Re: Multicasting past routers?
Re: Multicasting past routers?
- Subject: Re: Multicasting past routers?
- From: Joshua Graessley <email@hidden>
- Date: Wed, 24 Mar 2004 10:55:15 -0800
Multicast has to be enabled in a router. A device and router use IGMP
to communicate memberships to multicasts. Most of "the internet" does
not support multicast routing to the best of my knowledge.
The AirPort base station is not a router. It's a NAT device. The
difference is that the NAT device mangles the packets in order to make
it appear as though packets from a number of machines came from one IP
address. I have no idea how or if most NATs support multicast. My guess
is that most NAT devices do not support multicast.
You may also need to use the socket options to join the multicast group
before sending. This will trigger the stack to use IGMP to join the
multicast group. If you have a router that does handle multicast
routing, this will notify the router you are interested in sending and
receiving packets on that multicast.
-josh
On Mar 24, 2004, at 6:52 AM, Tomas Zahradnicky wrote:
>
Hi,
>
>
multicasting should be able to pass through routers. Whether or not
>
should be determined by TTL, group address I broadcast to and router
>
settings. I've tried to do multicast on airport machine A and get it
>
on another machine C on ethernet through my powerbook B acting as
>
airport<->ethernet router (I turned on ethernet->airport sharing in
>
system prefs), but machine C (and vice versa) did not get any
>
multicast from machine A.
>
>
Is machine C supposed to get multicast from machine A if I set TTL
>
(according to Stevens) to 32 and do the multicast to a group address:
>
224.50.54.85?
>
>
Thanks,
>
>
Tomas
>
--
>
Ing. Tomas Zahradnicky, Jr.
>
Production Manager, 24U Software
>
Associate Member, Filemaker Solutions Alliance
>
mailto:email@hidden
>
http://www.24uSoftware.com
>
_______________________________________________
>
macnetworkprog mailing list | email@hidden
>
Help/Unsubscribe/Archives:
>
http://www.lists.apple.com/mailman/listinfo/macnetworkprog
>
Do not post admin requests to the list. They will be ignored.
[demime 0.98b removed an attachment of type application/pkcs7-signature which had a name of smime.p7s]
_______________________________________________
macnetworkprog mailing list | email@hidden
Help/Unsubscribe/Archives:
http://www.lists.apple.com/mailman/listinfo/macnetworkprog
Do not post admin requests to the list. They will be ignored.