Subject: Re: Minimum bandwidth for MBONE

From: John Roberts <[email-masked]>
Date: Fri, 11 Apr 1997 16:39:00 -0400

Thanks to all for the information of BW requirements.

How would I deploy MBONE services within my orgization when we have a
firewall segment (with registered addresses) routed to our internal
segments (non-registered 192.168.x.x addresses).

Would I run mrouted on a machine attached to our firewall segment (ie.
registered address) then tunnel from that machine to our internal stations
on the various 192.168.x.x address space?

Thanks,

-John
[email-masked]

At 03:56 PM 4/11/97 -0400, Mark Handley wrote:
>
>>I've heard discussions of MBONE over ISDN, Frame Relay etc..
>>
>>What is the minimum bandwidth/connectivity method to get the full effect of
>>MBONE?
>>
>>A T1 is the simple answer but will a 512k frame connection perform?  Or
>>would there be degradation (over a T1) even at those speeds?
>
>There isn't a simple single answer to this question.  It depends on
>the sessions you want to participate in.
>
>Typically a session such as the IETF or WWW conference may push out
>128Kbps video, 32 or 64Kbps audio and variable rate whiteboard data.
>So to receive such a session without being concerned about local loss,
>you'd get away with a 256Kbps link assuming not too much overhead from
>routing and periodic traffic bursts which get pruned.  In fact many
>people get away with 128Kbps of ISDN and use mrouted's prioritisation
>to preferentially throw away some of the video when the link gets
>saturated.
>
>There are good low rate codecs for audio and video available these
>days and I expect a lot of lower rate sessions to start appearing in
>the near future.  Mbone access over modems hasn't been a priority in
>the past, but a part of the market will go that way in the future,
>especially as RTP header compression starts to get deployed.  In
>addition, as workstations get faster, expect to see higher bandwidth,
>higher quality sessions appear too.
>
>If you're feeding more than one user, they will probably want to watch
>different sessions simultaneously.  The Mbone used to be engineered
>for 512Kbps traffic loads, but these restrictions are no longer in
>place, and transit sites often see significantly in excess of 512Kbps
>these days.  I expect this to grow significantly as multicast moves
>from being a Unix-only experiment into being generally available.
>
>Of course any answer also depends greatly upon what other traffic your
>multicast traffic would share your access link with.
>
>Mark
>
>

---

From: Bill Fenner <[email-masked]>
Date: Sat, 12 Apr 1997 10:11:34 PDT

>segments (non-registered 192.168.x.x addresses).

The best solution to this problem is to have two totally seperate multicast
routing domains - one on the firewall segment, connected to the MBone, and
one internal.  Set up application gateways (e.g. an RTP translator) on a
machine which is in both domains.  The hard part is starting up the application
gateway at the right time (e.g. when people start tools on the inside).
Ross Finlayson presented a firewall infrastructure similar to this at the
MMUSIC session of an IETF (but I don't remember which).

  Bill