[Udpcast] throttle output of udp-cast

Alain Knaff alain at knaff.lu
Tue Sep 23 22:47:26 CEST 2008


Sorry for the slow answers, I've been busy with other projects (LLL) for
a while. Let's hope it's not too late yet.

David Crider wrote:
> Is it possible to do dynamically throttled UPDcast transmission? We need
> to throttle the data flow to a Logic Innovations IP encapsulator (with
> LI's documentation attached with their permission).
> The udpcast mutlticast address is considered a single route to the IPE.
> The IPE sends out flow-control messages (described in document) that
> shows how many bytes are available for traffic for each route every 100
> milliseconds in a multicastand comes from a user specified multicast of
> its own. Attached is the LI document, again with the manufactures
> permission. Also, you can contact Theo Aukerman,   taukerman at logici.com
> for any additional info.

In today's version (20080914), I've implemented a possibility to plug in
so called "rate governor" modules. These are modules that decide how
fast udpcast transmits.

The examples/rateGovernor subdirectory contains as an example a
rateGovernor listeing to the Logic Innovations IPE's flow control messages.

The example can be compiled by typing "make" in that directory, after
having installed the udpcast/rateGovernor.h file under /usr/include

To activate it, add the following option to the udp-sender command line:

udp-sender -g ipe.so:ip=224.1.2.3,port=5555

this instructs the module to listen for flow control packets on the
multicast address 224.1.2.3 on port 5555.

I assumed that all integer values in these flow control packets are in
network byte order. Should this not be the case, this can be changed easily.

The plugin architecture also allows to easily add support for other IP
encapsulators.

> I'm asking these questions because IF this is possible, then this would
> be an almost complete framework for an open source Data-casting network,
> and can be used for over the air data-broadcasting from any DTV
> transmitter or any other system with null packets. I currently work as
> an engineer for a TV station that does data transmission, but would like
> to move to an open source model.

Congratulation for your decision to move to open source.

Let's hope it'll still be useful despite the long delay. Sorry again.

Regards,

Alain



More information about the Udpcast mailing list