amend some small typos in techdoc

[spider.git] / techdoc / protocol.pod

diff --git a/techdoc/protocol.pod b/techdoc/protocol.pod
index 5ea94c6642c0ecd73a5977673ff6006fc146e8ac..3c3ccdcc4af5bb5539d17b4600ecd5851a4380ef 100644 (file)
--- a/techdoc/protocol.pod
+++ b/techdoc/protocol.pod
@@ -1,6 +1,6 @@
 =head1 NAME
 
 =head1 NAME
 

-DXSpiderWeb Orthogonal Communications Protocol 
+Aranea Orthogonal Communications Protocol 

 
 $Revision$
 
 
 $Revision$
 


@@ -31,25 +31,77 @@ for inter-node communications.
 
 =head1 DESCRIPTION
 
 
 =head1 DESCRIPTION
 

-This protocol is encoded in UTF8 with HTTP style escaping. It is
-designed to be an extensible basis for any type of one to many
+This protocol is
+designed to be an extensible basis for any type of one too many

 "instant" line-based communications tasks.
 
 This protocol is designed to be flood routed in a meshed network in
 "instant" line-based communications tasks.
 
 This protocol is designed to be flood routed in a meshed network in

-as efficient a manner as possible.
+as efficient a manner as possible. The reason we have chosen this
+mechanism is that most L</Messages> need to be broadcast to all nodes.
+
+Experience has shown that nodes will appear and (more infrequently) 
+disappear without much (or any) notice. 
+Therefore, the constantly changing and uncoordinated
+nature of the network doesn't lend itself to fixed routing policies.
+
+Having said that: directed routing is available where routes have
+been learned through past traffic.
+Those L</Messages> that could be routed (mainly single line one to 
+one "talk" L</Messages>) 
+happen sufficiently infrequently that, should they need to be flood routed
+(because no route has been learned yet) it is a small cost overall.
+
+=head1 Messages
+
+A message is a single line of UTF8 encoded and HTTP escaped text 
+terminated in the standard internet manner with a <CR><LF>. 

 
 Each message consists of a L</Routing Section> and a L</Command Section>. 
 
 Each message consists of a L</Routing Section> and a L</Command Section>. 

-The two sections are separated with the '|' character and the whole
-message is terminated in the standard RFC/Internet manner with the
-ascii <carraige return><linefeed> characters. It follows that these
-characters (as well as a small number of other reserved characters)
+The two sections are separated with the '|' character. 
+It follows that these
+characters (as well as non-printable characters, <CR>, <LF> and
+a small number of other reserved characters)

 can only be sent escaped. This is described further in the 
 can only be sent escaped. This is described further in the 

-L</Command Section>.
+L</Command Section> and L</Fields>.

 
 Most of this document is concerned with the L</Routing Section>, however
 some L</Standard Commands> which all implementation should issue and
 must accept are described.
 
 
 Most of this document is concerned with the L</Routing Section>, however
 some L</Standard Commands> which all implementation should issue and
 must accept are described.
 

+=head1 Applications
+
+In the past messaging applications such as DX Cluster software have maintained
+a fairly strict division between "nodes" and "users". This protocol attempts
+to get away from that distinction by allowing any entity to connect to any 
+other. 
+
+Applications that use this protocol are essentially all peers and therefore
+nodes the only real difference between a "node" and a "user" (using this 
+protocol) is that a "node" has one or more listeners running that will,
+potentially, allow incoming connections. A "user" simply becomes an end
+point that never uses the L</FrmUser> or L</ToUser> slots in the 
+L</Routing Section>.
+
+The reason for this is that modern clients are more intelligent than simple
+character based connections such as telnet or ax25. They wish to be able to
+distinguish between the various classes of message, such as: DX spots, 
+announces, talk, logging info etc. It is a pain to have to do it, as now,
+by trying to make sense of the (slightly different for each piece of node 
+software) human readable "user" version of the output. Far better to pass on
+regular, specified, easily computer decodable versions of the message,
+i.e. in this protocol, and leave
+the human presentation to the client software.
+
+Having said that, the protocol allows for traditional, character based,
+connections, as in the past. But it is up to applications
+to service and control that type of connection and to provide human readable
+"user" output. 
+
+One of the legacy, character based connections that will probably have to be
+serviced is that of existing PC protocol based nodes. They should be treated
+as local clients, B<not> as peers in this protocol. It is likely that, in order
+to do this, some extra L</Tag>s will need to be defined at application level. 
+

 =head1 Routing Section
 
 The application that implements this protocol is essentially a line
 =head1 Routing Section
 
 The application that implements this protocol is essentially a line


@@ -58,7 +110,7 @@ effectively a datagram.
 
 It is assumed that nodes are connected to
 each other using a "reliable" streaming protocol such as TCP/IP or
 
 It is assumed that nodes are connected to
 each other using a "reliable" streaming protocol such as TCP/IP or

-AX25. Having said that: in context, messages in this protocol could be 
+AX25. Having said that: in context, L</Messages> in this protocol could be 

 multi/broadcast, either "as is" or wrapped in some other framing
 protocol. 
 
 multi/broadcast, either "as is" or wrapped in some other framing
 protocol. 
 


@@ -67,10 +119,10 @@ through your node" protocol, there is no guarantee that a message
 will get to the other side of a mesh of nodes. There may be a
 discontinuity either caused by outage or deliberate filtering. 
 
 will get to the other side of a mesh of nodes. There may be a
 discontinuity either caused by outage or deliberate filtering. 
 

-However, as it is envisaged that most messages will be flood routed or,
-in the case of directed messages (those that have L</To> and/or
+However, as it is envisaged that most L</Messages> will be flood routed or,
+in the case of directed L</Messages> (those that have L</To> and/or

 L</ToUser> fields) down some/most/all interfaces showing a route for that
 L</ToUser> fields) down some/most/all interfaces showing a route for that

-direction, it is unlikely that messages will be lost in practice.
+direction, it is unlikely that L</Messages> will be lost in practice.

 
 =head2 Field Description
 
 
 =head2 Field Description
 


@@ -137,7 +189,7 @@ neighbouring nodes must increment this field before passing
 it on to higher layers for onward processing.
 
 Implementations may have an upper limit to this field and may
 it on to higher layers for onward processing.
 
 Implementations may have an upper limit to this field and may

-silently drop incoming messages with a L</Hop> count greater than the
+silently drop incoming L</Messages> with a L</Hop> count greater than the

 limit.
 
 =item B<FrmUser>
 limit.
 
 =item B<FrmUser>


@@ -223,7 +275,7 @@ tuple. The basic system will learn which interfaces can see what nodes
 by looking at the tuple and merging that with the L</Hop> count. 
 Each interface remembers the latest L</TimeSeq> with the lowest L</Hop>
 for each L</Origin> that arrives on that interface. It also remembers
 by looking at the tuple and merging that with the L</Hop> count. 
 Each interface remembers the latest L</TimeSeq> with the lowest L</Hop>
 for each L</Origin> that arrives on that interface. It also remembers

-the number of messages for that L</Origin> that has been received on
+the number of L</Messages> for that L</Origin> that has been received on

 that interface.
 
 Any message for onward broadcast is duplicated and sent out on all
 that interface.
 
 Any message for onward broadcast is duplicated and sent out on all


@@ -255,8 +307,8 @@ duplicated!
 =head2 Examples
 
  # on link startup from GB7BAA (both sides hello)
 =head2 Examples
 
  # on link startup from GB7BAA (both sides hello)

- GB7TLH,3D02350001,0,GB7BAA|HELLO,Aranea,1.2,24.123
- GB7BAA,3D02355421,1,GB7TLH|HELLO,Aranea,1.1,23.245
+ GB7TLH,3D02350001,0|HELLO,Aranea,1.2,24.123
+ GB7BAA,3D02355421,1|HELLO,Aranea,1.1,23.245

 
  # on user startup to GB7TLH
  GB7TLH,3D042506F2,0,G1TLH|HELLO,PClient,1.3
 
  # on user startup to GB7TLH
  GB7TLH,3D042506F2,0,G1TLH|HELLO,PClient,1.3


@@ -323,7 +375,7 @@ vertical bar '|',
 percent '%', 
 equals '=' 
 and non printable characters less than 127 (or %7F in hex)
 percent '%', 
 equals '=' 
 and non printable characters less than 127 (or %7F in hex)

-[including newline and carraige return] are tranlated to
+[including newline and carraige return] are translated to

 their two hex digit equivalent preceeded by the percent '%' character.
 
 For example:
 their two hex digit equivalent preceeded by the percent '%' character.
 
 For example:


@@ -341,7 +393,7 @@ are written according to this specification must say:
  use UTF8;
 
 A message (or line) is terminated with <carriage return><linefeed>
  use UTF8;
 
 A message (or line) is terminated with <carriage return><linefeed>

-0x0d 0x0a. Incoming messages must be accepted even when terminated
+0x0d 0x0a. Incoming L</Messages> must be accepted even when terminated

 with just <linefeed>.
 
 Care must be taken to make sure that fields have any reserved characters
 with just <linefeed>.
 
 Care must be taken to make sure that fields have any reserved characters