How to be a good MBONE neighbor

Bill Fenner

Table of Contents

• Stan Barber's Notes
• February 1997 NANOG Home Page

Stan Barber's Notes

The Mbone is a virtual network overlaying the Internet. There are 4000 subnets on the Mbone now.

Why do it?

• Your customers want it. Your customers will tunnel over you if you don't do it.
• Because multicast is much more efficient at data delivery.

What should you be doing if you are on the mbone?

• Monitor your topology for loss.
• Rate limit appropriately
• Don't exceed your router's capacity for tunnel fanout
• Use tools like rtpmon to monitor stuff.
• Create a multicast@<provider> address for consistent contact address
• Require your customers to deploy pruning.

To monitor, use ping the end point of tunnels for loss.

• mtrace -T is good, but some counters are not working correctly.

Quality can be affected by routing.

A rate limit of 500 kbps is a was a good idea when customers are mostly T1. It's not appropriate any more.

For links inside providers, turning off rate limit is a good idea. Rate limit on customers may be a good idea.

Be careful when adding tunnels. The CPU has to replicate the packets.

NOC need to know about the MBONE. Is it advertised in sdr? What is the session name?

Multiaccess links do not put good counters in mtrace -T

Filter routes coming from your customers.

Use Cisco 11.1 IOS or mrouted 3.X only.

Questions & Answers

Bill Manning asks about the distribution of versions of mbone software on the Internet.

There are a number of old versions out there. The old versions don't do pruning. In some cases, a kernel modification will be required.

Will mrouted have the notion of a injected default?

We have had some work done in this area, but is not completed.

What about hierarchical DVMRP?

The stuff that has been done had too many simplifications in it to be useable in the mbone. Hopefully, DVMRP will be replaced soon by some other multicast routing protocol.