XRPi Documentation - Servers

Chat Server

Name

CHAT-SRV -- CHAT Server.

Description

XRPi's integral chat server allows groups of users to hold live multi-way conversations without having to manage several TNC streams at once.

It is available to all callers, and is accessed by using the CHAT command at the main prompt, or by connecting directly to its callsign or alias. TCP/IP users can additionally access it by TELNETting to port 3600 (this port can be reassigned or disabled using the CHATPORT directive in XROUTER.CFG).

The server is tri-standard, i.e. it can exist on, and interact with 3 completely different types of chat network simultaneously, namely XRchat, "Tampa Ping Pong Converse", and W0RLI RoundTable chat, as used by BPQ. XRPi's server is a fully functional RoundTable node, however data is NEVER transferred between networks. e.g. what is said on the RoundTable network is never propogated around the XRchat network and vice versa.

Channels

The "XRchat" system has 32767 channels or " chat rooms", each of which can support an unlimited number of users, so it is possible for groups to have their own "private" room, or to reserve certain rooms for specific topics.

Channels 1 to 255 (except 101 - see below) are "local" to each chat server, and the remaining channels 256-32767 are "global", i.e. they are linked with all other XRouter chat servers, providing there is at least one link set up with another server.

Room 101 is a gateway to the W0RLI "RoundTable" / BPQChat network, providing there is at least one link with a RoundTable or BPQChat peer. Within room 101, users may create and occupy private chat spaces called "topics". The default topic at login is "general".

In addition to the "positive" channel numbers, there are another 32768 channels numbered 0 to -32767. These correspond to channels 0 to 32767 on the "Tampa Ping Pong" system.

XRouter allows only limited interconnection between these two systems, because the channel layouts and topologies are completely incompatible. XRchat was specifically designed for use on an anarchic, slow radio network, whereas Ping-Pong requires a more planned network topology to avoid loops, and is largely carried on Internet links. The sheer volume of chat in the Ping-Pong system would overwhelm marginal radio links.

Data received from Ping-pong is not propogated via the Xrouter chat interlinks and vice versa. In effect, Xrouter can be a stub Ping-Pong host, but not part of the Ping-Pong network.

Channel 1000 is the default channel to which users are assigned at log-on, but they may set their preferred login channel using the "/CHANNEL DEFAULT" command.

Users may "join" as many channels as they wish, so they may take part in several separate conversations at once. Users may listen on any number of positive and negative channels simultaneously, but may only *send* on one channel at a time.

Once logged onto a channel, anything sent by the user is copied to all other users of that channel, except for lines beginning with a forward slash (/), which are interpreted as chat server commands. The distributed text is prefixed by the channel number and the sender's callsign and name, to allow the recipients to identify who sent it.

Commands

All chat server commands begin with a forward slash (/), and most of them may be abbreviated to the initial letter. The /? command shows the available commands and syntax, while /HELP gives more details.

The /NAME command is used to enter the user's first name, and serves as a "login". Users are not permitted to join any channels until they have supplied a name. TCP/IP users must additionally supply a callsign with the /USER command.

/CHANNEL, /JOIN and /LEAVE are used to select the desired channel, /WHO shows the active channels and who is using them, and /QUIT terminates the chat session. The full command set is shown in more detail in the command reference section.

Users who log on to more than one chat server at once are treated as separate entities, and must supply their name and callsign on each server. Note that the RoundTable network does not allow a user to be logged on at more than one server, but there are often valid reasons for doing so, therefore the XRchat protocol allows multiple logins by design.

Configuration

The chat server is fully automatic and requires minimal setting up. It is configured using entries in XROUTER.CFG as follows:

CHATCALL

defines the chat callsign for AX25 and NetRom operations. A SSID of -8 is strongly recommended for all XRchat systems.

CHATALIAS

specifies the alias for AX25 and NetRom operations. It is recommended that this should begin with something geographically relevant, and end with "CHT" e.g. BHMCHT for Birmingham, LDSCHT for Leeds etc., so it can be easily identified in node tables.

CHATQUAL

specifies the NetRom "quality" assigned to the chat server and alias for L3/4 operations. If set to 0, the server will not be visible on the network. A setting of 255 makes the chat server as visible as the node, which just fills up the nodes tables. A value somewhere in between, to give medium visibility, is suggested.

CHATLOG

specifies the amount of detail that is logged. A value of 0 suppresses logging. Add together the values corresponding to the desired options from this table:

	1	Local user connect / disconnect event
	2	Remote user connect / disconnect event
	4	Peer server connect / disconnect event
	8	Local channels 1-255 join / leave events
	16	Public channel join / leave events
	32      Log channel notifications
	64	Log the text of conversations
	128	Use a single logfile, instead of daily ones

CHATPORT

adjusts or disables the TCP port which the chat server normally listens on. The default is 3600, but you may need to adjust this if you have another system or application using that port.

CHATLINKS

specifies the callsigns of other servers to link to (see below).

Configuring Links With Other Servers

• Links with RoundTable/BPQChat can only use NetRom.
• Links with Tampa Ping-Pong peers can only use TCP/IP.
• Links with XRChat peers may use either NetRom or TCP/IP, but NetRom is the norm.

If NetRom linking is used, you must specify the peer's CALLSIGN not the alias. The peer's callsign and alias must exist in your nodes table, i.e. you can't link with peers beyond the NetRom "horizon".

Unilateral linking is not allowed, and will not work. You *must* co-ordinate it with your peers, such that you are in their CHATLINKS list and they are in yours. Attempts to link unilaterally will result in links being "parked".

You should avoid linking to peer servers via slow links. If the link isn't up to the job, frames will be dumped, and the users will therefore get a poor service.

Links With XRouter Peers

NetRom links with XRouter chat peers are specified in XROUTER.CFG as follows (you can put several peers in one CHATLINKS directive, or use one directive per link, or any combination thereof):

	CHATLINKS=<netrom_call>,<netrom_call>,...

e.g. 	CHATLINKS=GB7GH-7,GB7BM-8,N0LBA-8

For TCP/IP links with XRouter chat peers, the IP address and TCP "port" number must be specified, along with the CHATALIAS of the peer server, and you can only specify one peer per line.

	CHATLINKS=<ip_address>:<tcp_port> <peer_alias>

e.g.	CHATLINKS=67.69.96.23:3600 KDRCHT

Links with RoundTable/BPQ Peers

Links with RoundTable/BPQ chat servers are defined similarly to the XRchat NetRom case, except that the peer callsigns must be prefixed with a '+', for example

	CHATLINKS=+XE1FH-11,+N1FGR

The '+' is very important - it tells XRPi to use RoundTable protocol instead of XRchat protocol!

Links with Tampa Ping-Pong Peers

Links with Tampa Ping-Pong converse servers are specified as follows. Note the <peername> is prefixed with a '*' to distinguish it from an XRchat TCP entry:

	CHATLINKS=<ip_address>:<tcp_port> *<peername>
e.g.	CHATLINKS=80.195.22.67:3601 *brmcht

Configuring Links At Run Time

Peer links may be added and removed at any time using the /LInks command.

XRChat Peers

NetRom: /LI ADD <netrom_call>
TCP/IP: /LI ADD <ipaddress>:<tcp_port> <peer_alias>

Examples:

	/LI ADD GB7BX-9
	/LI ADD 67.69.96.23:3600 KDRCHT

RoundTable / BPQ Peers

Syntax:	/LI ADD +<netrom_call>

Example:

	/LI ADD +XE1FH-11

Tampa Ping Ping Converse Peers

Syntax: /LI ADD <ipaddress>:<tcp_port> *<peername>

Example:

	/LI ADD 80.195.22.67:3601 *brmcht

Files

The chat server stores user accounts in the CHAT subdirectory, and reads its HELP files from CHAT/HELP/ subdirectory.

If transaction logging has been enabled by a non-zero CHATLOG directive in XROUTER.CFG, chat server activity is recorded in the LOG subdirectory. If the "use single logfile" option is enabled, everything is logged to file CHATSERV.LOG, otherwise it is logged to dialy logfiles with names in the form yymmddCH.LOG, where yymmdd are the year, month and day.

See also

CHAT(1) -- CHAT command.
CHATCMDS(1) -- Detailed description of chat server commands.
XROUTER.CFG(8) -- Main Configuration File.