+# -*- perl -*-
=head1 NAME
-DXSpiderWeb Orthogonal Communications Protocol
+Aranea Orthogonal Communications Protocol
$Revision$
=head1 SYNOPSIS
- <Origin>,<TimeSeq>,<Hop>,<FrmUser>,<To>,<ToUser>|<Tag>,<Data>...
+ <Origin>,<Group>,<TimeSeq>,<Hop>[,<From>]|<Tag>,<Data>...
=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 ofL</Node>s. This environment has probably never, reliably,
been achieved in practice; certainly not recently.
There have always been loops, sometimes bringing the network to its
fully looped network, is inherently extensible and should be simple
to implement (especially in perl).
-All implementations of this protocol shall B<only> use this protocol
+All implementations shall use b<only> 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</Messages> need to be broadcast to all nodes.
+mechanism is that most L</Messages> need to be broadcast to allL</Node>s.
-Experience has shown that nodes will appear and (more infrequently)
+Experience has shown thatL</Node>s 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>)
+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</Messages> that could be routed (likely to be mainly single line one to
+one "talk" L</Messages>) 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
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
+some L</Standard Commands> 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 L</Node>s and L</User>s. 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 L</Node>s and L</User>s is that a node has one or more
+listeners running that will,
+potentially, allow incoming connections from other L</Node>s, L</Endpoint>s or L</User>s. These
+routable entities are called L</Terminal>s.
+
+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</Terminal> in this protocol. It is called an L</Endpoint>.
+
+An L</Endpoint> is called a L</Node> if it accepts connections from L</Endpoint>s and is
+prepared to route messages on their behalf to other L</Node>s or L</Endpoint>s. 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</Endpoint> 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 L</User>s, 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 Definitions
+
+In this document we use a number of terms that need to be defined.
+
+=head2 Terminal
+
+A L</Terminal> is a routable entity, in other words: a callsign or service that can be routed
+to, that lives at one or a few L</Node>s.
+
+=head2 User
+
+A L</User> is a connection to a L</Node> (that allows such connections)
+that does not occur in protocol. All L</User>s 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</Node> to which this L</User> is connected.
+
+=head2 Endpoint
+
+An L</Endpoint> is a connection to a L</Node> that uses the protocol. From a routing point of
+view, it is indistiguishable from a L</Node>. The L</Endpoint> is responsible for creating and decoding
+well formed protocol messages. An L</Endpoint> does not route beyond the immediate L</Node>(s) to
+which it is connected. It may also be a L</Service> connected to a L</Node> which provides some
+addressable service (such as a database) that can be queried.
+
+=head2 Node
+
+A L</Node> is connected to other L</Node>s. It is responsible for routing messages in protocol
+from other L</Node>s or L</Endpoint>s, whether directly connected or not. Optionally, a L</Node>
+may provide other interfaces, such as direct L</User> connections or legacy PC protocol speaking
+DX Clusters.
+
+=head2 Channel
+
+A L</Channel> is a L</Group> address that is not a L</Terminal>. It is (unless qualified by a L</Terminal>)
+broadcast on all a L</Node>s interfaces unless preventing by some filtering or other local policy on
+that L</Node>.
+
+=head2 Service
+
+A L</Service> is application that either plugs into or connects as an L</Endpoint> to a L</Node>. It is an
+application that, in effect, is a database. In other words: queries are sent to the L</Service> 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 thatL</Node>s are connected to
each other using a "reliable" streaming protocol such as TCP/IP or
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.
-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 L</Node>s 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 L</Node>s. There may be a
discontinuity either caused by outage or deliberate filtering.
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
+in the case of directed L</Messages> (those that have a L</Group> containing a L</Terminal> of some kind)
+down some/most/all interfaces showing a route for that
direction, it is unlikely that L</Messages> will be lost in practice.
-=head2 Field Description
+Assuming that there is a path between all the L</Node>s 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 L</Node>s more than once. L</Node>s are responsible for deduplicating those messages
+using the information in the L</Routing Section>.
-Only the first three fields in the L</Routing Section> are compulsory
-and indicate that this is a broadcast to be sent to all nodes coming
-from the L</Origin>. If the message needs to be identified as coming
-from a user on a node, then the L</FrmUser> field is added.
+=head2 Field Description
-Adding a L</To> and/or L</ToUser> field will restrict the destinations
-or recipients that receive this message.
+All fields in the L</Routing Section> are compulsory except the L</From> field. If it is missing
+so is the separating comma.
The L</Hop> 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.
=item B<Origin>
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<Group>
+
+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</Terminal> connected at a specific L</Node>, or even a
+particular L</Terminal> in a L</Group>,
+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</Terminal> or some other string which is interpreted
+as broadcastable group address. Any message that has a L</Group> that is not recognised as a L</Terminal> 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 L</Node>s may pass every L</Group> field, depending on local policy.
+
=item B<TimeSeq>
This is a compulsory field. It is a 10 hexadecimal digit string which
The date portion is constructed as:
- my $date = ((((gmtime)[3] < 1) | $ntpflag) < 18) | (time % 86400);
+ my $date = ((((gmtime)[3] << 1) | $ntpflag) << 18) | (time % 86400);
The sequence number is simply an unsigned short (or 16 bit) number
starting at 0.
silently drop incoming L</Messages> with a L</Hop> count greater than the
limit.
-=item B<FrmUser>
-
-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<To>
-
-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</Channel>. Any message can be sent
-down any L</Channel>. The names of L</Channel>s and their usage
-is entirely up to the implementor.
+=item B<From>
-It is assumed that node names can be differentiated from user
-names and L</Channel> 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<ToUser>
-
-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</To> field
-will be set, by the originating node, to the identifier of the node
-on which this user resides.
-
-If the L</To> 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</To> field and proceed
-with a more directed approach.
-
-If it becomes apparent (on route) that there may be more than
-one possible L</To> destination for a L</ToUser> then a node
-may duplicate the message (keeping the same L</TimeSeq>) and
-route it onwards. Because of the L</DeDuplication> 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</Origin>,
-L</TimeSeq>) will determine uniqueness.
-
-This field can, in the case where L</To>
-is set to the name of a node, be set to a L</Channel>. If this
-is the case then this will cause this message to be sent to
-a L</Channel> on the L</To> node only.
+The L</From> field is optional. When present, it represents a L</Terminal> at
+the originating L</Node>. If it is missing then either it is not relevant or it
+is assumed to be the L</Origin>.
=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</Command Section>) 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
=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
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:
=item B<PING>
- PING,<ping id>
+ PING,<user>,<ping id>
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
=item B<PONG>
- PONG,<ping id>,<no of hops on ping>
+ PONG,<ping id>,<user>,<no of hops on ping>
Command to reply to a ping. This is sent as a reply to an incoming ping command.
The <ping id> is the one supplied and the <no of hops on ping> is the number of
=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.
projects / spider.git / blobdiff