Basically, the netpd-server acts as an OSC (Open Sound Control) packet relay service: it forwards incoming OSC packets to one or many clients. The first field of the OSC address of an OSC packet from a client is considered to be the receiver ID. This may be a number that identifies a connected client, but some more receiver IDs? with special meanings are valid, too. The netpd-server reads this field and forwards the message accordingly. While doing so, the netpd-server replaces the receiver ID by the sender ID, i. e. the socket number of the sender of the packet. The receiving client might just read the first field of the address to know where the OSC packet originated.

list of valid receivers

/b          broadcast:     OSC packet is forwarded to all connected clients

/s          server:        OSC packet is forwarded to the server (or any additional server module)

/<socket>   socket number: OSC packet is forwarded to the client with specified socket number.
                           there are some restrictions about the socket number format:
                             - it must be an integer (floats are ignored)
                             - it must not contain any other characters than digits from 0 -> 9
                             - it must not exceed 6 digits (due to pd's way of representing high numbers)
                             - it can contain preceding zeros as long as above requirements are met

due to this restrictions, the maximum number of clients is limited to 999'999.


this server is intended to provide minimum functionality needed for a working setup. however, the functionality of this server can be expanded by modules. modules are patches, that are started within the same instance of pd as the server patch. the server patch provides a simple API, so that methods provided by modules can be called transparently. each module is addressed by the second field of the OSC address. if there is a module 'log' listening on '/log' on the server, it can be addressed from the client with '/s/log'.

methods of the server

the server patch provides its methods on '/server', respectively on '/s/server' (from the clients perspective).

list of server methods

CLIENT      /s/server/socket            request the own socket number
SERVER      /server/socket <socket>     server sends this packet only to the requesting client

CLIENT      /s/server/ip
SERVER      /server/ip <ip address>     the ip address is formatted as a list with four numbers

SERVER      /server/num_of_clients <num_of_clients>
                                        this message is broadcasted to all clients without being requested


Check the bottom of the download page.