Using the network package for multicasting

Discussion in 'Java' started by Sona, Sep 26, 2003.

  1. Sona

    Sona Guest

    Hi,

    Can someone point me out to a good article on how to create/use IP
    multicasting in Java applications? I'm interested in developing a
    program that will use it. Thanks

    Sona
    Sona, Sep 26, 2003
    #1
    1. Advertising

  2. Sona

    Roedy Green Guest

    On Sat, 27 Sep 2003 03:09:47 +1000, Sona <>
    wrote or quoted :

    >
    >Can someone point me out to a good article on how to create/use IP
    >multicasting in Java applications?


    I can show you some code to do UDP. If the multicast IP is set up
    already, all you would have to do is send to that magic IP.

    How you go about setting up a list of recipients for a multicast, I
    don't know.

    I have not yet found a description of just how multicast works and
    what its limitations are. There are "send to everyone on the LAN"
    addresses in Ethernet that might be useful in implementing it.

    I proposed a multicast protocol that does not need multicast IPs.
    See http://mindprod.com/projinternetradio.html

    --
    Canadian Mind Products, Roedy Green.
    Coaching, problem solving, economical contract programming.
    See http://mindprod.com/jgloss/jgloss.html for The Java Glossary.
    Roedy Green, Sep 26, 2003
    #2
    1. Advertising

  3. Sona

    Rene Guest

    Roedy Green <> wrote:
    > On Sat, 27 Sep 2003 03:09:47 +1000, Sona <>
    > wrote or quoted :
    >
    > >
    > >Can someone point me out to a good article on how to create/use IP
    > >multicasting in Java applications?

    >
    > I can show you some code to do UDP. If the multicast IP is set up
    > already, all you would have to do is send to that magic IP.


    Yep. But there is no need to specially mention UDP. There is no multicast
    TCP and there can't be. (TCP requires acknowledgmentes, a back channel. But
    there is only one sender that sends his one single stream of packages and
    does not ever get anything return - there is no retransmission or
    acknowledge in multicast)

    > How you go about setting up a list of recipients for a multicast, I
    > don't know.


    You don't - the system does it for you. Just look at it this way, imagine
    the multicast IP the sender sends to is not an address but a channel. The
    recievers then tune in to the channel and get the messages. Like with a
    standard radio broadcast, the sender does not know how many people are
    tuned in.

    On a technical level, the recievers send a sort of "I want to join that
    channel/IP" which then causes their routers to try to get the multicast
    stream so that they can serve their client. The routers split (multiply)
    the multicast traffic down all their physical nodes that want to recieve
    that stream, they are forming a sort of one way flow tree.

    There are different ways how those trees are built up. (A trivial but
    wasteful one is: Send to every other router and then cut back/prune those
    out who don't want it) You can do that on a local scope but not on the
    internet.

    Btw. multicast doesn't work on the whole internet. There are only a
    fraction of nodes who can do multicast. It usually only works in LANs where
    support for multicast is explicitly enabled and configured.

    > I have not yet found a description of just how multicast works and
    > what its limitations are. There are "send to everyone on the LAN"
    > addresses in Ethernet that might be useful in implementing it.


    That's what you can do on one single ethernet segment, just a physical
    ethernet broadcast. However when your stream spans different segments or
    subnets, you need routers that know how to handle and forward multicast.

    As for documentation, this one from Cisco is the best I have:
    http://www.cisco.com/en/US/tech/tk828/tk363/tech_protocol_family_home.html

    If you don't want the nutty details, click left on "Overview" and then on
    "Technology Briefs" followed by "Internet Protocol IP Multicast Technology"

    > I proposed a multicast protocol that does not need multicast IPs.
    > See http://mindprod.com/projinternetradio.html


    I skimmed through that page of yours. It does already exist. Search google
    for "P2P radio" and you should find plenty of links.

    CU

    Rene

    --
    -------------------- http://NewsReader.Com/ --------------------
    Usenet Newsgroup Service New Rate! $9.95/Month 50GB
    Rene, Sep 26, 2003
    #3
    1. Advertising

Want to reply to this thread or ask your own question?

It takes just 2 minutes to sign up (and it's free!). Just click the sign up button to choose a username and then you can ask your own questions on the forum.
Similar Threads
  1. Kal
    Replies:
    1
    Views:
    9,520
    Kevin Spencer
    Jun 21, 2004
  2. smeer_alwosabi

    boradcasting and multicasting in java

    smeer_alwosabi, Sep 14, 2004, in forum: Java
    Replies:
    1
    Views:
    434
    Andrew Thompson
    Sep 14, 2004
  3. Jan Meskens

    Multicasting

    Jan Meskens, Apr 13, 2006, in forum: Java
    Replies:
    2
    Views:
    618
    Steve W. Jackson
    Apr 17, 2006
  4. Daemon Le

    Multicasting with Ruby?

    Daemon Le, May 20, 2004, in forum: Ruby
    Replies:
    5
    Views:
    375
    Daemon Le
    May 22, 2004
  5. Christoffer Lernö

    Reliable multicasting

    Christoffer Lernö, Oct 11, 2007, in forum: Ruby
    Replies:
    5
    Views:
    103
    Christoffer Lernö
    Oct 12, 2007
Loading...

Share This Page