Multicast Traffic on Backbones

Sun Jun 10 12:41:04 UTC 2001

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

On Sun, 10 Jun 2001, Joshua Goodall wrote:

>
> On Sat, 9 Jun 2001, Tim Winders wrote:
>
> > UUnet has two levels of multicast capabilities.  Their "Basic" package is
> > receive only and is free.  Their "Gold" package is full send/receive, but
> > they charge a ton for it.  The basic package seems pretty useless to me.
> > To join a multicast group, you have to be able to send to it, right?
>
> not right. with many/most multicast protocols, you can (sometimes must)
> build a source-rooted tree, not a shared tree. joining as a receiver
> is then a matter of becoming another branch off the tree, hopefully
> along the reverse shortest path to the sender. in this case, you can
> send but not receive.

Now my eye's are glazing over.  :-)  Did you mean "receive but not send"
or actually, "send but not receive" as you wrote above?

UUnet's arguement for charging to sendis that you can potentially chew up
large portions of their network bandwith with only a small connection
yourself.

> possibly the difference is in your permissions to establish a (s,g) pair
> or to announce a core (RP).

With their basic package, you don't get to announce an RP at all.

> which multicast routing protocols are on offer? PIM-SM? MSDP? MBGP?
> if you can't get your multicast across the border, it may not be useful
> to you.

Their "Gold" package is PIM-SDM/MSDP/MBGP.  Their "Basic" package is
PIM-SDM/SDR with DVMRP unicast-routing.  I was told UUnet runs PIM
Dense-Mode on their multicast backbone.

> there are better protocols in the literature than are deployed
> but the arcana is often politically anathema for inertial, commercial
> or plain lack-of-working-code reasons.
>
> > I have found that most sales reps don't know what multicast is, or why it
> > is important to have.
>
> many network engineers glaze over at the mention of multicast. it
> takes some serious grey matter work to fathom the entire subject.

Very true.  I am having a hard time grasping the technical specifics.  It
has taken quite a bit of study and discussion to figure out what I have so
far, and I am sure I have misunderstood many things.  Unfortunately, what
I am finding out, is that multicast is a subject that rarely comes up as
an option with customers.  There isn't a demand, so the providers don't
put the resources into it...

=== Tim

     **********************************************
        Tim Winders, MCSE, CNE, CCNA
        Associate Dean of Information Technology
        South Plains College
        Levelland, TX  79336

        Phone:	806-894-9611 x 2369
        FAX:	806-894-1549
        Email:	TWinders at SPC.cc.tx.us
     **********************************************

-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.0.6 (OSF1)
Comment: Made with pgp4pine 1.76

iEYEARECAAYFAjsjauMACgkQTPuHnIooYbwIdgCaAmerFCuB2N2cqbDdER1mrbKm
JlcAnAygYKNWA7hRSgQesQiYtYvURS3s
=88GE
-----END PGP SIGNATURE-----