[BXXPwg] new BEEP core draft (in HTML)

Marshall T. Rose mrose+mtr.netnews@dbc.mtview.ca.us
Thu, 4 Jan 2001 21:08:07 -0800


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<html><head><title>The Blocks Extensible Exchange Protocol Core</title>
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CLASS=3D"link2"><font face=3D"monaco, MS Sans Serif" color=3D"#ffffff" =
size=3D"1"><b>&nbsp;TOC&nbsp;</b></font></a><br></td></tr></table>
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cellpadding=3D"2" cellspacing=3D"1">
<tr valign=3D"top"><td width=3D"33%" bgcolor=3D"#666666" =
class=3D"header">Network Working Group</td><td width=3D"33%" =
bgcolor=3D"#666666" class=3D"header">M.T. Rose</td></tr>
<tr valign=3D"top"><td width=3D"33%" bgcolor=3D"#666666" =
class=3D"header">Internet-Draft</td><td width=3D"33%" =
bgcolor=3D"#666666" class=3D"header">Invisible Worlds, Inc.</td></tr>
<tr valign=3D"top"><td width=3D"33%" bgcolor=3D"#666666" =
class=3D"header">Expires: July 5, 2001</td><td width=3D"33%" =
bgcolor=3D"#666666" class=3D"header">January 4, 2001</td></tr>
</table></td></tr></table>
<div align=3D"right"><font face=3D"monaco, MS Sans Serif" =
color=3D"#990000" size=3D"+3"><b><br><span class=3D"title">The Blocks =
Extensible Exchange Protocol Core</span></b></font></div>
<div align=3D"right"><font face=3D"monaco, MS Sans Serif" =
color=3D"#666666" size=3D"+2"><b><span =
class=3D"filename">draft-ietf-beep-framework-10</span></b></font></div>
<font face=3D"verdana, helvetica, arial, sans-serif" size=3D"2">

<h3>Status of this Memo</h3>
<p>
This document is an Internet-Draft and is in full conformance with all =
provisions of Section 10 of RFC2026.</p>
<p>
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups.
Note that other groups may also distribute working documents as
Internet-Drafts.</p>
<p>
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any =
time.
It is inappropriate to use Internet-Drafts as reference material or to =
cite
them other than as "work in progress."</p>
<p>
The list of current Internet-Drafts can be accessed at
<a =
href=3D'http://www.ietf.org/ietf/1id-abstracts.txt'>http://www.ietf.org/i=
etf/1id-abstracts.txt</a>.</p>
<p>
The list of Internet-Draft Shadow Directories can be accessed at
<a =
href=3D'http://www.ietf.org/shadow.html'>http://www.ietf.org/shadow.html<=
/a>.</p>
<p>
This Internet-Draft will expire on July 5, 2001.</p>

<h3>Copyright Notice</h3>
<p>
Copyright (C) The Internet Society (2001). All Rights Reserved.</p>

<h3>Abstract</h3>

<p>
This memo describes a generic application protocol
kernel for connection-oriented,
asynchronous interactions called BEEP.
BEEP permits simultaneous and independent exchanges
within the context of a single application user-identity,
supporting both textual and binary messages.
</p>
<a name=3D"toc"><br><hr size=3D"1" shade=3D"0"></a>
<table border=3D"0" cellpadding=3D"0" cellspacing=3D"2" width=3D"30" =
height=3D"15" align=3D"right"><tr><td bgcolor=3D"#990000" =
align=3D"center" width=3D"30" height=3D"15"><a href=3D"#toc" =
CLASS=3D"link2"><font face=3D"monaco, MS Sans Serif" color=3D"#ffffff" =
size=3D"1"><b>&nbsp;TOC&nbsp;</b></font></a><br></td></tr></table>
<h3>Table of Contents</h3>
<ul compact class=3D"toc">
<b><a href=3D"#anchor1">1.</a>&nbsp;
Introduction<br></b>
<b><a href=3D"#anchor2">2.</a>&nbsp;
The BEEP Core<br></b>
<b><a href=3D"#anchor3">2.1</a>&nbsp;
Roles<br></b>
<b><a href=3D"#exchange.styles">2.1.1</a>&nbsp;
Exchange Styles<br></b>
<b><a href=3D"#messages">2.2</a>&nbsp;
Messages and Frames<br></b>
<b><a href=3D"#frame.syntax">2.2.1</a>&nbsp;
Frame Syntax<br></b>
<b><a href=3D"#frame.header">2.2.1.1</a>&nbsp;
Frame Header<br></b>
<b><a href=3D"#frame.payload">2.2.1.2</a>&nbsp;
Frame Payload<br></b>
<b><a href=3D"#frame.trailer">2.2.1.3</a>&nbsp;
Frame Trailer<br></b>
<b><a href=3D"#frame.semantics">2.2.2</a>&nbsp;
Frame Semantics<br></b>
<b><a href=3D"#anchor4">2.2.2.1</a>&nbsp;
Poorly-formed Messages<br></b>
<b><a href=3D"#channel.mgmt">2.3</a>&nbsp;
Channel Management<br></b>
<b><a href=3D"#beep.messages">2.3.1</a>&nbsp;
Message Semantics<br></b>
<b><a href=3D"#greeting.message">2.3.1.1</a>&nbsp;
The Greeting Message<br></b>
<b><a href=3D"#start.message">2.3.1.2</a>&nbsp;
The Start Message<br></b>
<b><a href=3D"#close.message">2.3.1.3</a>&nbsp;
The Close Message<br></b>
<b><a href=3D"#ok.message">2.3.1.4</a>&nbsp;
The OK Message<br></b>
<b><a href=3D"#error.message">2.3.1.5</a>&nbsp;
The Error Message<br></b>
<b><a href=3D"#session.estab">2.4</a>&nbsp;
Session Establishment and Release<br></b>
<b><a href=3D"#transport.mapping">2.5</a>&nbsp;
Transport Mappings<br></b>
<b><a href=3D"#anchor5">2.5.1</a>&nbsp;
Session Management<br></b>
<b><a href=3D"#anchor6">2.5.2</a>&nbsp;
Message Exchange<br></b>
<b><a href=3D"#anchor7">2.6</a>&nbsp;
Asynchrony<br></b>
<b><a href=3D"#anchor8">2.6.1</a>&nbsp;
Within a Single Channel<br></b>
<b><a href=3D"#anchor9">2.6.2</a>&nbsp;
Between Different Channels<br></b>
<b><a href=3D"#anchor10">2.6.3</a>&nbsp;
Pre-emptive Replies<br></b>
<b><a href=3D"#anchor11">2.6.4</a>&nbsp;
Interference<br></b>
<b><a href=3D"#anchor12">2.7</a>&nbsp;
Peer-to-Peer Behavior<br></b>
<b><a href=3D"#anchor13">3.</a>&nbsp;
Transport Security<br></b>
<b><a href=3D"#tls.profile">3.1</a>&nbsp;
The TLS Transport Security Profile<br></b>
<b><a href=3D"#anchor14">3.1.1</a>&nbsp;
Profile Identification and Initialization<br></b>
<b><a href=3D"#anchor15">3.1.2</a>&nbsp;
Message Syntax<br></b>
<b><a href=3D"#tls.messages">3.1.3</a>&nbsp;
Message Semantics<br></b>
<b><a href=3D"#anchor16">3.1.3.1</a>&nbsp;
The Ready Message<br></b>
<b><a href=3D"#anchor17">3.1.3.2</a>&nbsp;
The Proceed Message<br></b>
<b><a href=3D"#anchor18">4.</a>&nbsp;
User Authentication<br></b>
<b><a href=3D"#sasl.profiles">4.1</a>&nbsp;
The SASL Family of Profiles<br></b>
<b><a href=3D"#anchor19">4.1.1</a>&nbsp;
Profile Identification and Initialization<br></b>
<b><a href=3D"#anchor20">4.1.2</a>&nbsp;
Message Syntax<br></b>
<b><a href=3D"#sasl.messages">4.1.3</a>&nbsp;
Message Semantics<br></b>
<b><a href=3D"#anchor21">5.</a>&nbsp;
Registration Templates<br></b>
<b><a href=3D"#profile.registration">5.1</a>&nbsp;
Profile Registration Template<br></b>
<b><a href=3D"#feature.registration">5.2</a>&nbsp;
Feature Registration Template<br></b>
<b><a href=3D"#initial.definitions">6.</a>&nbsp;
Initial Registrations<br></b>
<b><a href=3D"#channelZ.definition">6.1</a>&nbsp;
Registration: BEEP Channel Management<br></b>
<b><a href=3D"#tls.definition">6.2</a>&nbsp;
Registration: TLS Transport Security Profile<br></b>
<b><a href=3D"#sasl.definition">6.3</a>&nbsp;
Registration: SASL Family of Profiles<br></b>
<b><a href=3D"#beep+xml.definition">6.4</a>&nbsp;
Registration: application/beep+xml<br></b>
<b><a href=3D"#anchor22">7.</a>&nbsp;
DTDs<br></b>
<b><a href=3D"#beep.dtd">7.1</a>&nbsp;
BEEP Channel Management DTD<br></b>
<b><a href=3D"#tls.dtd">7.2</a>&nbsp;
TLS Transport Security Profile DTD<br></b>
<b><a href=3D"#sasl.dtd">7.3</a>&nbsp;
SASL Family of Profiles DTD<br></b>
<b><a href=3D"#reply-codes">8.</a>&nbsp;
Reply Codes<br></b>
<b><a href=3D"#anchor23">9.</a>&nbsp;
Security Considerations<br></b>
<b><a href=3D"#rfc.references">&#167;</a>&nbsp;
References<br></b>
<b><a href=3D"#rfc.authors">&#167;</a>&nbsp;
Author's Address<br></b>
<b><a href=3D"#anchor24">A.</a>&nbsp;
Acknowledgements<br></b>
<b><a href=3D"#anchor25">B.</a>&nbsp;
IANA Considerations<br></b>
<b><a href=3D"#rfc.copyright">&#167;</a>&nbsp;
Full Copyright Statement<br></b>
</ul>
<br clear=3D"all">

<a name=3D"anchor1"><br><hr size=3D"1" shade=3D"0"></a>
<table border=3D"0" cellpadding=3D"0" cellspacing=3D"2" width=3D"30" =
height=3D"15" align=3D"right"><tr><td bgcolor=3D"#990000" =
align=3D"center" width=3D"30" height=3D"15"><a href=3D"#toc" =
CLASS=3D"link2"><font face=3D"monaco, MS Sans Serif" color=3D"#ffffff" =
size=3D"1"><b>&nbsp;TOC&nbsp;</b></font></a><br></td></tr></table>
<h3>1.&nbsp;Introduction</h3>

<p>
This memo describes a generic application protocol
kernel for connection-oriented, asynchronous interactions called BEEP.
</p>

<p>
At BEEP's core is a framing mechanism that
permits simultaneous and independent exchanges of messages between =
peers.
Messages are arbitrary <a href=3D"#RFC2045">MIME</a>[1] content,
but are usually textual
(structured using <a href=3D"#W3C.XML">XML</a>[2]).
</p>

<p>
All exchanges occur in the context of a channel &#151;
a binding to a well-defined aspect of the application,
such as transport security, user authentication, or data exchange.
</p>

<p>
Each channel has an associated "profile" that defines the syntax and
semantics of the messages exchanged.
Implicit in the operation of BEEP is the notion of channel management.
In addition to defining BEEP's channel management profile,
this document defines:

<ul class=3D"text">

<li>
the <a href=3D"#RFC2246">TLS</a>[3] transport security profile; and,
</li>

<li>
the <a href=3D"#RFC2222">SASL</a>[4] family of profiles.
</li>

</ul>

Other profiles,
such as those used for data exchange,
are defined by an application protocol designer.
</p>

<a name=3D"anchor2"><br><hr size=3D"1" shade=3D"0"></a>
<table border=3D"0" cellpadding=3D"0" cellspacing=3D"2" width=3D"30" =
height=3D"15" align=3D"right"><tr><td bgcolor=3D"#990000" =
align=3D"center" width=3D"30" height=3D"15"><a href=3D"#toc" =
CLASS=3D"link2"><font face=3D"monaco, MS Sans Serif" color=3D"#ffffff" =
size=3D"1"><b>&nbsp;TOC&nbsp;</b></font></a><br></td></tr></table>
<h3>2.&nbsp;The BEEP Core</h3>

<p>
A BEEP session is mapped onto an underlying transport service.
A separate series of documents describe how a particular transport
service realizes a BEEP session.
For example,
<a href=3D"#BEEP-TCPMAPPING">[5]</a> describes how a BEEP session is
mapped onto a single <a href=3D"#RFC0793">TCP</a>[6] connection.
</p>

<p>
When a session is established,
each BEEP peer advertises the profile it supports.
Later on,
during the creation of a channel,
the client supplies one or more proposed profiles for that channel.
If the server creates the channel,
it selects one of the profiles and sends it in a reply;
otherwise,
it may indicate that none of the profiles are acceptable,
and decline creation of the channel.
</p>

<p>
Channel usage falls into one of two categories:

<blockquote class=3D"text"><dl>

<dt>initial tuning:</dt>
<dd>

these are used by profiles that perform initialization once the
BEEP session is established
(e.g., negotiating the use of transport security);
although several exchanges may be required to perform the =
initialization,
these channels become inactive early in the BEEP session and remain so
for the duration.
</dd>

<dt>continuous:</dt>
<dd>

these are used by profiles that support data exchange;
typically,
these channels are created after the initial tuning channels have gone
quiet.
</dd>

</dl></blockquote>

Note that because of their special nature,
only one tuning channel may be established at any given time;
in contrast,
BEEP allows multiple data exchange channels to be simultaneously in
use.
</p>

<p>

</p>

<h4><a name=3D"anchor3">2.1</a>&nbsp;Roles</h4>

<p>
Although BEEP is peer-to-peer,
it is convenient to label each peer in the context of the role it is
performing at a given time:

<ul class=3D"text">

<li>
When a BEEP session is established,
the peer that awaits new connections is acting in the
listening role,
and the other peer,
which establishes a connection to the listener,
is acting in the initiating role.
In the examples which follow,
these are referred to as "L:" and "I:",
respectively.
</li>

<li>
A BEEP peer starting an exchange is termed the client;
similarly,
the other BEEP peer is termed the server.
In the examples which follow,
these are referred to as "C:" and "S:",
respectively.
</li>

</ul>

Typically,
a BEEP peer acting in the server role is also acting in a listening =
role.
However,
because BEEP is peer-to-peer in nature,
no such requirement exists.
</p>

<h4><a name=3D"exchange.styles">2.1.1</a>&nbsp;Exchange Styles</h4>

<p>
BEEP allows three styles of exchange:

<blockquote class=3D"text"><dl>

<dt>MSG/RPY:</dt>
<dd>
the client sends a "MSG" message asking the
server to perform some task,
the server performs the task and replies with a "RPY" message
(termed a positive reply).
</dd>

<dt>MSG/ERR:</dt>
<dd>
the client sends a "MSG" message,
the server does not perform any task and replies with an "ERR" message
(termed a negative reply).
</dd>

<dt>MSG/ANS:</dt>
<dd>
the client sends a "MSG" message,
the server,
during the course of performing some task,
replies with zero or more "ANS" messages,
and,
upon completion of the task,
sends a "NUL" message,
which signifies the end of the reply.
</dd>

</dl></blockquote>

The first two styles are termed one-to-one exchanges,
whilst the third style is termed a one-to-many exchange.
</p>

<p>

</p>

<h4><a name=3D"messages">2.2</a>&nbsp;Messages and Frames</h4>

<p>
A message is structured according to the rules of MIME.
Accordingly,
each message may begin with "entity-headers"
(c.f., <a href=3D"#RFC2045">MIME</a>[1]'s Section 3).
If none,
or only some,
of the "entity-headers" are present:

<ul class=3D"text">

<li>
the default "Content-Type" is "application/octet-stream"; and,
</li>

<li>
the default "Content-Transfer-Encoding" is "binary".
</li>

</ul>

</p>

<p>
Normally,
a message is sent in a single frame.
However,
it may be convenient or necesary to segment a message into multiple =
frames
(e.g., if only part of a message is ready to be sent).
</p>

<p>
Each frame consists of a header, the payload, and a trailer.
The header and trailer are each represented using printable ASCII
characters and are terminated with a CRLF pair.
Between the header and the trailer is the payload,
consisting of zero or more octets.
</p>

<p>
For example,
here is a message contained in a single frame that contains a payload
of 132 octets spread over 5 lines
(each line is terminated with a CRLF pair):
</p>
</font><pre>
    C: MSG 0 1 . 52 132
    C: Content-Type: application/beep+xml
    C:
    C: &lt;start number=3D'1'>
    C:    &lt;profile uri=3D'http://xml.resource.org/profiles/sasl/OTP' =
/>
    C: &lt;/start>
    C: END
</pre><font face=3D"verdana, helvetica, arial, sans-serif" size=3D"2">

<p>
In this example,
note that the entire message is represented in a single frame.
</p>

<p>

</p>

<h4><a name=3D"frame.syntax">2.2.1</a>&nbsp;Frame Syntax</h4>

<p>
The <a href=3D"#RFC2234">ABNF</a>[7] for a frame is:
</p>
</font><pre>
frame      =3D data / mapping

data       =3D header payload trailer

header     =3D msg / rpy / err / ans / nul

msg        =3D "MSG" SP common          CR LF
rpy        =3D "RPY" SP common          CR LF
ans        =3D "ANS" SP common SP ansno CR LF
err        =3D "ERR" SP common          CR LF
nul        =3D "NUL" SP common          CR LF

common     =3D channel SP msgno SP more SP seqno SP size
channel    =3D 0..2147483647
msgno      =3D 0..2147483647
more       =3D "." / "*"
seqno      =3D 0..4294967295
size       =3D 0..2147483647
ansno      =3D 0..2147483647

payload    =3D *OCTET

trailer    =3D "END" CR LF

mapping    =3D ;; each transport mapping may define additional frames
</pre><font face=3D"verdana, helvetica, arial, sans-serif" size=3D"2">

<p>

</p>

<h4><a name=3D"frame.header">2.2.1.1</a>&nbsp;Frame Header</h4>

<p>
The frame header consists of a three-character keyword
(one of: "MSG", "RPY", "ERR", "ANS", or "NUL"),
followed by zero or more parameters.
A single space character (decimal code 32, " ") separates each =
component.
The header is terminated with a CRLF pair.
</p>

<p>
The channel number ("channel") must be a non-negative integer
(in the range 0..2147483647).
</p>

<p>
The message number ("msgno") must be a non-negative integer
(in the range 0..2147483647)
and have a different value than all other "MSG" messages on the same
channel for which a reply has not been completely received.
</p>

<p>
The continuation indicator
("more", one of: decimal code 42, "*",
or decimal code 46, ".")
specifies whether this is the final frame of the message:

<blockquote class=3D"text"><dl>

<dt>   intermediate ("*"):</dt>
<dd>

at least one other frame follows for the message; or,
</dd>

<dt>   complete ("."):</dt>
<dd>

this frame completes the message.
</dd>

</dl></blockquote>

</p>

<p>
The sequence number ("seqno") must be a non-negative integer
(in the range 0..4294967295) and specifies the sequence number of the
first octet in the payload,
for the associated channel
(c.f., <a href=3D"#frame.payload">Frame Payload</a>).
</p>

<p>
The payload size ("size") must be a non-negative integer
(in the range 0..2147483647) and specifies the exact number of octets
in the payload.
(This does not include either the header or trailer.)
</p>

<p>
Note that a frame may have an empty payload,
e.g.,
</p>
</font><pre>
    S: RPY 0 1 * 287 20
    S:     ...
    S:     ...
    S: END
    S: RPY 0 1 . 307 0
    S: END
</pre><font face=3D"verdana, helvetica, arial, sans-serif" size=3D"2">

<p>
The answer number ("ansno") must be a non-negative integer
(in the range 0..4294967295) and must have a different value than all
other answers in progress for the message being replied to.
</p>

<p>

</p>

<p>
There are two kinds of frames: data and mapping.
each transport mapping (c.f., <a href=3D"#transport.mapping">Transport =
Mappings</a>) may
define its own frames.
For example,
<a href=3D"#BEEP-TCPMAPPING">[5]</a> defines the SEQ frame.
The remainder of this section discusses data frames.
</p>

<p>
When a message is segmented and sent as several frames,
those frames must be sent sequentally,
without any intervening frames from other messages on the same channel.
However,
there are two exceptions:
first,
no restriction is made with respect to the interleaving of frames for
other channels;
and,
second,
in a one-to-many exchange,
multiple answers may be simultaneously in progress.
Accordingly,
frames for "ANS" messages may be interleaved on the same channel &#151;
the answer number is used for collation,
e.g.,
</p>
</font><pre>
    S: ANS 1 0 * 0 20 0
    S:     ...
    S:     ...
    S: END
    S: ANS 1 0 * 20 20 1
    S:     ...
    S:     ...
    S: END
    S: ANS 1 0 . 40 10 0
    S:     ...
    S: END
</pre><font face=3D"verdana, helvetica, arial, sans-serif" size=3D"2">

<p>
which shows two "ANS" messages interleaved on channel 1 as
part of a reply to message number 0.
Note that the sequence number is advanced for each frame sent on the
channel,
and is independent of the messages sent in those frames.
</p>

<p>

</p>

<p>
There are several rules for identifying poorly-formed frames:

<ul class=3D"text">

<li>
if the header doesn't start with "MSG", "RPY", "ERR", "ANS", or "NUL";=20
</li>

<li>
if any of the parameters in the header cannot be determined or are
invalid (i.e., syntactically incorrect);
</li>

<li>
if the value of the channel number doesn't refer to an existing
channel;
</li>

<li>
if the header starts with "MSG",
and the message number refers to a "MSG" message that has been =
completely
received but for which a reply has not been completely sent;
</li>

<li>
if the header doesn't start with "MSG",
and refers to a message number for which a reply has already been
completely received;
</li>

<li>
if the header doesn't start with "MSG",
and refers to a message number that has never been sent
(except during session establishment,
c.f., <a href=3D"#greeting.message">The Greeting Message</a>);
</li>

<li>
if the header starts with "MSG", "RPY", "ERR", or "ANS",
and refers to a message number for which at least one other frame has
been received,
and the three-character keyword starting this frame and the
immediately-previous received frame for this message number are not
identical;
</li>

<li>
if the header starts with "NUL",
and refers to a message number for which at least one other frame has
been received,
and the keyword of of the immediately-previous received frame for this
reply isn't "ANS";
</li>

<li>
if the continuation indicator of the previous frame received on
the same channel was intermediate ("*"),
and its message number isn't identical to this frame's message number;
</li>

<li>
if the value of the sequence number doesn't correspond to the
expected value for the associated channel
(c.f., <a href=3D"#frame.payload">Frame Payload</a>); or,
</li>

<li>
if the header starts with "NUL",
and the continuation indicator is intermediate ("*") or the payload
size is non-zero.
</li>

</ul>

If a frame is poorly-formed,
then the session is terminated without generating a response,
and it is recommended that a diagnostic entry be logged.
</p>

<p>

</p>

<h4><a name=3D"frame.payload">2.2.1.2</a>&nbsp;Frame Payload</h4>

<p>
The frame payload consists of zero or more octets.
</p>

<p>
Every payload octet sent in each direction on a channel has an
associated sequence number.
Numbering of payload octets within a frame is such that the first =
payload
octet is the lowest numbered,
and the following payload octets are numbered consecutively.
(When a channel is created,
the sequence number associated with the first payload octet of the
first frame is 0.)
</p>

<p>
The actual sequence number space is finite,
though very large,
ranging from 0..4294967295 (2**32 - 1).
Since the space is finite,
all arithmetic dealing with sequence numbers is performed modulo 2**32.
This unsigned arithmetic preserves the relationship of sequence
numbers as they cycle from 2**32 - 1 to 0 again.
Consult Sections 2 through 5 of <a href=3D"#RFC1982">[8]</a> for a
discussion of the arithmetic properties of sequence numbers.
</p>

<p>
When receiving a frame,
the sum of its sequence number and payload size,
modulo 4294967296 (2**32),
gives the expected sequence number associated with the first payload =
octet of
the next frame received.
Accordingly,
when receiving a frame if the sequence number isn't the expected
value for this channel,
then the BEEP peers have lost synchronization,
then the session is terminated without generating a response,
and it is recommended that a diagnostic entry be logged.
</p>

<p>

</p>

<h4><a name=3D"frame.trailer">2.2.1.3</a>&nbsp;Frame Trailer</h4>

<p>
The frame trailer consists of "END" followed by a CRLF pair.
</p>

<p>
When receiving a frame,
if the characters immediately following the payload don't correspond
to a trailer,
then the session is terminated without generating a response,
and it is recommended that a diagnostic entry be logged.
</p>

<p>

</p>

<h4><a name=3D"frame.semantics">2.2.2</a>&nbsp;Frame Semantics</h4>

<p>
The semantics of each message is channel-specific.
Accordingly,
the profile associated with a channel must define:

<ul class=3D"text">

<li>
the initialization messages,
if any,
exchanged during channel creation;
</li>

<li>
the messages that may be exchanged in the payload of the channel; and,
</li>

<li>
the semantics of these messages.
</li>

</ul>

A <a href=3D"#profile.registration">profile registration template</a>
organizes this information.
</p>

<h4><a name=3D"anchor4">2.2.2.1</a>&nbsp;Poorly-formed Messages</h4>

<p>
When defining the behavior of the profile,
the template must specify how poorly-formed "MSG" messages are replied
to.
For example,
the channel management profile sends a negative reply containing an
error message (c.f., <a href=3D"#error.message">The Error Message</a>).
</p>

<p>
If a poorly-formed reply is received on channel zero,
the session is terminated without generating a response,
and it is recommended that a diagnostic entry be logged.
</p>

<p>
If a poorly-formed reply is received on another channel,
then the channel must be closed using the procedure in
<a href=3D"#close.message">The Close Message</a>.
</p>

<p>

</p>

<h4><a name=3D"channel.mgmt">2.3</a>&nbsp;Channel Management</h4>

<p>
When a BEEP session starts,
only channel number zero is defined,
which is used for channel management.
<a href=3D"#channelZ.definition">Registration: BEEP Channel =
Management</a> contains the profile registration for
BEEP channel management.
</p>

<p>
Channel management allows each BEEP peer to advertise the profiles
that it supports
(c.f., <a href=3D"#greeting.message">The Greeting Message</a>),
bind an instance of one of those profiles to a channel
(c.f., <a href=3D"#start.message">The Start Message</a>),
and then later close any channels or release the BEEP session
(c.f., <a href=3D"#close.message">The Close Message</a>).
</p>

<p>
A BEEP peer should support at least 257 concurrent channels.
</p>

<p>

</p>

<h4><a name=3D"beep.messages">2.3.1</a>&nbsp;Message Semantics</h4>

<h4><a name=3D"greeting.message">2.3.1.1</a>&nbsp;The Greeting =
Message</h4>

<p>
When a BEEP session is established,
each BEEP peer signifies its availability by immediately sending a
positive reply with a message number of zero that contains a
"greeting" element, e.g.,
</p>
</font><pre>
    L: &lt;wait for incoming connection>
    I: &lt;open connection>
    L: RPY 0 0 . 0 122
    L: Content-Type: application/beep+xml
    L:
    L: &lt;greeting>
    L:    &lt;profile uri=3D'http://xml.resource.org/profiles/TLS' />
    L: &lt;/greeting>
    L: END
    I: RPY 0 0 . 0 52
    I: Content-Type: application/beep+xml
    I:
    I: &lt;greeting />
    I: END
</pre><font face=3D"verdana, helvetica, arial, sans-serif" size=3D"2">

<p>
Note that this example implies that the BEEP peer in the
initiating role waits until the BEEP peer in the listening role sends =
its
greeting &#151; this is an artifact of the presentation;
in fact,
both BEEP peers send their replies independently.
</p>

<p>
The "greeting" element has two optional attributes
("features" and "localize")
and zero or more "profile" elements,
one for each profile supported by the BEEP peer acting in a server role:

<ul class=3D"text">

<li>
the "features" attribute,
if present,
contains one or more feature tokens,
each indicating an optional feature of the channel management profile
supported by the BEEP peer;
</li>

<li>
the "localize" attribute,
if present,
contains one or more language tokens (defined in <a =
href=3D"#RFC1766">[9]</a>),
each identifying a desirable language tag to be used by the remote
BEEP peer when generating textual diagnostics for the "close" and
"error" elements
(the tokens are ordered from most to least desirable); and,
</li>

<li>
each "profile" element contained within the "greeting" element =
identifies
a profile,
and unlike the "profile" elements that occur within the "start" element,
the content of each "profile" element may not contain an optional
initialization message.
</li>

</ul>

</p>

<p>
<a href=3D"#feature.registration">Feature Registration Template</a> =
defines a registration
template for optional features.
</p>

<p>

</p>

<h4><a name=3D"start.message">2.3.1.2</a>&nbsp;The Start Message</h4>

<p>
When a BEEP peer wants to create a channel,
it sends a "start" element on channel zero,
e.g.,
</p>
</font><pre>
    C: MSG 0 1 . 52 132
    C: Content-Type: application/beep+xml
    C:
    C: &lt;start number=3D'1'>
    C:    &lt;profile uri=3D'http://xml.resource.org/profiles/sasl/OTP' =
/>
    C: &lt;/start>
    C: END
</pre><font face=3D"verdana, helvetica, arial, sans-serif" size=3D"2">

<p>
The "start" element has a "number" attribute,
an optional "serverName" attribute,
and one or more "profile" elements:

<ul class=3D"text">

<li>
the "number" attribute indicates the channel number=20
(in the range 1..2147483647)
used to identify the channel in future messages;
</li>

<li>
the "serverName" attribute,
an arbitrary string,
indicates the desired server name for this BEEP session; and,
</li>

<li>
each "profile" element contained with the "start" element has a
"uri" attribute,
an optional "encoding" attribute,
and arbitrary character data as content:

<ul class=3D"text">

<li>
the "uri" attribute authoritatively identifies the profile;
</li>

<li>
the "encoding" attribute,
if present,
specifies whether the content of the "profile" element is represented
as a base64-encoded string; and,
</li>

<li>
the content of the "profile" element,
if present,
must be no longer than 4K octets in length and specifies an
initialization message given to the channel as soon as it is created.
</li>

</ul>

</li>

</ul>

</p>

<p>
To avoid conflict in assigning channel numbers when requesting the
creation of a channel,
BEEP peers acting in the initiating role use only positive integers that =
are
odd-numbered;
similarly,
BEEP peers acting in the listening role use only positive integers that =
are
even-numbered.
</p>

<p>
The "serverName" attribute for the first successful "start" element
received by a BEEP peer is meaningful for the duration of the BEEP
session.
If present,
the BEEP peer decides whether to operate as the indicated "serverName";
if not,
an "error" element is sent in a negative reply.
</p>

<p>
When a BEEP peer receives a "start" element on channel zero,
it examines each of the proposed profiles,
and decides whether to use one of them to create the channel.
If so,
the appropriate "profile" element is sent in a positive reply;
otherwise,
an "error" element is sent in a negative reply.
</p>

<p>
When creating the channel,
the value of the "serverName" attribute from the first successful
"start" element is consulted to provide configuration information,
e.g., the desired server-side certificate when starting the
<a href=3D"#tls.profile">TLS transport security profile</a>.
</p>

<p>
For example,
a successful channel creation might look like this:
</p>
</font><pre>
    C: MSG 0 1 . 52 209
    C: Content-Type: application/beep+xml
    C:=20
    C: &lt;start number=3D'1'>
    C:    &lt;profile uri=3D'http://xml.resource.org/profiles/sasl/OTP' =
/>
    C:    &lt;profile
    C:       uri=3D'http://xml.resource.org/profiles/sasl/ANONYMOUS' />
    C: &lt;/start>
    C: END
    S: RPY 0 1 . 264 99
    S: Content-Type: application/beep+xml
    S:
    S: &lt;profile uri=3D'http://xml.resource.org/profiles/sasl/OTP' />
    S: END
</pre><font face=3D"verdana, helvetica, arial, sans-serif" size=3D"2">

<p>
Similarly,
an unsuccessful channel creation might look like this:
</p>
</font><pre>
    C: MSG 0 1 . 52 132
    C: Content-Type: application/beep+xml
    C:=20
    C: &lt;start number=3D'2'>
    C:    &lt;profile uri=3D'http://xml.resource.org/profiles/sasl/OTP' =
/>=20
    C: &lt;/start>
    C: END
    S: ERR 0 1 . 264 127
    S: Content-Type: application/beep+xml
    S:
    S: &lt;error code=3D'501'>number attribute
    S: in &amp;lt;start&amp;gt; element must be odd-valued&lt;/error>
    S: END
</pre><font face=3D"verdana, helvetica, arial, sans-serif" size=3D"2">

<p>
Finally,
here's an example in which an initialization element is exchanged
during channel creation:
</p>
</font><pre>
    C: MSG 0 1 . 52 170
    C: Content-Type: application/beep+xml
    C:
    C: &lt;start number=3D'1'>
    C:    &lt;profile uri=3D'http://xml.resource.org/profiles/TLS'>
    C:        &lt;![CDATA[&lt;ready />]]&gt;
    C:    &lt;/profile>
    C: &lt;/start>
    C: END
    S: RPY 0 1 . 122 133
    S: Content-Type: application/beep+xml
    S:
    S: &lt;profile uri=3D'http://xml.resource.org/profiles/TLS'>
    S:     &lt;![CDATA[&lt;proceed />]]&gt;
    S: &lt;/profile>
    S: END
</pre><font face=3D"verdana, helvetica, arial, sans-serif" size=3D"2">

<p>

</p>

<h4><a name=3D"close.message">2.3.1.3</a>&nbsp;The Close Message</h4>

<p>
When a BEEP peer wants to close a channel,
it sends a "close" element on channel zero,
e.g.,
</p>
</font><pre>
    C: MSG 0 2 . 247 71
    C: Content-Type: application/beep+xml
    C:
    C: &lt;close number=3D'1' code=3D'200' />
    C: END
</pre><font face=3D"verdana, helvetica, arial, sans-serif" size=3D"2">

<p>
The "close" element has a "number" attribute,
a "code" attribute,
an optional "xml:lang" attribute,
and an optional textual diagnostic as its content:

<ul class=3D"text">

<li>
the "number" attribute indicates the channel number;
</li>

<li>
the "code" attribute is a three-digit reply code meaningful to programs
(c.f., <a href=3D"#reply-codes">Reply Codes</a>);
</li>

<li>
the "xml:lang" attribute identifies the language that the element's
content is written in
(the value is suggested,
but not mandated,
by the "localize" attribute of the "greeting" element sent by the
remote BEEP peer); and,
</li>

<li>
the textual diagnostic (which may be multiline) is
meaningful to implementers,
perhaps administrators,
and possibly even users,
but never programs.
</li>

</ul>

Note that if the textual diagnostic is present,
then the "xml:lang" attribute is absent only if the language
indicated as the remote BEEP peer's first choice is used.
</p>

<p>
If the value of the "number" attribute is zero,
then the BEEP peer wants to release the BEEP session
(c.f., <a href=3D"#session.estab">Session Establishment and Release</a>) =
&#151; otherwise the value of
the "number" attribute refers to an existing channel,
and the remainder of this section applies.
</p>

<p>
A BEEP peer may send a "close" message for a channel whenever
all "MSG" messages it has sent on that channel have been acknowledged.
(Acknowledgement consists of the first frame of a reply being received
by the BEEP peer that sent the MSG "message".)
</p>

<p>
After sending the "close" message,
that BEEP peer must not send any more "MSG" messages on that channel
being closed until the reply to the "close" message has been received
(either by an "error" message rejecting the request to close the =
channel,
or by an "ok" message subsequently followed by the channel being
successfully started).
</p>

<p>
NOTE WELL: until a positive reply to the request to close the
channel is received,
the BEEP peer must be prepared to process any "MSG" messages that it
receives on that channel.
</p>

<p>
 When a BEEP peer receives a "close" message for a channel,
it may,
at any time,
reject the request to close the channel by sending an "error" message in =
a
negative reply.
</p>

<p>
Otherwise,
before accepting the request to close the channel,
and sending an "ok" message in a positive reply,
it must:

<ul class=3D"text">

<li>
finish sending any queued "MSG" messages on that channel of its own;
</li>

<li>
await complete replies to any outstanding "MSG" messages it has
sent on that channel; and,
</li>

<li>
finish sending complete replies to any outstanding "MSG"
messages it has received on that channel, and ensure that the final
frames of those replies have been successfully delivered, i.e.,

<ul class=3D"text">

<li>
for transport mappings that guarantee inter-channel ordering of
messages,
the replies must be sent prior to sending the "ok" message in a
positive reply; otherwise,
</li>

<li>
the replies must be sent and subsequently acknowledged by the
underlying transport service prior to sending the "ok" message in a
positive reply.
</li>

</ul>

</li>

</ul>

</p>

<p>

</p>

<p>
Briefly,
a successful channel close might look like this:
</p>
</font><pre>
    C: MSG 0 2 . 247 71
    C: Content-Type: application/beep+xml
    C:
    C: &lt;close number=3D'1' code=3D'200' />
    C: END
    S: RPY 0 2 . 447 46
    S: Content-Type: application/beep+xml
    S:
    S: &lt;ok />
    S: END
</pre><font face=3D"verdana, helvetica, arial, sans-serif" size=3D"2">

<p>
Similarly,
an unsuccessful channel close might look like this:
</p>
</font><pre>
    C: MSG 0 2 . 247 71
    C: Content-Type: application/beep+xml
    C:
    C: &lt;close number=3D'1' code=3D'200' />
    C: END
    S: ERR 0 2 . 447 79
    S: Content-Type: application/beep+xml
    S:
    S: &lt;error code=3D'550'>still working&lt;/error>
    S: END
</pre><font face=3D"verdana, helvetica, arial, sans-serif" size=3D"2">

<p>

</p>

<h4><a name=3D"ok.message">2.3.1.4</a>&nbsp;The OK Message</h4>

<p>
When a BEEP peer agrees to close a channel
(or release the BEEP session),
it sends an "ok" element in a positive reply.
</p>

<p>
The "ok" element has no attributes and no content.
</p>

<h4><a name=3D"error.message">2.3.1.5</a>&nbsp;The Error Message</h4>

<p>
When a BEEP peer declines the creation of a channel,
it sends an "error" element in a negative reply,
e.g.,
</p>
</font><pre>
    I: MSG 0 1 . 52 127
    I: Content-Type: application/beep+xml
    I:=20
    I: &lt;start number=3D'2'>
    I:    &lt;profile uri=3D'http://xml.resource.org/profiles/FOO' />
    I: &lt;/start>
    I: END
    L: ERR 0 1 . 264 105
    L: Content-Type: application/beep+xml
    L:
    L: &lt;error code=3D'550'>all requested profiles are
    L: unsupported&lt;/error>
    L: END
</pre><font face=3D"verdana, helvetica, arial, sans-serif" size=3D"2">

<p>
The "error" element has a "code" attribute,
an optional "xml:lang" attribute,
and an optional textual diagnostic as its content:

<ul class=3D"text">

<li>
the "code" attribute is a three-digit reply code meaningful to programs
(c.f., <a href=3D"#reply-codes">Reply Codes</a>);
</li>

<li>
the "xml:lang" attribute identifies the language that the element's
content is written in
(the value is suggested,
but not mandated,
by the "localize" attribute of the "greeting" element sent by the
remote BEEP peer); and,
</li>

<li>
the textual diagnostic (which may be multiline) is
meaningful to implementers,
perhaps administrators,
and possibly even users,
but never programs.
</li>

</ul>

Note that if the textual diagnostic is present,
then the "xml:lang" attribute is absent only if the language
indicated as the remote BEEP peer's first choice is used.
</p>

<p>

</p>

<p>
In addition,
a BEEP peer sends an "error" element whenever:

<ul class=3D"text">

<li>
it receives a "MSG" message containing a poorly-formed or
unexpected element;
</li>

<li>
it receives a "MSG" message asking to close a channel=20
(or release the BEEP session)
and it declines to do so; or
</li>

<li>
a BEEP session is established,
the BEEP peer is acting in the listening role,
and that BEEP peer is unavailable
(in this case,
the BEEP acting in the listening role does not send a "greeting" =
element).
</li>

</ul>


In the final case,
both BEEP peers terminate the session,
and it is recommended that a diagnostic entry be logged by both BEEP
peers.
</p>

<p>

</p>

<h4><a name=3D"session.estab">2.4</a>&nbsp;Session Establishment and =
Release</h4>

<p>
When a BEEP session is established,
each BEEP peer signifies its availability by immediately sending a
positive reply with a message number of zero on channel zero that =
contains a
"greeting" element, e.g.,
</p>
</font><pre>
    L: &lt;wait for incoming connection>
    I: &lt;open connection>
    L: RPY 0 0 . 0 122
    L: Content-Type: application/beep+xml
    L:
    L: &lt;greeting>
    L:    &lt;profile uri=3D'http://xml.resource.org/profiles/TLS' />
    L: &lt;/greeting>
    L: END
    I: RPY 0 0 . 0 52
    I: Content-Type: application/beep+xml
    I:
    I: &lt;greeting />
    I: END
</pre><font face=3D"verdana, helvetica, arial, sans-serif" size=3D"2">

<p>
Alternatively,
if the BEEP peer acting in the listening role is unavailable,
it sends a negative reply,
e.g.,
</p>
</font><pre>
    L: &lt;wait for incoming connection>
    I: &lt;open connection>
    L: ERR 0 0 . 0 60
    L: Content-Type: application/beep+xml
    L:
    L: &lt;error code=3D'421' />
    L: END
    I: RPY 0 0 . 0 52
    I: Content-Type: application/beep+xml
    I:
    I: &lt;greeting />
    I: END
    I: &lt;close connection>
    L: &lt;close connection>
    L: &lt;wait for next connection>
</pre><font face=3D"verdana, helvetica, arial, sans-serif" size=3D"2">

<p>
and the "greeting" element sent by the BEEP peer acting in
the initiating role is ignored.
It is recommended that a diagnostic entry be logged by both BEEP
peers.
</p>

<p>
Note that both of these examples imply that the BEEP peer in the
initiating role waits until the BEEP peer in the listening role sends =
its
greeting &#151; this is an artifact of the presentation;
in fact,
both BEEP peers send their replies independently.
</p>

<p>
When a BEEP peer wants to release the BEEP session,
it sends a "close" element with a zero-valued "number" attribute on
channel zero.
The other BEEP peer indicates its willingness by sending an "ok"
element in a positive reply,
e.g.,
</p>
</font><pre>
    C: MSG 0 1 . 52 60
    C: Content-Type: application/beep+xml
    C:
    C: &lt;close code=3D'200' />
    C: END
    S: RPY 0 1 . 264 46
    S: Content-Type: application/beep+xml
    S:
    S: &lt;ok />
    S: END
    I: &lt;close connection>
    L: &lt;close connection>
    L: &lt;wait for next connection>
</pre><font face=3D"verdana, helvetica, arial, sans-serif" size=3D"2">

<p>
Alternatively,
if the other BEEP doesn't want to release the BEEP session,
the exchange might look like this:
</p>
</font><pre>
    C: MSG 0 1 . 52 60
    C: Content-Type: application/beep+xml
    C:
    C: &lt;close code=3D'200' />
    C: END
    S: ERR 0 1 . 264 79
    S: Content-Type: application/beep+xml
    S:
    S: &lt;error code=3D'550'>still working&lt;/error>
    S: END
</pre><font face=3D"verdana, helvetica, arial, sans-serif" size=3D"2">

<p>
If session release is declined,
the BEEP session should not be terminated,
if possible.
</p>

<p>

</p>

<h4><a name=3D"transport.mapping">2.5</a>&nbsp;Transport Mappings</h4>

<p>
All transport interactions occur in the context of a session &#151;
a mapping onto a particular transport service.
Accordingly,
this memo defines the requirements that must be satisified by any
document describing how a particular transport service realizes a BEEP
session.
</p>

<h4><a name=3D"anchor5">2.5.1</a>&nbsp;Session Management</h4>

<p>
A BEEP session is connection-oriented.
A mapping document must define:

<ul class=3D"text">

<li>
how a BEEP session is established;
</li>

<li>
how a BEEP peer is identified as acting in the listening role;
</li>

<li>
how a BEEP peer is identified as acting in the initiating role;
</li>

<li>
how a BEEP session is released; and,
</li>

<li>
how a BEEP session is terminated.
</li>

</ul>

</p>

<h4><a name=3D"anchor6">2.5.2</a>&nbsp;Message Exchange</h4>

<p>
A BEEP session is message-oriented.
A mapping document must define:

<ul class=3D"text">

<li>
how messages are reliably sent and received;
</li>

<li>
how messages on the same channel are received in the same order as
they were sent; and,
</li>

<li>
how messages on different channels are sent without ordering constraint.
</li>

</ul>

</p>

<p>

</p>

<h4><a name=3D"anchor7">2.6</a>&nbsp;Asynchrony</h4>

<p>
BEEP accomodates asynchronous interactions,
both within a single channel and between separate channels.
This feature allows pipelining (intra-channel) and parallelism
(inter-channel).
</p>

<h4><a name=3D"anchor8">2.6.1</a>&nbsp;Within a Single Channel</h4>

<p>
A BEEP peer acting in the client role may send multiple "MSG" messages
on the same channel without waiting to receive the corresponding
replies.
This provides pipelining within a single channel.
</p>

<p>
A BEEP peer acting in the server role must process all "MSG"
messages for a given channel in the same order as they are received.
As a consequence,
the BEEP peer must generate replies
in the same order as the corresponding "MSG" messages are received on
a given channel.
</p>

<p>
Note that in one-to-many exchanges
(c.f., <a href=3D"#exchange.styles">Exchange Styles</a>),
the reply to the "MSG" message consists of zero or more "ANS"
messages followed by a "NUL" message.
In this style of exchange,
the "ANS" messages comprising the reply may be interleaved.
When the BEEP peer acting in the server role signifies the end of the
reply by generating the "NUL" message,
it may then process the next "MSG" message received for that channel.
</p>

<h4><a name=3D"anchor9">2.6.2</a>&nbsp;Between Different Channels</h4>

<p>
A BEEP peer acting in the client role may send multiple "MSG" messages
on different channels without waiting to receive the corresponding
replies.
The channels operate independently, in parallel.
</p>

<p>
A BEEP peer acting in the server role may process "MSG" messages
received on different channels in any order it chooses.
As a consequence,
although the replies for a given channel appear to be generated in the
same order in which the corresponding "MSG" messages are received,
there is no ordering constraint for replies on different channels.
</p>

<p>

</p>

<h4><a name=3D"anchor10">2.6.3</a>&nbsp;Pre-emptive Replies</h4>

<p>
A BEEP peer acting in the server role may send a negative reply
before it receives the final "MSG" frame of a message.
If it does so,
that BEEP peer is obliged to ignore any subsequent "MSG" frames for
that message,
up to and including the final "MSG" frame.
</p>

<p>
If a BEEP peer acting in the client role receives a negative reply
before it sends the final "MSG" frame for a message,
then it is required to send a "MSG" frame with a continuation status
of complete (".") and having a zero-length payload.
</p>

<h4><a name=3D"anchor11">2.6.4</a>&nbsp;Interference</h4>

<p>
If the processing of a particular message has sequencing impacts on
other messages (either intra-channel or inter-channel),
then the corresponding profile should define this behavior, e.g.,
a profile whose messages alter the underlying transport mapping.
</p>

<p>

</p>

<h4><a name=3D"anchor12">2.7</a>&nbsp;Peer-to-Peer Behavior</h4>

<p>
BEEP is peer-to-peer &#151; as such both peers must be
prepared to receive all messages defined in this memo.
Accordingly,
an initiating BEEP peer capable of acting only in the client role must
behave gracefully if it receives a "MSG" message.
Accordingly,
all profiles must provide an appropriate error message for replying
to unexpected "MSG" messages.
</p>

<p>
As a consequence of the peer-to-peer nature of BEEP,
message numbers are unidirectionally-significant.
That is,
the message numbers in "MSG" messages sent by a BEEP peer acting in the
initiating role are unrelated to the message numbers in "MSG" messages
sent by a BEEP peer acting in the listening role.
</p>

<p>
For example, these two messages
</p>
</font><pre>
    I: MSG 0 1 . 52 132
    I: Content-Type: application/beep+xml
    I:=20
    I: &lt;start number=3D'1'>
    I:    &lt;profile uri=3D'http://xml.resource.org/profiles/sasl/OTP' =
/>=20
    I: &lt;/start>
    I: END
    L: MSG 0 1 . 264 128
    L: Content-Type: application/beep+xml
    L:=20
    L: &lt;start number=3D'2'>
    L:    &lt;profile uri=3D'http://xml.resource.org/profiles/IMXP' />
    L: &lt;/start>
    L: END
</pre><font face=3D"verdana, helvetica, arial, sans-serif" size=3D"2">

<p>
refer to different messages sent on channel zero.
</p>

<a name=3D"anchor13"><br><hr size=3D"1" shade=3D"0"></a>
<table border=3D"0" cellpadding=3D"0" cellspacing=3D"2" width=3D"30" =
height=3D"15" align=3D"right"><tr><td bgcolor=3D"#990000" =
align=3D"center" width=3D"30" height=3D"15"><a href=3D"#toc" =
CLASS=3D"link2"><font face=3D"monaco, MS Sans Serif" color=3D"#ffffff" =
size=3D"1"><b>&nbsp;TOC&nbsp;</b></font></a><br></td></tr></table>
<h3>3.&nbsp;Transport Security</h3>

<p>
When a BEEP session is established,
plaintext transfer,
without privacy,
is provided.
Accordingly,
transport security in BEEP is achieved using an initial tuning profile.
</p>

<p>
This document defines one profile:

<ul class=3D"text">

<li>
the TLS transport security profile,
based on <a href=3D"#RFC2246">TLS version one</a>[3].
</li>

</ul>

Other profiles may be defined and deployed on a bilateral basis.
Note that because of their intimate relationship with the transport =
service,
a given transport security profile tends to be relevant to a single
transport mapping (c.f., <a href=3D"#transport.mapping">Transport =
Mappings</a>).
</p>

<p>
When a channel associated with transport security begins the
underlying negotiation process,
all channels (including channel zero) are closed on the BEEP session.
Accordingly,
upon completion of the negotiation process,
regardless of its outcome,
a new greeting is issued by both BEEP peers.
(If the negotiation process fails,
then either BEEP peer may instead terminate the session,
and it is recommended that a diagnostic entry be logged.)
</p>

<p>
A BEEP peer may choose to issue different greetings
based on whether privacy is in use, e.g.,
</p>
</font><pre>
    L: &lt;wait for incoming connection>
    I: &lt;open connection>
    L: RPY 0 0 . 0 122
    L: Content-Type: application/beep+xml
    L:
    L: &lt;greeting>
    L:    &lt;profile uri=3D'http://xml.resource.org/profiles/TLS' />
    L: &lt;/greeting>
    L: END
    I: RPY 0 0 . 0 52
    I: Content-Type: application/beep+xml
    I:
    I: &lt;greeting />
    I: END
    I: MSG 0 1 . 52 170
    I: Content-Type: application/beep+xml
    I:=20
    I: &lt;start number=3D'1'>
    I:    &lt;profile uri=3D'http://xml.resource.org/profiles/TLS'>
    I:        &lt;![CDATA[&lt;ready />]]&gt;
    I:    &lt;/profile>
    I: &lt;/start>
    I: END
    L: RPY 0 1 . 122 133
    L: Content-Type: application/beep+xml
    L:
    L: &lt;profile uri=3D'http://xml.resource.org/profiles/TLS'>
    L:     &lt;![CDATA[&lt;proceed />]]&gt;
    L: &lt;/profile>
    L: END

        ... successful transport security negotiation ...

    L: RPY 0 0 . 0 264
    L: Content-Type: application/beep+xml
    L:
    L: &lt;greeting>
    L:    &lt;profile
    L:       uri=3D'http://xml.resource.org/profiles/sasl/ANONYMOUS' />
    L:    &lt;profile uri=3D'http://xml.resource.org/profiles/sasl/OTP' =
/>
    L:    &lt;profile uri=3D'http://xml.resource.org/profiles/IMXP' />
    L: &lt;/greeting>
    L: END
    I: RPY 0 0 . 0 52
    I: Content-Type: application/beep+xml
    I:
    I: &lt;greeting />
    I: END
</pre><font face=3D"verdana, helvetica, arial, sans-serif" size=3D"2">

<p>
Of course,
not all BEEP peers need be as single-minded:
</p>
</font><pre>
    L: &lt;wait for incoming connection>
    I: &lt;open connection>
    L: RPY 0 0 . 0 323
    L: Content-Type: application/beep+xml
    L:
    L: &lt;greeting>
    L:    &lt;profile
    L:       uri=3D'http://xml.resource.org/profiles/sasl/ANONYMOUS' />
    L:    &lt;profile uri=3D'http://xml.resource.org/profiles/sasl/OTP' =
/>
    L:    &lt;profile uri=3D'http://xml.resource.org/profiles/IMXP' />
    L:    &lt;profile uri=3D'http://xml.resource.org/profiles/TLS' />
    L: &lt;/greeting>
    L: END
    I: RPY 0 0 . 0 52
    I: Content-Type: application/beep+xml
    I:
    I: &lt;greeting />
    I: END
    I: MSG 0 1 . 52 170
    I: Content-Type: application/beep+xml
    I:=20
    I: &lt;start number=3D'1'>
    I:    &lt;profile uri=3D'http://xml.resource.org/profiles/TLS'>
    I:        &lt;![CDATA[&lt;ready />]]&gt;
    I:    &lt;/profile>
    I: &lt;/start>
    I: END
    L: RPY 0 1 . 323 133
    L: Content-Type: application/beep+xml
    L:
    L: &lt;profile uri=3D'http://xml.resource.org/profiles/TLS'>
    L:     &lt;![CDATA[&lt;proceed />]]&gt;
    L: &lt;/profile>
    L: END

        ... failed transport security negotiation ...

    L: RPY 0 0 . 0 323
    L: Content-Type: application/beep+xml
    L:
    L: &lt;greeting>
    L:    &lt;profile
    L:       uri=3D'http://xml.resource.org/profiles/sasl/ANONYMOUS' />
    L:    &lt;profile uri=3D'http://xml.resource.org/profiles/sasl/OTP' =
/>
    L:    &lt;profile uri=3D'http://xml.resource.org/profiles/IMXP' />
    L:    &lt;profile uri=3D'http://xml.resource.org/profiles/TLS' />
    L: &lt;/greeting>
    L: END
    I: RPY 0 0 . 0 52
    I: Content-Type: application/beep+xml
    I:
    I: &lt;greeting />
    I: END
</pre><font face=3D"verdana, helvetica, arial, sans-serif" size=3D"2">

<p>

</p>

<h4><a name=3D"tls.profile">3.1</a>&nbsp;The TLS Transport Security =
Profile</h4>

<p>
<a href=3D"#tls.definition">Registration: TLS Transport Security =
Profile</a> contains the registration for this
profile.
</p>

<h4><a name=3D"anchor14">3.1.1</a>&nbsp;Profile Identification and =
Initialization</h4>

<p>
The TLS transport security profile is identified as:
</p>
</font><pre>
    http://xml.resource.org/profiles/TLS
</pre><font face=3D"verdana, helvetica, arial, sans-serif" size=3D"2">

<p>
in the BEEP "profile" element during channel creation.
</p>

<p>
During channel creation,
the corresponding "profile" element in the BEEP "start" element may
contain a "ready" element.
If channel creation is successful,
then before sending the corresponding reply,
the BEEP peer processes the "ready" element and includes the resulting
response in the reply,
e.g.,
</p>
</font><pre>
    C: MSG 0 1 . 52 170
    C: Content-Type: application/beep+xml
    C:
    C: &lt;start number=3D'1'>
    C:    &lt;profile uri=3D'http://xml.resource.org/profiles/TLS'>
    C:        &lt;![CDATA[&lt;ready />]]&gt;
    C:    &lt;/profile>
    C: &lt;/start>
    C: END
    S: RPY 0 1 . 122 133
    S: Content-Type: application/beep+xml
    S:
    S: &lt;profile uri=3D'http://xml.resource.org/profiles/TLS'>
    S:     &lt;![CDATA[&lt;proceed />]]&gt;
    S: &lt;/profile>
    S: END
</pre><font face=3D"verdana, helvetica, arial, sans-serif" size=3D"2">

<p>
Note that it is possible for the channel to be created,
but for the encapsulated operation to fail, e.g.,
</p>
</font><pre>
    C: MSG 0 1 . 52 185
    C: Content-Type: application/beep+xml
    C:
    C: &lt;start number=3D'1'>
    C:    &lt;profile uri=3D'http://xml.resource.org/profiles/TLS'>
    C:        &lt;![CDATA[&lt;ready version=3D"oops" />]]&gt;
    C:    &lt;/profile>
    C: &lt;/start>
    C: END
    S: RPY 0 1 . 122 205
    S: Content-Type: application/beep+xml
    S:
    S: &lt;profile uri=3D'http://xml.resource.org/profiles/TLS'>
    S:     &lt;![CDATA[&lt;error code=3D'501'>version attribute
    S: poorly formed in &amp;lt;ready&amp;gt; element&lt;/error>]]&gt;
    S: &lt;/profile>
    S: END
</pre><font face=3D"verdana, helvetica, arial, sans-serif" size=3D"2">

<p>
In this case,
a positive reply is sent (as channel creation succeeded),
but the encapsulated response contains an indication as to why the
operation failed.
</p>

<h4><a name=3D"anchor15">3.1.2</a>&nbsp;Message Syntax</h4>

<p>
<a href=3D"#tls.dtd">TLS Transport Security Profile DTD</a> defines the =
messages that are used in the
TLS transport security profile.
</p>

<p>

</p>

<h4><a name=3D"tls.messages">3.1.3</a>&nbsp;Message Semantics</h4>

<h4><a name=3D"anchor16">3.1.3.1</a>&nbsp;The Ready Message</h4>

<p>
The "ready" element has an optional "version" attribute and no content:

<ul class=3D"text">

<li>
the "version" element defines the earliest version of TLS
acceptable for use.
</li>

</ul>

</p>

<p>
When a BEEP peer sends the "ready" element,
it must not send any further traffic on the underlying transport service
until a corresponding reply ("proceed" or "error") is received;
similarly,
the receiving BEEP peer must wait until any pending replies have been
generated and sent before it processes a "ready" element.
</p>

<h4><a name=3D"anchor17">3.1.3.2</a>&nbsp;The Proceed Message</h4>

<p>
The "proceed" element has no attributes and no content.
It is sent as a reply to the "ready" element.
</p>

<p>
When a BEEP peer receives the "ready" element,
it must not send any further traffic on the underlying transport
service until it generates a corresponding reply.
If the BEEP peer decides to allow transport security negotation,
it implicitly closes all channels (including channel zero),
and sends the "proceed" element,
and awaits the underlying negotiation process for transport security.
</p>

<p>
When a BEEP peer receives a "proceed" element in reply to its
"ready" message,
it implicitly closes all channels (including channel zero),
and immediately begins the underlying negotiation process for
transport security.
</p>

<a name=3D"anchor18"><br><hr size=3D"1" shade=3D"0"></a>
<table border=3D"0" cellpadding=3D"0" cellspacing=3D"2" width=3D"30" =
height=3D"15" align=3D"right"><tr><td bgcolor=3D"#990000" =
align=3D"center" width=3D"30" height=3D"15"><a href=3D"#toc" =
CLASS=3D"link2"><font face=3D"monaco, MS Sans Serif" color=3D"#ffffff" =
size=3D"1"><b>&nbsp;TOC&nbsp;</b></font></a><br></td></tr></table>
<h3>4.&nbsp;User Authentication</h3>

<p>
When a BEEP session is established,
anonymous access,
without trace information,
is provided.
Accordingly,
user authentication in BEEP is achieved using an initial tuning profile.
</p>

<p>
This document defines a family of profiles based on SASL mechanisms:

<ul class=3D"text">

<li>
each mechanism in the
<a =
href=3D"http://www.isi.edu/in-notes/iana/assignments/sasl-mechanisms">IAN=
A SASL registry</a>
has an associated profile.
</li>

</ul>

Other profiles may be defined and deployed on a bilateral basis.
</p>

<p>
Whenever a successful authentication occurs,
on any channel,
the authenticated identity is updated for all existing and future
channels on the BEEP session;
further,
no additional attempts at authentication are allowed.
</p>

<p>
Note that regardless of transport security and user authentication,
authorization is an internal matter for each BEEP peer.
As such,
each peer may choose to restrict the operations it allows based on the
authentication credentials provided
(i.e., unauthorized operations might be rejected with error code 530).
</p>

<p>

</p>

<h4><a name=3D"sasl.profiles">4.1</a>&nbsp;The SASL Family of =
Profiles</h4>

<p>
<a href=3D"#sasl.definition">Registration: SASL Family of Profiles</a> =
contains the registration for this
profile.
</p>

<p>
Note that SASL may provide both user authentication and transport =
security.
Once transport security is successfully negotiated for a BEEP session,
then a SASL security layer must not be negotiated;
similarly,
once any SASL negotiation is successful,
a transport security profile must not begin its underlying negotiation
process.
</p>

<p>
Section 4 of the SASL <a href=3D"#RFC2222">specification</a>[4]
requires the following information be supplied by a protocol
definition:

<blockquote class=3D"text"><dl>

<dt>service name:</dt>
<dd>
"beep"
</dd>

<dt>initiation sequence:</dt>
<dd>
Creating a channel using a BEEP profile
corresponding to a SASL mechanism starts the exchange.
An optional parameter corresponding to the "initial response" sent by
the client is carried within a "blob" element during channel
creation.
</dd>

<dt>exchange sequence:</dt>
<dd>
"Challenges" and "responses" are
carried in exchanges of the "blob" element.
The "status" attribute of the "blob" element is used both by a server
indicating a successful completion of the exchange,=20
and a client aborting the exchange,
The server indicates failure of the exchange by sending an "error" =
element.
</dd>

<dt>security layer negotiation:</dt>
<dd>
When a security layer starts
negotiation,
all channels (including channel zero) are closed on the BEEP session.
Accordingly,
upon completion of the negotiation process,
regardless of its outcome,
a new greeting is issued by both BEEP peers.
<br>

If a security layer is successfully negotiated,
it takes effect immediately following the message that concludes the
server's successful completion reply.
</dd>

<dt>use of the authorization identity:</dt>
<dd>
This is made
available to all channels for the duration of the BEEP session.
</dd>

</dl></blockquote>

</p>

<p>

</p>

<h4><a name=3D"anchor19">4.1.1</a>&nbsp;Profile Identification and =
Initialization</h4>

<p>
Each SASL mechanism registered with the IANA is identified as:
</p>
</font><pre>
    http://xml.resource.org/profiles/sasl/MECHANISM
</pre><font face=3D"verdana, helvetica, arial, sans-serif" size=3D"2">

<p>
where "MECHANISM" is the token assigned to that mechanism
by the IANA.
</p>

<p>
Note that during channel creation,
a BEEP peer may provide multiple profiles to the remote peer, e.g.,
</p>
</font><pre>
    C: MSG 0 1 . 52 209
    C: Content-Type: application/beep+xml
    C:
    C: &lt;start number=3D'1'>
    C:    &lt;profile
    C:       uri=3D'http://xml.resource.org/profiles/sasl/ANONYMOUS' />
    C:    &lt;profile uri=3D'http://xml.resource.org/profiles/sasl/OTP' =
/>
    C: &lt;/start>
    C: END
    S: RPY 0 1 . 264 99
    S: Content-Type: application/beep+xml
    S:
    S: &lt;profile uri=3D'http://xml.resource.org/profiles/sasl/OTP' />
    S: END
</pre><font face=3D"verdana, helvetica, arial, sans-serif" size=3D"2">

<p>
During channel creation,
the corresponding "profile" element in the BEEP "start" element may
contain a "blob" element.
Note that it is possible for the channel to be created,
but for the encapsulated operation to fail, e.g.,
</p>
</font><pre>
    C: MSG 0 1 . 52 195
    C: Content-Type: application/beep+xml
    C:
    C: &lt;start number=3D'1'>
    C:    &lt;profile uri=3D'http://xml.resource.org/profiles/sasl/OTP'>
    C:        &lt;![CDATA[&lt;blob>AGJsb2NrbWFzdGVy&lt;/blob>]]&gt;
    C:    &lt;/profile>
    C: &lt;/start>
    C: END
    S: RPY 0 1 . 264 190
    S: Content-Type: application/beep+xml
    S:
    S: &lt;profile uri=3D'http://xml.resource.org/profiles/sasl/OTP'>
    S:     &lt;![CDATA[&lt;error code=3D'534'>authentication mechanism =
is
    S: too weak&lt;/error>]]&gt;
    S: &lt;/profile>
    S: END
</pre><font face=3D"verdana, helvetica, arial, sans-serif" size=3D"2">

<p>
In this case,
a positive reply is sent (as channel creation succeeded),
but the encapsulated response contains an indication as to why the
operation failed.
</p>

<p>
Otherwise,
the server sends a challenge (or signifies success), e.g.,
</p>
</font><pre>
    C: MSG 0 1 . 52 195
    C: Content-Type: application/beep+xml
    C:
    C: &lt;start number=3D'1'>
    C:    &lt;profile uri=3D'http://xml.resource.org/profiles/sasl/OTP'>
    C:        &lt;![CDATA[&lt;blob>AGJsb2NrbWFzdGVy&lt;/blob>]]&gt;
    C:    &lt;/profile>
    C: &lt;/start>
    C: END
    S: RPY 0 1 . 264 183
    S: Content-Type: application/beep+xml
    S:
    S: &lt;profile uri=3D'http://xml.resource.org/profiles/sasl/OTP'>
    S:    =
&lt;![CDATA[&lt;blob>b3RwLXNoYTEgOTk5NyBwaXh5bWlzYXM4NTgwNSBleHQ=3D
                                                           =
&lt;/blob>]]&gt;
    S: &lt;/profile>
    S: END
</pre><font face=3D"verdana, helvetica, arial, sans-serif" size=3D"2">

<p>
Note that this example implies that the "blob" element in
the server's reply appears on two lines &#151; this is an artifact of
the presentation;
in fact,
only one line is used.
</p>

<p>
If a challenge is received,
then the client responds and awaits another reply,
e.g.,
</p>
</font><pre>
    C: MSG 1 0 . 0 97
    C: Content-Type: application/beep+xml
    C:
    C: &lt;blob>d29yZDpmZXJuIGhhbmcgYnJvdyBib25nIGhlcmQgdG9n&lt;/blob>
    C: END
    S: RPY 1 0 . 0 66
    S: Content-Type: application/beep+xml
    S:
    S: &lt;blob status=3D'complete' />
    S: END
</pre><font face=3D"verdana, helvetica, arial, sans-serif" size=3D"2">

<p>
Of course,
the client could abort the authentication process by sending
"&lt;blob status=3D'abort' />" instead.
</p>

<p>
Alternatively,
the server might reject the response with an error:
e.g.,
</p>
</font><pre>
    C: MSG 1 0 . 0 97
    C: Content-Type: application/beep+xml
    C:
    C: &lt;blob>d29yZDpmZXJuIGhhbmcgYnJvdyBib25nIGhlcmQgdG9n&lt;/blob>
    C: END
    S: ERR 1 1 . 0 60
    S: Content-Type: application/beep+xml
    S:
    S: &lt;error code=3D'535' />
    S: END
</pre><font face=3D"verdana, helvetica, arial, sans-serif" size=3D"2">

<p>
Finally,
depending on the SASL mechanism,
an initialization element may be exchanged unidirectionally during
channel creation, e.g.,
</p>
</font><pre>
    C: MSG 0 1 . 52 145
    C: Content-Type: application/beep+xml
    C:
    C: &lt;start number=3D'1'>
    C:    &lt;profile
    C:        uri=3D'http://xml.resource.org/profiles/sasl/CRAM-MD5' />
    C: &lt;/start>
    C: END
    S: RPY 0 1 . 264 197
    S: Content-Type: application/beep+xml
    S:
    S: &lt;profile =
uri=3D'http://xml.resource.org/profiles/sasl/CRAM-MD5'>
    S: =
&lt;![CDATA[&lt;blob>PDE4OTYuNjk3MTcwOTUyQHBvc3RvZmZpY2UucmVzdG9uLm1
                                                  =
jaS5uZXQ+&lt;/blob>]]&gt;
    S: &lt;/profile>
    S: END
</pre><font face=3D"verdana, helvetica, arial, sans-serif" size=3D"2">

<p>
Note that this example implies that the "blob" element in
the server's reply appears on two lines &#151; this is an artifact of
the presentation;
in fact,
only one line is used.
</p>

<h4><a name=3D"anchor20">4.1.2</a>&nbsp;Message Syntax</h4>

<p>
<a href=3D"#sasl.dtd">SASL Family of Profiles DTD</a> defines the =
messages that are used for
each profile in the SASL family.
</p>

<p>
Note that because many SASL mechanisms exchange binary data,
the content of the "blob" element is always a base64-encoded string.
</p>

<p>

</p>

<h4><a name=3D"sasl.messages">4.1.3</a>&nbsp;Message Semantics</h4>

<p>
The "blob" element has an optional "status" attribute,
and arbitrary octets as its content:

<ul class=3D"text">

<li>
the "status" attribute, if present, takes one of three values:

<blockquote class=3D"text"><dl>

<dt>abort:</dt>
<dd>
used by a client to indicate that it is aborting
the authentication process;
</dd>

<dt>complete:</dt>
<dd>
used by a server to indicate that the exchange is
complete and successful; or,
</dd>

<dt>continue:</dt>
<dd>
used by either a client or server, otherwise.
</dd>

</dl></blockquote>

</li>

</ul>

</p>

<p>
Finally,
note that SASL's EXTERNAL mechanism works with an "external
authentication" service,
which is provided by one of:

<ul class=3D"text">

<li>
a transport security profile,
capable of providing authentication information
(e.g., <a href=3D"#tls.profile">The TLS Transport Security Profile</a>),
being active on the connection;
</li>

<li>
a network service,
capable of providing strong authentication
(e.g., <a href=3D"#RFC2401">IPSec</a>[12]),
underlying the connection;
or,
</li>

<li>
a locally-defined security service.
</li>

</ul>
For authentication to succeed,
two conditions must hold:

<ul class=3D"text">

<li>
an external authentication service must be active; and,
</li>

<li>
if present,
the authentication identity must be consistent with
the credentials provided by the external authentication service
(if the authentication identity is empty,
then an authorization identity is automatically derived from the
credentials provided by the external authentication service).
</li>

</ul>

</p>

<a name=3D"anchor21"><br><hr size=3D"1" shade=3D"0"></a>
<table border=3D"0" cellpadding=3D"0" cellspacing=3D"2" width=3D"30" =
height=3D"15" align=3D"right"><tr><td bgcolor=3D"#990000" =
align=3D"center" width=3D"30" height=3D"15"><a href=3D"#toc" =
CLASS=3D"link2"><font face=3D"monaco, MS Sans Serif" color=3D"#ffffff" =
size=3D"1"><b>&nbsp;TOC&nbsp;</b></font></a><br></td></tr></table>
<h3>5.&nbsp;Registration Templates</h3>

<h4><a name=3D"profile.registration">5.1</a>&nbsp;Profile Registration =
Template</h4>

<p>
When a profile is registered,
the following information is supplied:

<blockquote class=3D"text"><dl>

<dt>Profile Identification:</dt>
<dd>
specify a
<a href=3D"#RFC2396">URI</a>[10] that authoritatively identifies this
profile.
</dd>

<dt>Message Exchanged during Channel Creation:</dt>
<dd>
specify the
datatypes that may be exchanged during channel creation.
</dd>

<dt>Messages starting one-to-one exchanges:</dt>
<dd>
specify the
datatypes that may be present when an exchange starts.
</dd>

<dt>Messages in positive replies:</dt>
<dd>
specify the
datatypes that may be present in a positive reply.
</dd>

<dt>Messages in negative replies:</dt>
<dd>
specify the
datatypes that may be present in a negative reply.
</dd>

<dt>Messages in one-to-many exchanges:</dt>
<dd>
specify the
datatypes that may be present in a one-to-many exchange.
</dd>

<dt>Message Syntax:</dt>
<dd>
specify the syntax of the datatypes
exchanged by the profile.
</dd>

<dt>Message Semantics:</dt>
<dd>
specify the semantics of the
datatypes exchanged by the profile.
</dd>

<dt>Contact Information:</dt>
<dd>
specify the postal and electronic
contact information for the author of the profile.
</dd>

</dl></blockquote>

</p>

<h4><a name=3D"feature.registration">5.2</a>&nbsp;Feature Registration =
Template</h4>

<p>
When a feature for the channel management profile is registered,
the following information is supplied:

<blockquote class=3D"text"><dl>

<dt>Feature Identification:</dt>
<dd>
specify a string that
identifies this feature.
Unless the feature is registered with the IANA,
the feature's identification must start with "x-".
</dd>

<dt>Feature Semantics:</dt>
<dd>
specify the semantics of the feature.
</dd>

<dt>Contact Information:</dt>
<dd>
specify the postal and electronic
contact information for the author of the feature.
</dd>

</dl></blockquote>

</p>

<a name=3D"initial.definitions"><br><hr size=3D"1" shade=3D"0"></a>
<table border=3D"0" cellpadding=3D"0" cellspacing=3D"2" width=3D"30" =
height=3D"15" align=3D"right"><tr><td bgcolor=3D"#990000" =
align=3D"center" width=3D"30" height=3D"15"><a href=3D"#toc" =
CLASS=3D"link2"><font face=3D"monaco, MS Sans Serif" color=3D"#ffffff" =
size=3D"1"><b>&nbsp;TOC&nbsp;</b></font></a><br></td></tr></table>
<h3>6.&nbsp;Initial Registrations</h3>

<h4><a name=3D"channelZ.definition">6.1</a>&nbsp;Registration: BEEP =
Channel Management</h4>

<p>

<blockquote class=3D"text"><dl>

<dt>Profile Identification:</dt>
<dd>
not applicable
</dd>

<dt>Messages exchanged during Channel Creation:</dt>
<dd>
not applicable
</dd>

<dt>Messages starting one-to-one exchanges:</dt>
<dd>
"start" or "close"
</dd>

<dt>Messages in positive replies:</dt>
<dd>
"greeting",
"profile", or "ok"
</dd>

<dt>Messages in negative replies:</dt>
<dd>
"error"
</dd>

<dt>Messages in one-to-many exchanges:</dt>
<dd>
none
</dd>

<dt>Message Syntax:</dt>
<dd>
c.f., <a href=3D"#beep.dtd">BEEP Channel Management DTD</a>
</dd>

<dt>Message Semantics:</dt>
<dd>
c.f., <a href=3D"#beep.messages">Message Semantics</a>
</dd>

<dt>Contact Information:</dt>
<dd>
c.f., the "Author's Address"
section of this memo
</dd>

</dl></blockquote>

</p>

<h4><a name=3D"tls.definition">6.2</a>&nbsp;Registration: TLS Transport =
Security Profile</h4>

<p>

<blockquote class=3D"text"><dl>

<dt>Profile Identification:</dt>
<dd>
<a =
href=3D"http://xml.resource.org/profiles/TLS">http://xml.resource.org/pro=
files/TLS</a>
</dd>

<dt>Messages exchanged during Channel Creation:</dt>
<dd>
"ready"
</dd>

<dt>Messages starting one-to-one exchanges:</dt>
<dd>
"ready"
</dd>

<dt>Messages in positive replies:</dt>
<dd>
"proceed"
</dd>

<dt>Messages in negative replies:</dt>
<dd>
"error"
</dd>

<dt>Messages in one-to-many exchanges:</dt>
<dd>
none
</dd>

<dt>Message Syntax:</dt>
<dd>
c.f., <a href=3D"#tls.dtd">TLS Transport Security Profile DTD</a>
</dd>

<dt>Message Semantics:</dt>
<dd>
c.f., <a href=3D"#tls.messages">Message Semantics</a>
</dd>

<dt>Contact Information:</dt>
<dd>
c.f., the "Author's Address"
section of this memo
</dd>

</dl></blockquote>

</p>

<p>

</p>

<h4><a name=3D"sasl.definition">6.3</a>&nbsp;Registration: SASL Family =
of Profiles</h4>

<p>

<blockquote class=3D"text"><dl>

<dt>Profile Identification:</dt>
<dd>
<a =
href=3D"http://xml.resource.org/profiles/sasl/MECHANISM">http://xml.resou=
rce.org/profiles/sasl/MECHANISM</a>,
where "MECHANISM" is a token registered with the
<a href=3D"http://www.iana.org/">IANA</a>
</dd>

<dt>Messages exchanged during Channel Creation:</dt>
<dd>
"blob"
</dd>

<dt>Messages starting one-to-one exchanges:</dt>
<dd>
"blob"
</dd>

<dt>Messages in positive replies:</dt>
<dd>
"blob"
</dd>

<dt>Messages in negative replies:</dt>
<dd>
"error"
</dd>

<dt>Messages in one-to-many exchanges:</dt>
<dd>
none
</dd>

<dt>Message Syntax:</dt>
<dd>
c.f., <a href=3D"#sasl.dtd">SASL Family of Profiles DTD</a>
</dd>

<dt>Message Semantics:</dt>
<dd>
c.f., <a href=3D"#sasl.messages">Message Semantics</a>
</dd>

<dt>Contact Information:</dt>
<dd>
c.f., the "Author's Address"
section of this memo
</dd>

</dl></blockquote>

</p>

<p>

</p>

<h4><a name=3D"beep+xml.definition">6.4</a>&nbsp;Registration: =
application/beep+xml</h4>

<p>

<blockquote class=3D"text"><dl>

<dt>MIME media type name:</dt>
<dd>
application
</dd>

<dt>MIME subtype name:</dt>
<dd>
beep+xml
</dd>

<dt>Required parameters:</dt>
<dd>
none
</dd>

<dt>Optional parameters:</dt>
<dd>
charset
(defaults to <a href=3D"#RFC2279">"UTF-8"</a>[13])
</dd>

<dt>Encoding considerations:</dt>
<dd>
This media type may contain
binary content;
accordingly,
when used over a transport that does not permit binary transfer,
an appropriate encoding must be applied
</dd>

<dt>Security considerations:</dt>
<dd>
none, per se; however,
any BEEP profile which uses this media type must describe its relevant
security considerations
</dd>

<dt>Interoperability considerations:</dt>
<dd>
n/a
</dd>

<dt>Published specification:</dt>
<dd>

This media type is a proper subset of the
<a href=3D"#W3C.XML">the XML 1.0 specification</a>[2].
Two restrictions are made.
<br>

First,
no entity references other than the five predefined general entities
references
("&amp;amp;",
"&amp;lt;",
"&amp;gt;",
"&amp;apos;", and
"&amp;quot;")
and numeric entity references may be present.
<br>
<br>

Second,
neither the "XML" declaration (e.g., &lt;?xml version=3D"1.0" ?>)
nor the "DOCTYPE" declaration (e.g., &lt;!DOCTYPE ...>) may
be present.
(Accordingly,
if another character set other than UTF-8 is desired,
then the "charset" parameter must be present.)
<br>
<br>

All other XML 1.0 instructions
(e.g., CDATA blocks, processing instructions, and so on) are allowed.
</dd>

<dt>Applications which use this media type:</dt>
<dd>
any BEEP profile
wishing to make use of this XML 1.0 subset
</dd>

<dt>Additional Information:</dt>
<dd>
none
</dd>

<dt>Contact for further information:</dt>
<dd>
c.f.,
the "Author's Address" section of this memo
</dd>

<dt>Intended usage:</dt>
<dd>
limited use
</dd>

<dt>Author/Change controller:</dt>
<dd>
the IESG
</dd>

</dl></blockquote>

</p>

<a name=3D"anchor22"><br><hr size=3D"1" shade=3D"0"></a>
<table border=3D"0" cellpadding=3D"0" cellspacing=3D"2" width=3D"30" =
height=3D"15" align=3D"right"><tr><td bgcolor=3D"#990000" =
align=3D"center" width=3D"30" height=3D"15"><a href=3D"#toc" =
CLASS=3D"link2"><font face=3D"monaco, MS Sans Serif" color=3D"#ffffff" =
size=3D"1"><b>&nbsp;TOC&nbsp;</b></font></a><br></td></tr></table>
<h3>7.&nbsp;DTDs</h3>

<h4><a name=3D"beep.dtd">7.1</a>&nbsp;BEEP Channel Management DTD</h4>
</font><pre>
&lt;!--
  DTD for BEEP Channel Management, as of 2000-10-29


  Refer to this DTD as:

    &lt;!ENTITY % BEEP PUBLIC "-//Blocks//DTD BEEP//EN"
               "http://xml.resource.org/profiles/BEEP/beep.dtd">
    %BEEP;
  -->


&lt;!--
  DTD data types:

        entity        syntax/reference     example
        =3D=3D=3D=3D=3D=3D        =
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D     =
=3D=3D=3D=3D=3D=3D=3D
    a channel number
        CHAN          1..2147483647        1

    authoritative profile identification
        URI          c.f., [RFC-2396]      http://invisible.net/

    one or more feature tokens, seperated by space
        FTRS         NMTOKENS              "magic"

    a language tag
        LANG         c.f., [RFC-1766]      "en", "en-US", etc.

    zero or more language tags
        LOCS         NMTOKENS              "en-US"

    a 3-digit reply code
        XYZ           [1-5][0-9][0-9]      500
-->


&lt;!ENTITY % CHAN       "CDATA">
&lt;!ENTITY % URI        "CDATA">
&lt;!ENTITY % FTRS       "NMTOKENS">
&lt;!ENTITY % LANG       "NMTOKEN">
&lt;!ENTITY % LOCS       "NMTOKEN">
&lt;!ENTITY % XYZ        "CDATA">




&lt;!--
  BEEP messages, exchanged as application/beep+xml

     role       MSG         RSP         ERR
    =3D=3D=3D=3D=3D=3D=3D     =3D=3D=3D         =3D=3D=3D         =
=3D=3D=3D
    I and L                 greeting    error

    I or L      start       profile     error=20

    I or L      close       ok          error
  -->


&lt;!ELEMENT greeting    (profile)*>
&lt;!ATTLIST greeting
          features    %FTRS;            #IMPLIED
          localize    %LOCS;            "i-default">

&lt;!ELEMENT start       (profile)+>
&lt;!ATTLIST start
          number      %CHAN;             #REQUIRED
          serverName  CDATA              #IMPLIED>

&lt;!-- profile element is empty if contained in a greeting -->
&lt;!ELEMENT profile     (#PCDATA)>
&lt;!ATTLIST profile
          uri         %URI;              #REQUIRED
          encoding    (none|base64)      "none">

&lt;!ELEMENT close       (#PCDATA)>
&lt;!ATTLIST close
          number      %CHAN;             "0"
          code        %XYZ;              #REQUIRED
          xml:lang    %LANG;             #IMPLIED>

&lt;!ELEMENT ok          EMPTY>

&lt;!ELEMENT error       (#PCDATA)>
&lt;!ATTLIST error
          code        %XYZ;              #REQUIRED
          xml:lang    %LANG;             #IMPLIED>

</pre><font face=3D"verdana, helvetica, arial, sans-serif" size=3D"2">

<p>

</p>

<h4><a name=3D"tls.dtd">7.2</a>&nbsp;TLS Transport Security Profile =
DTD</h4>
</font><pre>
&lt;!--
  DTD for the TLS Transport Security Profile, as of 2000-09-04


  Refer to this DTD as:

    &lt;!ENTITY % TLS PUBLIC "-//Blocks//DTD TLS//EN"
               "http://xml.resource.org/profiles/TLS/tls.dtd">
    %TLS;
  -->


&lt;!--
  TLS messages, exchanged as application/beep+xml

     role       MSG         RSP         ERR
    =3D=3D=3D=3D=3D=3D      =3D=3D=3D         =3D=3D=3D         =
=3D=3D=3D
    I or L      ready       proceed     error        =20
  -->


&lt;!ELEMENT ready       EMPTY>
&lt;!ATTLIST ready
          version     CDATA              "1">

&lt;!ELEMENT proceed     EMPTY>

</pre><font face=3D"verdana, helvetica, arial, sans-serif" size=3D"2">

<p>

</p>

<h4><a name=3D"sasl.dtd">7.3</a>&nbsp;SASL Family of Profiles DTD</h4>
</font><pre>
&lt;!--
  DTD for the SASL Family of Profiles, as of 2000-09-04


  Refer to this DTD as:

    &lt;!ENTITY % SASL PUBLIC "-//Blocks//DTD SASL//EN"=20
               "http://xml.resource.org/profiles/sasl/sasl.dtd">
    %SASL;
  -->


&lt;!--
  SASL messages, exchanged as application/beep+xml

     role       MSG         RSP         ERR
    =3D=3D=3D=3D=3D=3D      =3D=3D=3D         =3D=3D=3D         =
=3D=3D=3D
    I or L      blob        blob        error
  -->


&lt;!ELEMENT blob        (#PCDATA)>
&lt;!ATTLIST blob
          xml:space   (default|preserve)
                                        "preserve"
          status      (abort|complete|continue)
                                         "continue">

</pre><font face=3D"verdana, helvetica, arial, sans-serif" size=3D"2">

<a name=3D"reply-codes"><br><hr size=3D"1" shade=3D"0"></a>
<table border=3D"0" cellpadding=3D"0" cellspacing=3D"2" width=3D"30" =
height=3D"15" align=3D"right"><tr><td bgcolor=3D"#990000" =
align=3D"center" width=3D"30" height=3D"15"><a href=3D"#toc" =
CLASS=3D"link2"><font face=3D"monaco, MS Sans Serif" color=3D"#ffffff" =
size=3D"1"><b>&nbsp;TOC&nbsp;</b></font></a><br></td></tr></table>
<h3>8.&nbsp;Reply Codes</h3>
</font><pre>
code    meaning
=3D=3D=3D=3D    =3D=3D=3D=3D=3D=3D=3D
200     success

421     service not available

450     requested action not taken
        (e.g., lock already in use)

451     requested action aborted
        (e.g., local error in processing)

454     temporary authentication failure

500     general syntax error
        (e.g., poorly-formed XML)

501     syntax error in parameters
        (e.g., non-valid XML)=20

504     parameter not implemented

530     authentication required

534     authentication mechanism insufficient
        (e.g., too weak, sequence exhausted, etc.)

535     authentication failure

537     action not authorized for user

538     authentication mechanism requires encryption

550     requested action not taken
        (e.g., no requested profiles are acceptable)

553     parameter invalid

554     transaction failed
        (e.g., policy violation)
</pre><font face=3D"verdana, helvetica, arial, sans-serif" size=3D"2">

<a name=3D"anchor23"><br><hr size=3D"1" shade=3D"0"></a>
<table border=3D"0" cellpadding=3D"0" cellspacing=3D"2" width=3D"30" =
height=3D"15" align=3D"right"><tr><td bgcolor=3D"#990000" =
align=3D"center" width=3D"30" height=3D"15"><a href=3D"#toc" =
CLASS=3D"link2"><font face=3D"monaco, MS Sans Serif" color=3D"#ffffff" =
size=3D"1"><b>&nbsp;TOC&nbsp;</b></font></a><br></td></tr></table>
<h3>9.&nbsp;Security Considerations</h3>

<p>
The BEEP framing mechanism,
per se,
provides no protection against attack;
however,
judicious use of initial tuning profiles provides varying degrees of
assurance:

<ol class=3D"text">

<li>
If one of the profiles from the SASL family is used,
refer to <a href=3D"#RFC2222">[4]</a>'s Section 9 for a discussion of
security considerations.
</li>

<li>
If the TLS transport security profile is used
(or if a SASL security layer is negotiated),
then:

<ol class=3D"text">

<li>
A man-in-the-middle may remove the security-related profiles
from the BEEP greeting or generate a negative reply to the
"ready" element of the TLS transport security profile.
A BEEP peer may be configurable to refuse to proceed without an
acceptable level of privacy.
</li>

<li>
A man-in-the-middle may cause a down-negotiation to the weakest
cipher suite available.
A BEEP peer should be configurable to refuse weak cipher suites.
</li>

<li>
A man-in-the-middle may modify any protocol exchanges prior to
a successful negotiation.
Upon completing the negotiation,
a BEEP peer must discard previously cached information about the BEEP
session.
</li>

</ol>

As different TLS ciphersuites provide varying levels of security,
administrators should carefully choose which ciphersuites are =
provisioned.
</li>

</ol>

</p>

<p>
As BEEP is peer-to-peer in nature,
before performing any task associated with a message,
each channel should apply the appropriate access control based on the
authenticated identity and privacy level associated with the BEEP =
session.
</p>
<a name=3D"rfc.references"><br><hr size=3D"1" shade=3D"0"></a>
<table border=3D"0" cellpadding=3D"0" cellspacing=3D"2" width=3D"30" =
height=3D"15" align=3D"right"><tr><td bgcolor=3D"#990000" =
align=3D"center" width=3D"30" height=3D"15"><a href=3D"#toc" =
CLASS=3D"link2"><font face=3D"monaco, MS Sans Serif" color=3D"#ffffff" =
size=3D"1"><b>&nbsp;TOC&nbsp;</b></font></a><br></td></tr></table>
<h3>
References</h3>
<table width=3D"99%" border=3D"0">
<tr><td class=3D"author-text" valign=3D"top"><b><a =
name=3D"RFC2045">[1]</a></b></td>
<td class=3D"author-text"><a href=3D"mailto:ned@innosoft.com">Freed, =
N.</a> and <a href=3D"mailto:nsb@nsb.fv.com">N. Borenstein</a>, "<a =
href=3D"ftp://ftp.isi.edu/in-notes/rfc2045.txt">Multipurpose Internet =
Mail Extensions (MIME) Part One: Format of Internet Message Bodies</a>", =
RFC 2045, November 1996.</td></tr>
<tr><td class=3D"author-text" valign=3D"top"><b><a =
name=3D"W3C.XML">[2]</a></b></td>
<td class=3D"author-text"><a href=3D"http://www.w3c.org">World Wide Web =
Consortium</a>, "<a =
href=3D"http://www.w3.org/TR/1998/REC-xml-19980210">Extensible Markup =
Language (XML) 1.0</a>", W3C XML, February 1998.</td></tr>
<tr><td class=3D"author-text" valign=3D"top"><b><a =
name=3D"RFC2246">[3]</a></b></td>
<td class=3D"author-text"><a =
href=3D"mailto:tdierks@certicom.com">Dierks, T.</a>, <a =
href=3D"mailto:callen@certicom.com">Allen, C.</a>, <a =
href=3D"mailto:treese@openmarket.com">Treese, W.</a>, <a =
href=3D"mailto:">Karlton, P. L.</a>, <a =
href=3D"mailto:freier@netscape.com">Freier, A. O.</a> and <a =
href=3D"mailto:pck@netcom.com">P. C. Kocher</a>, "<a =
href=3D"ftp://ftp.isi.edu/in-notes/rfc2246.txt">The TLS Protocol Version =
1.0</a>", RFC 2246, January 1999.</td></tr>
<tr><td class=3D"author-text" valign=3D"top"><b><a =
name=3D"RFC2222">[4]</a></b></td>
<td class=3D"author-text"><a href=3D"mailto:jgmyers@netscape.com">Myers, =
J.G.</a>, "<a href=3D"ftp://ftp.isi.edu/in-notes/rfc2222.txt">Simple =
Authentication and Security Layer (SASL)</a>", RFC 2222, October =
1997.</td></tr>
<tr><td class=3D"author-text" valign=3D"top"><b><a =
name=3D"BEEP-TCPMAPPING">[5]</a></b></td>
<td class=3D"author-text"><a href=3D"mailto:mrose@invisible.net">Rose, =
M.T.</a>, "<a =
href=3D"http://www.ietf.org/internet-drafts/draft-ietf-beep-tcpmapping-06=
.txt">Mapping the BEEP Core onto TCP</a>", draft-ietf-beep-tcpmapping-06 =
(work in progress), January 2001.</td></tr>
<tr><td class=3D"author-text" valign=3D"top"><b><a =
name=3D"RFC0793">[6]</a></b></td>
<td class=3D"author-text">Postel, J., "<a =
href=3D"ftp://ftp.isi.edu/in-notes/rfc793.txt">Transmission Control =
Protocol</a>", RFC 793, STD 7, Sep 1981.</td></tr>
<tr><td class=3D"author-text" valign=3D"top"><b><a =
name=3D"RFC2234">[7]</a></b></td>
<td class=3D"author-text"><a href=3D"mailto:dcrocker@imc.org">Crocker, =
D. H.</a> and <a href=3D"mailto:paulo@turnpike.com">P. Overell</a>, "<a =
href=3D"ftp://ftp.isi.edu/in-notes/rfc2234.txt">Augmented BNF for Syntax =
Specifications: ABNF</a>", RFC 2234, November 1997.</td></tr>
<tr><td class=3D"author-text" valign=3D"top"><b><a =
name=3D"RFC1982">[8]</a></b></td>
<td class=3D"author-text"><a href=3D"mailto:kre@munnari.OZ.AU">Elz, =
R.</a> and <a href=3D"mailto:randy@psg.com">R. Bush</a>, "<a =
href=3D"ftp://ftp.isi.edu/in-notes/rfc1982.txt">Serial Number =
Arithmetic</a>", RFC 1982, August 1996.</td></tr>
<tr><td class=3D"author-text" valign=3D"top"><b><a =
name=3D"RFC1766">[9]</a></b></td>
<td class=3D"author-text"><a =
href=3D"mailto:Harald.T.Alvestrand@uninett.no">Alvestrand, H.</a>, "<a =
href=3D"ftp://ftp.isi.edu/in-notes/rfc1766.txt">Tags for the =
Identification of Languages</a>", RFC 1766, March 1995.</td></tr>
<tr><td class=3D"author-text" valign=3D"top"><b><a =
name=3D"RFC2396">[10]</a></b></td>
<td class=3D"author-text"><a href=3D"mailto:timbl@w3.org">Berners-Lee, =
T.</a>, <a href=3D"mailto:fielding@ics.uci.edu">Fielding, R.T.</a> and =
<a href=3D"mailto:masinter@parc.xerox.com">L. Masinter</a>, "<a =
href=3D"ftp://ftp.isi.edu/in-notes/rfc2396.txt">Uniform Resource =
Identifiers (URI): Generic Syntax</a>", RFC 2396, August 1998.</td></tr>
<tr><td class=3D"author-text" valign=3D"top"><b><a =
name=3D"RFC2444">[11]</a></b></td>
<td class=3D"author-text"><a =
href=3D"mailto:chris.newman@innosoft.com">Newman, C.</a>, "<a =
href=3D"ftp://ftp.isi.edu/in-notes/rfc2444.txt">The One-Time-Password =
SASL Mechanism</a>", RFC 2444, October 1998.</td></tr>
<tr><td class=3D"author-text" valign=3D"top"><b><a =
name=3D"RFC2401">[12]</a></b></td>
<td class=3D"author-text"><a href=3D"mailto:kent@bbn.com">Kent, S.</a> =
and <a href=3D"mailto:rja@corp.home.net">R. Atkinson</a>, "<a =
href=3D"ftp://ftp.isi.edu/in-notes/rfc2401.txt">Security Architecture =
for the Internet Protocol</a>", RFC 2401, November 1998.</td></tr>
<tr><td class=3D"author-text" valign=3D"top"><b><a =
name=3D"RFC2279">[13]</a></b></td>
<td class=3D"author-text"><a href=3D"mailto:fyergeau@alis.com">Yergeau, =
F.</a>, "<a href=3D"ftp://ftp.isi.edu/in-notes/rfc2279.txt">UTF-8, a =
transformation format of ISO 10646</a>", RFC 2279, January =
1998.</td></tr>
<tr><td class=3D"author-text" valign=3D"top"><b><a =
name=3D"RFC2078">[14]</a></b></td>
<td class=3D"author-text"><a href=3D"mailto:John.Linn@ov.com">Linn, =
J.</a>, "<a href=3D"ftp://ftp.isi.edu/in-notes/rfc2078.txt">Generic =
Security Service Application Program Interface, Version 2</a>", RFC =
2078, January 1997.</td></tr>
</table>

<a name=3D"rfc.authors"><br><hr size=3D"1" shade=3D"0"></a>
<table border=3D"0" cellpadding=3D"0" cellspacing=3D"2" width=3D"30" =
height=3D"15" align=3D"right"><tr><td bgcolor=3D"#990000" =
align=3D"center" width=3D"30" height=3D"15"><a href=3D"#toc" =
CLASS=3D"link2"><font face=3D"monaco, MS Sans Serif" color=3D"#ffffff" =
size=3D"1"><b>&nbsp;TOC&nbsp;</b></font></a><br></td></tr></table>
<h3>Author's Address</h3>
<table width=3D"99%" border=3D"0" cellpadding=3D"0" cellspacing=3D"0">
<tr><td class=3D"author-text">&nbsp;</td>
<td class=3D"author-text">Marshall T. Rose</td></tr>
<tr><td class=3D"author-text">&nbsp;</td>
<td class=3D"author-text">Invisible Worlds, Inc.</td></tr>
<tr><td class=3D"author-text">&nbsp;</td>
<td class=3D"author-text">1179 North McDowell Boulevard</td></tr>
<tr><td class=3D"author-text">&nbsp;</td>
<td class=3D"author-text">Petaluma, CA  94954-6559</td></tr>
<tr><td class=3D"author-text">&nbsp;</td>
<td class=3D"author-text">US</td></tr>
<tr><td class=3D"author" align=3D"right">Phone:&nbsp;</td>
<td class=3D"author-text">+1 707 789 3700</td></tr>
<tr><td class=3D"author" align=3D"right">EMail:&nbsp;</td>
<td class=3D"author-text"><a =
href=3D"mailto:mrose@invisible.net">mrose@invisible.net</a></td></tr>
<tr><td class=3D"author" align=3D"right">URI:&nbsp;</td>
<td class=3D"author-text"><a =
href=3D"http://invisible.net/">http://invisible.net/</a></td></tr>
</table>

<a name=3D"anchor24"><br><hr size=3D"1" shade=3D"0"></a>
<table border=3D"0" cellpadding=3D"0" cellspacing=3D"2" width=3D"30" =
height=3D"15" align=3D"right"><tr><td bgcolor=3D"#990000" =
align=3D"center" width=3D"30" height=3D"15"><a href=3D"#toc" =
CLASS=3D"link2"><font face=3D"monaco, MS Sans Serif" color=3D"#ffffff" =
size=3D"1"><b>&nbsp;TOC&nbsp;</b></font></a><br></td></tr></table>
<h3>Appendix A.&nbsp;Acknowledgements</h3>

<p>
The author gratefully acknowledges the contributions of:
David Clark,
Dave Crocker,
Steve Deering,
Wesley Michael Eddy,
Huston Franklin,
Marco Gazzetta,
Danny Goodman,
Steve Harris,
Robert Herriot,
Ken Hirsch,
Greg Hudson,
Ben Laurie,
Carl Malamud,
Michael Mealling,
Keith McCloghrie,
Paul Mockapetris,
RL 'Bob' Morgan,
Frank Morton,
Darren New,
Chris Newman,
Joe Touch,
Paul Vixie,
Gabe Wachob,
Daniel Woods,
and,
James Woodyatt.
In particular,
Dave Crocker provided helpful suggestions on the nature of=20
segmentation in the framing mechanism.
</p>

<a name=3D"anchor25"><br><hr size=3D"1" shade=3D"0"></a>
<table border=3D"0" cellpadding=3D"0" cellspacing=3D"2" width=3D"30" =
height=3D"15" align=3D"right"><tr><td bgcolor=3D"#990000" =
align=3D"center" width=3D"30" height=3D"15"><a href=3D"#toc" =
CLASS=3D"link2"><font face=3D"monaco, MS Sans Serif" color=3D"#ffffff" =
size=3D"1"><b>&nbsp;TOC&nbsp;</b></font></a><br></td></tr></table>
<h3>Appendix B.&nbsp;IANA Considerations</h3>

<p>
The IANA registers "beep" as a <a href=3D"#RFC2078">GSSAPI</a>[14]
service name,
as specified in <a href=3D"#sasl.profiles">The SASL Family of =
Profiles</a>.
</p>

<p>
The IANA maintains a list of:

<ul class=3D"text">

<li>
standards-track BEEP profiles,
c.f., <a href=3D"#profile.registration">Profile Registration =
Template</a>; and,
</li>

<li>
standards-track features for the channel management profile,
c.f., <a href=3D"#feature.registration">Feature Registration =
Template</a>.
</li>

</ul>

For each list,
the IESG is responsible for assigning a designated expert to review
the specification prior to the IANA making the assignment.
As a courtesy to developers of non-standards track BEEP profiles and
channel management features,
the mailing list bxxpwg@invisible.net may be used to solicit commentary.
</p>

<p>
The IANA makes the registrations specified in
<a href=3D"#tls.definition">Registration: TLS Transport Security =
Profile</a> and <a href=3D"#sasl.definition">Registration: SASL Family =
of Profiles</a>.
It is recommended that the IANA register these profiles using the IANA
as a URI-prefix,
and populate those URIs with the respective profile registrations.
</p>
<a name=3D"rfc.copyright"><br><hr size=3D"1" shade=3D"0"></a>
<table border=3D"0" cellpadding=3D"0" cellspacing=3D"2" width=3D"30" =
height=3D"15" align=3D"right"><tr><td bgcolor=3D"#990000" =
align=3D"center" width=3D"30" height=3D"15"><a href=3D"#toc" =
CLASS=3D"link2"><font face=3D"monaco, MS Sans Serif" color=3D"#ffffff" =
size=3D"1"><b>&nbsp;TOC&nbsp;</b></font></a><br></td></tr></table>
<h3>Full Copyright Statement</h3>
<p class=3D'copyright'>
Copyright (C) The Internet Society (2001). All Rights Reserved.</p>
<p class=3D'copyright'>
This document and translations of it may be copied and furnished to
others, and derivative works that comment on or otherwise explain it
or assist in its implementation may be prepared, copied, published and
distributed, in whole or in part, without restriction of any kind,
provided that the above copyright notice and this paragraph are
included on all such copies and derivative works. However, this
document itself may not be modified in any way, such as by removing
the copyright notice or references to the Internet Society or other
Internet organizations, except as needed for the purpose of
developing Internet standards in which case the procedures for
copyrights defined in the Internet Standards process must be
followed, or as required to translate it into languages other than
English.</p>
<p class=3D'copyright'>
The limited permissions granted above are perpetual and will not be
revoked by the Internet Society or its successors or assigns.</p>
<p class=3D'copyright'>
This document and the information contained herein is provided on an
&quot;AS IS&quot; basis and THE INTERNET SOCIETY AND THE INTERNET =
ENGINEERING
TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING
BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION
HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.</p>
<h3>Acknowledgement</h3>
<p class=3D'copyright'>
Funding for the RFC editor function is currently provided by the
Internet Society.</p>
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