[OT, Q] Architecture for Message Broadcasting

Joshua Gargus schwa at fastmail.us
Wed Jul 4 01:13:17 UTC 2007


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 at smalltalkconsulting.com>
> Corporate Smalltalk Consulting Ltd.  http:// 
> www.smalltalkconsulting.com
> ====================================================================== 
> =====
>
>
>




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