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The Postscript, PDF and HTML formats of RFC-2524 are not the authoritative RFC. The formal, authoritative publication of RFC-2524 is the text format published at the online RFC library.
The author has made every effort to ensure that the Postscript, PDF and HTML formats contain the exact same text as the original. If there are any discrepancies between the Postscript, PDF, HTML formats and the original text version, the original text version is always authoritative.
This memo provides information for the Internet community. It does not specify an Internet standard of any kind. Distribution of this memo is unlimited.
Copyright (C) The Internet Society (1999). All Rights Reserved.
The protocol specified in this document may be satisfactory for
limited use in private wireless IP networks. However, it is
unsuitable for general-purpose message transfer or for transfer of
messages over the public Internet, because of limitations that
include the following:
- Lack of congestion control
EMSD is layered on ESRO [RFC 2188], which does not provide
congestion control. This makes EMSD completely unsuitable for
end-to-end use across the public Internet. EMSD should be
considered for use in a wireless network only if all EMSD email
exchanged between the wireless network and the public Internet
will transit an EMSD<->SMTP gateway between the two regions.
- Inadequate security
The document specifies only clear-text passwords for
authentication. EMSD should be used across a wireless network
only if sufficiently strong encryption is in use to protect the
clear-text password.
- Lack of character set internationalization
EMSD has no provision for representation of characters outside of
the ASCII repertoire or for language tags.
- Poorly defined gatewaying to and from Internet Mail
Because Internet Mail and EMSD have somewhat different and
conflicting service models and different data models, mapping
between them may provide good service only in limited cases, and
this may cause operational problems.
The IESG therefore recommends that EMSD deployment be limited to
narrow circumstances, i.e., only to communicate with devices that
have inherent limitations on the length and format of a message (no
more than a few hundred bytes of ASCII text), using either:
a. wireless links with adequate link-layer encryption and gatewayed
to the public Internet, or
b. a private IP network that is either very over-provisioned or has
some means of congestion control.
In the near future, the IESG may charter a working group to define an
Internet standards-track protocol for efficient transmission of
electronic mail messages, which will be highly compatible with
existing Internet mail protocols, and which wil be suitable for
operation over the global Internet, including both wireless and wired
links.
This document specifies the protocol and format encodings for Efficient Mail Submission and Delivery (EMSD). EMSD is a messaging protocol that is highly optimized for submission and delivery of short Internet mail messages. EMSD is designed to be a companion to existing Internet mail protocols.
This specification narrowly focuses on submission and delivery of short mail messages with a clear emphasis on efficiency. EMSD is designed specifically with wireless network (e.g., CDPD, Wireless-IP, Mobile-IP) usage in mind. EMSD is designed to be a natural enhancement to the mainstream of Internet mail protocols when efficiency in mail submission and mail delivery are important. As such, EMSD is anticipated to become an initial basis for convergence of Internet Mail and IP-based Two-Way Paging.
The reliability requirement for message submission and message delivery in EMSD are the same as existing email protocols. EMSD protocol accomplishes reliable connectionless mail submission and delivery services on top of Efficient Short Remote Operations (ESRO) protocols as specified in RFC-2188 [1].
Most existing Internet mail protocols are not efficient. Most existing Internet mail protocols are designed with simplicity and continuity with SMTP traditions as two primary requirements. EMSD is designed with efficiency as a primary requirement.
The early use of EMSD in the wireless environment is manifested as IP-based Two-Way Paging services. The efficiency of this protocol also presents significant benefits for large centrally operated Internet mail service providers.
Mail in the Internet was not a well-planned enterprise, but instead arose in more of an "organic" way.
This introductory section is not intended to be a reference model and concept vocabulary for mail in the Internet. Instead, it only provides the necessary preliminaries for the concepts and terms that are essential to this specification.
For the purposes of this specification, mail submission is the process of putting mail into the mail transfer system (MTS).
For the purposes of this specification, mail delivery is the process of the MTS putting mail into a user's final mail-box.
Throughout the Internet, presently most of mail submission and delivery is done through SMTP.
SMTP was defined as a message *transfer* protocol, that is, a means to route (if needed) and deliver mail by putting finished (complete) messages in a mail-box. Originally, users connected to servers from terminals, and all processing occurred on the server. Now, a split-MUA (Mail User Agent) model is common, with MUA functionality occurring on both the user's own system and the server.
In the split-MUA model, getting the messages to the user is accomplished through access to a mail-box on the server through such protocols as POP and IMAP. In the split-MUA model, user's access to its message is a "Message Pull" paradigm where the user is required to poll his mailbox. Proper message delivery based on a "Message Push" paradigm is presently not supported. The EMSD protocol addresses this shortcoming with an emphasis on efficiency.
In the split-MUA model, message submission is often accomplished through SMTP. SMTP is widely used as a message *submission* protocol. Widespread use of SMTP for submission is a reality, regardless of whether this is good or bad. EMSD protocol provides an alternative mechanism for message submission which emphasizes efficiency.
Various Internet mail protocols facilitate accomplishment of various functions in mail processing.
Figure 1, categorizes the capabilities of SMTP, IMAP, POP and EMSD based on the following functions:
In Figure 1, the number of "X"es in each box denotes the extent to which a particular function is supported by a particular protocol.
Figure 1 clearly shows that combinations of these protocols can be used to complement each other in providing rich functionality to the user. For example, a user interested in highly mobile messaging functionalities can use EMSD for "submission and delivery of time critical and important messages" and use IMAP for comprehensive access to his/her mail-box.
For mail submission and delivery of short messages EMSD is up to 5 times more efficient than SMTP both in terms of the number of packets transmitted and in terms of number of bytes transmitted. Even with PIPELINING and other possible optimizations of SMTP, EMSD is up to 3 times more efficient than SMTP both in terms of the number of packets transmitted and in terms of number of bytes transmitted. Various efficiency studies comparing EMSD with SMTP, POP and IMAP are available. See Section C.1.1 for more information about comparison of SMTP and EMSD's efficiency.
The requirements and goals driving design of EMSD protocol are enumerated below.
Any network and network operator which has significant bandwidth and capacity limitations can benefit from the use of EMSD. Any network user who must bear high costs for measured network usage can benefit from the use of EMSD.
Initial uses of EMSD is anticipated to be primarily over IP-based wireless networks to provide two-way paging services.
EMSD can also function as an adjunct to Mail Access Protocols for "Mail Notification Services".
Considering:
the EMSD protocol is designed to facilitate the convergence of IP-based two-way paging and Internet email.
Mail submission and delivery take place at the edges of the network. More than one mail submission and delivery protocols which address requirements specific to a particular user's environment are likely to be developed. Such diversity on the edges of the network is desirable and with the right protocols, this diversity does not adversely impact the integrity of the mail transfer system. EMSD is the initial basis for the mail submission and delivery protocol to be used when the user's environment demands efficiency.
The following informal definitions and acronyms are intended to help describe EMSD model described in this specification.
The protocol used to transfer messages between the EMSD - Server
Agent (e.g., a Message Center) and the EMSD - User Agent (e.g., a
Two-Way Pager), see Figure ![[*]](/latex2html-98.1p1/icons.gif/cross_ref_motif.gif){kind=icon}
.
Collection of MTAs responsible for mail routing.
An Application Process which conforms to this protocol specification and accepts mail from an EMS-UA and transfers it towards its recipients.
An Application Process which conforms to this protocol specification and delivers mail to an EMD-UA.
An Application Process which incorporates both EMS-SA and EMD-SA capabilities.
An Application Process which conforms to this protocol specification and submits mail to EMS-SA.
An Application Process which conforms to this protocol specification and accepts delivery of mail from EMD-SA.
An Application Process which incorporates both EMS-UA and EMD-UA capabilities.
The key words "MUST", "MUST NOT", "SHOULD", "SHOULD NOT", and "MAY" in this specification are to be interpreted as defined in [2].
This specification uses the ES-OPERATION notation defined in Efficient Short Remote Operations (ESRO) protocols as specified in RFC-2188 [1].
Operations and information objects are typically described using the ES-OPERATION and ASN.1 notations in the relevant sections of the specification.
The complete machine verifiable ASN.1 modules are also compiled in one place in Appendix A and Appendix B.
This protocol specification constitutes a point-of-record. It documents information exchanges and behaviors of existing implementations. It is a basis for implementation of efficient mail submission and delivery user agents and servers.
This specification has been developed entirely outside of IETF. It has had the benefit of review by many outside of IETF. Much has been learned from existing implementations of this protocol. A number of deficiencies and areas of improvement have been identified and are documented in this specification.
This protocol specification is being submitted on October 23, 1998 for timely publication as an Informational RFC.
Future development and enhancements to this protocol may take place inside of IETF.
This section offers a high level view of the Efficient Mail Submission and Delivery Protocol and Format Standards (EMSD-P&FS).
The EMSD-P&FS are used to transfer messages between the EMSD - Server Agent (e.g., a Message Center) and the EMSD - User Agent (e.g., a Two-Way Pager), see Figure 2.
This specification defines the protocols between an EMSD - User Agent (EMSD-UA) and an EMSD - Server Agent (EMSD-SA). The EMSD - P&FS consist of two independent components:
EMSD-FS is a non-textual form of compact encoding of Internet mail (RFC-822) messages which facilitates efficient transfer of messages. EMSD-FS is used in conjunction with the EMSD-P but is not a general replacement for RFC-822. EMSD-FS defines a method of representation of short interpersonal messages. It defines the "Content" encoding (Header + Body). Although EMSD-FS contains end-to-end information its scope is purely point-to-point. EMSD-FS relies on EMSD-P (see 2 below) for the transfer of the content to its recipients.
This is described in the section entitled EMSD Format Standards.
EMSD-P is responsible for wrapping an EMSD-FS message (see 1 above) in a point-to-point envelope and submitting or delivering it. EMSD-P relies on the services of Efficient Short Remote Operation Services (ESROS) as specified in RFC-2188 [1] for transporting the point-to-point envelope. Some of the services of EMSD-P include: message originator authentication and optional message segmentation and reassembly. The EMSD-P is expressed in terms of abstract services using the ESROS notation. This is described in the section entitled Efficient Mail Submission and Delivery Protocol.
It is important to recognize that EMSD-P and EMSD-FS are not end-to-end, but focus on the point-to-point transfer of messages. The two points being EMSD-SA and EMSD-UA. EMSD-P function as elements of the Internet mail environment, which provide end-to-end (EMSD-User to any other Messaging Originator or Recipient) services.
Figure 2 illustrates how the EMSD-P&FS defines the communication between a specific EMSD-UA and a specific EMSD-SA. The Message Transfer System may include a number of EMSD-SAs. Each EMSD-SA may have any number of EMSD-UAs with which it communicates.
The Efficient Mail Submission and Delivery Services use the Efficient Short Remote Operation Services (ESROS). They also use the Duplicate Operation Detection Support Functions as described in the section entitled Duplicate Operation Detection Support Functions. These functions guarantee that an operation is performed no more than once.
EM Submission is the process of transferring a message from EMSD-UA to EMSD-SA. EM Delivery is the process of transferring a message from EMSD-SA to EMSD-UA.
The Message-submission service enables an EMSD-UA to submit a message to the EMSD-SA for transfer and delivery to one or more recipients. The Message-submission Service comprises of the submit operation - invoked by the EMSD-UA - and possibly the submitVerify operation - invoked by the EMSD-SA.
The Message-delivery service enables the EMSD-SA to deliver a message to an EMSD-UA. The Message-delivery Service comprises of the deliver operation - invoked by the EMSD-SA - and possibly the deliverVerify operation - invoked by the EMSD-UA.
EMSD-UA uses the following services:
EMSD-SA uses the following services:
This specification expresses information objects using ASN.1 [X.208].
This specification expresses Remote Operations based on the model of ESROS as specified in Efficient Short Remote Operations (RFC-2188) [1]. The ES-OPERATION notation of (RFC-2188) is used throughout this specification to define specific operations.
This specification uses the Duplicate Operation Detection Support functions as specified in Section 4.
ESRO protocol, as specified in (RFC-2188 [1]), provides reliable connectionless remote operation services on top of UDP [6] with minimum overhead. ESRO protocol supports segmentation and reassembly, concatenation and separation.
ESRO Services (2-Way and 3-Way handshake) shall be used by the EMSD-P.
ESRO Service Access Point (SAP) selectors used by EMSD-P are enumerated in the protocol.
EMSD-P through ESRO MUST use UDP [6] port number 642 (esro-emsdp).
Note that specification of Service Access Points (SAP) for EMSD-P include the UDP Port Number specification in addition to ESRO SAP selector specifications. In other words, EMSD-P's use of ESRO SAPs does not preclude use of the same SAP selectors by other protocols which use a UDP port other than port 642. Such usage of ESRO is a design characteristic of ESRO which results into bandwidth efficiency and is not a scalability limitation.
Use of Basic Encoding Rules (BER) [5] is mandatory for both EMSD Format Standards and EMSD Protocol.
In order to minimize data transfer, the following restrictions shall be maintained in the formatting of EMSD PDUs:
Parameter Encoding Type of "0" MUST be used in ESRO Protocol to identify Basic Encoding Rules for operation arguments.
The following operations are invoked by EMSD-UA:
The submit operation uses the duplication detection functional unit while deliveryControl and deliveryVerify don't use the duplication detection.
The complete definition of these operations follows.
The submit ES-OPERATION enables an EMSD-UA to submit a message to the EMSD-SA for transfer and delivery to one or more recipients.
submit ES-OPERATION
ARGUMENT SubmitArgument
RESULT SubmitResult
ERRORS
{
submissionControlViolated,
securityError,
resourceError,
protocolViolation,
messageError
} ::= 33;
Duplicate operation detection is necessary for this operation.
The successful completion of the ES-OPERATION signifies that the EMSD-SA has accepted responsibility for the message (but not that it has delivered it to its intended recipients).
The disruption of the ES-OPERATION by an error signifies that the EMSD-SA cannot assume responsibility for the message.
This operation's arguments are:
SubmitArgument ::= SEQUENCE
{
-- Security features
security [0] IMPLICIT SecurityElement OPTIONAL,
-- Segmentation features for efficient transport
segment-info SegmentInfo OPTIONAL,
-- Content type of the message
content-type ContentType,
--
-- THE CONTENT --
--
-- The submission content
content ANY DEFINED BY content-type
};
The fields are:
See Section 3.4.1, "SecurityElements".
See Section 3.4.2, "Message Segmentation and Reassembly".
This argument identifies the type of the content of the message. It identifies the abstract syntax and the encoding rules used.
This argument contains the information the message is intended to convey to the recipient(s). It shall be generated by the originator of the message.
This operation's results are:
SubmitResult ::= SEQUENCE
{
-- Permanent identifier for this message.
-- Also contains the message submission time.
-- See comment regarding assignment of message identifiers,
-- at the definition of EMSDLocalMessageId.
message-id EMSDLocalMessageId
};
The fields are:
This result contains an EMSD-SA-identifier that uniquely and unambiguously identifies the message-submission. It shall be generated by the EMSD-SA.
See Section 3.4.3.
The deliveryControl ES-OPERATION enables the EMSD-UA to temporarily limit the operations that the EMSD-SA may invoke, and the messages that the EMSD-SA may deliver to the EMSD-UA via the Message delivery ES-OPERATION.
deliveryControl ES-OPERATION
ARGUMENT DeliveryControlArgument
RESULT DeliveryControlResult
ERRORS
{
securityError,
resourceError,
protocolViolation
} ::= 2;
The duplicate operation detection is not required for this operation.
The EMSD-SA shall hold until a later time, rather than abandon, ES-OPERATIONS and messages that are presently suspended.
The successful completion of the ES-OPERATION signifies that the specified controls are now in force.
The ES-OPERATION returns an indication of any ES-OPERATIONS that the EMSD-SA would invoke, or any message types that the EMSD-SA would deliver, were it not for the prevailing controls.
This operation's arguments are:
DeliveryControlArgument ::= SEQUENCE
{
-- Request an addition of or removal of a set of restrictions
restrict [0] IMPLICIT Restrict DEFAULT update,
-- Which operations are to be placed in the restriction set
permissible-operations [1] IMPLICIT Operations OPTIONAL,
-- What maximum content length should be allowed
permissible-max-content-length
[2] IMPLICIT INTEGER
(0..ub-content-length) OPTIONAL,
-- What is the lowest priority message which may be delivered
permissible-lowest-priority
[3] IMPLICIT ENUMERATED
{
non-urgent (0),
normal (1),
urgent (2)
} OPTIONAL,
-- Security features
security [4] IMPLICIT SecurityElement
OPTIONAL,
-- User Feature selection
user-features [5] IMPLICIT OCTET STRING
OPTIONAL
};
This argument indicates whether the controls on ES-OPERATIONS are to be updated or removed. It may be generated by the EMSD-UA.
This argument may have one of the following values:
In the absence of this argument, the default update shall be assumed.
This argument indicates the ES-OPERATIONS that the EMSD-SA may invoke on the EMSD-UA. It may be generated by the EMSD-UA.
This argument may have the value allowed or prohibited for each of the following:
In the absence of this argument, the ES-OPERATIONS that the EMSD-SA may invoke on the EMSD-UA are unchanged.
This argument contains the content-length, in octets, of the longest-content message that the EMSD-SA shall deliver to the EMSD-UA via the deliver ES-OPERATIONS. It may be generated by the EMSD-UA.
In the absence of this argument, the permissible-maximum-content-length of a message that the EMSD-SA may deliver to the EMSD-UA is unchanged.
This argument contains the priority of the lowest priority message that the EMSD-SA shall deliver to the EMSD-UA via the deliver ES-OPERATIONS. It may be generated by the EMSD-UA.
This argument may have one of the following values of the priority argument of the submit ES-OPERATIONS: normal, non-urgent or urgent.
In the absence of this argument, the priority of the lowest priority message that the EMSD-SA shall deliver to the EMSD-UA is unchanged.
See Section 3.4.1, "SecurityElements".
This argument contains information that allows the EMSD-UA to convey to MTS the feature set that the user is capable of supporting. This argument will be defined when the setConfiguration and getConfiguration operations are defined.
DeliveryControlResult ::= SEQUENCE
{
-- Operation types queued at the EMSD-SA due to existing
-- restrictions.
waiting-operations [0] IMPLICIT Operations DEFAULT { },
-- Types of messages queued at the EMSD-SA due to
-- existing restrictions
waiting-messages [1] IMPLICIT WaitingMessages
DEFAULT { },
-- Content Types of messages queued at the EMSD-SA
waiting-content-types SEQUENCE SIZE (0..ub-content-types) OF
ContentType DEFAULT { }
};
Restrict ::= ENUMERATED
{
update (1),
remove (2)
};
Operations ::= BIT STRING
{
submission (0),
delivery (1)
};
WaitingMessages ::= BIT STRING
{
long-content (0),
low-priority (1)
};
This result indicates the ES-OPERATIONS being held by the EMSD-SA, and that the EMSD-SA would invoke on the EMSD-UA if it were not for the prevailing controls. It may be generated by the EMSD-SA.
This result may have the value holding or not-holding for each of the following:
In the absence of this result, it may be assumed that the EMSD-SA is not holding any messages for delivery due to the prevailing controls.
This result indicates the kind of messages the EMSD-SA is holding for delivery to the EMSD-UA, and would deliver via the deliver ES-OPERATIONS, if it were not for the prevailing controls. It may be generated by the EMSD-SA.
This result may have one or more of the following values:
In the absence of this result, it may be assumed that the EMSD-SA is not holding any messages for delivery to the EMSD-UA due to the permissible-maximum-content- length, permissible-lowest-priority or permissible-security context controls currently in force.
See Section 3.4.3.
The deliveryVerify ES-OPERATIONS enables the EMSD-UA to verify delivery of a message when it receives FAILURE.indication for deliver ES-OPERATIONS.
deliveryVerify ES-OPERATION
ARGUMENT DeliveryVerifyArgument
RESULT DeliveryVerifyResult
ERRORS
{
verifyError,
resourceError,
protocolViolation
} ::= 5;
The duplicate operation detection is not required for this operation.
This operation's arguments are:
DeliveryVerifyArgument ::= SEQUENCE
{
-- Identifier of this message. This is the same identifier that
-- was provided to the originator in the Submission Result.
-- See comment regarding assignment of message identifiers,
-- at the definition of EMSDMessageId.
message-id EMSDMessageId
};
This argument contains an EMSD-SA-identifier that distinguishes the message from all other messages. It shall be generated by the EMSD-SA, and shall have the same value as the message-submission-identifier supplied to the originator of the message when the message was submitted.
DeliveryVerifyResult ::= SEQUENCE
{
status DeliveryStatus
};
DeliveryStatus ::= ENUMERATED
{
no-report-is-sent-out (1),
delivery-report-is-sent-out (2),
non-delivery-report-is-sent-out (3)
};
This result indicates that EMSD-SA has received the delivery verify and no report is sent out (either because it has not been requested or EMSD-SA has problems and can not send it out).
This result indicates that EMSD-SA has received the delivery verify and has sent the delivery report out.
This result indicates that EMSD-SA has received the delivery verify but it has already sent out a non-Delivery report. This should not happen in normal cases but a wrong user profile on EMSD-SA side can result in this outcome.
See Section 3.4.3.
This section defines the operations invoked by the EMSD-SA:
The deliver operation uses 3-Way handshake service of ESROS. This operation always uses the duplication detection functional unit.
The submissionControl and submissionVerify operations use 2-Way handshake service of ESROS without duplication detection.
The deliver ES-OPERATIONS enables the EMSD-SA to deliver a message to an EMSD-UA.
deliver ES-OPERATION
ARGUMENT DeliverArgument
RESULT NULL
ERRORS
{
deliveryControlViolated,
securityError,
resourceError,
protocolViolation,
messageError
} ::= 35;
The EMSD-UA MUST not refuse performing the deliver ES-OPERATION unless the delivery would violate the deliveryControl restrictions then in force.
This operation's arguments are:
DeliverArgument ::= SEQUENCE
{
-- Identifier of this message. This is the same identifier that
-- was provided to the originator in the Submission Result.
-- See comment regarding assignment of message identifiers,
-- at the definition of EMSDMessageId.
message-id EMSDMessageId,
-- Time the message was delivered to the recipient by EMSD-SA
message-delivery-time DateTime,
-- Time EMSD-SA originally took responsibility for processing
-- of this message. This field shall be omitted if the message-id
-- contains an EMSDLocalMessageId, because that field contains
-- the submission time within it.
message-submission-time [0] IMPLICIT DateTime OPTIONAL,
-- Security features
security [1] IMPLICIT SecurityElement OPTIONAL,
-- SegContentTypementation features for efficient transport
segment-info SegmentInfo OPTIONAL,
-- The type of the content
content-type ContentType,
--
-- THE CONTENT --
--
-- The submitted (and now being delivered) content
content ANY DEFINED BY content-type
};
This argument contains an EMSD-SA-identifier that distinguishes the message from all other messages. When within the EMSD, it MUST be generated by the EMSD-SA, and MUST have the same value as the message-submission-identifier supplied to the originator of the message when the message was submitted.
This argument contains the Time at which delivery occurs and at which the EMSD-SA is relinquishing responsibility for the message. It shall be generated by the EMSD-SA.
This operation returns an empty result as indication of success.
See Section 3.4.3.
submissionControl ES-OPERATION
ARGUMENT SubmissionControlArgument
RESULT SubmissionControlResult
ERRORS
{
securityError,
resourceError,
protocolViolation
} ::= 4;
The submissionControl ES-OPERATIONS enables the EMSD-SA to temporarily limit the operations that the EMSD-UA may invoke, and the messages that the EMSD-UA may submit to the EMSD-SA via the submit ES-OPERATIONS.
The duplicate operation detection is not required for this operation.
The EMSD-UA should hold until a later time, rather than abandon, ES-OPERATIONS and messages that are presently suspended.
The successful completion of the ES-OPERATIONS signifies that the specified controls are now in force. These controls supersede any previously in force, and remain in effect until the association is released or the EMSD-SA re-invokes the submissionControl ES-OPERATIONS.
The ES-OPERATIONS returns an indication of any ES-OPERATIONS that the EMSD-UA would invoke were it not for the prevailing controls.
This operation's arguments are:
SubmissionControlArgument ::= SEQUENCE
{
-- Request an addition of or removal of a set of restrictions
restrict [0] IMPLICIT Restrict DEFAULT update,
-- Which operations are to be placed in the restriction set
permissible-operations [1] IMPLICIT Operations OPTIONAL,
-- What maximum content length should be allowed
permissible-max-content-length
[2] IMPLICIT INTEGER
(0..ub-content-length) OPTIONAL,
-- Security features
security [3] IMPLICIT SecurityElement
OPTIONAL
};
This argument indicates whether the controls on ES-OPERATIONS are to be updated or removed. It may be generated by the EMSD-SA.
This argument may have one of the following values:
In the absence of this argument, the default update shall be assumed.
This argument indicates the ES-OPERATIONS that the EMSD-UA may invoke on the EMSD-SA. It may be generated by the EMSD-SA.
This argument may have the value allowed or prohibited for each of the following:
In the absence of this argument, the ES-OPERATIONS that the EMSD-UA may invoke on the EMSD-SA are unchanged.
This argument contains the content-length, in octets, of the longest-content message that the EMSD-UA shall submit to the EMSD-SA via the submit ES-OPERATIONS. It may be generated by the EMSD-SA.
In the absence of this argument, the permissible-maximum-content-length of a message that the EMSD-UA may submit to the EMSD-SA is unchanged.
See Section 3.4.1, "SecurityElements".
SubmissionControlResult ::= SEQUENCE
{
-- Operation types queued at the EMSD-SA due to existing
-- restrictions.
waiting-operations [0] IMPLICIT Operations DEFAULT { }
};
This result indicates the ES-OPERATIONS being held by the EMSD-UA, and that the EMSD-UA would invoke if it were not for the prevailing controls. It may be generated by the EMSD-UA.
This result may have the value holding or not-holding for each of the following:
In the absence of this result, it may be assumed that the EMSD-UA is not holding any messages for submission due to the prevailing controls.
See Section 3.4.3.
The submissionVerify ES-OPERATIONS enables the EMSD-SA to verify if the EMSD-UA has received the result of its submission.
submissionVerify ES-OPERATION
ARGUMENT SubmissionVerifyArgument
RESULT SubmissionVerifyResult
ERRORS
{
submissionVerifyError,
resourceError,
protocolViolation
} ::= 6;
The duplicate operation detection is not required for this operation.
This operation's arguments are:
SubmissionVerifyArgument ::= SEQUENCE
-- Identifier of this message. This is the same identifier that
-- was provided to the originator in the Submission Result.
-- See comment regarding assignment of message identifiers,
-- at the definition of EMSDMessageId.
{
message-id EMSDMessageId
};
This argument contains an EMSD-SA-identifier that distinguishes the message from all other messages. It shall be generated by the EMSD-SA, and shall have the same value as the message-submission-identifier supplied to the originator of the message when the message was submitted.
SubmissionVerifyResult ::= SEQUENCE
{
status SubmissionStatus
};
SubmissionStatus::= ENUMERATED
{
send-message (1),
drop-message (2)
};
This result indicates that EMSD-SA is supposed to send the message out.
This result indicates that EMSD-SA is supposed to drop the message.
See Section 3.4.3.
SecurityElement ::= SEQUENCE
{
credentials Credentials,
contentIntegrityCheck ContentIntegrityCheck OPTIONAL
};
Credentials ::= CHOICE
{
simple [0] IMPLICIT SimpleCredentials
-- Strong Credentials are for future study
-- strong [1] IMPLICIT StrongCredentials
-- externalProcedure [2] EXTERNAL
};
SimpleCredentials ::= SEQUENCE
{
eMSDAddress EMSDAddress OPTIONAL,
password [0] IMPLICIT OCTET STRING
SIZE (0..ub-password-length)) OPTIONAL
};
-- StrongCredentials ::= NULL
-- for now.
-- ContentIntegrityCheck is a 16-bit checksum of content
ContentIntegrityCheck ::= INTEGER (0..65535);
Small messages can benefit from the efficiencies of connectionless feature of ESROS (See Efficient Short Remote Operations, RFC-2188 [1]).
Very large messages are transferred using protocols (e.g., SMTP) that rely on Connection Oriented Transport Service (e.g., TCP).
When a message is too large to fit in a single connectionless PDU but is not large enough to justify the overhead of connection establishment, it may be more efficient for the message to be segmented and reassembled while the connectionless service of ESROS is used. If the underlying Remote Operation Service is capable of efficient segmentation/reassembly over connectionless (CL) services, then use of the segmenting/reassembly mechanism introduced in this section is not necessary. This feature is accommodated in this layer by:
SegmentInfo ::= CHOICE
{
first [APPLICATION 2] IMPLICIT FirstSegment,
other [APPLICATION 3] IMPLICIT OtherSegment
};
FirstSegment ::= SEQUENCE
{
sequence-id INTEGER,
number-of-segments INTEGER
-- number-of-segments must not exceed ub-total-number-of-segments
};
OtherSegment ::= SEQUENCE
{
sequence-id INTEGER,
segment-number INTEGER
};
Segmentation and reassembly only applies to Message-submission and Message-delivery.
The sender of the message is responsible for segmenting the message content into segments that fit in CL PDUs. The segmented content is sent in a sequence of message- segments each carrying a segment of the content. sequence-Id is a unique identifier that is present in all message-segments. In addition to sequence identifier, the first message- segment specifies the total number of segments (number-of-segments). Other message- segments have a segment sequence number (segment-number). The receiver is responsible for sequencing (based on segment-number) and reassembling the entire message.
The sender of the message maps the original message into an ordered sequence of message-segments. This sequence shall not be interrupted by other messages over the same ESROS association.
All message-segments in the sequence shall be assigned a sequence identifier by sender. The sequence identifier shall be incremented by one by the sender after transmission of a complete message sequence.
The first message-segment specifies the total number of segments. All message- segments in the sequence except the first one shall be sequentially numbered, starting at 1 (first message-segment has implicit segment number of 0).
Each message-segment is transmitted by issuing a Message-submission or Message-delivery ES-OPERATIONS. All segments of a segmented message are identified by the same sequence-id. For a given message, the receiver should not impose any restriction on the order of arrival of message-segments.
There is no requirement that any message-segment content be of maximum length allowed by ESROS for connectionless transmission; however, no more than ub-total-number-of-segments segments can be derived from a single message.
The receiver reassembles a sequence of message-segments into a single message. A message shall not be further processed unless all segments of the message are received. Failure to receive the message shall be determined by the following events:
In the event of the above mentioned failures, the receiver shall discard a partially assembled sequence.
In Reassembly process, all arguments other than content are ignored in all segments except the first one. The content parts of all segments are concatenated to compose the original message content.
When sender receives FAILURE.indication (as opposed to a resourceError) for a message-segment, the whole message shall be retransmitted.
In the case of submission and delivery operations, the verify function is used as described below:
Receiver ignores FAILURE.indications received for message-segments, and just collects the message-segments to complete the message. However, it keeps a failure status for a segmented message which says if any segment of the message has received FAILURE.indication. When receiver succeeds to assemble the whole segmented message, then if the status of the message shows there has been a FAILURE.indication for any of the message-segments, it verifies the message through verify operation. It's not enough to invoke verify operation just based on the last message-segment because the sender might send a segment without waiting for the result of the previous segment. In such cases, there might be any combination of success and failure for message- segments on the sender side.
Receiver uses the error code ResourceError (see Section 3.4.3) to ask for retransmission of a single segment and uses the error code MessageError (see Section 3.4.3) to ask for retransmission of all segments (the whole message).
The Reassembly Timer is a local timer maintained by the receiver of message-segments that assists in performing the reassembly function. This timer determines how long a receiver waits for all segments of a message-segment sequence to be received. The timer protects the receiver from the loss of a series of segments and possible sequence identifier wrap-around.
The Reassembly Timer shall be started on receipt of a message-segment with different sequence identifier than that previously received. The timer shall be stopped on receipt of all segments composing the sequence.
The value of Reassembly Timer is defined based on the network characteristics and the number of segments. This requires that the transmission of all segments of a single message must be completed within this time limit.
protocolVersionNotRecognized ERROR PARAMETER NULL ::= 1; submissionControlViolated ERROR PARAMETER NULL ::= 2; messageIdentifierInvalid ERROR PARAMETER NULL ::= 3; securityError ERROR PARAMETER security-problem SecurityProblem ::= 4; deliveryControlViolated ERROR PARAMETER NULL ::= 5; resourceError ERROR PARAMETER NULL ::= 6; protocolViolation ERROR PARAMETER NULL ::= 7; messageError ERROR PARAMETER NULL ::= 8; SecurityProblem ::= INTEGER (0..127);
The major and minor protocol versions presented do not match those recognized as being valid.
The Submission control violated error reports the violation by the MTS-user of a control on submission services imposed by the MTS via the Submission control service. The Submission control violated abstract-error has no parameters.
The Message Identifier Invalid error reports that the Message Identifier presented to the MTS is not considered valid.
The Security error reports that the requested operation could not be provided by the MTS or MTS-user because it would violate the security policy in force.
The Delivery control violated error reports the violation by the MTS of a control on delivery operations imposed by the MTS-user via the Delivery-control operation.
The messaging agent cannot currently support this operation. In the case of segmentation and reassembly, resourceError is by the receiver used to request that the sender retransmit of a single segment.
Indicates that one or more mandatory argument(s) were missing.
For a multi-segment message, this error indicates that the messaging agent has not received the message completely and that the message must be retransmitted.
To ensure the security-policy is not violated during delivery, the message-security-label is checked against the security-context. If delivery is barred by the security -policy then, subject to the security policy, a report instruction for this is generated.
ContentType ::= INTEGER
{
-- Content type 0 is reserved and shall never be transmitted.
reserved (0),
-- Content types between 1 and 31 (inclusive) are for
-- internal-use only
probe (1), -- reserved
delivery-report (2), -- reserved
-- Content types between 32 and 63 (inclusive) are for
-- message types defined within this specifications.
emsd-interpersonal-messaging-1995 (32),
voice-messaging (33) -- reserved
-- Content types beyond and including 64 are for
-- bilaterally-agreed use between peers.
} (0..127);
If this message was originated as an RFC-822 message, then this EMSDMessageId shall be the ``Message-Id:" field from that message. If this message was originated within the EMSD domain, then this identifier shall be unique for the EMSD-SA generating this id.
EMSDMessageId ::= CHOICE
{
EMSDLocalMessageId [APPLICATION 4]
IMPLICIT EMSDLocalMessageId,
rfc822MessageId [APPLICATION 5]
IMPLICIT AsciiPrintableString
(SIZE (0..ub-message-id-length))
};
EMSDLocalMessageId ::= SEQUENCE
{
submissionTime DateTime,
messageNumber INTEGER (0..ub-local-message-nu)
};
EMSDORAddress ::= CHOICE
{
-- This is the local-format address
emsd-local-address-format EMSDAddress,
-- This is a globally-unique RFC-822 Address
rfc822DomainAddress AsciiPrintableString
};
In the global sense Originators and Recipients are represented by EMSDORAddress. The rfc822Domain may be used to address any recipient.
EMSDAddress ::= SEQUENCE
{
emsd-address OCTET STRING (SIZE
(1..ub-emsd-address-length)),
-- emsd-address is a decimal integer in BCD
(Binary Encoded Decimal) format.
-- If it had an odd number of digits, it is
-- padded with 0 on the left.
emsd-name [0] IMPLICIT OCTET STRING
(SIZE (0..ub-emsd-name-length))
OPTIONAL
};
Originator and Recipients in the scope of EMSD network are identified by a digit based addressing scheme. EMSDAddress can only be used where the scope of addressing has clearly been limited to the EMSD network.
DateTime ::= INTEGER;
DateTime is a Julian date, expressed as the number of seconds since 00:00:00 UTC, January 1, 1970.
Iso8859String ::= GeneralString;
AsciiPrintableString ::= [APPLICATION 0]
IMPLICIT Iso8859String (FROM
(" "|"!"|"#"|"$"|"%"|"&"|"'"|"("|")"|"*"|"+"|","|"-"|"."|"/"|
"0"|"1"|"2"|"3"|"4"|"5"|"6"|"7"|"8"|"9"|":"|";"|"<"|"="|">"|
"?"|"@"|"A"|"B"|"C"|"D"|"E"|"F"|"G"|"H"|"I"|"J"|"K"|"L"|"M"|
"N"|"O"|"P"|"Q"|"R"|"S"|"T"|"U"|"V"|"W"|"X"|"Y"|"Z"|"["|"]"|
"^"|"_"|"`"|"a"|"b"|"c"|"d"|"e"|"f"|"g"|"h"|"i"|"j"|"k"|"l"|
"m"|"n"|"o"|"p"|"q"|"r"|"s"|"t"|"u"|"v"|"w"|"x"|"y"|"z"|"{"|
"|"|"}"|"~"|"\"|""""));
ProtocolVersionNumber ::= [APPLICATION 1] SEQUENCE
{
version-major INTEGER,
version-minor [0] IMPLICIT INTEGER DEFAULT 0
}
Table 1 provides a comprehensive summary of EMSD-P operations, the SAP selectors used and the operation IDs used.
The semantics of a submission operation is Exactly Once. Exactly Once means that every operation is carried out exactly one time, no more and no less. This semantic can not be fully implemented because, if after invoking the operation, an invoker has a Success (e.g. result) indication and the performer has a FAILURE.indication, and the network goes down, the result of the operation will be Zero (and not Exactly Once).
No more than one is controlled and guaranteed by the performer by using the Duplicate Operation Detection Support Functions (see the chapter entitled Duplicate Operation Detection Support).
Not zero but one is realized by performer by using the SubmissionVerify operation. When the performer receives FAILURE.indication, it's responsibility is to resolve the case by using SubmissionVerify resulting in Not zero but one.
Submission procedure is as follows:
The semantic of SubmissionVerify operation is At Least Once. This type of semantics corresponds to the case that invoker keeps trying over and over until it gets a proper reply. This operation can be performed more than once without any harm.
Implications:
The semantics of Deliver operation is Exactly Once. Exactly Once means that every operation is carried out exactly one time, no more and no less. This semantic can not be fully implemented and if after invoking the operation, invoker has Success indication and performer has FAILURE.indication, and the network goes down, the result of the operation will be Zero (and not Exactly Once).
No more than one is controlled and guaranteed by performer and by using the Duplicate Operation Detection Support Functions.
Not zero but one is realized by performer by using the DeliveryVerify operation. When performer receives FAILURE.indication, it's responsible to resolve the case by using DeliveryVerify resulting in Not zero but one.
Delivery procedure is as follows:
The semantic of DeliveryVerify operation is At Least Once. This type of semantics corresponds to the case that invoker keeps trying over and over until it gets a proper reply. This operation can be performed more than once without any harm.
Implications:
Some operations are idempotent in nature, i.e. they can be performed more than once without any harm. However, some other operations are non-idempotent in nature, i.e. they should be performed only once. In the case of non-idempotent operations, performer should be able to detect duplicate operations and perform each non- idempotent operation only once.
Examples of non-idempotent operations are Submission and Delivery of messages which shouldn't be performed more than once. Examples of idempotent operations are Submission-control and Delivery-control which can be performed more than once with no harm.
ESRO Services don't detect duplicate invocation of operations. As a result, the Duplicate Operation Detection Support Functional Unit is used to detect duplication when the same operation instance is invoked more than once. Invoker assigns an Operation Instance Identifier to an operation and this Operation Instance Identifier is used at the peer performer entity to detect the duplicate invocation of the same operation.
Using this support, non-idempotent operations can be repeated over and over with no harm because the duplicate invocations are detected by this functional unit. This support helps the performer not to perform an operation more than once.
Support for duplication detection is realized through allocating Operation Instance Id (see Section 4.1.2, "Operation Instance Identifier") to an operation by invoker. When an operation is invoked using duplication detection support, performer logs the Operation Instance Identifier and checks the next operations against duplication.
Operation value identifies whether performer should detect duplicate operations (see Section 4.1.1, ``Operation Value") and Operation Instance Id is assigned by invoker and sent as the first byte of operation's parameter.
Operation Values are divided into two groups. Operation values from 0 to 31 do not have Duplicate Operation Detection Support (0 to 31) and operation values from 32 to 63 have Duplicate Operation Detection Support.
Duplicate Operation Detection Functional Unit checks for duplication only if Operation Value is in the range of 32 to 63.
When invoker user uses an Operation Value in the range of 32 to 63 which means operation with support for duplication detection, the user should specify an Operation Instance ID for the operation (see next section).
To support duplication detection, an Operation Instance Identifier is assigned by invoker user and sent as the first byte of the operation's parameter. This identifier is used on performer side to detect duplicate invocation of the same operation. Characteristics of Operation Instance Identifier is as follows:
The following sections shows the general procedures to be used in the implementation of the EMSD Message Transfer Server (MTS) and the EMSD User Agent (UA), with the option for 3-Way or 2-Way handshakes on operations which support them. These procedures do not constitute complete behavior specifications for implementations. The following sections contain information helpful to implementors.
The MTS and the UA are event-driven. Each waits for any of the possible event types, and, upon receiving an event, processes it. After processing the event, the next event is waited upon.
The MTS is event-driven.
If it received an event from ESROS, then it could be any of the following types:
For an ESROS event responsibility is passed to the MTS performer (Section 5.1.1).
If the MTS received an event:
then responsibility is passed to the MTS invoker (Section 5.1.5).
The MTS performer is responsible for processing the following operations, received from ESROS:
The MTS performer should first make sure that it has received an INVOKE.indication. Any other type of primitive shouldn't be occurring at this point, and should be ignored.
If there's something wrong with the PDU or operation data, the MTS performer should send back an error to the proper invoker:
If there isn't anything wrong with the PDU or operation data, then the MTS performer has received a valid event from ESROS. This could be any of the defined Submission and Delivery Protocol operations.
This operation can be processed immediately. After it is processed, the appropriate result is returned.
This operation occurs when the UA doesn't think that the MTS has received the RESULT.indication from a previously delivered message. The UA wants to make sure that the MTS knows it has been delivered. The MTS will determine what it knows of the specified message, and send back a result. This can be processed immediately, as it doesn't need to deal with duplicate detection.
The MTS invoker is responsible for processing the following operations, received from ESROS:
Process the Submission Control request.
If the UA profile indicated that Complete mode was to be used, keep track of the fact that this message has been successfully delivered (as far as the MTS is concerned), so that if the UA sends us a Delivery Verify operation, we know that we consider the message to be delivered.
As long as a FAILURE.indication is returned and the number of retries has not been exceeded, keep trying to verify the delivery.
The Submission-verify operation is always issued on the 2-Way SAP. The response is awaited. If a response doesn't come, the request is queued and attempted again later.
Issue an INVOKE.request containing a Submit operation with a content type of Non- Delivery Report, to the UA. This operation is always issued on the 2-Way SAP. The response is awaited. If a response doesn't come, the request is queued and attempted again later.
The User Agent is event-driven.
If it received an event from ESROS, then it could be any of the following types:
For an ESROS event responsibility is passed to the UA performer (Section 5.2.1).
IF the UA received an event indicating that there's a message from the user, for submission, then responsibility is passed to the UA invoker (Section 5.2.2).
The performer on the UA side is responsible for processing the following operations:
Either way, the message can now be ignored.
There are three possible results from sending the delivery verification to the MTS: Fail (see #18), ResponseNonDelivery (see #20) or ResponseDelivery (see #23).
Process the Submission-verify request and return.
This operation can be processed immediately. After it is processed, the appropriate result is returned.
The invoker on the UA side is responsible for processing the following operations:
General procedures for UA's Message-submission mirror that of MTS's Message-delivery.
If we got a local failure in issuing the Invoke Request, wait a while and then try again (up to the limit of the maximum number of retries).
General procedures for UA's Delivery-verify mirror that of MTS's Submission-verify.
EMSD Format Standard (EMSD-FS) is a non-textual form of compact encoding of Internet mail (RFC-822) messages which facilitates efficient transfer of messages. EMSD-FS is used in conjunction with the EMSD-P but is not a general replacement for RFC-822. EMSD-FS defines a method of representation of short interpersonal message. It defines the ``Content'' encoding (Header + Body). Although EMSD-FS contains end-to-end information its scope is purely point-to-point.
The "Efficient InterPersonal Message Format Standard" is defined in this section. This standard is primarily intended for communication among people.
The EMSD Format Standard is designed to be fully consistent with RFC-822 [3]. In many ways EMSD-FS can be considered to be an efficiency oriented encoder and decoder. Through use of EMSD-FS an RFC-822 message is converted to a more compact binary encoding. This more compact message is then transfered between an EMSD-SA and EMSD-UA. The compact message (represented in EMSD-FS) may then be converted back to RFC-822 intact.
For messages that are originated (submitted) with EMSD protocol, certain fields (e.g., addresses, message-id) can have special forms that are specialized and produce more compact EMSD-FS encoding. These special forms are legitimate values of RFC-822 messages.
This specification expresses information objects using ASN.1 [X.208]. Encoding of ASN.1 shall be based on Basic Encoding Rules (BER) [5]. Future revisions of this specification will use Packed Encoding Rules (PER) [4].
The convention of (O) "OPTIONAL", (D) "DEFAULT", (C) "CONDITIONAL" and (M) "MANDATORY" which express requirements for presence of information is used in this section.
An interpersonal message (IPM) consists of a heading and a body.
IPM ::= SEQUENCE
{
heading Heading,
body Body OPTIONAL
};
The fields that may appear in the Heading of an IPM are defined and described below.
Heading ::= SEQUENCE
{
-- Address of the sending agent (person, program, machine) of
-- this message. This field is mandatory if the sender
-- is different than the originator.
sender [0] EMSDORAddress OPTIONAL,
-- Address of the originator of the message
-- (not necessarily the sender)
originator EMSDORAddress,
-- List of recipients and flags associated with each.
recipient-data SEQUENCE SIZE (1..ub-recipients)
OF PerRecipientFields,
-- Flags applying to this entire message
per-message-flags [1] IMPLICIT BIT STRING
{
-- Priority values
-- At most one of "non-urgent" and "urgent" may be specified
-- concurrently. If neither is specified, then a Priority
-- level of "normal" is assumed.
priority-non-urgent (0),
priority-urgent (1),
-- Importance values
-- At most one of "low" and "high" may be specified
-- concurrently. If neither is specified, then an
-- Importance level of "normal" is assumed.
importance-low (2),
importance-high (3),
-- Indication of whether this message has been
automatically forwarded
auto-forwarded (4)
} OPTIONAL,
-- User-specified recipient who is to receive replies
to this message.
reply-to [2] IMPLICIT SEQUENCE SIZE
(1..ub-reply-to)
OF EMSDORAddress OPTIONAL,
-- Identifier of a previous message, for which this message
-- is a reply
replied-to-IPM EMSDMessageId OPTIONAL,
-- Subject of the message.
subject [3] IMPLICIT AsciiPrintableString
(SIZE (0..ub-subject-field))
OPTIONAL,
-- RFC-822 header fields not explicitly provided for in
-- this Heading. For messages incoming from the external
-- world (i.e. in RFC-822 format), the Message-Id: field
-- need not go here, as it is placed in the
-- Envelope's EMSDMessageId (message-id) field.
extensions [4] IMPLICIT SEQUENCE
(SIZE (0..ub-header-extensions))
OF IPMSExtension OPTIONAL,
-- MIME Version (if other than 1.0)
mime-version [5] IMPLICIT AsciiPrintableString
(SIZE (0..ub-mime-version-length))
OPTIONAL,
-- Top-level MIME Content Type
mime-content-type [6] IMPLICIT AsciiPrintableString
(SIZE (0..
ub-mime-content-type-length))
OPTIONAL,
-- MIME Content Id
mime-content-id [7] IMPLICIT AsciiPrintableString
(SIZE (0..
ub-mime-content-id-length))
OPTIONAL,
-- MIME Content Description
mime-content-description [8] IMPLICIT AsciiPrintableString
(SIZE (0..ub-mime-content-
description-length))
OPTIONAL,
-- Top-level MIME Content Type
mime-content-transfer-encoding
[9] IMPLICIT AsciiPrintableString
(SIZE (0..ub-mime-content-
transfer-encoding))
OPTIONAL
};
Some fields have components and thus are composite, rather than indivisible. A field component is called a sub-field.
This field is mandatory if the sender is different from the originator.
The Originator heading field (O) identifies the IPM's originator.
PerRecipientFields ::= SEQUENCE
{
recipient-address EMSDORAddress,
per-recipient-flags BIT STRING
{
-- Recipient Types.
-- At most one of "copy" and "blind-copy" may be
-- specified concurrently for a single recipient. If
-- neither is specified, than the recipient
-- is assumed to be a "primary" recipient.
recipient-type-copy (0),
recipient-type-blind-copy (1),
-- Notification Request Types.
-- Only one of "rn" and "nrn" may be specified
-- concurrently, \\x110011 for a single recipient.
-- "rn" implies "nrn" in addition.
notification-request-rn (2),
notification-request-nrn (3),
notification-request-ipm-return (4),
-- Report Request Types
-- At most one of these should be set for a
-- particular recipient. "delivery" implies "non-delivery"
-- in addition.
report-request-non-delivery (5),
report-request-delivery (6),
-- Originator-to-Recipient request for a reply.
reply-requested (7)
} DEFAULT { report-request-non-delivery }
};
The Primary Recipients heading field identifies the zero or more users who are the "primary recipients" of the IPM. The primary recipients might be those users who are expected to act upon the IPM.
The Copy Recipients heading field identifies the zero or more users who are the "copy recipients" of the IPM. The copy recipients might be those users to whom the IPM is conveyed for information.
This field is set if the recipient is on the Carbon Copy (CC) list.
This field is set if the recipient is on the Blind Carbon Copy (BCC) list.
The Blind Copy Recipients heading field (C) identifies zero or more users who are the intended blind copy recipients of the IPM.
The phrase "copy recipients" above has the same meaning as in "Copy Recipients" from Section 6.2.1 . A blind copy recipient is one whose role as such is disclosed to neither primary nor copy recipients.
In the instance of an IPM intended for a blind copy recipient, this conditional field shall be present and identify that user. Whether it shall also identify the other blind copy recipients is a local matter. In the instance of the IPM intended for a primary or copy recipient, the field shall be absent.
A receipt notification (rn) reports its originator's receipt, or his expected and arranged future receipt, of an IPM.
A non-receipt notification (nrn) reports its originator's failure to receive, to accept, or his delay in receiving, an IPM.
When this field is set, the contents of the message are returned along with the notification.
The report request enables the MTS to acknowledge to the MTS-user one or more outcomes of a previous invocation of the message-submission or probe-submission abstract-operations.
A report is returned only in case of non-delivery.
For the message-submission, report-delivery indicates the delivery or non-delivery of the submitted message to one or more recipients. For the probe-submission, the report- delivery indicates whether or not a message could be delivered if the message were to be submitted.
When set this field indicates that the originator requests that a recipient send a message in reply to the message which carries the request.
The Priority field (default is normal) identifies the priority that the authorizing users attach to the IPM. It may assume any one of the following values: urgent, normal, or non-urgent.
At most one of either "non-urgent" or "urgent" may be specified concurrently. If neither is specified, then a Priority level of "normal" is assumed.
The Importance heading field (default normal) identifies the importance that the authorizing users attach to the IPM. It may assume any one of the following values: low, normal, or high.
At most one of either "low" or "high" may be specified concurrently. If neither is specified, then a Importance level of "normal" is assumed.
The values above are not defined by this specification; they are given meaning by users.
The Auto-forwarded heading field (default is false) indicates whether the IPM is the result of auto-forwarding. It is a Boolean value.
User-specified recipient or recipients who are to receive replies to this message.
The Replied-to IPM heading field (C) identifies the IPM to which the present IPM is a reply. It comprises an IPM identifier.
This conditional field shall be present if, and only if, the IPM is a reply.
Note - In the context of forwarding, care should be taken to distinguish between the forwarding IPM and the forwarded IPM. This field should identify whichever of these two IPMs to which the reply responds.
The Subject heading field (O) identifies the subject of the IPM. It corresponds to the "Subject:" field of RFC-822.
The Extensions heading field [D no extensions (i.e. members)] conveys information accommodated by no other heading field. It comprises a Set of zero or more IPMS extensions, each conveying one such information item.
IPMSExtension ::= SEQUENCE
{
x-header-label AsciiPrintableString,
x-header-value AsciiPrintableString
};
The types of body parts that may appear in the Body of an IPM are structured using the MIME specification.
Body ::= SEQUENCE
{
compression-method [0] IMPLICIT CompressionMethod
OPTIONAL,
-- If compression method is not specified,
-- "no-compression" is implied.
message-body OCTET STRING
-- See MIME for structure of the Body.
-- If a compression method is specified, the entire text containing
-- the Content-Type: element followed by the RFC-822 body are
-- compressed using the specified method, and placed herein.
};
CompressionMethod ::= INTEGER
{
-- Compression Methods numbered 0 to 63 are reserved for
-- assignment within this and associated specifications.
no-compression (0),
lempel-ziv (1)
-- Compression Methods numbered between 64 and 127 may be
-- used on a bilaterally-agreed basis between peers.
} (0..127)
In the context of Limited Size Messaging (LSM) over CDPD and pACT over Narrowband PCS, AT&T Wireless Services (AWS), funded work which was relevant to the development of the EMSD protocols.
This protocol supports simple authentication of the originator's address by the EMSD-SA and simple authentication of EMSD-SA by EMSD-UA.
Mainstream Internet mail security mechanisms can be used in conjunction with the EMSD protocol.
Mohsen Banan Neda Communications, Inc. 17005 SE 31st Place Bellevue, WA 98008 email: mohsen@neda.com
This section compiles in one place the complete ASN.1 Module for EM Submission and Delivery Protocol.
EMSD-SubmissionAndDeliveryProtocol DEFINITIONS ::=
BEGIN
EXPORTS EMSDORAddress, AsciiPrintableString, ContentType,
DateTime, EMSDMessageId, EMSDORAddress, ProtocolVersionNumber;
-- Upper bounds
ub-recipients INTEGER ::= 256;
-- also defined in EMSD-InterpersonalMessaging1995
ub-reply-to INTEGER ::= 256;
-- also defined in EMSD-InterpersonalMessaging1995
ub-subject-field INTEGER ::= 128;
-- also defined in EMSD-InterpersonalMessaging1995
ub-password-length INTEGER ::= 16;
ub-content-length INTEGER ::= 65535;
-- also defined in EMSD-Probe
ub-content-types INTEGER ::= 128;
ub-message-id-length INTEGER ::= 127;
ub-total-number-of-segments INTEGER ::= 32;
ub-header-extensions INTEGER ::= 64;
-- also defined in EMSD-InterpersonalMessaging1995
ub-emsd-name-length INTEGER ::= 64;
ub-emsd-address-length INTEGER ::= 20;
ub-rfc822-name-length INTEGER ::= 127;
ub-mime-version-length INTEGER ::= 8;
-- also defined in EMSD-InterpersonalMessaging1995
ub-mime-content-type-length INTEGER ::= 127;
-- also defined in EMSD-InterpersonalMessaging1995
ub-mime-content-id-length INTEGER ::= 127;
-- also defined in EMSD-InterpersonalMessaging1995
ub-mime-content-description-length INTEGER ::= 127;
-- also defined in EMSD-InterpersonalMessaging1995
ub-mime-content-transfer-encoding INTEGER ::= 127;
-- also defined in EMSD-InterpersonalMessaging1995
ub-local-message-nu INTEGER ::= 4096;
----------------------
-- SUBMIT Operation --
----------------------
submit ES-OPERATION
ARGUMENT SubmitArgument
RESULT SubmitResult
ERRORS
{
submissionControlViolated,
securityError,
resourceError,
protocolViolation,
messageError
} ::= 33;
SubmitArgument ::= SEQUENCE
{
-- Security features
security [0] IMPLICIT SecurityElement
OPTIONAL,
-- Segmentation features for efficient transport
segment-info SegmentInfo OPTIONAL,
-- Content type of the message
content-type ContentType,
--
-- THE CONTENT --
--
-- The submission content
content ANY DEFINED BY content-type
};
SubmitResult ::= SEQUENCE
{
-- Permanent identifier for this message.
-- Also contains the message submission time.
-- See comment regarding assignment of message
-- identifiers, at the definition of EMSDLocalMessageId.
message-id EMSDLocalMessageId
};
--------------------------------
-- Delivery Control Operation --
--------------------------------
deliveryControl ES-OPERATION
ARGUMENT DeliveryControlArgument
RESULT DeliveryControlResult
ERRORS
{
securityError,
resourceError,
protocolViolation
} ::= 2;
DeliveryControlArgument ::= SEQUENCE
{
-- Request an addition of or removal of a set of restrictions
restrict [0] IMPLICIT Restrict DEFAULT update,
-- Which operations are to be placed in the restriction set
permissible-operations [1] IMPLICIT Operations OPTIONAL,
-- What maximum content length should be allowed
permissible-max-content-length
[2] IMPLICIT INTEGER
(0..ub-content-length) OPTIONAL,
-- What is the lowest priority message which may be delivered
permissible-lowest-priority
[3] IMPLICIT ENUMERATED
{
non-urgent (0),
normal (1),
urgent (2)
} OPTIONAL,
-- Security features
security [4] IMPLICIT SecurityElement
OPTIONAL,
-- User Feature selection
user-features [5] IMPLICIT OCTET STRING OPTIONAL
};
DeliveryControlResult ::= SEQUENCE
{
-- Operation types queued at the EMSD-SA due to existing
-- restrictions.
waiting-operations [0] IMPLICIT Operations DEFAULT { },
-- Types of messages queued at the EMSD-SA due to
-- existing restrictions
waiting-messages [1] IMPLICIT WaitingMessages DEFAULT { },
-- Content Types of messages queued at the EMSD-SA
waiting-content-types SEQUENCE SIZE (0..ub-content-types) OF
ContentType DEFAULT { }
};
Restrict ::= ENUMERATED
{
update (1),
remove (2)
};
Operations ::= BIT STRING
{
submission (0),
delivery (1)
};
WaitingMessages ::= BIT STRING
{
long-content (0),
low-priority (1)
};
-- Delivery Verify Operation
deliveryVerify ES-OPERATION
ARGUMENT DeliveryVerifyArgument
RESULT DeliveryVerifyResult
ERRORS
{
verifyError,
resourceError,
protocolViolation
} ::= 5;
DeliveryVerifyArgument ::= SEQUENCE
{
-- Identifier of this message. This is the same identifier that
-- was provided to the originator in the Submission Result.
-- See comment regarding assignment of message identifiers,
-- at the definition of EMSDMessageId.
message-id EMSDMessageId
};
DeliveryVerifyResult ::= SEQUENCE
{
status DeliveryStatus
};
DeliveryStatus ::= ENUMERATED
{
no-report-is-sent-out (1),
delivery-report-is-sent-out (2),
non-delivery-report-is-sent-out (3)
};
-----------------------
-- DELIVER Operation --
-----------------------
deliver ES-OPERATION
ARGUMENT DeliverArgument
RESULT NULL
ERRORS
{
deliveryControlViolated,
securityError,
resourceError,
protocolViolation,
messageError
} ::= 35;
DeliverArgument ::= SEQUENCE
{
-- Identifier of this message. This is the same identifier that
-- was provided to the originator in the Submission Result.
-- See comment regarding assignment of message identifiers,
-- at the definition of EMSDMessageId.
message-id EMSDMessageId,
-- Time the message was delivered to the recipient by EMSD-SA
message-delivery-time DateTime,
-- Time EMSD-SA originally took responsibility for processing
-- of this message. This field shall be omitted if the message-id
-- contains an EMSDLocalMessageId, because that field contains
-- the submission time within it.
message-submission-time [0] IMPLICIT DateTime OPTIONAL,
-- Security features
security [1] IMPLICIT SecurityElement OPTIONAL,
-- SegContentTypementation features for efficient transport
segment-info SegmentInfo OPTIONAL,
-- The type of the content
content-type ContentType,
--
-- THE CONTENT --
--
-- The submitted (and now being delivered) content
content ANY DEFINED BY content-type
};
-- Submission Control Operation
submissionControl ES-OPERATION
ARGUMENT SubmissionControlArgument
RESULT SubmissionControlResult
ERRORS
{
securityError,
resourceError,
protocolViolation
} ::= 4;
SubmissionControlArgument ::= SEQUENCE
{
-- Request an addition of or removal of a set of restrictions
restrict [0] IMPLICIT Restrict DEFAULT update,
-- Which operations are to be placed in the restriction set
permissible-operations [1] IMPLICIT Operations OPTIONAL,
-- What maximum content length should be allowed
permissible-max-content-length
[2] IMPLICIT INTEGER
(0..ub-content-length) OPTIONAL,
-- Security features
security [3] IMPLICIT SecurityElement
OPTIONAL
};
SubmissionControlResult ::= SEQUENCE
{
-- Operation types queued at the EMSD-SA due to existing
-- restrictions.
waiting-operations [0] IMPLICIT Operations DEFAULT { }
};
----------------------------------
-- Submission Verify Operation --
----------------------------------
submissionVerify ES-OPERATION
ARGUMENT SubmissionVerifyArgument
RESULT SubmissionVerifyResult
ERRORS
{
submissionVerifyError,
resourceError,
protocolViolation
} ::= 6;
SubmissionVerifyArgument ::= SEQUENCE
-- Identifier of this message. This is the same identifier that
-- was provided to the originator in the Submission Result.
-- See comment regarding assignment of message identifiers,
-- at the definition of EMSDMessageId.
{
message-id EMSDMessageId
};
SubmissionVerifyResult ::= SEQUENCE
{
status SubmissionStatus
};
SubmissionStatus::= ENUMERATED
{
send-message (1),
drop-message (2)
};
-- GetConfiguration Operation
-- To be fully defined later. This will possibly include,
-- but not be limited to:
-- get-local-time-zone
-- get-protocol-version
-- etc.
getConfiguration ES-OPERATION
ARGUMENT NULL
RESULT NULL
ERRORS
{
resourceError,
protocolViolation
} ::= 7;
-- SetConfiguration Operation
-- To be fully defined later.
setConfiguration ES-OPERATION
ARGUMENT NULL
RESULT NULL
ERRORS
{
resourceError,
protocolViolation
} ::= 8;
-- Security --
SecurityElement ::= SEQUENCE
{
credentials Credentials,
contentIntegrityCheck ContentIntegrityCheck OPTIONAL
};
Credentials ::= CHOICE
{
simple [0] IMPLICIT SimpleCredentials
-- Strong Credentials are for future study
-- strong [1] IMPLICIT StrongCredentials
-- externalProcedure [2] EXTERNAL
};
SimpleCredentials ::= SEQUENCE
{
eMSDAddress EMSDAddress OPTIONAL,
password [0] IMPLICIT OCTET STRING
(SIZE (0..ub-password-length)) OPTIONAL
};
-- StrongCredentials ::= NULL
-- for now.
-- ContentIntegrityCheck is a 16-bit checksum of content
ContentIntegrityCheck ::= INTEGER (0..65535);
SegmentInfo ::= CHOICE
{
first [APPLICATION 2] IMPLICIT FirstSegment,
other [APPLICATION 3] IMPLICIT OtherSegment
};
FirstSegment ::= SEQUENCE
{
sequence-id INTEGER,
number-of-segments INTEGER
-- number-of-segments must not exceed ub-total-number-of-segments
};
OtherSegment ::= SEQUENCE
{
sequence-id INTEGER,
segment-number INTEGER
};
-----------
-- Errors --
------------
protocolVersionNotRecognized ERROR PARAMETER NULL ::= 1;
submissionControlViolated ERROR PARAMETER NULL ::= 2;
messageIdentifierInvalid ERROR PARAMETER NULL ::= 3;
securityError ERROR PARAMETER security-problem SecurityProblem ::= 4;
deliveryControlViolated ERROR PARAMETER NULL ::= 5;
resourceError ERROR PARAMETER NULL ::= 6;
protocolViolation ERROR PARAMETER NULL ::= 7;
messageError ERROR PARAMETER NULL ::= 8;
SecurityProblem ::= INTEGER (0..127);
--
-- EXPORTED Definitions (for use by associated specifications) --
--
ContentType ::= INTEGER
{
-- Content type 0 is reserved and shall never be transmitted.
reserved (0),
-- Content types between 1 and 31 (inclusive) are for
-- internal-use only
probe (1), -- reserved
delivery-report (2), -- reserved
-- Content types between 32 and 63 (inclusive) are for
-- message types defined within this specifications.
emsd-interpersonal-messaging-1995 (32),
voice-messaging (33) -- reserved
-- Content types beyond and including 64 are for
-- bilaterally-agreed use between peers.
} (0..127);
-- If this message was originated as an RFC-822 message, then this
-- EMSDMessageId shall be the "Message-Id:" field from that message.
-- If this message was originated within the EMSD domain,
-- then this identifier shall be unique for the Message Center
-- generating this id.
EMSDMessageId ::= CHOICE
{
emsdLocalMessageId [APPLICATION 4] IMPLICIT
EMSDLocalMessageId,
rfc822MessageId [APPLICATION 5] IMPLICIT
AsciiPrintableString
(SIZE (0..ub-message-id-length))
};
EMSDLocalMessageId ::= SEQUENCE
{
submissionTime DateTime,
messageNumber INTEGER (0..ub-local-message-nu)
};
-- An Originator/Recipient Address in EMSD Environment
EMSDORAddress ::= CHOICE
{
-- This is the local-format address
emsd-local-address-format EMSDAddress,
-- This is a globally-unique RFC-822 Address
rfc822DomainAddress AsciiPrintableString
};
EMSDAddress ::= SEQUENCE
{
emsd-address OCTET STRING
(SIZE (1..ub-emsd-address-length)),
-- emsd-address is a decimal integer in BCD (Binary Encoded Decimal)
-- format.
-- If it had an odd number of digits, it is padded with 0 on
-- the left.
emsd-name [0] IMPLICIT OCTET STRING
(SIZE (0..ub-emsd-name-length))
OPTIONAL
};
DateTime ::= INTEGER;
Iso8859String ::= GeneralString;
AsciiPrintableString ::= [ APPLICATION 0 ]
IMPLICIT Iso8859String (FROM
(" "|"!"|"#"|"$"|"%"|"&"|"'"|"("|")"|"*"|"+"|","|"-"|"."|"/"|
"0"|"1"|"2"|"3"|"4"|"5"|"6"|"7"|"8"|"9"|":"|";"|"<"|"="|">"|
"?"|"@"|"A"|"B"|"C"|"D"|"E"|"F"|"G"|"H"|"I"|"J"|"K"|"L"|"M"|
"N"|"O"|"P"|"Q"|"R"|"S"|"T"|"U"|"V"|"W"|"X"|"Y"|"Z"|"["|"]"|
"^"|"_"|"`"|"a"|"b"|"c"|"d"|"e"|"f"|"g"|"h"|"i"|"j"|"k"|"l"|
"m"|"n"|"o"|"p"|"q"|"r"|"s"|"t"|"u"|"v"|"w"|"x"|"y"|"z"|"{"|
"|"|"}"|"~"|"\"|""""));
ProtocolVersionNumber ::= [APPLICATION 1] SEQUENCE
{
version-major INTEGER,
version-minor [0] IMPLICIT INTEGER DEFAULT 0
}
END -- end of EMSD-SubmissionAndDeliveryProtocol
This section compiles in one place the complete ASN.1 Module for EMSD-IPM.
EMSD-InterpersonalMe