T-11. What are the plans of router vendors
w.r.t. multicasting?*** This page is under construction, suggestions welcome ***
The European Mbone FAQ is written as an effort for the RIPE Mbone WG.
This is the European edition of the Multicast Backbone (Mbone) Frequently Asked Questions (FAQ) and their answers. This document contains numberous links to other documents available on the Internet. The author is grateful to all maintainers of those documents for having them on-line.
There are several reasons for having a Euro-FAQ, besides the world-wide FAQ that is maintained. One of them being the fact that in Europe bandwidth is still scarcely available in some places and therefore in Europe you cannot allow more than one Mbone tunnel accross the same physical wire.
DISCLAIMER: The FAQ comes without any warrenty. The author can not guarantee the correctness and completeness of all information contained in this FAQ at any point in time.
Additions and corrections are welcome. Please send them to the author (address at the end of this document).
Mbone is the overlay network, on top of the Internet, as a result of IETF developed technology. The Mbone is still (permanently?) under construction while new technologies are being introduced. The Mbone is also expanding, more users hook into Mbone every week.
Mbone is the implementation of multicasting technology. Several application can use a multicast capable network, auch as video, audio and shared workspaces.
First of all, since Mbone is not a full-fledged services, provided by all Internet Service Providers, documentation can sometimes be lacking. There are several nice starting points, though, listed here:
YES! The MICE Project uses the Mbone multicasting infrastructure. The MICE National Support Center - The Netherlands is one example to look at. You can use this as a starting point for learning more about the MICE Project.
Mbone is an overlay network on top of the Internet, sometimes also called a virtual network. Mbone consists of "multicast routers" (mrouters) and "tunnels" between the mrouters.
An mrouters is a multicast capable router. In today's Mbone most mrouters are Suns running SunOS 4.1.X with the mroute-daemon (mrouted). New developments however are underway (see appropriate questions below).
Mrouters maintain connections, called "tunnels" between each other. Mrouters connecting to an ethernet also have the possibility of broadcasting the multicast packets over the ethernet. An mrouter is only an mrouter if it has at least two tunnels (or one tunnel and an ethernet interface).
A tunnel is a connection between two mrouters. There are two technologies in use for implementing a tunnel, however one of them is obsolete.
The first, and now most important, implementation is "IP over IP". The second, and now obsolete, implementation is loose source routing.
A tunnel always has a source and a destination, but written as an IPv4 address. A tunnel also has two parameters called "metric" and "threshold", defining the chraracteristics of the tunnel.
Sure. Various people created maps, and some of them are even maintained. Have a look at:
The metric of a particular tunnel is used in calculating routing. The lowest value of the metric is 1. Each mrouter holds a routing table which has a next hop for each destination in the Mbone, with the metric being lowest.
You don't really have much of a choice at the moment. Mrouted version 2.2 is the only one which is supported by the multicast code in the Solaris 2.3 kernel. You can pick up a copy of the source for mrouted 2.2 and a patch from Richard Murphy to make it compile on Solaris 2.3 in: ftp://ftp.ucs.ed.ac.uk/pub/videoconference/mrouted/mrouted.tar.Z and ftp://ftp.ucs.ed.ac.uk/pub/videoconference/mrouted/mrouted.2.2.solaris-patch.
T-11. What are the plans of router vendors
w.r.t. multicasting?Cisco says: Multicast routing support is in IOS 10.2.
Yes, you can, provided that you have the correct hardware installed. In case you want to send both audio and video, make sure you have the correct frame grabber installed and the audio connected to you workstation.
Please bare in mind that not everybody on Mbone might be interested in your transmission. Do not consume more bandwidth than stricktly needed, by make sure your thesholds are set right (refer to the technical section in case you are lost now).
Yes. It is possible to have Mbone traffic through a unicast firewall. What you need is that two protocols on top of IP are permitted through the firewall: - port 2 - port 4
This is an example for a Cisco router, where 192.1.1.1 is the remote Mbone router (somewhere in the Internet) and 192.2.2.2 is the local one, behind the unicast firewall on ethernet 0:
! Define the ethernet with the local Mbone router: interface Ethernet 0 ip address 192.2.2.2 255.255.255.0 ip access-group 100 ! Define the acces-list: access-list 100 permit 2 192.1.1.1 0.0.0.0 192.2.2.2 0.0.0.0 access-list 100 permit 4 192.1.1.1 0.0.0.0 192.2.2.2 0.0.0.0
First of all, try sending your question to your national list (see Q-99). In case this does not help and in case nobody is able to help you or point you to a location where help is available, try sending e-mail to the European Mbone list mentioned in the Mbone Working Group Info Page. In case this fails, try the worldwide list. Please use this order for things.
Many people helped in getting this FAQ into the stage in where it is now. Thanks go to the following people (in alphabetical order):