If you want to send one message and have everyone hear it then you have to use UDP, which is connectionless.
Can you elaborate on this? How could this be done? Any sample code or doc on this?
Thanks in advance.
J J said
If you want to send one message and have everyone hear it then you have
to use UDP, which is connectionless.
and S.J.Chun asks
Can you elaborate on this? How could this be done? Any sample code or doc
on this?
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
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 ======================================================================== ===
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 ====================================================================== =====
On Jul 4, 2007, at 3:13 , Joshua Gargus wrote:
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.
That might change with more widespread adoption of IPv6. We do have an IPv6 implementation for Unix (the OLPC mesh will be IPv6), other platforms will surely follow.
- Bert -
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"S.J.Chun" -
Bert Freudenberg -
Frank Shearar -
John M McIntosh -
Joshua Gargus