Mbone

Key takeaways

Mbone belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Mbone to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Mbone from memory before moving on to harder problems.

Reference excerpt

Mbone (short for "multicast backbone") was an experimental backbone and virtual network built on top of the Internet for carrying IP multicast traffic on the Internet. It was developed in the early 1990s and required specialized hardware and software. Since the operators of most Internet routers have disabled IP multicast due to concerns regarding bandwidth tracking and billing, the Mbone was created to connect multicast-capable networks over the existing Internet infrastructure.

History Mbone was created by Van Jacobson, Steve Deering and Stephen Casner in 1992 based on a suggestion by Allison Mankin. During March 16–20, 1992 the first significant use of the MBONE took place from the Internet Engineering Task Force (IETF) meeting in San Diego with 20 sites listening. On May 23, 1993, Wax or the Discovery of Television Among the Bees was streamed over the Mbone, becoming "the first movie to be transmitted on the Internet." On June 24, 1993, the band Severe Tire Damage was the first to perform live on the Mbone. On November 11, 1993 Sky Cries Mary performed on the Mbone from Bellevue, WA sponsored by Starwave. On August 23, 1994, the band Deth Specula broadcast the first live concert over the Mbone. A November 1994 Rolling Stones concert at the Cotton Bowl in Dallas with 50,000 fans was the "first major cyberspace multicast concert." Mick Jagger opened the concert by saying, "I wanna say a special welcome to everyone that's, uh, climbed into the Internet tonight and, uh, has got into the M-bone. And I hope it doesn't all collapse." A year later the Mbone was used, this time symmetrically (simultaneous transmission and reception without hierarchy among participants), for a first experience of real-time graphical interaction without the intermediary of any Center (Poietic Generator). By 1995, there were M-bone links in Russia, as well as at the McMurdo Sound research station in Antarctica. Mbone was predominantly used by research and scientific entities, including NASA. Mbone was used for shared communication such as video teleconferences or shared collaborative workspaces. It was not generally connected to commercial Internet service providers, but often to universities and research institutions. Some other projects and network testbeds, such as Internet2's Abilene Network, made Mbone obsolete. A "virtual room video conferencing system" (VRVS) started operation in 1997 using the Mbone, and was in operation through 2008. A revived mboned (mbone deployment) working group was chartered by the Internet Engineering Task Force in 2014, as a forum to coordinate and document multicast deployment challenges and best practices.

Details The purpose of Mbone was to minimize the amount of data required for multipoint audio/video-conferencing. Mbone was free and it used a network of routers that support IP multicast, and it enables access to real-time interactive multimedia on the Internet. Many older routers do not support IP multicast. To cope with this, tunnels must be set up on both ends: multicast packets are encapsulated in unicast packets and sent through a tunnel. Mbone uses a small subset of the class D IP address space (224.0.0.0–239.255.255.255) assigned for multicast traffic. Mbone uses 224.2.0.0 for multimedia conferencing.

Characteristics topology: a combination of mesh and star networks IP addresses: 224.2.0.0 routing schemes: DVMRP, MOSPF session registration: IGMP traffic requirement: audio 32-64 kbit/s, video 120 kbit/s

Mbone tools Videoconferencing: vic -t ttl destination-host/port (supports: NV, H.261, CellB, MPEG, mJPEG) Audioconferencing: vat -t ttl destination-host/port (supports: LPC, PCMU, DVI4, GSM) Whiteboard: wb destination-host/port/ttl Session Directory: sdr Collective art : gp (Poietic Generator)

See also CastGate—an attempt at providing connectivity to the multicast network for hosts which have none

References

External links MBONE: Multicasting Tomorrow's Internet: Classic book about MBONE, by Kevin Savetz, Neil Randall, and Yves Lepage, complete on-line IETF MBONE Deployment working group How to connect to the MBone AccessGrid.org Making the MBone Real—Ajit S. Thyagarajan, Stephen L. Casner, and Stephen E. Deering, Proc. INET '95. Internet Society. May 10, 1995

Historical clients LBNL's tools MICE's tools Telecom Paristech (ex-ENST Paris)

Illustrations

Mbone: Mbone session directory (sd), February 1996 — Mbone session directory (sd), February 1996

Worked examples

Example 1 — a first encounter with Mbone

Start with the simplest possible case. Write down what Mbone claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Mbone before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Mbone ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Mbone

In research: Mbone appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Mbone in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Mbone is common in secondary-school and first-year university syllabi. It links to neighbouring topics Internet architecture, so understanding it makes those chapters shorter.
In everyday life: Look for Mbone outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

How to study Mbone in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Mbone means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Mbone out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Mbone in simple terms?

Mbone (short for "multicast backbone") was an experimental backbone and virtual network built on top of the Internet for carrying IP multicast traffic on the Internet. It was developed in the early 1990s and required specialized hardware and software.

Why does Mbone matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Mbone?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Mbone.