<?xmlversion="1.0" encoding="US-ASCII"?>version='1.0' encoding='UTF-8'?> <?xml-stylesheet type=<?xml version="1.0" encoding="US-ASCII"?><?xml-stylesheet type='text/xsl' href='rfc2629.xslt' ?> <?rfc toc="yes" ?> <?rfc symrefs="yes" ?> <?rfc sortrefs="no"?> <?rfc iprnotified="no" ?> <?rfc strict="no" ?> <?rfc compact="no" ?> <?rfc subcompact="no" ?><!DOCTYPE rfc SYSTEM"rfc2629.dtd" [ <!ENTITY RFC2392 SYSTEM "http://xml.resource.org/public/rfc/bibxml/reference.RFC.2392.xml"> <!ENTITY RFC2818 SYSTEM "http://xml.resource.org/public/rfc/bibxml/reference.RFC.2818.xml"> <!ENTITY RFC3261 SYSTEM "http://xml.resource.org/public/rfc/bibxml/reference.RFC.3261.xml"> <!ENTITY RFC3262 SYSTEM "http://xml.resource.org/public/rfc/bibxml/reference.RFC.3262.xml"> <!ENTITY RFC3428 SYSTEM "http://xml.resource.org/public/rfc/bibxml/reference.RFC.3428.xml"> <!ENTITY RFC3986 SYSTEM "http://xml.resource.org/public/rfc/bibxml/reference.RFC.3986.xml"> <!ENTITY RFC4119 SYSTEM "http://xml.resource.org/public/rfc/bibxml/reference.RFC.4119.xml"> <!ENTITY RFC5031 SYSTEM "http://xml.resource.org/public/rfc/bibxml/reference.RFC.5031.xml"> <!ENTITY RFC5222 SYSTEM "http://xml.resource.org/public/rfc/bibxml/reference.RFC.5222.xml"> <!ENTITY RFC5234 SYSTEM "http://xml.resource.org/public/rfc/bibxml/reference.RFC.5234.xml"> <!ENTITY RFC7303 SYSTEM "http://xml.resource.org/public/rfc/bibxml/reference.RFC.7303.xml"> <!ENTITY RFC3629 SYSTEM "http://xml.resource.org/public/rfc/bibxml/reference.RFC.3629.xml"> <!ENTITY RFC8224 SYSTEM "http://xml.resource.org/public/rfc/bibxml/reference.RFC.8224.xml"> <!ENTITY RFC8225 SYSTEM "http://xml.resource.org/public/rfc/bibxml/reference.RFC.8225.xml"> <!ENTITY RFC3325 SYSTEM "http://xml.resource.org/public/rfc/bibxml/reference.RFC.3325.xml"> <!ENTITY RFC6442 SYSTEM "http://xml.resource.org/public/rfc/bibxml/reference.RFC.6442.xml"> <!ENTITY RFC6443 SYSTEM "http://xml.resource.org/public/rfc/bibxml/reference.RFC.6443.xml"> <!ENTITY RFC6881 SYSTEM "http://xml.resource.org/public/rfc/bibxml/reference.RFC.6881.xml"> <!ENTITY RFC7378 SYSTEM "http://xml.resource.org/public/rfc/bibxml/reference.RFC.7378.xml"> <!ENTITY RFC7852 SYSTEM "http://xml.resource.org/public/rfc/bibxml/reference.RFC.7852.xml"> <!ENTITY RFC8174 SYSTEM "http://xml.resource.org/public/rfc/bibxml/reference.RFC.8174.xml"> ]>"rfc2629-xhtml.ent"> <rfc xmlns:xi="http://www.w3.org/2001/XInclude" number="8876" consensus="true" category="std" docName="draft-ietf-ecrit-data-only-ea-22"ipr="trust200902">ipr="trust200902" obsoletes="" updates="" submissionType="IETF" xml:lang="en" tocInclude="true" symRefs="true" sortRefs="false" version="3"> <front><title>Non-Interactive<title>Non-interactive Emergency Calls</title> <seriesInfo name="RFC" value="8876"/> <author initials="B." surname="Rosen" fullname="Brian Rosen"> <address> <postal> <street>470 Conrad Dr</street> <city>Mars</city> <region> PA </region> <code>16046 </code><country>US </country><country>United States of America</country> </postal> <phone> </phone> <email>br@brianrosen.net </email> </address> </author> <author initials="H." surname="Schulzrinne" fullname="Henning Schulzrinne"> <organization abbrev="Columbia U.">Columbia University</organization> <address> <postal> <street>Department of Computer Science</street> <street>450 Computer Science Building</street> <city>New York</city> <region>NY</region> <code>10027</code><country>US</country><country>United States of America</country> </postal> <phone>+1 212 939 7004</phone> <email>hgs+ecrit@cs.columbia.edu</email><uri>http://www.cs.columbia.edu</uri><uri>https://www.cs.columbia.edu</uri> </address> </author> <author initials="H." surname="Tschofenig" fullname="Hannes Tschofenig"><organization>ARM Limited</organization><address> <postal> <street> </street> <country>Austria</country> </postal> <email>Hannes.Tschofenig@gmx.net</email><uri>http://www.tschofenig.priv.at</uri><uri>https://www.tschofenig.priv.at</uri> </address> </author> <author fullname="Randall Gellens" initials="R." surname="Gellens"> <organization>Core Technology Consulting</organization> <address> <email>rg+ietf@coretechnologyconsulting.com</email> <uri>http://www.coretechnologyconsulting.com</uri> </address> </author> <date month="September" year="2020"/> <area>ART</area> <workgroup>ECRIT</workgroup><keyword>Internet-Draft</keyword><keyword>CAP</keyword> <keyword>Common Alerting Protocol</keyword> <keyword>Non-Interactive Emergency calls</keyword> <abstract> <t> Use of the Internet for emergency calling is described in RFC 6443, 'Framework for Emergency Calling Using Internet Multimedia'. In some cases of emergency calls, the transmission of application data is all that isneededneeded, and no interactive media channel is established: a situation referred to as 'non-interactive emergency calls', where, unlike most emergency calls, there is notwo waytwo-way interactive media such as voice or video or text. This document describes use of a SIP MESSAGE transaction that includes a container for the data based on the Common Alerting Protocol (CAP). That type of emergency request does not establish a session, distinguishing it from SIP INVITE, which does. Any device that needs to initiate a request for emergency services without an interactive media channel would use the mechanisms in this document. </t> </abstract> </front> <middle><!-- ////////////////////////////////////////////////////////////////////////////////// --><section anchor="introduction"title="Introduction">numbered="true" toc="default"> <name>Introduction</name> <t><xreftarget="RFC6443"/>target="RFC6443" format="default"/> describes how devices use the Internet to place emergency calls and how Public Safety Answering Points (PSAPs) handle Internet multimedia emergency calls natively. The exchange of multimedia traffic for emergency services involves a SIP session establishment starting with a SIP INVITE that negotiates various parameters for that session.</t> <t>In some cases, however, there is only application data to be conveyed from the end devices to a PSAP or an intermediary. Examples of such environments include sensors issuing alerts, and certain types of medical monitors. These messages may beone-shotalerts to emergency authorities and do not require establishment of a session. These types of interactions are called 'non-interactive emergency calls'. In this document, we use the term "call" so that similarities between non-interactive alerts and sessions with interactive media are more obvious. </t> <t>Non-interactive emergency calls are similar to regular emergency calls in the sense that they require the emergency indications, emergency call routingfunctionalityfunctionality, and location. However, the communication interaction will not lead to the exchange of interactive media, that is, Real-Time Transport Protocol <xref target="RFC3550"/> packets, such as voice,video datavideo, or real-time text.</t><t>The<t> The Common Alerting Protocol (CAP) <xreftarget="cap"/>target="CAP" format="default"/> is a format for exchanging emergency alerts and public warnings. CAP is mainly used for conveying alerts and warnings between authorities and from authorities tocitizens/individuals. This document is concerned with citizen-to-authority "alerts", wherethealertpublic. The scope of this document is conveying CAP alerts from private devices to emergency service authorities, as a call without any interactivemedia.</t>media. </t> <t>This document describes a method of including a CAPmessagealert in a SIP transaction by defining it as a block of "additional data" as defined in <xreftarget="RFC7852"/>.target="RFC7852" format="default"/>. The CAPmessagealert is included either by value (the CAPmessagealert is in the body of the message, using a CID) or by reference (the message includes a URI that, when dereferenced, returns the CAPmessage).alert). The additional data mechanism is also used to send alert-specific data beyond that available in the CAPmessage.alert. This document also describes how a SIP MESSAGE <xreftarget="RFC3428"/>target="RFC3428" format="default"/> transaction can be used to send a non-interactive call.</t> </section><!-- ////////////////////////////////////////////////////////////////////////////////// --><section anchor="terminology"title="Terminology"> <t>Thenumbered="true" toc="default"> <name>Terminology</name> <t> The key words"MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY","<bcp14>MUST</bcp14>", "<bcp14>MUST NOT</bcp14>", "<bcp14>REQUIRED</bcp14>", "<bcp14>SHALL</bcp14>", "<bcp14>SHALL NOT</bcp14>", "<bcp14>SHOULD</bcp14>", "<bcp14>SHOULD NOT</bcp14>", "<bcp14>RECOMMENDED</bcp14>", "<bcp14>NOT RECOMMENDED</bcp14>", "<bcp14>MAY</bcp14>", and"OPTIONAL""<bcp14>OPTIONAL</bcp14>" in this document are to be interpreted as described inBCP 14BCP 14 <xref target="RFC2119"/> <xref target="RFC8174"/> when, and only when, they appear in all capitals, as shownhere.</t> <t>A non-interactivehere. </t> <dl> <dt>Non-interactive emergencycall is ancall: </dt> <dd>An emergency call where there is no two-way interactivemedia. </t> <t>SIP is the Sessionmedia </dd> <dt>SIP: </dt> <dd>Session Initiation Protocol <xreftarget="RFC3261"/></t> <t>PIDF-LO is Presencetarget="RFC3261"/> </dd> <dt>PIDF-LO: </dt> <dd>Presence Information Data Format-Location Object, a data structure for carrying location <xreftarget="RFC4119"/></t> <t>LoST is the Locationtarget="RFC4119"/> </dd> <dt>LoST: </dt> <dd>Location To Service Translation protocol <xreftarget="RFC5222"/></t> <t>CID is Content-IDtarget="RFC5222"/> </dd> <dt>CID: </dt> <dd>Content-ID <xreftarget="RFC2392"/></t> <t>CAP is the Commontarget="RFC2392"/> </dd> <dt>CAP: </dt> <dd>Common Alerting Protocol <xreftarget="cap"/></t> <t>PSAP is a Publictarget="CAP"/> </dd> <dt>PSAP: </dt> <dd>Public Safety Answering Point, the call center for emergencycalls.</t> <t>ESRP is an Emergencycalls </dd> <dt>ESRP: </dt> <dd>Emergency Services Routing Proxy, a type of SIP Proxy Server used in some emergency servicesnetworks</t>networks </dd> </dl> </section><!-- ////////////////////////////////////////////////////////////////////////////////// --><section anchor="arch"title="Architectural Overview">numbered="true" toc="default"> <name>Architectural Overview</name> <t>This section illustrates two envisioned usage modes: targeted and location-based emergency alert routing.</t><t><list style="numbers"><ol spacing="normal" type="1"> <li> <t>Emergency alerts containing only data are targeted to an intermediary recipient responsible for evaluating the next steps. These steps could include:<list style="numbers"> <t>Sending</t> <ol spacing="normal" type="a"> <li>Sending a non-interactive call containing only data towards a Public Safety Answering Point (PSAP);</t> <t>Establishing</li> <li>Establishing a third-party-initiated emergency call towards a PSAP that could include audio, video, and data.</t> </list> </t> <t>Emergency</li> </ol> </li> <li>Emergency alerts may be targeted to aServiceservice URN <xreftarget="RFC5031"/>target="RFC5031" format="default"/> used for IP-based emergency calls where the recipient is not known to the originator. In this scenario, the alert may contain only data (e.g., aCAP,SIP MESSAGE with CAP content, a Geolocation headerfieldfield, and one or more Call-Info header fields containingAdditional Dataadditional data <xreftarget="RFC7852"/> in a SIP MESSAGE). </t> </list> </t>target="RFC7852" format="default"/>). </li> </ol> <t> <xreftarget="targeted"/>target="targeted" format="default"/> shows a deployment variant where a sensor is pre-configured (using techniques outside the scope of this document) to issue an alert to an aggregator that processes these messages and performs whatever steps are necessary to appropriately react to the alert. For example, a security firm may use different sensor inputs to dispatch their security staff to a building they protect or to initiate a third-party emergency call.</t><t><figureanchor="targeted" title="Targetedanchor="targeted"> <name>Targeted Emergency AlertRouting">Routing</name> <artworkxml:space="preserve"> <![CDATA[name="" type="" align="left" alt=""><![CDATA[ +------------+ +------------+ | Sensor | | Aggregator | | | | | +---+--------+ +------+-----+ | | Sensors | trigger | emergency | alert | | SIP MESSAGE with CAP | |----------------------------->| | | | Aggregator | processes | emergency | alert | SIP 200 (OK) | |<-----------------------------| | | | | ]]></artwork> </figure></t><t> In <xreftarget="location"/>target="location" format="default"/>, a scenario is shownwherebywhere the alert is routed using location information and aServiceservice URN. An emergency services routing proxy (ESRP) may use LoST (a protocol defined by <xreftarget="RFC5222"/>target="RFC5222" format="default"/>, which translates a location to a URI used to route an emergency call) to determine the next-hop proxy to route the alert message to. A possible receiver is aPSAPPSAP, and the recipient of the alert may be a call taker. In the generic case, there is very likely no prior relationship between the originator and the receiver, e.g., a PSAP. For example, a PSAP is likely to receive and accept alerts from entities it has no previous relationship with. This scenario is similar to a classic voice emergency servicescallcall, and the description in <xreftarget="RFC6881"/>target="RFC6881" format="default"/> is applicable. In this use case, the only difference between an emergency call and an emergency non-interactive call is that the former uses INVITE, creates a session, and negotiates one or more media streams, while the latter uses MESSAGE, does not create a session, and does not have interactive media. </t><t><figureanchor="location" title="Location-Basedanchor="location"> <name>Location-Based Emergency AlertRouting">Routing</name> <artworkxml:space="preserve"> <![CDATA[name="" type="" align="left" alt=""><![CDATA[ +----------+ +----------+ +-----------+ |Sensor or | | ESRP | | PSAP | |Aggregator| | | | | +----+-----+ +---+------+ +----+------+ | | | Sensors | | trigger | | emergency | | alert | | | | | | | | | SIP MESSAGE w/CAP | | | (includingServiceservice URN, | | such as urn:service:sos) | |------------------>| | | | | | ESRP performs | | emergency alert | | routing | | | MESSAGE with CAP | | | (including identity info) | | |----------------------------->| | | | | | PSAP | | processes | | emergency | | alert | | SIP 200 (OK) | | |<-----------------------------| | | | | SIP 200 (OK) | | |<------------------| | | | | | | | ]]></artwork> </figure></t></section><!-- ////////////////////////////////////////////////////////////////////////////////// --><sectiontitle="Protocol Specification">numbered="true" toc="default"> <name>Protocol Specification</name> <sectiontitle="CAP Transport"> <t>A CAP message is sent in the initial message of any SIP transaction. However, thisnumbered="true" toc="default"> <name>CAP Transport</name> <t>This documentonlyaddresses sending a CAPmessagealert in a SIP MESSAGE transaction for aone-shot,non-interactive emergency call. Behavior with other transactions is not defined.</t> <t>The CAPmessagealert is included in a SIP message as anadditional-dataadditional data block <xreftarget="RFC7852"/>.target="RFC7852" format="default"/>. Accordingly, it isintroduced toconveyed in the SIP message with a Call-Info header field with a purpose of "EmergencyCallData.cap". The header field may contain a URI that is used by the recipient (or in some cases, an intermediary) to obtain the CAPmessage.alert. Alternatively, the Call-Info header field may contain a Content-IDurlURL <xreftarget="RFC2392"/>target="RFC2392" format="default"/> and the CAPmessagealert included in the body of the message. In the latter case, the CAPmessagealert is located in a MIME block of the type 'application/emergencyCallData.cap+xml'.</t> <t>If the SIP server does not support the functionality required to fulfill therequestrequest, then a 501 Not Implemented will be returned as specified in <xreftarget="RFC3261"/>.target="RFC3261" format="default"/>. This is the appropriate response when a User Agent Server (UAS) does not recognize the request method and is not capable of supporting it for any user.</t> <t>The 415 Unsupported Media Type error will be returned as specified in <xreftarget="RFC3261"/>target="RFC3261" format="default"/> if the SIP server is refusing to service the request because the message body of the request is in a format not supported by the server for the requested method. The serverMUST<bcp14>MUST</bcp14> return a list of acceptable formats using the Accept, Accept-Encoding, or Accept-Language header fields, depending on the specific problem with the content.</t> </section> <sectiontitle="Profilingnumbered="true" toc="default"> <name>Profiling of the CAP DocumentContent">Content</name> <t>The usage of CAPMUST<bcp14>MUST</bcp14> conform to the specification provided with <xreftarget="cap"/>.target="CAP" format="default"/>. For usage withSIPSIP, the following additional requirements are imposed (where "sender" and "author" are as defined in CAP and"Originator""originator" is the entity sending thealert):CAP alert, which may be different from the entity sending the SIP MESSAGE): </t><t><list style="hanging"> <t hangText="sender:">The<dl newline="false" spacing="normal"> <dt>sender:</dt> <dd> <t>The following restrictions and conditions apply to setting the value of the <sender> element:<list style="symbols"> <t></t> <ul spacing="normal"> <li> Originator is a SIP entity, Author indication irrelevant: When the alert was created by a SIP-based originator and it is not useful to be explicit about the author of the alert, then the <sender> elementMUST<bcp14>MUST</bcp14> be populated with the SIP URI of the user agent.</t> <t></li> <li> Originator is a non-SIP entity, Author indication irrelevant: When the alert was created by anon-SIP basednon-SIP-based entity and the identity of this original sender is to be preserved, then this identityMUST<bcp14>MUST</bcp14> be placed into the <sender> element. In thissituationsituation, it is not useful to be explicit about the author of the alert. The specific type of identity being used will depend on the technology used by theoriginaloriginator.</t> <t></li> <li> Author indication relevant: When the author is different from theactualoriginator of the message and this distinction should be preserved, then the <sender> elementMUST NOT<bcp14>MUST NOT</bcp14> contain the SIP URI of the user agent.</t> </list></t> <t hangText="incidents:"></li> </ul> </dd> <dt>incidents:</dt> <dd> <t> The <incidents> elementMUST<bcp14>MUST</bcp14> be present. This incident identifierMUST<bcp14>MUST</bcp14> be chosen in such a way that it is unique for a given <sender, expires, incidents> combination. Note that the <expires> element isOPTIONAL<bcp14>OPTIONAL</bcp14> and might not bepresent.<vspace blankLines="1"/></t> <t hangText="scope:">Thepresent.</t> </dd> <dt>scope:</dt> <dd> <t>The value of the <scope> elementMAY<bcp14>MAY</bcp14> be set to "Private" if the alert is not meant for public consumption. The <addresses> element is, however, not used by this specification since the message routing is performed by SIP and the respective address information is already available in other SIP header fields. Populating information twice into different parts of the message may lead to inconsistency.<vspace blankLines="1"/></t><t hangText="parameter:">The</dd> <dt>parameter:</dt> <dd> The <parameter> elementMAY<bcp14>MAY</bcp14> contain additional information specific to the sender, conforming to the CAPmessagealert syntax.<vspace blankLines="1"/></t> <t hangText="area:">It</dd> <dt>area:</dt> <dd>It isRECOMMENDED<bcp14>RECOMMENDED</bcp14> to omit this element when constructing a message. If the CAPmessagealert is given to the SIP entity to transport and it already contains an <area> element, then the specified location informationSHOULD<bcp14>SHOULD</bcp14> be copied into a PIDF-LO structure (the data format for location used by emergency calls on the Internet) referenced by the SIP 'Geolocation' header field. If the CAPmessagealert is being created by the SIP entity using a PIDF-LO structure referenced by 'geolocation' to construct <area>, implementers must be aware that <area> is limited to a circle or polygon, and conversion of other shapes will be required. PointsSHOULD<bcp14>SHOULD</bcp14> be converted to a circle with a radius equal to the uncertainty of the point.Arc- bandsArc-bands and ellipsesSHOULD<bcp14>SHOULD</bcp14> be converted to polygons with similar coverage, and 3D locationsSHOULD<bcp14>SHOULD</bcp14> be converted to 2D forms with similar coverage.</t> </list></t></dd> </dl> </section> <sectiontitle="Sendingnumbered="true" toc="default"> <name>Sending anon-interactiveNon-interactive EmergencyCall">Call</name> <t>A non-interactive emergency call is sent using a SIP MESSAGE transaction with a CAP URI or body part as described above in a manner similar to how an emergency call with interactive media is sent, as described in <xreftarget="RFC6881"/>.target="RFC6881" format="default"/>. The MESSAGE transaction does not create a session nor establish interactive media streams, but otherwise, the header content of the transaction, routing, and processing of non-interactive calls are the same as those of other emergency calls.</t> </section> </section><!-- ////////////////////////////////////////////////////////////////////////////////// --><section anchor="error"title="Error Handling">numbered="true" toc="default"> <name>Error Handling</name> <t>This section defines a new error response code and a header field for additional information.</t> <sectiontitle="425numbered="true" toc="default"> <name>425 (Bad Alert Message) ResponseCode">Code</name> <t>This SIP extension creates a newlocation-specificresponsecode,code defined as follows:<list style="empty"> <t>425</t> <ul empty="true" spacing="normal"> <li>425 (Bad AlertMessage)</t> </list> </t>Message)</li> </ul> <t>The 425 response code is a rejection of the request, indicating that it was malformed enough that no reasonable emergency response to the alert can be determined.</t> <t>A SIP intermediary can also use this code to reject an alert it receives from a User Agent (UA) when it detects that the provided alert is malformed.</t><t><xref target="error-header"/><t> <xref target="error-header" format="default"/> describes an AlertMsg-Error header field with more details about what was wrong with the alert message in the request. This header fieldMUST<bcp14>MUST</bcp14> be included in the 425 response.</t> <t>It is usually the case that emergency calls are not rejected if there is any useful information that can be acted upon. It is only appropriate to generate a 425 response when the responding entity has no other information in the request that is usable by the responder.</t> <t>A 425 response codeMUST NOT<bcp14>MUST NOT</bcp14> be sent in response to a request that lacks an alertmessage,message (i.e., CAP data), as the user agent in that case may not support this extension. </t> <t>A 425 response is a final response within atransaction,transaction andMUST NOT<bcp14>MUST NOT</bcp14> terminate an existing dialog.</t> </section> <section anchor="error-header"title="Thenumbered="true" toc="default"> <name>The AlertMsg-Error HeaderField">Field</name> <t>The AlertMsg-Error header field provides additional information about what was wrong with the original request. In somecasescases, the provided information will be used for debugging purposes.</t> <t>The AlertMsg-Error header field has the following ABNF <xreftarget="RFC5234"/>:</t> <t> <figure> <artwork> <![CDATA[target="RFC5234" format="default"/>:</t> <sourcecode type="abnf"> message-header =/ AlertMsg-Error ; (message-header fromRFC3261)RFC 3261) AlertMsg-Error = "AlertMsg-Error" HCOLON ErrorValue ErrorValue = error-code *(SEMI error-params) error-code = 3DIGIT error-params = error-code-text / generic-param ; fromRFC3261RFC 3261 error-code-text = "message" EQUAL quoted-string ; fromRFC3261 ]]></artwork> </figure> </t>RFC 3261 </sourcecode> <t>HCOLON, SEMI, and EQUAL are defined in <xreftarget="RFC3261"/>.target="RFC3261" format="default"/>. DIGIT is defined in <xreftarget="RFC5234"/>.</t>target="RFC5234" format="default"/>.</t> <t>The AlertMsg-Error header fieldMUST<bcp14>MUST</bcp14> contain only one ErrorValue to indicate what was wrong with the alert payload the recipient determined was bad.</t> <t> The ErrorValue contains a 3-digit error code indicating what was wrong with the alert in the request. This error code has a corresponding quoted error text string that is human readable. The text string isOPTIONAL,<bcp14>OPTIONAL</bcp14>, butRECOMMENDED<bcp14>RECOMMENDED</bcp14> for human readability, similar to the string phrase used for SIP response codes. The strings in this document arerecommendations,recommendations and are not standardized -- meaning an operator can change the strings--butMUST NOT<bcp14>MUST NOT</bcp14> change the meaning of the error code. The code space for ErrorValue is separate from SIP Status Codes. </t> <t> The AlertMsg-Error header fieldMAY<bcp14>MAY</bcp14> be included in any response if an alert message was in the request part of the same transaction. For example, suppose a UA includes an alert in a MESSAGE to a PSAP. The PSAP can accept this MESSAGE, even though its UA determined that the alert message contained in the MESSAGE was bad. The PSAP merely includes an AlertMsg-Error header field value in the 200 OK to the MESSAGE, thus informing the UA that the MESSAGE was accepted but the alert provided was bad.</t> <t>If, on the other hand, the PSAP cannot accept the transaction without a suitable alert message, a 425 response is sent.</t> <t>A SIP intermediary that requires the UA's alert message in order to properly process the transaction may also send a 425 response with an AlertMsg-Error code.</t> <t>This document defines an initial list of AlertMsg-Error values for any SIP response, including provisional responses (other than 100 Trying) and the new 425 response. ThereMUST NOT<bcp14>MUST NOT</bcp14> be more than one AlertMsg-Error code in a SIP response. AlertMsg-Error values sent in provisional responsesMUST<bcp14>MUST</bcp14> be sent using the mechanism defined in <xreftarget="RFC3262"/>;target="RFC3262" format="default"/>; or, if that mechanism is not negotiated,MUSTthey <bcp14>MUST</bcp14> be repeated in the final response to the transaction. </t><t>AlertMsg-Error:<sourcecode> AlertMsg-Error: 100 ; message="CannotProcessprocess theAlert Payload"</t> <t>AlertMsg-Error:alert payload" AlertMsg-Error: 101 ; message="AlertPayloadpayload was not present or could not befound"</t> <t>AlertMsg-Error:found" AlertMsg-Error: 102 ; message="Not enough information to determine the purpose of thealert"</t> <t>AlertMsg-Error:alert" AlertMsg-Error: 103 ; message="AlertPayloadpayload wascorrupted"</t>corrupted" </sourcecode> <t>Additionally, if an entity cannot or chooses not to process the alert message from a SIP request, a 500 (Server Internal Error)SHOULD<bcp14>SHOULD</bcp14> be used with or without a configurable Retry-After header field.</t> </section> </section><!-- ////////////////////////////////////////////////////////////////////////////////// --><section anchor="callbacks"title="Call Backs">numbered="true" toc="default"> <name>Call Backs</name> <t>This document does not describe any method for the recipient to call back the sender of a non-interactive call. Usually, these alerts are sent by automata, which do not have a mechanism to receive calls of any kind. The identifier in the 'From' header field may be useful to obtain more information, but any such mechanism is not defined in this document. The CAPmessagealert may contain related contact information for the sender.</t> </section> <section anchor="largedata"title="Handlingnumbered="true" toc="default"> <name>Handling Large Amounts ofData"> <t>It is not atypical for sensors toData</name> <t>Sensors may have large quantities of data that they may wish to send. Including large amounts of data (tens of kilobytes) in a MESSAGE is notadvisable,advisable because SIP entities are usually not equipped to handle very large messages. In such cases, the senderSHOULD<bcp14>SHOULD</bcp14> make use of the by-reference mechanisms defined in <xreftarget="RFC7852"/>,target="RFC7852" format="default"/>, which involves making the data available via HTTPS <xreftarget="RFC2818"/>target="RFC2818" format="default"/> (either at the originator or at another entity), placing a URI to the data in the 'Call-Info' header field, and the recipient uses HTTPS to retrieve the data. The CAPmessagealert itself can be sent by reference using this mechanism, as can any or all of theAdditional Dataadditional data blocks that may contain sensor-specific data.</t> <t>There are norate limitingrate-limiting mechanisms for any SIP transactions that are standardized, although implementations often include such functions. Non-interactive emergency calls are typically handled the same as any emergency call, which means a human call-taker is involved. Implementations should take note of this limitation, especially when calls are placed automatically without human initiation.</t> </section><!-- ////////////////////////////////////////////////////////////////////////////////// --><section anchor="example"title="Example">numbered="true" toc="default"> <name>Example</name> <t>The following example shows a CAP document indicating a BURGLARY alert issued by a sensor called 'sensor1@example.com'. The location of the sensor can be obtained from the attached location information provided via the'geolocation''Geolocation' header field contained in the SIP MESSAGE structure. Additionally, the sensor provided some data along with the alert message, using proprietary information elements intended only to be processed by the receiver, a SIP entity acting as an aggregator.</t><t><figureanchor="warning1" title="Exampleanchor="warning1"> <name>Example MessageconveyingConveying an Alert to anaggregator"> <artwork> <![CDATA[Aggregator</name> <sourcecode><![CDATA[ MESSAGE sip:aggregator@example.com SIP/2.0 Via: SIP/2.0/TCP sensor1.example.com;branch=z9hG4bK776sgdkse Max-Forwards: 70 From: sip:sensor1@example.com;tag=49583 To: sip:aggregator@example.com Call-ID: asd88asd77a@2001:db8::ff Geolocation: <cid:abcdef@example.com> ;routing-allowed=yes Supported: geolocation CSeq: 1 MESSAGE Call-Info: cid:abcdef2@example.com;purpose=EmergencyCallData.cap Content-Type: multipart/mixed; boundary=boundary1 Content-Length: ... --boundary1 Content-Type: application/EmergencyCallData.cap+xml Content-ID: <abcdef2@example.com> Content-Disposition: by-reference;handling=optional <?xml version="1.0" encoding="UTF-8"?> <alert xmlns="urn:oasis:names:tc:emergency:cap:1.1"> <identifier>S-1</identifier> <sender>sip:sensor1@example.com</sender> <sent>2020-01-04T20:57:35Z</sent> <status>Actual</status> <msgType>Alert</msgType> <scope>Private</scope> <incidents>abc1234</incidents> <info> <category>Security</category> <event>BURGLARY</event> <urgency>Expected</urgency> <certainty>Likely</certainty> <severity>Moderate</severity> <senderName>SENSOR 1</senderName> <parameter> <valueName>SENSOR-DATA-NAMESPACE1</valueName> <value>123</value> </parameter> <parameter> <valueName>SENSOR-DATA-NAMESPACE2</valueName> <value>TRUE</value> </parameter> </info> </alert> --boundary1 Content-Type: application/pidf+xml Content-ID: <abcdef2@example.com> <?xml version="1.0" encoding="UTF-8"?> <presence xmlns="urn:ietf:params:xml:ns:pidf" xmlns:gp="urn:ietf:params:xml:ns:pidf:geopriv10" xmlns:gbp= "urn:ietf:params:xml:ns:pidf:geopriv10:basicPolicy" xmlns:cl="urn:ietf:params:xml:ns:pidf:geopriv10:civicAddr" xmlns:gml="http://www.opengis.net/gml" xmlns:dm="urn:ietf:params:xml:ns:pidf:data-model" entity="pres:alice@atlanta.example.com"> <dm:device id="sensor"> <gp:geopriv> <gp:location-info> <gml:location> <gml:Point srsName="urn:ogc:def:crs:EPSG::4326"> <gml:pos>44.85249659 -93.238665712</gml:pos> </gml:Point> </gml:location> </gp:location-info> <gp:usage-rules> <gbp:retransmission-allowed>false </gbp:retransmission-allowed> <gbp:retention-expiry>2020-02-04T20:57:29Z </gbp:retention-expiry> </gp:usage-rules> <gp:method>802.11</gp:method> </gp:geopriv> <dm:timestamp>2020-01-04T20:57:29Z</dm:timestamp> </dm:device> </presence> --boundary1--]]></artwork>]]></sourcecode> </figure></t><t>The following shows the same CAP document sent as a non-interactive emergency call towards a PSAP.</t><t><figureanchor="warning2" title="Exampleanchor="warning2"> <name>Example MessageconveyingConveying an Alert to aPSAP"> <artwork> <![CDATA[PSAP</name> <sourcecode><![CDATA[ MESSAGE urn:service:sos SIP/2.0 Via: SIP/2.0/TCP sip:aggreg.1.example.com;branch=z9hG4bK776abssa Max-Forwards: 70 From: sip:aggregator@example.com;tag=32336 To: 112 Call-ID: asdf33443a@example.com Route: sip:psap1.example.gov Geolocation: <cid:abcdef@example.com> ;routing-allowed=yes Supported: geolocation Call-info: cid:abcdef2@example.com;purpose=EmergencyCallData.cap CSeq: 1 MESSAGE Content-Type: multipart/mixed; boundary=boundary1 Content-Length: ... --boundary1 Content-Type: application/EmergencyCallData.cap+xml Content-ID: <abcdef2@example.com> <?xml version="1.0" encoding="UTF-8"?> <alert xmlns="urn:oasis:names:tc:emergency:cap:1.1"> <identifier>S-1</identifier> <sender>sip:sensor1@example.com</sender> <sent>2020-01-04T20:57:35Z</sent> <status>Actual</status> <msgType>Alert</msgType> <scope>Private</scope> <incidents>abc1234</incidents> <info> <category>Security</category> <event>BURGLARY</event> <urgency>Expected</urgency> <certainty>Likely</certainty> <severity>Moderate</severity> <senderName>SENSOR 1</senderName> <parameter> <valueName>SENSOR-DATA-NAMESPACE1</valueName> <value>123</value> </parameter> <parameter> <valueName>SENSOR-DATA-NAMESPACE2</valueName> <value>TRUE</value> </parameter> </info> </alert> --boundary1 Content-Type: application/pidf+xml Content-ID: <abcdef2@example.com> <?xml version="1.0" encoding="UTF-8"?> <presence xmlns="urn:ietf:params:xml:ns:pidf" xmlns:gp="urn:ietf:params:xml:ns:pidf:geopriv10" xmlns:gbp= "urn:ietf:params:xml:ns:pidf:geopriv10:basicPolicy" xmlns:cl="urn:ietf:params:xml:ns:pidf:geopriv10:civicAddr" xmlns:gml="http://www.opengis.net/gml" xmlns:dm="urn:ietf:params:xml:ns:pidf:data-model" entity="pres:alice@atlanta.example.com"> <dm:device id="sensor"> <gp:geopriv> <gp:location-info> <gml:location> <gml:Point srsName="urn:ogc:def:crs:EPSG::4326"> <gml:pos>44.85249659 -93.2386657124</gml:pos> </gml:Point> </gml:location> </gp:location-info> <gp:usage-rules> <gbp:retransmission-allowed>false </gbp:retransmission-allowed> <gbp:retention-expiry>2020-02-04T20:57:25Z </gbp:retention-expiry> </gp:usage-rules> <gp:method>802.11</gp:method> </gp:geopriv> <dm:timestamp>2020-01-04T20:57:25Z</dm:timestamp> </dm:device> </presence> --boundary1--]]></artwork>]]> </sourcecode> </figure></t></section><!-- ////////////////////////////////////////////////////////////////////////////////// --><section anchor="sec-cons"title="Security Considerations">numbered="true" toc="default"> <name>Security Considerations</name> <t> This section discusses security considerations when SIP user agents issue emergency alerts utilizing MESSAGE and CAP. Location-specific threats are not unique to this document and are discussed in <xreftarget="RFC7378"/>target="RFC7378" format="default"/> and <xreftarget="RFC6442"/>.</t>target="RFC6442" format="default"/>.</t> <t>TheECRITEmergency Context Resolution with Internet Technologies (ECRIT) emergency services architecture <xreftarget="RFC6443"/>target="RFC6443" format="default"/> considers classic individual-to-authority emergency calling where the identity of the emergency caller does not play a role at the time of the call establishment itself, i.e., a response to the emergency call does not depend on the identity of the caller. In the case of emergency alerts generated by devices such as sensors, the processing may be different in order to reduce the number of falsely generated emergency alerts. Alerts could get triggered based on certain sensor input that might have been caused by factors other than the actual occurrence of an alert-relevant event. For example, a sensor may simply be malfunctioning. For this reason, not all alert messages are directly sent to a PSAP, butratherrather, may be pre-processed by a separate entity, potentially under supervision by a human, to filter alerts and potentially correlate received alerts with others to obtain a larger picture of the ongoing situation. </t> <t>In any case, for alerts initiated by sensors, the identity could play an important role in deciding whether to accept or ignore an incoming alert message. With the scenario shown in <xreftarget="targeted"/>target="targeted" format="default"/>, it is very likely that only authenticated sensor input will be processed. For this reason, it needs to be possible to refuse to accept alert messages from unknown origins. Two types of information elements can be used for this purpose:<list style="numbers"> <t>SIP</t> <ol spacing="normal" type="1"> <li>SIP itself provides security mechanisms that allow the verification of the originator's identity, such as P-Asserted-Identity <xreftarget="RFC3325"/>target="RFC3325" format="default"/> or SIP Identity <xreftarget="RFC8224"/>.target="RFC8224" format="default"/>. The latter provides a cryptographic assurance while the former relies on achain of trustchain-of-trust model. These mechanisms can bereused.</t> <t>CAPreused.</li> <li>CAP provides additional security mechanisms and the ability to carry further information about the sender's identity. Section 3.3.4.1 of <xreftarget="cap"/>target="CAP" format="default"/> specifies the signing algorithms of CAPdocuments.</t> </list></t>documents.</li> </ol> <t>The specific policy and mechanisms used in a given deployment are out of scope for this document.</t> <t>There is no rate limiting mechanisms in SIP, and all kinds of emergency calls, including those defined in thisdocumentdocument, could be used by maliciousactors,actors or misbehaving devices to effect adenial of servicedenial-of-service attack on the emergency services. The mechanism defined in this document does not introduce any newconsiderationsconsiderations, although it may be more likely that devices that place non-interactive emergency calls without a human initiating them may be more likely than those that require a user to initiate them.</t> <t>Implementors should note that automated emergency calls may be prohibited or regulated in some jurisdictions, and there may be penalties for "false positive" calls.</t> <t>This document describes potential retrieval of information by dereferencing URIs found in a Call Info header of a SIP MESSAGE. These may include a CAPmessagealert as well as otherAdditional Data (RFC7852)additional data <xref target="RFC7852"/> blocks. The domain of the device sending the SIPMESSAGE,MESSAGE; the domain of the server holding the CAPmessage,alert, if sent byreference,reference; and the domain of otherAdditional Dataadditional data blocks, if sent by reference, may all be different. No assumptions can be made that there are trust relationships between these entities. RecipientsMUST<bcp14>MUST</bcp14> take precautions in retrieving anyAdditional Dataadditional data blocks passed by reference, including the CAPmessage,alert, because the URI may point to a malicious actor or entity not expecting to be referred to for this purpose. The considerations in handling URIs in <xreftarget="RFC3986"/>target="RFC3986" format="default"/> apply.</t> <t>Use of timestamps to prevent replay is subject to the availability of accurate time at all participants. Because emergency event notification via this mechanism is relatively low frequency and generally involves human interaction, implementations may wish to consider messages with times within a small number of seconds of each other to be effectively simultaneous for the purposes of detecting replay. Implementations may also wish to consider that most deployed time distribution protocols likely to be used by these systems are not presently secure.</t> <t>In addition to the desire to perform identity-based access control, the classic communication security threats need to be considered, including integrity protection to prevent forgery or replay of alert messages in transit. To deal with replay of alerts, a CAP document contains the mandatory <identifier>, <sender>, and <sent> elements and an optional <expire> element. Together, these elements make the CAP document unique for a specific sender and provide time restrictions. An entity that has already received a CAPmessagealert within the indicated timeframe is able to detect a replayed message and, if the content of that message is unchanged, then no additional security vulnerability is created. Additionally, it isRECOMMENDED<bcp14>RECOMMENDED</bcp14> to make use of SIP security mechanisms, such as the SIP Identity PASSporT <xreftarget="RFC8225"/>,target="RFC8225" format="default"/>, to tie the CAPmessagealert to the SIP message. To provide protection of the entire SIP message exchange between neighboring SIP entities, the usage of TLS isRECOMMENDED.<bcp14>RECOMMENDED</bcp14>. <xreftarget="RFC6443"/>target="RFC6443" format="default"/> discusses the issues of using TLS with emergency calls, which are equally applicable to non-interactive emergencycalls</t>calls.</t> <t>Note that none of the security mechanisms in this document protect against a compromised sensor sending crafted alerts. Confidentiality provided for any emergency calls, including non-interactive messages, is subject to local regulations. Privacy issues are discussed in <xreftarget="RFC7852"/>target="RFC7852" format="default"/> and are applicable here. </t> </section><!-- ////////////////////////////////////////////////////////////////////////////////// --><sectiontitle="IANA Considerations">numbered="true" toc="default"> <name>IANA Considerations</name> <sectiontitle="Registration of the 'application/EmergencyCallData.cap+xml' media type"> <t> <list style="hanging"> <t hangText="To:"> ietf-types@iana.org<vspace blankLines="1"/> </t> <t hangText="Subject:">Registration of media type application/ EmergencyCallData.cap+xml<vspace blankLines="1"/></t> <t hangText="Type name:"> application <vspace blankLines="1"/></t> <t hangText="Subtype name:">cap+xml <vspace blankLines="1"/></t> <t hangText="Required parameters:"> (none)<vspace blankLines="1"/>numbered="true" toc="default"> <name>'application/EmergencyCallData.cap+xml' Media Type</name> <dl newline="false" spacing="normal"> <dt>Type name:</dt> <dd> <t>application </t><t hangText="Optional parameters:"></dd> <dt>Subtype name:</dt> <dd> <t>EmergencyCallData.cap+xml</t> </dd> <dt>Required parameters:</dt> <dd> <t>N/A</t> </dd> <dt>Optional parameters:</dt> <dd> <t> charset; Indicates the character encoding of enclosed XML. Default is UTF-8 <xreftarget="RFC3629"/>.<vspace blankLines="1"/></t> <t hangText="Encoding considerations:">target="RFC3629" format="default"/>.</t> </dd> <dt>Encoding considerations:</dt> <dd> <t> 7bit,8bit8bit, or binary. See <xreftarget="RFC7303"/>, Section 3.2.<vspace blankLines="1"/></t> <t hangText="Security considerations:">sectionFormat="of" target="RFC7303" section="3.2"/>.</t> </dd> <dt>Security considerations:</dt> <dd> <t> This content type is designed to carry payloads of the Common Alerting Protocol (CAP). RFCXXX [Replace by the RFC number of this specification]8876 discusses security considerations for this.<vspace blankLines="1"/></t> <t hangText="Interoperability considerations:"></t> </dd> <dt>Interoperability considerations:</dt> <dd> <t> This content type provides a way to convey CAPpayloads.<vspace blankLines="1"/> </t> <t hangText="Published specification:"> RFC XXX [Replace by thepayloads.</t> </dd> <dt>Published specification:</dt> <dd> <t> RFCnumber of this specification]. <vspace blankLines="1"/></t> <t hangText="Applications which8876</t> </dd> <dt>Applications that use this mediatype:">type:</dt> <dd> <t> Applications that convey alerts and warnings according to the CAPstandard.<vspace blankLines="1"/></t> <t hangText="Fragment Identifier Considerations: N/A"> .<vspace blankLines="1"/></t> <t hangText="Additional information:">standard.</t> </dd> <dt>Fragment identifier considerations: N/A</dt> <dd> </dd> <dt>Additional information:</dt> <dd> <t> OASIS has published the Common Alerting Protocol athttp://www.oasis-open.org/committees/documents.php&wg_abbrev=emergency <vspace blankLines="1"/></t> <t hangText="Person<eref target="https://docs.oasis-open.org/emergency/cap/v1.2/CAP-v1.2-os.pdf" brackets="angle"/></t> </dd> <dt>Person and email address to contact for furtherinformation:"> Hannes Tschofenig, hannes.tschofenig@gmx.net <vspace blankLines="1"/></t> <t hangText="Intended usage:">information:</dt> <dd> <t><br/><contact fullname="Hannes Tschofenig"/> <hannes.tschofenig@gmx.net></t> </dd> <dt>Intended usage:</dt> <dd> <t> Limited use<vspace blankLines="1"/></t> <t hangText="Author/Change controller:"></t> </dd> <dt>Author/Change controller:</dt> <dd> <t> The IESG<vspace blankLines="1"/></t> <t hangText="Other information:"></t> </dd> <dt>Other information:</dt> <dd> <t> This media type is a specialization ofapplication/xml'application/xml' <xreftarget="RFC7303"/>,target="RFC7303" format="default"/>, and many of the considerations described there also apply toapplication/cap+xml. <vspace blankLines="1"/></t> </list> </t>application/EmergencyCallData.cap+xml.</t> </dd> </dl> </section> <sectiontitle="IANA Registration of 'cap'numbered="true" toc="default"> <name>'cap' Additional DataBlock"> <t>This document registersBlock</name> <t>Per this document, IANA has registered a new block type in thesub-registry called 'Emergency"Emergency Call DataTypes'Types" subregistry of theEmergency"Emergency Call AdditionalData RegistryData" registry defined in <xreftarget="RFC7852"/>.target="RFC7852" format="default"/>. The token is "cap", the Data About is "TheCall"Call", and the reference is this document. </t> </section> <sectiontitle="IANA Registration for 425numbered="true" toc="default"> <name>425 ResponseCode">Code</name> <t>In the SIPResponse Codes"Response Codes" registry, the followingis added</t> <t>Reference: RFC-XXXX (i.e., this document)</t> <t>Response code: 425 (recommended number to assign)</t> <t>Default reason phrase: Bad Alert Message</t> <t> <figure> <artwork> <![CDATA[ Registry: Response Code Reference ------------------------------------------ ---------has been added under Request Failure4xx 425 Bad4xx.</t> <table anchor="bad-alert-message"> <name>Response Codes Registry Addition </name> <thead> <tr> <th>Response Code</th> <th>Description</th> <th>Reference</th> </tr> </thead> <tbody> <tr> <td>425</td> <td>Bad AlertMessage [this doc] ]]></artwork> </figure> </t>Message</td> <td>RFC 8876</td> </tr> </tbody> </table> <t>This SIP Response code is defined in <xreftarget="error"/>.</t>target="error" format="default"/>.</t> </section> <sectiontitle="IANA Registration of New AlertMsg-Errornumbered="true" toc="default"> <name>AlertMsg-Error HeaderField">Field</name> <t>The SIPAlertMsg-errorAlertMsg-Error header field is created by this document, with its definition and rules in <xreftarget="error"/>, to be added to thetarget="error" format="default"/>. The IANASession"Session Initiation Protocol (SIP)ParametersParameters" registrywith two actions: <list style="numbers"> <t>Updatehas been updated as follows. </t> <ol spacing="normal" type="1"> <li> <t>In theHeader Fields registry with <vspace blankLines="1"/> <figure> <artwork> <![CDATA[ Registry: Header Name compact Reference ----------------- ------- --------- AlertMsg-Error [this doc] ]]></artwork> </figure>"Header Fields" subregistry, the following has been added: </t> <table anchor="header-fields-registry"> <name>Header Fields Registry Addition </name> <thead> <tr> <th>Head Name</th> <th>compact </th> <th>Reference </th> </tr> </thead> <tbody> <tr> <td>AlertMsg-Error </td> <td> </td> <td>RFC 8876</td> </tr> </tbody> </table> </li> <li> <t>In theportion titled"Header Field Parameters and ParameterValues", add <vspace blankLines="1"/> <figure> <artwork> <![CDATA[ Predefined HeaderValues" subregistry, the following has been added: </t> <table anchor="header-field-parameters-values"> <name>Header Field Parameters and ParameterNameValuesReference ----------------- ------------------- ---------- --------- AlertMsg-Error code no [this doc] ]]></artwork> </figure> </t> </list> </t>Registry Addition </name> <thead> <tr> <th>Header Field</th> <th>Parameter Name</th> <th>Predefined Values</th> <th>Reference</th> </tr> </thead> <tbody> <tr> <td>AlertMsg-Error </td> <td>code </td> <td>no </td> <td>RFC 8876 </td> </tr> </tbody> </table> </li> </ol> </section> <sectiontitle="IANA Registration for the SIPnumbered="true" toc="default"> <name>SIP AlertMsg-ErrorCodes">Codes</name> <t>This document creates a new registryfor SIP,called"AlertMsg-Error"SIP AlertMsg-Error Codes". AlertMsg-Error codes provide reasons for an error discovered by a recipient, categorized by the action to be taken by the error recipient. The initial values for this registry are shownbelow.</t> <t>Registry Name: AlertMsg-Error Codes</t> <t>Reference: [this doc]</t> <t>Registration Procedures:below. The registration procedure is SpecificationRequired</t> <t> <figure> <artwork> <![CDATA[ Code DefaultRequired <xref target="RFC8126"/>.</t> <table anchor="registry-initial-values"> <name>SIP AlertMsg-Error Codes Registry Creation </name> <thead> <tr> <th>Code </th> <th>Default Reason PhraseReference ---- --------------------------------------------------- --------- 100 "Cannot Process</th> <th>Reference </th> </tr> </thead> <tbody> <tr> <td>100 </td> <td>"Cannot process theAlert Payload" [this doc] 101 "Alert Payloadalert payload" </td> <td>RFC 8876 </td> </tr> <tr> <td>101 </td> <td>"Alert payload was not present or could not be found"[this doc] 102 "Not</td> <td>RFC 8876 </td> </tr> <tr> <td>102 </td> <td>"Not enough information to determine the purpose of the alert"[this doc] 103 "Alert Payload</td> <td>RFC 8876 </td> </tr> <tr> <td>103 </td> <td>"Alert payload was corrupted"[this doc] ]]></artwork> </figure> </t></td> <td>RFC 8876 </td> </tr> </tbody> </table> <t>Details of these error codes are in <xreftarget="error"/>.</t>target="error" format="default"/>.</t> </section> </section><!-- ////////////////////////////////////////////////////////////////////////////////// --></middle> <back> <references> <name>References</name> <references> <name>Normative References</name> <reference anchor="CAP" target="https://docs.oasis-open.org/emergency/cap/v1.2/CAP-v1.2-os.pdf"> <front> <title>Common Alerting Protocol Version 1.2 </title> <author fullname="Elysa Jones" initials="E." surname="Jones"> <organization>Warning Systems, Inc</organization> </author> <author fullname="Art Botterell" initials="A." surname="Botterell"> <organization>Individual</organization> </author> <date month="July" year="2010"/> </front> <refcontent>OASIS Standard CAP-V1.2</refcontent> </reference> <xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.2119.xml"/> <xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.2392.xml"/> <xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.2818.xml"/> <xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.3261.xml"/> <xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.3262.xml"/> <xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.3428.xml"/> <xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.4119.xml"/> <xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.5234.xml"/> <xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.7303.xml"/> <xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.3629.xml"/> <xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.3986.xml"/> <xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.6442.xml"/> <xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.6881.xml"/> <xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.7852.xml"/> <xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.8174.xml"/> <xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.8225.xml"/> </references> <references> <name>Informative References</name> <xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.7378.xml"/> <xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.8126.xml"/> <xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.8224.xml"/> <xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.5031.xml"/> <xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.3325.xml"/> <xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.5222.xml"/> <xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.6443.xml"/> <xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.3550.xml"/> </references> </references> <sectiontitle="Acknowledgments">numbered="false" toc="default"> <name>Acknowledgments</name> <t>The authors would like to thank the participants of the Early Warningadhocad hoc meeting atIETF#69IETF 69 for their feedback. Additionally, we would like to thank the members of the NENA Long Term Direction Working Group for their feedback. </t> <t>Additionally, we would like to thankMartin Thomson, James Winterbottom, Shida Schubert, Bernard Aboba, Marc Linsner, Christer Holmberg and Ivo Sedlacek<contact fullname="Martin Thomson"/>, <contact fullname="James Winterbottom"/>, <contact fullname="Shida Schubert"/>, <contact fullname="Bernard Aboba"/>, <contact fullname="Marc Linsner"/>, <contact fullname="Christer Holmberg"/>, and <contact fullname="Ivo Sedlacek"/> for their review comments.</t> </section><!-- ////////////////////////////////////////////////////////////////////////////////// --> </middle> <!-- ////////////////////////////////////////////////////////////////////////////////// --> <back> <references title="Normative References"> <reference anchor="RFC2119" > <front> <title abbrev="RFC Key Words">Key words for use in RFCs to Indicate Requirement Levels</title> <author fullname="Scott Bradner" initials="S." surname="Bradner"> <organization>Harvard University</organization> </author> <date month="March" year="1997"/> </front> <format octets="4723" target="ftp://ftp.isi.edu/in-notes/rfc2119.txt" type="TXT"/> </reference> <reference anchor="cap" target="https://docs.oasis-open.org/emergency/cap/v1.2/CAP-v1.2-os.pdf"> <front> <title>Common Alerting Protocol v. 1.2 </title> <author fullname="Elysa Jones" initials="E." surname="Jones"> <organization>Warning Systems, Inc</organization> </author> <author fullname="Art Botterell" initials="A." surname="Botterell"> <organization>Individual</organization> </author> <date month="October" year="2005"/> </front> <format type="PDF"/> </reference> &RFC2392; &RFC2818; &RFC3261; &RFC3262; &RFC3428; &RFC4119; &RFC5234; &RFC7303; &RFC3629; &RFC3986; &RFC6442; &RFC6881; &RFC7852; &RFC8174; &RFC8225; </references> <references title="Informative References"> &RFC7378; &RFC8224; &RFC5031; &RFC3325; &RFC5222; &RFC6443; </references></back> </rfc>