Summary: MBONE Multicasting

From: Rasana Atreya (
Date: Mon Oct 14 1996 - 11:11:04 CDT

First of all, my grateful thanks to Tim Henrion (Computer Sciences Corporation He was the only one who responded, and answered all my
questions incredibly patiently (in 3 separate emails).

In my original post, I had lots of questions on how to set a connection to
the mbone (for audio/video conferencing).

Since I did not really find a good HOWTO, I've written up one. Hopefully
it'll save someone the same frustrations.

                        Rasana's MBONE HOWTO ;)
First, read:

Article (


You need to get mrouted (multicast router daemon) only if you are audio/video
conferencing across subnets. You do not need one if you're doing it on 2
machines on the same subnet.

For sparc and Solaris 2.x, go to and
get mrouted. mrouted is used for routing the multicast packets across subnets.
It has very easy to install instructions. You need one mrouter per subnet
since multicast packets cannot cross routers. You do not need the mrouted or
/etc/mrouted.conf on a host (as opposed to the workstation dedicated as the
mrouter), but you do need to install the above package in the host mode to
modify kernel files (so that it can participate in the conferencing - I do
not know the details of what it actually does).

sdr: sessions directory - what you use to create or join conferences. When
you join a conference, sd/sdr passes the appropriate parameters to the other
tools to start them. You have to make sure that these tools are in the path
of the user starting up sdr. Read the help pages in the GUI.

vic: tool for video - read man page
vat: tool for audio - read man page
wb: white board for drawing - read post script file included

Get sdr, sd is obsolete (also sd and sdr are incompatible). Get vic instead
of nv.

You do not need to start up these tools individually. As long as they are in
the path of the user, sdr does it for you.

Now you need to connect to an outside mrouter who is willing to "feed" you
(form a tunnel with you as the end-point). Send email to the mbone mailing list
mbone-na-request@ISI.EDU to subscribe, then post to the list requesting a

Once you get a response, put this IP address in your /etc/mrouted.conf as

   tunnel Your_IP_address Your_feed's_IP_address metric 1 threshold 64

Metric is 1 if you connect to them directly (they are one hop away)
Threshold is 32/64 (time to live parameter). This parameter should be the
same in both /etc/mrouted.conf files across the tunnel.

To test if your feed has enabled you, do an "mrinfo feed_IP"
mrinfo -> ( [1/32/tunnel/down/leaf]

You should see their IP address point to yours. Your host name in
parenthesis. In square brackets is metric 1, threshold 32. After tunnel you
if you see "down" it indicates a problem. The correct report should be: -> ( [1/32/tunnel/leaf]


To check which software goes with your setup:

A Sparc 2 has built in speakers, so you can receive audio. To transmit
audio, you need external microphones.

You need only one Ethernet card to get by.

To receive video you do not need any special hardware, it's all done in
software. To transmit, you do need a camera/camcorder, and also a frame/video
grabber (a Sun video card).

When you run sdr, you don't see any items show up. Some of the possible ways to
explore why this isn't working:

- On your multicast router, make sure that it knows about your host's group
membership, and that its tunnel is considered to be up. Use "snoop" or some
other network monitoring tool to see if the router is sending out IGMP queries
and if your host is responding to them.

- Read man pages on mrinfo, mtrace, map-mbone, mstat

- Search MBONE Mailing List Archives

- Search rem-conf Archives



~ Rasana Atreya Voice: (415) 476-3623 ~
~ System Administrator Fax: (415) 476-4653 ~
~ Library & Ctr for Knowledge Mgmt, Univ. of California at San Francisco ~
~ 530 Parnassus Ave, Box 0840, San Francisco, CA 94143-0840 ~
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