2 Replies Latest reply on Mar 21, 2005 9:46 AM by mazz

    multicasting and routers

    mazz Master

      I'm getting into a networking/hardware area of which I know nothing :-)

      I'm setting up this Network Registry stuff and auto-detection of remote servers (using the MulticastDetector).

      The thing I am questioning is - is there anything special from an OS or router perspective that I have to configure to enable multicasting?

      I have a Netgear WGR614 wireless router and the only setting I see related to multicast is "RIP Direction" and "RIP Version". RIP Version of RIP_2B seems to relate to enabling multicast but I have no idea if I actually have to enable that? RIP Direction can be "in only", "out only" or "both" - is that something to do with packets going from router-to-router and thus I don't care?? (I have only a single router in my network - internet pipe from cable modem goes directly into it).

      I don't know of anything on the OS side (using Windows XP) that enables or disables or configures multicasting.

      Its hard for me to figure out how to even test to make sure this registry and detection stuff is either working or not - I plan on getting another computer on my network with my stuff installed, but right now I was hoping I could run two JBossAS servers each with a different bind address (I can go through my wireless or wired interface I supposed - since they have different IP addresses).

      Any tips/tricks would be appreciated.

        • 1. Re: multicasting and routers
          Tom Elrod Master

          Can't really speak to the configuration of your Netgear in particular. Would have to research to understand what the settings mean. However, most network devices that act as a switch and provide DHCP service will not allow muliticast past the device by default (have a wireless DLink where this is the case, but gave up trying to configure it to allow multicast because it is pos).

          There are a couple of tools you can use. One is the DetectorUtil within the remoting package. It is a simple class that will start eitehr a multicast or jndi detector and output the NetworkRegistry's entries every 3 seconds. This will at least give you insite as to what the detector can see. For a little lower level too to figure out if multicast is working, can run the jgroups org.jgropus.demos.Draw class (just need jgroups and commons-logging jar to run it). This will start a whiteboard. If start the Draw program on both machines and they see each other, via drawing on one and showing up on the other, then you know multicast is working (this only uses multicast to communicate). If this tool does not work, then is down to looking at network config, which will depend on your specific network (and can't help much without hands on)

          Hope this helps.


          • 2. Re: multicasting and routers
            mazz Master

            To close this thread - I did get it to work with no real configuration changes needed. Just have to make sure you use a multicast IP address (224.*.*.* - 239.*.*.*) for the MulticastDetector port - the default JBoss/Remoting is obviously fine here. What I ended up doing is connecting my laptop to the network via my router using two interfaces (the wireless and the normal wired connection). Then I just started two JBossAS servers using "-b {wireless addr}" and "-b {wired addr}". Things worked fine.