Hi,
Thank you very much for your all answers. As I said in my previous mail, I cannot assume that I can use multicast/broadcast support because there's some routers which do not support these features.
It seems that my original idea - though TCP part could be replaced by UDP for efficiency - might be my last choice. My current idea is that all clients are connected to the server and between clients and server, single byte data (kind of ping) is exchanged periodically and if the clients received some new data is received to the server, then client fetched the data and display. Any client can post new data to the server through another transport(maybe TCP for this case?). I think this kind of application will be helpful for broadcasting messages to the people(like flashmob :-)
Thank you again.
----- Original Message ----- From: Joshua Gargus schwa@fastmail.us To: johnmci@smalltalkconsulting.com, The general-purpose Squeak developers list squeak-dev@lists.squeakfoundation.org Sent: 07-07-04 10:13:17 Subject: Re: Re: [OT, Q] Architecture for Message Broadcasting
Various versions of Croquet have used UDP broadcast for LAN discovery. I haven't heard of anyone doing IP multicast in Squeak; as others have noted, support for IP multicast is not widespread on the internet at large.
We might be wandering away from solving S.J.Chun's real problem. Depending on what he (she?) is trying to accomplish, his original approach may be quite viable. At a very high level of abstraction, a Croquet router could be said to work in that way.
Josh
On Jul 3, 2007, at 5:25 PM, John M McIntosh wrote:
Technically support for this is in various unix flavors (osx) of the VM. I think. You might need to set some TCP/IP options to exploit via the socket plugin prim interface for setting options.
On the other hand I've not heard of anyone using it to confirm it works. Can not speak for windows, no idea how XP would treat this or if support in the windows VM socket code.
In both cases you would need to cross check the source code.
On Jul 3, 2007, at 1:40 PM, Frank Shearar wrote:
J J's referring to sending UDP to multicast addresses. Basically, interested parties signal (say, through the Internet Group Management Protocol, IGMP (RFC 2236)) that they want to receive data sent to a particular multicast address (RFC 3171 defines the (PIv4) multicast address range as 224.0.0.0 to 239.255.255.255. Likely you'd be interested in an address in the 224.0.0.0/24 block, which is for link local multicast.). Datagrams sent to that multicast address are duplicated and sent to all the interested parties.
http://en.wikipedia.org/wiki/IP_Multicast is a good starting point for multicast.
One thing to bear in mind is that any routers between the sender/s and receiver/s must support multicast.
frank
--
===== John M. McIntosh johnmci@smalltalkconsulting.com Corporate Smalltalk Consulting Ltd. http:// www.smalltalkconsulting.com ====================================================================== =====
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