
   mechanism for specifying streams is as an element content to the
    tag.  The only content defined today is the
   reverse tag.

   By default, the User Interface monitors key presses emanating from
   the User Interface.  Given a dialog identifier of Call-ID, local-tag,
   and remote-tag, the User Interface monitors the key presses
   associated with the local-tag.

   In the media proxy case, and potentially other cases, there is a need
   to monitor the key presses arriving from the remote user agent.  The
   optional  element to the  tag specifies which stream
   to monitor.  The only legal value is "reverse", which means to
   monitor the stream associated with the remote-tag.  The User
   Interface MUST ignore other values.
      NOTE:  The reason this is a tag is so individual stream selection,
      if needed, can be addressed in a backwards-compatible way.
      NOTE:  Further specification of the stream to monitor is the
      subject of future standardization.  The current thoughts revolve
      around negotiating MIME parameters that describe namespaces
      declaring the filters specification of the stream.

3.8  Multiple Simultaneous Subcriptions

   Some User Interfaces may support multiple key press event
   notification subscriptions at the same time.  In this situation, the
   User Interface honors each subscription individually and
   independently.

   A SIP user agent may request multiple subscriptions on the same
   SUBSCRIBE dialog, using the id parameter to the kpml event request.

   One or more SIP user agents may request independent subscriptions on
   different SIP dialogs.

   If the User Interface does not support multiple, simultaneous
   subscriptions, the User Interface MUST return a KPML document with
   the KPML status code set to 533 on the dialog that requested the



Burger & Dolly           Expires April 1, 2005                 [Page 19]

Internet-Draft                    KPML                      October 2004


   second subscription.  The User Interface MUST NOT modify the state of
   the first subscription on account of the second subscription attempt.

4.  KPML Behavior

4.1  Constructing Event Requests

   A kpml request document contains a  element with a series of
    tags.  The  element specifies a pattern for the User
   Interface to report on.  The section Section 5.1 describes the
   DRegex, or digit regular expression, language.

   KPML specifies key press event notification filters.  The MIME type
   for KPML requests is application/kpml-request+xml.

   The KPML request document MUST be well-formed and SHOULD be valid.
   KPML documents MUST conform to XML 1.0 [21] and MUST use UTF-8
   encoding.

   Because of the potentially sensitive nature of the information
   reported by KPML, subscribers SHOULD use sips: and MAY use S/MIME on
   the content.

   Subscribers MUST be prepared for the notifier to insist on
   authentication at a minimum and SHOULD expect encryption on the
   documents.

4.2  Receiving Event Requests

   The user information transported by KPML is potentially sensitive.
   For example, it could include calling card or credit card numbers.
   Thus the first action of the User Interface (notifier) SHOULD be to
   authenticate the requesting party.

   User Interfaces MUST support digest authentication at a minimum.

   User Interfaces MUST support the sips: scheme and TLS.

   Upon authenticating the requesting party, the User Interface
   determines if the requesting party has authorization to monitor the
   user's key presses.  Determining authorization policies and
   procedures is beyond the scope of this specification.
      NOTE:  While it would be good to require both authorization and
      user notification for KPML, some uses, such as lawful intercept
      pen registers, have very strict authorization requirements yet
      have a requirement of no user notification.  Conversely, pre-paid
      applications running on a private network may have no
      authorization requirements and already have implicit user



Burger & Dolly           Expires April 1, 2005                 [Page 20]

Internet-Draft                    KPML                      October 2004


      acceptance of key press monitoring.  Thus we cannot give any
      normative rules here.

   After authorizing the request (RECOMMENDED), the User Interface
   checks to see if the request is to terminate a subscription.  If the
   request will terminate the subscription, the User Interface does the
   appropriate processing, including the procedures described in Section
   5.2.

   If the request has no KPML body, then any KPML document running on
   that dialog, and addressed by the event id, if present, immediately
   terminates.  This is a mechanism for unloading a KPML document while
   keeping the SUBSCRIBE-initiated dialog active.  This can be important
   for secure sessions that have high costs for session establishment,
   such as TLS.  The User Interface follows the procedures described in
   Section 5.2.

   If the dialog referenced by the kpml subscription does not exist, the
   User Interface follows the procedures in Section 5.3.  Note the User
   Interface MUST issue a 200 OK before issuing the NOTIFY, as the
   SUBSCRIBE itself is well-formed.

   If the request has a KPML body, the User Interface parses the KPML
   document.  The User Interface SHOULD validate the XML document
   against the schema presented in Section 5.2.  If the document is not
   valid, the User Interface performs the procedures described in.  If
   there is a loaded KPML document on the dialog (and given event id, if
   present), the User Interface unloads the document.

   In addition, if there is a loaded KPML document on the dialog (with
   the given event id, if present), the end device unloads the document.

   It is possible for a dialog to terminate during key press collection.
   The cases enumerated here are explicit subscription termination,
   automatic subscription termination, and underlying (INVITE-initiated)
   dialog termination.

   If a SUBSCRIBE request has an expires of zero (explicit SUBSCRIBE
   termination), includes a KPML document, and there is buffered User
   Input, then the User Interface attempts to process the buffered
   digits against the document.  If there is a match, the User Interface
   MUST generate the appropriate KPML report with the KPML status code
   of 200.  The SIP NOTIFY body terminates the subscription by setting
   the subscription state to "terminated" and a reason of "timeout".

   If the SUBSCRIBE request has an expires of zero and no KPML body or
   the expires timer on the SUBSCRIBE-initiated dialog fires at the User
   Interface (notifier), then the User Interface MUST issue a KPML



Burger & Dolly           Expires April 1, 2005                 [Page 21]

Internet-Draft                    KPML                      October 2004


   report with the KPML status code 487, Subscription Expired.  The
   report also includes the User Input collected up to the time the
   expires timer expired or when the subscription with expires equal to
   zero was processed.  This could be the null string.

   Per the mechanisms of RFC3265 [5], the User Interface MUST terminate
   the SIP SUBSCRIBE dialog.  The User Interface does this via the SIP
   NOTIFY body transporting the final report described in the preceding
   paragraph.  In particular, the subscription state will be
   "terminated" and a reason of "timeout".

   Terminating the subscription when a dialog terminates ensures
   reauthorization (if necessary) for attaching to subsequent
   subscriptions.

   If a SUBSCRIBE request references a dialog that is not present at the
   User Interface, the User Interface MUST generate a KPML report with
   the KPML status code 481, Dialog Not Found.  The User Interface
   terminates the subscription by setting the subscription state to
   "terminated".

   If the KPML document is not valid, the User Interface generates a
   KPML report with the KPML status code 501, Bad Document.  The User
   Interface terminates the subscription by setting the subscription
   state to "terminated".

   If the document is valid but the User Interface does not support a
   namespace in the document, the User Interface MUST respond with a
   KPML status code 502, Namespace Not Supported.

4.3  Constructing Event Responses

   The User Interface (notifier in SUBSCRIBE/NOTIFY parlance) generates
   NOTIFY requests based on the requirements of RFC3265 [5].
   Specifically, unless a SUBSCRIBE request is not valid, all SUBSCRIBE
   requests will result in an immediate NOTIFY.

   The KPML payload distinguishes between a NOTIFY that RFC3265 mandates
   and a NOTIFY informing of key presses.  If there is no User Input
   buffered at the time of the SUBSCRIBE (see  below) or the buffered
   User Input does not match the new KPML document, then the immediate
   NOTIFY MUST NOT contain a KPML body.  If User Interface has User
   Input buffered that result in a match using the new KPML document,
   then the NOTIFY MUST return the appropriate KPML document.

   The NOTIFY in response to a SUBSCRIBE request has no KPML if there
   are no matching buffered digits.  An example of this is in Figure 9.




Burger & Dolly           Expires April 1, 2005                 [Page 22]

Internet-Draft                    KPML                      October 2004


   If there are buffered digits in the SUBSCRIBE request that match a
   pattern, then the NOTIFY message in response to the SUBSCRIBE request
   MUST include the appropriate KPML document.

   NOTIFY sip:application@example.com SIP/2.0
   Via: SIP/2.0/UDP proxy.example.com
   Max-Forwards: 70
   To: 
   From: 
   Call-Id: 439hu409h4h09903fj0ioij
   Subscription-State: active; expires=7200
   CSeq: 49851 NOTIFY
   Event: kpml

                   Figure 9: Immediate NOTIFY Example

   All subscriptions MUST be authenticated, particularly those that
   match on buffered input.

   KPML specifies the key press notification report format.  The MIME
   type for KPML reports is application/kpml-response+xml.  The default
   MIME type for the kpml event package is
   application/kpml-response+xml.

   If the requestor is not using a secure transport protocol such as TLS
   (e.g., by using a sips: URI), the User Interface SHOULD use S/MIME to
   protect the user information in responses.

   When the user enters key press(es) that match a  tag, the User
   Interface will issue a report.

   After reporting, the interpreter terminates the KPML session unless
   the subscription has a persistence indicator.  If the subscription
   does not have a persistence indicator, the User Interface MUST set
   the state of the subscription to "terminated" in the NOTIFY report.

   If the subscription does not have a persistence indicator, to collect
   more digits the requestor must issue a new request.

      NOTE: This highlights the "one shot" nature of KPML, reflecting
      the balance of features and ease of implementing an interpreter.
      If your goal is to build an IVR session, we strongly suggest you
      investigate more appropriate technologies.

   KPML reports have two mandatory attributes, code and text.  These
   attributes describe the state of the KPML interpreter on the User
   Interface.  Note the KPML status code is not necessarily related to
   the SIP result code.  An important example of this is where a legal



Burger & Dolly           Expires April 1, 2005                 [Page 23]

Internet-Draft                    KPML                      October 2004


   SIP subscription request gets a normal SIP 200 OK followed by a
   NOTIFY, but there is something wrong with the KPML request.  In this
   case, the NOTIFY would include the KPML status code in the KPML
   report.  Note that from a SIP perspective, the SUBSCRIBE and NOTIFY
   were successful.  Also, if the KPML failure is not recoverable, the
   User Interface will most likely set the Subscription-Sate to
   "terminated".  This lets the SIP machinery know the subscription is
   no longer active.

   If a pattern matches, the User Interface will emit a KPML report.
   Since this is a success report, the code is "200" and the text is
   "OK".

   The KPML report includes the actual digits matched in the digit
   attribute.  The digit string uses the conventional characters '*' and
   '#' for star and octothorpe respectively.  The KPML report also
   includes the tag attribute if the regex that matched the digits had a
   tag attribute.

   If the subscription requested digit suppressionand the User Interface
   suppressed digits, the suppressed attribute indicates "true".  The
   default value of suppressed is "false".

      NOTE: KPML does not include a timestamp.  There are a number of
      reasons for this.  First, what timestamp would in include?  Would
      it be the time of the first detected key press?  The time the
      interpreter collected the entire string?  A range?  Second, if the
      RTP timestamp is a datum of interest, why not simply get RTP in
      the first place?  That all said, if it is really compelling to
      have the timestamp in the response, it could be an attribute to
      the  tag.

4.3.1  Rate of Notifications

   The User Interface MUST NOT generate messages faster than 25 messages
   per second, or one message every 40 milliseconds.  This is the
   minimum time period for MF digit spills.  Even 30-millisecond DTMF,
   as one sometimes finds in Japan, has a 20-millisecond off time,
   resulting in a 50-millisecond interdigit time.  This document
   strongly RECOMMENDS AGAINST using KPML for digit-by-digit messaging,
   such as would be the case if the only  is "x".

   The sustained rate of notification shall be no more than 100 Notifies
   per minute.

   The User Interface MUST reliably deliver notifications.  Because
   there is no meaningful metric for throttling requests, the User
   Interface SHOULD send NOTIFY messages over a congestion-controlled



Burger & Dolly           Expires April 1, 2005                 [Page 24]

Internet-Draft                    KPML                      October 2004


   transport, such as TCP or SCTP.

   User Interfaces MUST at a minimum implement SIP over TCP.

4.4  Receiving Event Responses

   If there is no KPML body, it means the SUBSCRIBE was successful.
   This establishes the dialog if there is no buffered User Input to
   report.

   If there is a KPML document, and the KPML status code is 200, then a
   match occurred.

   If there is a KPML document, and the KPML status code is 4xx, then an
   error occurred with User Input collection.  The most likely cause is
   a timeout condition.

   If there is a KPML document, and the KPML status code is 5xx, then an
   error occurred with the subscription.  See Section 6 for more on the
   meaning of KPML status codes.

   The subscriber MUST be mindful of the subscription state.  The User
   Interface may terminate the subscription at any time.

5.  Formal Syntax

5.1  DRegex

   The following definition follows RFC2234 [2].  The definition of
   DIGIT is from the CORE specification of RFC2234, namely the
   characters "0" through "9".  Note the DRegexCharacater is not a
   HEXDIG from RFC2234.  In particular, DRegexCharacter neither includes
   "E" nor "F".  Moreover DRegexCharacter is case insensitive, unlike
   HEXDIG.

















Burger & Dolly           Expires April 1, 2005                 [Page 25]

Internet-Draft                    KPML                      October 2004


   DRegex           = 1*( DRegexPosition [ RepeatCount ] )
   DRegexPosition   = DRegexSymbol / DRegexSet
   DRegexSet        = ( "[" DRegexSetList "]" ) /
                      ( "[^" DigitList "]" )
   DRegexSetList    = 1*( (DIGIT "-" DIGIT) / DRegexSymbol )
   DigitList        = 1*( (DIGIT "-" DIGIT) / DIGIT )
   DRegexSymbol     = DRegexCharacter / ( "L" DRegexCharacter )
   RepeatCount      = "." / "{" RepeatRange "}"
   RepeatRange      = Count / ( Count "," Count ) /
                              ( Count "," ) / ( "," Count )
   Count            = 1*(DIGIT)
   DRegexCharacter  = DIGIT / "*" / "#" / "A" / "a" / "B" / "b" /
                              "x" / "X" / "C" / "c" / "D" / "d"

   Note that future extensions to this document may introduce other
   characters for DRegexCharacter, in the scheme of H.248.1 [16] or
   possibly as named strings or XML namespaces.

5.2  KPML Request

   The following syntax for KPML requests uses the XML Schema [8].

   
   
   
     
       
         IETF Keypad Markup Language Request
         
       
       
         
           
             
               
                 
                 
               
             
           
           
             
               



Burger & Dolly           Expires April 1, 2005                 [Page 26]

Internet-Draft                    KPML                      October 2004


                 
                   
                     
                       Default is to not flush buffer
                     
                   
                   
                     
                       
                     
                   
                 
                 
                   
                     
                       Key press notation is a string to allow
                       for future extension of non-16 digit
                       keypads or named keys
                     
                   
                   
                     
                       
                         
                           
                             
                           
                         
                       
                       
                     
                     
                   
                 
               
               
                 
                   Default is "one-shot"
                   
                 
                 
                   
                     
                     
                     
                   
                 



Burger & Dolly           Expires April 1, 2005                 [Page 27]

Internet-Draft                    KPML                      October 2004


               
               
                 
                   Default is 4000 (ms)
                   
                 
               
               
                 
                   Default is 1000 (ms)
                   
                 
               
               
                 
                   Default is 500 (ms)
                   
                 
               
               
               
               
                 
                   Default is false
                   
                 
               
               
                 
                   No default enterkey
                   
                 
               
             
           
         
         



Burger & Dolly           Expires April 1, 2005                 [Page 28]

Internet-Draft                    KPML                      October 2004


       
     
   

                Figure 11: XML Schema for KPML Requests


5.3  KPML Response

   The following syntax for KPML responses uses the XML Schema [8].

   
   
   
     
       
         IETF Keypad Markup Language Response
         
       
       
         
         
         
         
         
           
             
               String for future use for e.g., number of digits lost.
             
           
         
         
         
           
             Matches tag from regex in request
             
           



Burger & Dolly           Expires April 1, 2005                 [Page 29]

Internet-Draft                    KPML                      October 2004


         
       
     
   


6.  Enumeration of KPML Status Codes

   KPML status codes broadly follow their SIP counterparts.  Codes that
   start with a 2 indicate success.  Codes that start with a 4 indicate
   failure.  Codes that start with a 5 indicate a server failure,
   usually a failure to interpret the document or to support a requested
   feature.

   KPML clients MUST be able to handle arbitrary status codes by
   examining the first digit only.

   Any text can be in a KPML report document.  KPML clients MUST NOT
   interpret the text field.

      +------+--------------------------------------------------+
      | Code | Text                                             |
      +------+--------------------------------------------------+
      | 200  | Success                                          |
      | 402  | User Terminated Without Match                    |
      | 423  | Timer Expired                                    |
      | 481  | Dialog Not Found                                 |
      | 487  | Subscription Expired                             |
      | 501  | Bad Document                                     |
      | 502  | Namespace Not Supported                          |
      | 531  | Persistent Subscriptions Not Supported           |
      | 532  | Multiple Regular Expressions Not Supported       |
      | 533  | Multiple Subscriptions on a Dialog Not Supported |
      +------+--------------------------------------------------+

                       Table 4: KPML Status Codes


7.  IANA Considerations

   This document registers a new SIP Event Package, two new MIME types,
   and two new XML namespaces.

7.1  SIP Event Package Registration







Burger & Dolly           Expires April 1, 2005                 [Page 30]

Internet-Draft                    KPML                      October 2004


   Package name: kpml
   Type: package
   Contact: Eric Burger, 
   Published Specification: RFCXXXX

7.2  MIME Media Type application/kpml-request+xml

   +---------------------------------+---------------------------------+
   +---------------------------------+---------------------------------+
   | MIME media type name:           | application                     |
   | MIME subtype name:              | kpml-request+xml                |
   | Required parameters:            | none                            |
   | Optional parameters:            | Same as charset parameter       |
   |                                 | application/xml as specified in |
   |                                 | XML Media Types [3]             |
   | Encoding considerations:        | See RFC3023 [3].                |
   | Security considerations:        | See Section 10 of RFC3023 [3]   |
   |                                 | and Section 8 of RFCXXXX        |
   | Interoperability                | See RFC2023 [3] and RFCXXXX     |
   | considerations:                 |                                 |
   | Published specification:        | RFCXXXX                         |
   | Applications which use this     | Session-oriented applications   |
   | media type:                     | that have primitive User        |
   |                                 | Interfaces.                     |
   | Personal and email address for  | Eric Burger  |
   | further information:            |                                 |
   | Intended usage:                 | COMMON                          |
   +---------------------------------+---------------------------------+

   Additional Information:
      Magic Number: None
      File Extension: .xml
      Macintosh file type code: "TEXT"


















Burger & Dolly           Expires April 1, 2005                 [Page 31]

Internet-Draft                    KPML                      October 2004


7.3  MIME Media Type application/kpml-response+xml

   +---------------------------------+---------------------------------+
   +---------------------------------+---------------------------------+
   | MIME media type name:           | application                     |
   | MIME subtype name:              | kpml-resposne+xml               |
   | Required parameters:            | none                            |
   | Optional parameters:            | Same as charset parameter       |
   |                                 | application/xml as specified in |
   |                                 | XML Media Types [3]             |
   | Encoding considerations:        | See RFC3023 [3].                |
   | Security considerations:        | See Section 10 of RFC3023 [3]   |
   |                                 | and Section 8 of RFCXXXX        |
   | Interoperability                | See RFC2023 [3] and RFCXXXX     |
   | considerations:                 |                                 |
   | Published specification:        | RFCXXXX                         |
   | Applications which use this     | Session-oriented applications   |
   | media type:                     | that have primitive User        |
   |                                 | Interfaces.                     |
   | Personal and email address for  | Eric Burger  |
   | further information:            |                                 |
   | Intended usage:                 | COMMON                          |
   +---------------------------------+---------------------------------+

   Additional Information:
      Magic Number: None
      File Extension: .xml
      Macintosh file type code: "TEXT"

7.4  URN Sub-Namespace Registration for urn:ietf:xml:ns:kpml-request

   URI: urn:ietf:params:xml:ns:kpml-request

   Registrant Contact: IETF, SIPPING Work Group , Eric
   Burger .

   XML:














Burger & Dolly           Expires April 1, 2005                 [Page 32]

Internet-Draft                    KPML                      October 2004


   
   
   
     
       
       Key Press Markup Language Request
     
     
       
Namespace for Key Press Markup Language Request

       
urn:ietf:params:xml:ns:kpml-request

       

   RFCXXXX.
       

     
   


7.5  URN Sub-Namespace Registration for urn:ietf:xml:ns:kpml-response

   URI: urn:ietf:params:xml:ns:kpml-response

   Registrant Contact: IETF, SIPPING Work Group , Eric
   Burger .

   XML:

   
   
   
     
       
       Key Press Markup Language Response
     
     
       
Namespace for Key Press Markup Language Response

       
urn:ietf:params:xml:ns:kpml-response

       

   RFCXXXX.
       

     
   






Burger & Dolly           Expires April 1, 2005                 [Page 33]

Internet-Draft                    KPML                      October 2004


7.6  KPML Request Schema Registration

   Per RFC3688 [7], please register the XML Schema for KPML as
   referenced in Section 5.2 of RFCXXXX.

   URI: Please assign.

   Registrant Contact: IETF, SIPPING Work Group , Eric
   Burger .

7.7  KPML Response Schema Registration

   Per RFC3688 [7], please register the XML Schema for KPML as
   referenced in Section 5.3 of RFCXXXX.

   URI: Please assign.

   Registrant Contact: IETF, SIPPING Work Group , Eric
   Burger .

8.  Security Considerations

   As an XML markup, all of the security considerations of RFC3023 [3]
   and RFC3406 [6] must be met.  Pay particular attention to the
   robustness requirements of parsing XML.

   Key press information is potentially sensitive.  For example, it can
   represent credit card, calling card, or other personal information.
   Hijacking sessions allow unauthorized entities access to this
   sensitive information.  Therefore, signaling SHOULD be secure, e.g.,
   use of TLS and sips: SHOULD be used.  Moreover, the information
   itself is sensitive, therefore the use of S/MIME or other appropriate
   mechanism SHOULD be used.

   Subscriptions MUST be authenticated.

   User Interfaces MUST support digest authentication.

   User Interfaces MUST support the sips: scheme and TLS.

   User Interfaces MUST NOT buffer USER input prior to an authenticated
   subscription.

   User Interfaces MUST buffer User Input upon receipt of an
   authenticated and accepted subscription.

   User Interfaces implementing this specification MUST implement TLS
   and SHOULD implement S/MIME at a minimum.



Burger & Dolly           Expires April 1, 2005                 [Page 34]

Internet-Draft                    KPML                      October 2004


9.  Examples

   This section is informative in nature.  If there is a discrepancy
   between this section and the normative sections above, the normative
   sections take precedence.

9.1  Monitoring for Octothorpe

   A common need for pre-paid and personal assistant applications is to
   monitor a conversation for a signal indicating a change in user focus
   from the party they called through the application to the application
   itself.  For example, if you call a party using a pre-paid calling
   card and the party you call redirects you to voice mail, digits you
   press are for the voice mail system.  However, many applications have
   a special key sequence, such as the octothorpe (#, or pound sign) or
   *9 that terminate the called party session and shift the user's focus
   to the application.

   Figure 15 shows the KPML for long octothorpe.

   
   
     
       L#
     
   

                   Figure 15: Long Octothorpe Example

   The regex value L indicates the following digit needs to be a
   long-duration key press.

9.2  Dial String Collection

   In this example, the User Interface collects a dial string.  The
   application uses KPML to quickly determine when the user enters a
   target number.  In addition, KPML indicates what type of number the
   user entered.









Burger & Dolly           Expires April 1, 2005                 [Page 35]

Internet-Draft                    KPML                      October 2004


   
   
     
       0
       00
       7[x][x][x]
       9xxxxxxx
       9401xxxxxxx
       9xxxxxxxxxx
       91xxxxxxxxxx
       011x.
     
   

                Figure 16: Dial String KPML Example Code

   Note the use of the "tag" attribute to indicate which regex matched
   the dialed string.  The interesting case here is if the user entered
   "94015551212".  This string matches both the "9401xxxxxxx" and
   "9xxxxxxxxxx" regular expressions.  By following the rules described
   in , the KPML interpreter will pick the "9401xxxxxxx" string, as it
   occurs first in document order (both expressions match the same
   length).  Figure 17 shows the response.

   
   

                  Figure 17: Dial String KPML Response


10.  Call Flow Examples

10.1  Supplemental Digits

   This section gives a non-normative example of an application that
   collects supplemental digits.  Supplemental digit collection is where
   the network requests additional digits after the caller enters the
   destination address.  A typical supplemental dial string is four



Burger & Dolly           Expires April 1, 2005                 [Page 36]

Internet-Draft                    KPML                      October 2004


   digits in length.

   Ingress Gateway      Application Server       Egress Gateway
          |                      |                      |
          |                      |                      |
          |                      |                      |
          |(1) INVITE            |                      |
          |-------------------------------------------->|
          |                      |                      |
          |                      |                      |
          |(2) 200 OK            |                      |
          |<--------------------------------------------|
          |                      |                      |
          |                      |                      |
          |(3) ACK               |                      |
          |-------------------------------------------->|
          |                      |                      |
          |                      |                      |
          |(4) SUBSCRIBE (one-shot)                     |
          |<---------------------|                      |
          |                      |                      |
          |                      |                      |
          |(5) 200 OK            |                      |
          |--------------------->|                      |
          |                      |                      |
          |                      |                      |
          |(6) NOTIFY            |                      |
          |--------------------->|                      |
          |                      |                      |
          |                      |                      |
          |(7) 200 OK            |                      |
          |<---------------------|                      |
          |                      |                      |
          |                      |                      |
          |(8)                   |                      |
          |......................|                      |
          |                      |                      |
          |                      |                      |
          |(9) NOTIFY (digits)   |                      |
          |--------------------->|                      |
          |                      |                      |
          |                      |                      |
          |(10) 200 OK           |                      |
          |<---------------------|                      |
          |                      |                      |
          |                      |                      |
          |                      |                      |
          |                      |                      |



Burger & Dolly           Expires April 1, 2005                 [Page 37]

Internet-Draft                    KPML                      October 2004


                Figure 18: Supplemental Digits Call Flow

   In messages (1-3), the ingress gateway establishes a dialog with an
   egress gateway.  The application learns the dialog ID through
   out-of-band mechanisms, such as the Dialog Package or being
   coresident with the egress gateway.  Part of the ACK message is
   below, to illustrate the dialog identifiers.

   ACK sip:gw@subA.example.com SIP/2.0
   Via: ...
   Max-Forwards: ...
   Route: ...
   From: ;tag=jfh21
   To: ;tag=onjwe2
   Call-ID: 12345592@subA.example.com
   ...

   In message (4), the application requests the gateway collect a string
   of four key presses.

   SUBSCRIBE sip:gw@subA.example.com SIP/2.0
   Via: SIP/2.0/TCP client.subB.example.com;branch=q4i9ufr4ui3
   From: ;tag=567890
   To: 
   Call-ID: 12345601@subA.example.com
   CSeq: 1 SUBSCRIBE
   Contact: 
   Max-Forwards: 70
   Event: kpml ;remote-tag=""
               ;local-tag="sip:gw@subA.example.com;tag=onjwe2"
               ;call-id="12345592@subA.example.com"
   Expires: 7200
   Accept: application/kpml-response+xml
   Content-Type: application/kpml-request+xml
   Content-Length: 292

   
   
     
       xxxx
     
   

   Message (5) is the acknowledgement of the subscription request.



Burger & Dolly           Expires April 1, 2005                 [Page 38]

Internet-Draft                    KPML                      October 2004


   SIP/2.0 200 OK
   Via: SIP/2.0/TCP subB.example.com;branch=q4i9ufr4ui3;
        received=192.168.125.12
   From: ;tag=567890
   To: ;tag=1234567
   Call-ID: 12345601@subA.example.com
   CSeq: 1 SUBSCRIBE
   Contact: 
   Expires: 3600
   Event: kpml

   Message (6) is the immediate notification of the subscription.

   NOTIFY sip:ap@client.subB.example.com SIP/2.0
   Via: SIP/2.0/UDP subA.example.com;branch=gw27id4993
   To: ;tag=567890
   From: ;tag=1234567
   Call-ID: 12345601@subA.example.com
   CSeq: 1000 NOTIFY
   Contact: 
   Event: kpml
   Subscription-State: active;expires=3599
   Max-Forwards: 70
   Content-Length: 0

   Message (7) is the acknowledgment of the notification message.

   SIP/2.0 200 OK
   Via: SIP/2.0/TCP subA.example.com;branch=gw27id4993
   To: ;tag=567890
   From: ;tag=1234567
   Call-ID: 12345601@subA.example.com
   CSeq: 1000 NOTIFY

   Some time elapses (8).

   The user enters the input.  The device provides the notification of
   the collected digits in message (9).  Since this was a one-shot
   subscription, note the Subscription-State is "terminated".












Burger & Dolly           Expires April 1, 2005                 [Page 39]

Internet-Draft                    KPML                      October 2004


   NOTIFY sip:ap@client.subB.example.com SIP/2.0
   Via: SIP/2.0/UDP subA.example.com;branch=gw27id4993
   To: ;tag=567890
   From: ;tag=1234567
   Call-ID: 12345601@subA.example.com
   CSeq: 1001 NOTIFY
   Contact: 
   Event: kpml
   Subscription-State: terminated
   Max-Forwards: 70
   Content-Type: application/kpml-response+xml
   Content-Length: 258

   
   

   Message (10) is the acknowledgement of the notification.

   SIP/2.0 200 OK
   Via: SIP/2.0/TCP subA.example.com;branch=gw27id4993
   To: ;tag=567890
   From: ;tag=1234567
   Call-ID: 12345601@subA.example.com
   CSeq: 1001 NOTIFY


10.2  Multiple Applications

   This section gives a non-normative example of multiple applications.
   One application collects a destination number to call.  That
   application then waits for a "long pound."  During the call, the call
   goes to a personal assistant application, which interacts with the
   user.  In addition, the personal assistant application looks for a
   "short pound."

   For clarity, we do not show the INVITE dialogs.

   Gateway           Card Application      Personal Assistant
      |                      |                      |
      |                      |                      |
      |                      |                      |
      |(1) SUBSCRIBE (persistent)                   |



Burger & Dolly           Expires April 1, 2005                 [Page 40]

Internet-Draft                    KPML                      October 2004


      |<---------------------|                      |
      |                      |                      |
      |                      |                      |
      |(2) 200 OK            |                      |
      |--------------------->|                      |
      |                      |                      |
      |                      |                      |
      |(3) NOTIFY            |                      |
      |--------------------->|                      |
      |                      |                      |
      |                      |                      |
      |(4) 200 OK            |                      |
      |<---------------------|                      |
      |                      |                      |
      |                      |                      |
      |(5)                   |                      |
      |......................|                      |
      |                      |                      |
      |                      |                      |
      |(6) NOTIFY (tag=card) |                      |
      |--------------------->|                      |
      |                      |                      |
      |                      |                      |
      |(7) 200 OK            |                      |
      |<---------------------|                      |
      |                      |                      |
      |                      |                      |
      |(8)                   |                      |
      |......................|                      |
      |                      |                      |
      |                      |                      |
      |(9) NOTIFY (tag=number)                      |
      |--------------------->|                      |
      |                      |                      |
      |                      |                      |
      |(10) 200 OK           |                      |
      |<---------------------|                      |
      |                      |                      |
      |                      |                      |
      |(11) SUBSCRIBE        |                      |
      |<--------------------------------------------|
      |                      |                      |
      |                      |                      |
      |(12) 200 OK           |                      |
      |-------------------------------------------->|
      |                      |                      |
      |                      |                      |
      |(13) NOTIFY           |                      |



Burger & Dolly           Expires April 1, 2005                 [Page 41]

Internet-Draft                    KPML                      October 2004


      |-------------------------------------------->|
      |                      |                      |
      |                      |                      |
      |(14) 200 OK           |                      |
      |<--------------------------------------------|
      |                      |                      |
      |                      |                      |
      |(15)                  |                      |
      |.............................................|
      |                      |                      |
      |                      |                      |
      |(16) NOTIFY (tag=number)                     |
      |-------------------------------------------->|
      |                      |                      |
      |                      |                      |
      |(17) 200 OK           |                      |
      |<--------------------------------------------|
      |                      |                      |
      |                      |                      |
      |(18)                  |                      |
      |.............................................|
      |                      |                      |
      |                      |                      |
      |(19) NOTIFY (tag=#)   |                      |
      |-------------------------------------------->|
      |                      |                      |
      |                      |                      |
      |(20) 200 OK           |                      |
      |<--------------------------------------------|
      |                      |                      |
      |                      |                      |
      |(21)                  |                      |
      |.............................................|
      |                      |                      |
      |                      |                      |
      |(22) NOTIFY (tag=number)                     |
      |-------------------------------------------->|
      |                      |                      |
      |                      |                      |
      |(23) 200 OK           |                      |
      |<--------------------------------------------|
      |                      |                      |
      |                      |                      |
      |(24)                  |                      |
      |.............................................|
      |                      |                      |
      |                      |                      |
      |(25) NOTIFY (L#)      |                      |



Burger & Dolly           Expires April 1, 2005                 [Page 42]

Internet-Draft                    KPML                      October 2004


      |--------------------->|                      |
      |                      |                      |
      |                      |                      |
      |(26) 200 OK           |                      |
      |<---------------------|                      |
      |                      |                      |
      |                      |                      |
      |                      |                      |
      |                      |                      |

               Figure 26: Multiple Application Call Flow

   Message (1) is the subscription request for the card number.

   SUBSCRIBE sip:gw@subA.example.com SIP/2.0
   Via: SIP/2.0/TCP client.subB.example.com;branch=3qo3j0ouq
   From: ;tag=978675
   To: 
   Call-ID: 12345601@subA.example.com
   CSeq: 20 SUBSCRIBE
   Contact: 
   Max-Forwards: 70
   Event: kpml ;remote-tag=""
               ;local-tag="sip:gw@subA.example.com;tag=oi43jfq"
               ;call-id="12345598@subA.example.com"
   Expires: 7200
   Accept: application/kpml-response+xml
   Content-Type: application/kpml-request+xml
   Content-Length: 339

   
   
     
       x{16}
       x{10}
     
   

   Messages 2-4 are not shown for brevity.  Message (6) is the
   notification of the card number.







Burger & Dolly           Expires April 1, 2005                 [Page 43]

Internet-Draft                    KPML                      October 2004


   NOTIFY sip:ap@client.subB.example.com SIP/2.0
   Via: SIP/2.0/UDP subA.example.com;branch=3qo3j0ouq
   To: ;tag=978675
   From: ;tag=9783453
   Call-ID: 12345601@subA.example.com
   CSeq: 3001 NOTIFY
   Contact: 
   Event: kpml
   Subscription-State: active;expires=3442
   Max-Forwards: 70
   Content-Type: application/kpml-response+xml
   Content-Length: 271

   
   

   Message (7) is the acknowledgement of the notification.  Time goes by
   in (8).  Message (9) is the notification of the dialed number.

   NOTIFY sip:ap@client.subB.example.com SIP/2.0
   Via: SIP/2.0/UDP subA.example.com;branch=3qo3j0ouq
   To: ;tag=978675
   From: ;tag=9783453
   Call-ID: 12345601@subA.example.com
   CSeq: 3001 NOTIFY
   Contact: 
   Event: kpml
   Subscription-State: active;expires=3542
   Max-Forwards: 70
   Content-Type: application/kpml-response+xml
   Content-Length: 278

   
   

   Message (11) is the request for long-pound monitoring.



Burger & Dolly           Expires April 1, 2005                 [Page 44]

Internet-Draft                    KPML                      October 2004


   SUBSCRIBE sip:gw@subA.example.com SIP/2.0
   Via: SIP/2.0/TCP client.subB.example.com;branch=3qo3j0ouq
   From: ;tag=978675
   To: 
   Call-ID: 12345601@subA.example.com
   CSeq: 21 SUBSCRIBE
   Contact: 
   Max-Forwards: 70
   Event: kpml ;remote-tag=""
               ;local-tag="sip:gw@subA.example.com;tag=oi43jfq"
               ;call-id="12345598@subA.example.com"
   Expires: 7200
   Accept: application/kpml-response+xml
   Content-Type: application/kpml-request+xml
   Content-Length: 295

   
   
     
       L#
     
   

   Message (13) is the request from the personal assistant application
   for number and pound sign monitoring.






















Burger & Dolly           Expires April 1, 2005                 [Page 45]

Internet-Draft                    KPML                      October 2004


   SUBSCRIBE sip:gw@subA.example.com SIP/2.0
   Via: SIP/2.0/TCP pahost.example.com;branch=xzvsadf
   From: ;tag=4rgj0f
   To: 
   Call-ID: 93845@pahost.example.com
   CSeq: 21 SUBSCRIBE
   Contact: 
   Max-Forwards: 70
   Event: kpml ;remote-tag=""
               ;local-tag="sip:gw@subA.example.com;tag=oi43jfq"
               ;call-id="12345598@subA.example.com"
   Expires: 7200
   Accept: application/kpml-response+xml
   Content-Type: application/kpml-request+xml
   Content-Length: 332

   
   
     
       x{10}
       #
     
   

   Message (18) is the notification of the number collected.

   NOTIFY sip:pa@example.com SIP/2.0
   Via: SIP/2.0/UDP subA.example.com;branch=xzvsadf
   To: ;tag=4rgj0f
   From: ;tag=9788823
   Call-ID: 93845@pahost.example.com
   CSeq: 3021 NOTIFY
   Contact: 
   Event: kpml
   Subscription-State: active;expires=3540
   Max-Forwards: 70
   Content-Type: application/kpml-response+xml
   Content-Length: 278

   
   

   Message (21) is the notification of pound sign detected.

   NOTIFY sip:pa@example.com SIP/2.0
   Via: SIP/2.0/UDP subA.example.com;branch=xzvsadf
   To: ;tag=4rgj0f
   From: ;tag=9788823
   Call-ID: 93845@pahost.example.com
   CSeq: 3022 NOTIFY
   Contact: 
   Event: kpml
   Subscription-State: active;expires=3540
   Max-Forwards: 70
   Content-Type: application/kpml-response+xml
   Content-Length: 264

   
   

   Message (27) is the notification of long pound to the card
   application.






















Burger & Dolly           Expires April 1, 2005                 [Page 47]

Internet-Draft                    KPML                      October 2004


   NOTIFY sip:ap@client.subB.example.com SIP/2.0
   Via: SIP/2.0/UDP subA.example.com;branch=3qo3j0ouq
   To: ;tag=978675
   From: ;tag=9783453
   Call-ID: 12345601@subA.example.com
   CSeq: 3037 NOTIFY
   Contact: 
   Event: kpml
   Subscription-State: active;expires=3216
   Max-Forwards: 70
   Content-Type: application/kpml-response+xml
   Content-Length: 256

   
   


11.  References

11.1  Normative References

   [1]  Bradner, S., "Key words for use in RFCs to Indicate Requirement
        Levels", BCP 14, RFC 2119, March 1997.

   [2]  Crocker, D. and P. Overell, "Augmented BNF for Syntax
        Specifications: ABNF", RFC 2234, November 1997.

   [3]  Murata, M., St. Laurent, S. and D. Kohn, "XML Media Types", RFC
        3023, January 2001.

   [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]  Roach, A., "Session Initiation Protocol (SIP)-Specific Event
        Notification", RFC 3265, June 2002.

   [6]  Daigle, L., van Gulik, D., Iannella, R. and P. Faltstrom,
        "Uniform Resource Names (URN) Namespace Definition Mechanisms",
        BCP 66, RFC 3406, October 2002.

   [7]  Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688, January



Burger & Dolly           Expires April 1, 2005                 [Page 48]

Internet-Draft                    KPML                      October 2004


        2004.

   [8]  Thompson, H., Beech, D., Maloney, M. and N. Mendelsohn, "XML
        Schema Part 1: Structures", W3C REC REC-xmlschema-1-20010502,
        May 2001.

11.2  Informative References

   [9]   Schulzrinne, H., Casner, S., Frederick, R. and V. Jacobson,
         "RTP: A Transport Protocol for Real-Time Applications", RFC
         1889, January 1996.

   [10]  Handley, M. and V. Jacobson, "SDP: Session Description
         Protocol", RFC 2327, April 1998.

   [11]  Fielding, R., Gettys, J., Mogul, J., Nielsen, H., Masinter, L.,
         Leach, P. and T. Berners-Lee, "Hypertext Transfer Protocol --
         HTTP/1.1", RFC 2616, June 1999.

   [12]  Schulzrinne, H. and S. Petrack, "RTP Payload for DTMF Digits,
         Telephony Tones and Telephony Signals", RFC 2833, May 2000.

   [13]  Rosenberg, J. and H. Schulzrinne, "An Offer/Answer Model with
         Session Description Protocol (SDP)", RFC 3264, June 2002.

   [14]  Olson, S., Camarillo, G. and A. Roach, "Support for IPv6 in
         Session Description Protocol (SDP)", RFC 3266, June 2002.

   [15]  Andreasen, F. and B. Foster, "Media Gateway Control Protocol
         (MGCP) Version 1.0", RFC 3435, January 2003.

   [16]  Groves, C., Pantaleo, M., Anderson, T. and T. Taylor, "Gateway
         Control Protocol Version 1", RFC 3525, June 2003.

   [17]  Institute of Electrical and Electronics Engineers, "Information
         Technology - Portable Operating System Interface (POSIX) - Part
         1: Base Definitions, Chapter 9", IEEE Standard 1003.1, June
         2001.

   [18]  "Packet-based Multimedia Communications Systems (includes Annex
         C - H.323 on ATM)", ITU-T Recommendation H.323v3, September
         1999.

   [19]  International Telecommunications Union, "CONTROL PROTOCOL FOR
         MULTIMEDIA COMMUNICATION", ITU Recommendation H.245, 1998.

   [20]  World Wide Web Consortium, "Voice Extensible Markup Language
         (VoiceXML) Version 2.0", W3C Working Draft , April 2002,



Burger & Dolly           Expires April 1, 2005                 [Page 49]

Internet-Draft                    KPML                      October 2004


         .

   [21]  Bray, T., Paoli, J., Sperberg-McQueen, C. and E. Maler,
         "Extensible Markup Language (XML) 1.0 (Second Edition)", W3C
         REC REC-xml-20001006, October 2000.

   [22]  Hunt, A. and S. McGlashan, "Speech Recognition Grammar
         Specification Version 1.0", W3C CR CR-speech-grammar-20020626,
         June 2002.

   [23]  Rosenberg, J., "A Framework for Application Interaction in the
         Session Initiation Protocol  (SIP)",
         draft-ietf-sipping-app-interaction-framework-01 (work in
         progress), February 2004.

   [24]  Burger (Ed.), E., Van Dyke, J. and A. Spitzer, "Basic Network
         Media Services with SIP", draft-burger-sipping-netann-08 (work
         in progress), February 2004.

   [25]  Burger, E., Van Dyke, J. and A. Spitzer, "Media Server Control
         Markup Language (MSCML) and Protocol", draft-vandyke-mscml-04
         (work in progress), March 2004.

   [26]  Rosenberg, J., "Obtaining and Using Globally Routable User
         Agent (UA) URIs (GRUU) in the  Session Initiation Protocol
         (SIP)", draft-ietf-sip-gruu-01 (work in progress), February
         2004.

   [27]  Rosenberg, J. and H. Schulzrinne, "An INVITE Inititiated Dialog
         Event Package for the Session Initiation  Protocol (SIP",
         draft-ietf-sipping-dialog-package-02 (work in progress), June
         2003.


Authors' Addresses

   Eric Burger
   Brooktrout Technology, Inc.
   18 Keewaydin Dr.
   Salem, NH  03079
   USA

   EMail: e.burger@ieee.org








Burger & Dolly           Expires April 1, 2005                 [Page 50]

Internet-Draft                    KPML                      October 2004


   Martin Dolly
   AT&T Labs

   EMail: mdolly@att.com

Appendix A.  Contributors

   Ophir Frieder of the Illinois Institute of Technology collaborated on
   the development of the buffer algorithm.

   Jeff Van Dyke worked enough hours and wrote enough text to be
   considered an author under the old rules.

   Robert Fairlie-Cuninghame, Cullen Jennings, Jonathan Rosenberg, and
   we were the members of the Application Stimulus Signaling Design
   Team.  All members of the team contributed to this work.  In
   addition, Jonathan Rosenberg postulated DML in his "A Framework for
   Stimulus Signaling in SIP Using Markup" draft.

   This version of KPML has significant influence from MSCML, the
   SnowShore Media Server Control Markup Language.  Jeff Van Dyke and
   Andy Spitzer were the primary contributors to that effort.

   That said, any errors, misinterpretation, or fouls in this document
   are our own.

Appendix B.  Acknowledgements

   Hal Purdy and Eric Cheung of AT&T Laboratories helped immensely
   through many conversations and challenges.

   Steve Fisher of AT&T Laboratories suggested the digit suppression
   syntax and provided excellent review of the document.

   Terence Lobo of SnowShore Networks made it all work.

   Jerry Kamitses, Swati Dhuleshia, Shaun Bharrat, Sunil Menon, and
   Bryan Hill helped with clarifying the buffer behavior and DRegex
   syntax.

   Silvano Brewster and Bill Fenner of AT&T Laboratories, and Joe
   Zebarth of Nortel helped considerably with makeing the text clear and
   DRegex tight.

   Bert Culpepper and Allison Manking gave an early version of this
   document a good scouring.

   Rohan Mahy gave us considerable moral support in the production of



Burger & Dolly           Expires April 1, 2005                 [Page 51]

Internet-Draft                    KPML                      October 2004


   this document.


















































Burger & Dolly           Expires April 1, 2005                 [Page 52]

Internet-Draft                    KPML                      October 2004


Intellectual Property Statement

   The IETF takes no position regarding the validity or scope of any
   Intellectual Property Rights or other rights that might be claimed to
   pertain to the implementation or use of the technology described in
   this document or the extent to which any license under such rights
   might or might not be available; nor does it represent that it has
   made any independent effort to identify any such rights.  Information
   on the procedures with respect to rights in RFC documents can be
   found in BCP 78 and BCP 79.

   Copies of IPR disclosures made to the IETF Secretariat and any
   assurances of licenses to be made available, or the result of an
   attempt made to obtain a general license or permission for the use of
   such proprietary rights by implementers or users of this
   specification can be obtained from the IETF on-line IPR repository at
   http://www.ietf.org/ipr.

   The IETF invites any interested party to bring to its attention any
   copyrights, patents or patent applications, or other proprietary
   rights that may cover technology that may be required to implement
   this standard.  Please address the information to the IETF at
   ietf-ipr@ietf.org.

   The IETF has been notified of intellectual property rights claimed in
   regard to some or all of the specification contained in this
   document.  For more information consult the online list of claimed
   rights.


Disclaimer of Validity

   This document and the information contained herein are provided on an
   "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS
   OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET
   ENGINEERING TASK FORCE DISCLAIM 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.


Copyright Statement

   Copyright (C) The Internet Society (2004).  This document is subject
   to the rights, licenses and restrictions contained in BCP 78, and
   except as set forth therein, the authors retain all their rights.





Burger & Dolly           Expires April 1, 2005                 [Page 53]

Internet-Draft                    KPML                      October 2004


Acknowledgment

   Funding for the RFC Editor function is currently provided by the
   Internet Society.















































Burger & Dolly           Expires April 1, 2005                 [Page 54]