Example Usage

Reliably transporting a file over multicast (assuming no packets are lost):

Pipeline(RateControlledFileReader("myfile"),
         SRM_Sender(),
         Multicast_transceiver("0.0.0.0", 0, "1.2.3.4", 1000),
        ).activate()

On the client:

class discardSeqnum(component):
    def main(self):
        while 1:
            if self.dataReady("inbox"):
                (_, data) = self.recv("inbox")
                self.send(data,"outbox")

Pipeline( Multicast_transceiver("0.0.0.0", 1000, "1.2.3.4", 0)
          SRM_Receiver(),
          discardSeqnum(),
          ConsoleEchoer()
        ).activate()

How does it work?

SRM_Sender is a Pipeline of three components:

• Annotator -- annotates a data stream with sequence numbers
• Framer -- frames the data
• DataChunker -- inserts markers between frames

SRM_Receiver is a Pipeline of three components:

• DataDeChunker -- recovers chunks based on markers
• DeFramer -- removes framing
• RecoverOrder -- sorts data by sequence numbers

These components will ensure that data arrives in the right order and that duplicates are removed. However it cannot recover lost data. But the final output is (seqnum,data) pairs - so there is enough information for the receiver to know that data has been lost.

The Annotator component receives data on its "inbox" inbox, and emits (seqnum, data) tuples on its "outbox" outbox. The sequence numbers start at 1 and increments by 1 for each item.

The Annotator component does not terminate and ignores messages arriving on its "control" inbox.

See documentation for the other components for details of their design and behaviour.

class Annotator(Axon.Component.component)

Annotator() -> new Annotator component.

Takes incoming data and outputs (n, data) where n is an incrementing sequence number, starting at 1.

class RecoverOrder(Axon.Component.component)

RecoverOrder() -> new RecoverOrder component.

Receives and buffers (seqnum, data) pairs, and reorders them by ascending sequence number and emits them (when its internal buffer is full).

prefab: SRM_Receiver

Simple Reliable Multicast receiver.

Dechunks, deframes and recovers the order of a data stream that has been encoded by SRM_Sender.

Final emitted data is (seqnum, data) pairs.

This is a Pipeline of components.

prefab: SRM_Sender

Simple Reliable Multicast sender.

Sequence numbers, frames and chunks a data stream, making it suitable for sending over an unreliable connection that may lose, reorder or duplicate data. Can be decoded by SRM_Receiver.

This is a Pipeline of components.