X-Git-Url: http://dxcluster.org/gitweb/gitweb.cgi?a=blobdiff_plain;f=techdoc%2Fprotocol.pod;h=1e1f2436995dc0e3f03acbc8f8f8206f7f90dfba;hb=da55cf63b3719d06fe69c76cab566c623d76f04d;hp=6a56b6389d1e5d680f10c5008a3a2be1ea8a5acf;hpb=6c8062c1356fe49974da2df121852b41971f7b77;p=spider.git
diff --git a/techdoc/protocol.pod b/techdoc/protocol.pod
index 6a56b638..1e1f2436 100644
--- a/techdoc/protocol.pod
+++ b/techdoc/protocol.pod
@@ -1,17 +1,18 @@
+# -*- perl -*-
=head1 NAME
-DXSpiderWeb Orthogonal Communications Protocol
+Aranea Orthogonal Communications Protocol
$Revision$
=head1 SYNOPSIS
- ,,,,,|,...
+ ,,,[,]|,...
=head1 ABSTRACT
For many years DX Clusters have used a protocol which was designed
-for a non-looped tree of nodes. This environment has probably never, reliably,
+for a non-looped tree ofLs. This environment has probably never, reliably,
been achieved in practice; certainly not recently.
There have always been loops, sometimes bringing the network to its
@@ -26,30 +27,33 @@ describes a complete replacement for the PC protocol. It allows a
fully looped network, is inherently extensible and should be simple
to implement (especially in perl).
-All implementations of this protocol shall B use this protocol
+All implementations shall use b this protocol
for inter-node communications.
=head1 DESCRIPTION
This protocol is
-designed to be an extensible basis for any type of one to many
+designed to be an extensible basis for any type of one -> many
"instant" line-based communications tasks.
-This protocol is designed to be flood routed in a meshed network in
+The protocol is designed to be flood routed in a meshed network in
as efficient a manner as possible. The reason we have chosen this
-mechanism is that most L need to be broadcast to all nodes.
+mechanism is that most L need to be broadcast to allLs.
-Experience has shown that nodes will appear and (more infrequently)
+Experience has shown thatLs 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 that could be routed (mainly single line one to
-one "talk" L)
+nature of the network doesn't lend itself to fixed routing policies. Therefore,
+whilst metrics and routing tables (more like routing hint tables) will be
+built up over time, an aggressive aging algorithm will also be employed to prevent
+a lot of stale routing information being retained.
+
+Having said that: where routes have
+been learned through past traffic, and this data is recent, then direct routing should be used.
+Those L that could be routed (likely to be mainly single line one to
+one "talk" L) that, anyway,
happen sufficiently infrequently that, should they need to be flood routed
-(because no route has been learned yet) it is a small cost overall.
+(because no route has been learned yet), it is a small cost overall.
=head1 Messages
@@ -65,50 +69,130 @@ can only be sent escaped. This is described further in the
L and L.
Most of this document is concerned with the L, however
-some L which all implementation should issue and
+some L which all implementations 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 Ls and Ls. This protocol attempts
+to get away from that by deliberately blurring (or, in some cases, removing)
+any distinction between the two.
+
+Applications that use this protocol are essentially all peers and therefore the
+only real difference between Ls and Ls is that a node has one or more
+listeners running that will,
+potentially, allow incoming connections from other Ls, Ls or Ls. These
+routable entities are called Ls.
+
+Any application that is a sink and/or source of data; is capable of obeying
+the protocol message construction rules and understands how to deduplicate incoming messages
+correctly can operate as a routeable entity or L in this protocol. It is called an L.
+
+An L is called a L if it accepts connections from Ls and is
+prepared to route messages on their behalf to other Ls or Ls. In addition it
+may provide some other, usually simpler, interface (eg simple telnet access) for direct user access. Acting
+in the protocol, on their behalf.
+
+The concept of an L has been invented because modern clients are
+capable of being more intelligent than simple
+character based connections such as telnet or ax25. They also 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 application.
+
+It also helps to modularise the various interfaces that may be implemented such
+as the legacy, character based connections of existing PC protocol based nodes.
+They should be treated
+as local clients, in fact as Ls, B as peers in this protocol. It is likely that, in order
+to do this, some extra Ls will need to be defined at application level.
+
+=head1 Definitions
+
+In this document we use a number of terms that need to be defined.
+
+=head2 Terminal
+
+A L is a routable entity, in other words: a callsign or service that can be routed
+to, that lives at one or a few Ls.
+
+=head2 User
+
+A L is a connection to a L (that allows such connections)
+that does not occur in protocol. All Ls shall be identified with a name
+of up to 12 characters in the set [-0-9A-Z_]. All messages have to be routed via the
+L to which this L is connected.
+
+=head2 Endpoint
+
+An L is a connection to a L that uses the protocol. From a routing point of
+view, it is indistiguishable from a L. The L is responsible for creating and decoding
+well formed protocol messages. An L does not route beyond the immediate L(s) to
+which it is connected. It may also be a L connected to a L which provides some
+addressable service (such as a database) that can be queried.
+
+=head2 Node
+
+A L is connected to other Ls. It is responsible for routing messages in protocol
+from other Ls or Ls, whether directly connected or not. Optionally, a L
+may provide other interfaces, such as direct L connections or legacy PC protocol speaking
+DX Clusters.
+
+=head2 Channel
+
+A L is a L address that is not a L. It is (unless qualified by a L)
+broadcast on all a Ls interfaces unless preventing by some filtering or other local policy on
+that L.
+
+=head2 Service
+
+A L is application that either plugs into or connects as an L to a L. It is an
+application that, in effect, is a database. In other words: queries are sent to the L and it sends
+back a reply.
+
=head1 Routing Section
The application that implements this protocol is essentially a line
oriented message router. One line equals one message. Each line is
effectively a datagram.
-It is assumed that nodes are connected to
+It is assumed thatLs are connected to
each other using a "reliable" streaming protocol such as TCP/IP or
AX25. Having said that: in context, L in this protocol could be
multi/broadcast, either "as is" or wrapped in some other framing
protocol.
-Because this is an unreliable, best effort, "please route my packets
-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
+Although the physical transport between Ls is reliable, the actual message
+is unreliable, because this is an unreliable, best effort, "please route my packets
+through your node" protocol. There is no guarantee that a message
+will get to the other side of a mesh of Ls. There may be a
discontinuity either caused by outage or deliberate filtering.
However, as it is envisaged that most L will be flood routed or,
-in the case of directed L (those that have L and/or
-L fields) down some/most/all interfaces showing a route for that
+in the case of directed L (those that have a L containing a L of some kind)
+down some/most/all interfaces showing a route for that
direction, it is unlikely that L will be lost in practice.
-=head2 Field Description
+Assuming that there is a path between all the Ls in a network, then it is guaranteed
+that a message will be delivered everywhere, eventually. It is possible (indeed likely) that
+copies of a message
+will arrive at Ls more than once. Ls are responsible for deduplicating those messages
+using the information in the L.
-Only the first three fields in the L are compulsory
-and indicate that this is a broadcast to be sent to all nodes coming
-from the L. If the message needs to be identified as coming
-from a user on a node, then the L field is added.
+=head2 Field Description
-Adding a L and/or L field will restrict the destinations
-or recipients that receive this message.
+All fields in the L are compulsory except the L field. If it is missing
+so is the separating comma.
The L field is incremented on receipt of a message on a node.
Fields are separated by the comma ',' character with the last field
required followed by the vertical bar '|' character.
-If trailing fields are missed out then superfluous commas can also
-be left out. If intervening fields are missing then no space needs
-to be left for the separating comma.
-
The characters allowed in the routing section are restricted. Any
invalid characters in any field will cause the whole message to be
silently dropped.
@@ -120,11 +204,42 @@ More detailed descriptions of the fields follow:
=item B
This is a compulsory field. It is the name of the originating node.
-The field can contain up to 12 characters in the set [-A-Z0-9_] in
+The field can contain up to 12 characters in the set [-A-Z0-9_/] in
any order. Higher layers may restrict this further.
The field must not be changed by any other node.
+=item B
+
+This is the Group (or Channel) to be used for this data. It is compulsory.
+
+It is a string of up to 12 characters
+in the set [-A-Z0-9_/] in any order.
+
+Optionally, for extra routing to
+a particular L connected at a specific L, or even a
+particular L in a L,
+it may have another 12 character
+string in the same set, concatenated with the first string. The two strings are separated by a ':'
+character. For example:
+
+ DX # the DX group
+ GB7DJK # the node GB7DJK
+ G1TLH # the user or endpoint G1TLH
+ GB7DJK:G1TLH # the user G1TLH at GB7DJK
+ DX:G1TLH # the user G1TLH in the DX group
+
+This field can contain either a L or some other string which is interpreted
+as broadcastable group address. Any message that has a L that is not recognised as a L must
+be broadcast.
+
+This means that messages to callsigns, for whom no specific routing information is available,
+will be found by means of a broadcast. Hopefully this will cause some kind of activity o.b.o
+that callsign will allow routing tables to be gathered that narrow down the scope of any future
+message to that callsign through the network.
+
+Remember that not all Ls may pass every L field, depending on local policy.
+
=item B
This is a compulsory field. It is a 10 hexadecimal digit string which
@@ -158,76 +273,14 @@ Implementations may have an upper limit to this field and may
silently drop incoming L with a L count greater than the
limit.
-=item B
-
-This field is optional. It is the identifier of the originating
-user. If it is missing then the message is
-assumed to come from the originating node itself.
-
-It can consist of up to 12 characters in the set [-A-Z0-9_]
-in any order. Higher layers may restrict this further.
-
-=item B
-
-This field is optional. It is a string of up to 12 characters
-in the set [-A-Z0-9_] in any order.
-
-This field is used either to indicate particular node destination
-or to differentiate this broadcast in some way by making this
-message as a member of a L. Any message can be sent
-down any L. The names of Ls and their usage
-is entirely up to the implementor.
+=item B
-It is assumed that node names can be differentiated from user
-names and L names.
-
-If the field is set to a particular node destination, it will
-be routed (rather than broadcast) to that node. However, any
-intervening nodes are free to duplicate the message and send
-it down more than one, likely looking, interface - depending on any
-network policies that may pertain.
-
-=item B
-
-This field is optional. It is a string of up to 12 characters
-in the set [-A-Z0-9_] in any order. Higher layers may restrict
-this further.
-
-Conventionally this field is used to indicate the user to whom
-this message is directed. In an ideal world the L field
-will be set, by the originating node, to the identifier of the node
-on which this user resides.
-
-If the L field is not set then this message will be
-broadcast. However, should a node become apparent (on route)
-then nodes are free to fill in the L field and proceed
-with a more directed approach.
-
-If it becomes apparent (on route) that there may be more than
-one possible L destination for a L then a node
-may duplicate the message (keeping the same L) and
-route it onwards. Because of the L inherent in
-the system, it is indeterminate as to which destination will
-receive the message. It is possible for all or just some
-destinations to receive the message. The tuple (L,
-L) will determine uniqueness.
-
-This field can, in the case where L
-is set to the name of a node, be set to a L. If this
-is the case then this will cause this message to be sent to
-a L on the L node only.
+The L field is optional. When present, it represents a L at
+the originating L. If it is missing then either it is not relevant or it
+is assumed to be the L.
=back
-=head2 Channel
-
-Channels are a concept very similar to that on IRC. It is a
-way of segregating data flows in a network. In principle, subject
-to local policy or application requirements, any data (or
-L) can be sent down any channel.
-
-It is up to the implementation whether to use this feature or not.
-
=head2 Routing
It is assumed that nodes will be connected in a looped network with
@@ -273,35 +326,32 @@ duplicated!
=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,ROUTE,3D02350001,0|HELLO,Aranea,1.2,24.123
+ GB7BAA,ROUTE,3D02355421,1|HELLO,Aranea,1.1,23.245
# on user startup to GB7TLH
- GB7TLH,3D042506F2,0,G1TLH|HELLO,PClient,1.3
+ GB7TLH,ROUTE,3D042506F2,0,G1TLH|HELLO,PClient,1.3
# on user disconnection
- GB7TLH,3D9534F32D,0,G1TLH|BYE
+ GB7TLH,ROUTE,3D9534F32D,0,G1TLH|BYE
# a talk (actually 'text') message to a user (some distance away
# from the origin node)
- GB7TLH,3D03450019,3,G1TLH,GB7BAA,G8TIC|T,Hiya Mike what's happening?
+ GB7TLH,G8TIC,3D03450019,3,G1TLH|T,Hiya Mike whats happening?
- # a talk/chat/text message to a channel or group
- GB7TLH,0413525F23,2,G1TLH,VHF|T,2m is opening on MS
+ # a talk/chat/text message to a Group
+ GB7TLH,VHF,0413525F23,2,G1TLH|T,2m is opening on MS
# a ping to find the whereabouts and distance of a user from a node
# the hex number on the end is the ping ID
- GB7TLH,1512346543,0,,,G7BRN|PING,9F4D
-
- # the same from a user on GB7TLH
- GB7TLH,1512346543,0,G1TLH,,G7BRN|PING,23
+ GB7TLH,G7BRN,1512346543,0,G1TLH|PING,9F4D
# this effectively asks whether the user is on-line on a particular node
- GB7TLH,1512346543,0,G1TLH,GB7DJK,G7BRN|PING,35DE
+ GB7TLH,GB7BAA:G7BRN,1512346543,0,G1TLH|PING,35DE
# A possible reply, same ID as ping followed by the no of hops on the
- # ping that was received
- GB7DJK,1512450534,3,G7BRN,GB7TLH,G1TLH|PONG,35DE,3
+ # ping that was received thus telling you how far away it is.
+ GB7BAA,G1TLH,1512450534,3,G7BRN|PONG,35DE,3
=head1 Command Section
@@ -341,7 +391,7 @@ vertical bar '|',
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:
@@ -414,7 +464,7 @@ disconnected.
=item B
- PING,
+ PING,,
Command to send a ping to a node or user. This command is used both by the software
and users to determine a) whether a node or user exists and b) how good the path is
@@ -426,7 +476,7 @@ will identify this ping using the tuple (L,) as unique.
=item B
- PONG,,
+ PONG,,,
Command to reply to a ping. This is sent as a reply to an incoming ping command.
The is the one supplied and the is the number of
@@ -447,7 +497,7 @@ Dirk Koopman, G1TLH, Edjk@tobit.co.ukE
=head1 COPYRIGHT AND LICENSE
-Copyright 2004 by Dirk Koopman, G1TLH
+Copyright 2004-2005 by Dirk Koopman, G1TLH
This library is free software; you can redistribute it and/or modify
it under the same terms as Perl itself.