Streaming video, how does it work?

[linux kid]

How is live video streamed on the internet? Since live/streaming video of course cannot be a single file. So how? Is it sent in small pieces or does data constantly flow from the source to the viewer? If so, how large is each piece?

 

[Anttech]

It is actually both, a single flow which is broken up into smaller frames. The "size" of the frames depends on the transmition medium, over the WAN like SDH for example. However your PC would never see or need to reassemble frames of this nature...

Video content is delievered through Multicasting, which is inbetween a broadcast and a unicast. There are 3 widely used version of this Sparce mode, Dence mode and Sparce-Dense Mode. For IPTV (live streaming TV) the Multicasting protocol would be a form of Sparce mode for delivery. Which is the same as over the GSM Network on 3G TV to mobile phones technology.

 

[chroot]

For standard IP networks -- the internet, for example -- all data is broken up into packets before being sent over the network. The network's responsibility is to route these individual packets from one place to another, based on the destination address.

The size of the packets is variable, and some devices (computers, hubs, routers, etc.) can handle larger packets than others. Generally, 1500 bytes is the maximum size of IP packets.

For streaming applications, the sending computer (server) does not need to send data to its clients at the fastest speed the network will support -- this is wasteful. Instead, the server can send data only as fast as is necessary to prevent the client from running out of data and having to stumble (drop frames) and make the video look choppy.

Most digital video formats allow the author to determine the "bandwidth" of the video stream. In other words, if the video's author encodes the video with an assumed 1 Mbps (one million bits per second) bandwidth, then any client who wishes to view it without dropping frames needs to be capable of downloading at least 1 Mbps.

- Warren

 

[Anttech]

Generally, 1500 bytes is the maximum size of IP packets.

Only applicable on Ethernet... Transmission technology's care about Time Windows, and typically mupltiplex streams into 64K segments, for easier extraction. The Majority of Internet traffic (IP traffic) runs over these types of networks, its just inside the cloud from your perceptive. MPLS over SDH is an example, The IP is there but encapsulated inside MPLS and in turn encapsualted inside SDH (SONET for Amercians)

Most digital video formats allow the author to determine the "bandwidth" of the video stream. In other words, if the video's author encodes the video with an assumed 1 Mbps (one million bits per second) bandwidth, then any client who wishes to view it without dropping frames needs to be capable of downloading at least 1 Mbps.

True, but you missed a key point, in that if 1000 users all need to view his video the sender doesn't need to send it at 1000* 1 Mbps only at 1Mbps as with multicasting the reproduction of packets is done close to the reciever within the telco cloud somewhere...

 

[chroot]

Only applicable on Ethernet... Transmission technology's care about Time Windows, and typically mupltiplex streams into 64K segments, for easier extraction. The Majority of Internet traffic (IP traffic) runs over these types of networks, its just inside the cloud from your perceptive.

I'm trying to simplify the process for the sake of the original poster. The majority of both of your posts here are likely incomprehensible to him, as they contain a huge number of unncessary, undefined acronyms and undefined terms.

True, but you missed a key point, in that if 1000 users all need to view his video the sender doesn't need to send it at 1000* 1 Mbps only at 1Mbps as with multicasting the reproduction of packets is don't withing the telco cloud somewhere...

Again, one doesn't need to understand the specifics of multicasting to understand the basic concept of packetized streaming video. Try to consider your audience, and pitch your responses at their level of understanding.

- Warren

 

[Anttech]

They are not undefined, nor are they unnecessary, they are actually widely used, and essential in understanding Streaming Video. The whole concept, is based around Multicasting, from cable TV to streaming IPTV content to your Xbox.

Streaming video has nothing to do with ethernet, nor is it broken into 1500 Bytes.. To say so is wrong...

Anyway sorry for over complicating, but if you ask an advanced question expect an advanced answer

 

[chroot]

They are not undefined, nor are they unnecessary, they are actually widely used, and essential in understanding Streaming Video. The whole concept, is based around Multicasting, from cable TV to streaming IPTV content to your Xbox.

You did not define them in your response, so they might as well be undefined. I wouldn't expect anyone to go hunting for references all over the web just to make sense of your response. In general, it isn't a good idea to use acronyms or terms without first being sure that your audience knows what they mean.

Streaming video has nothing to do with ethernet, nor is it broken into 1500 Bytes.. To say so is wrong...

Okay. I'll concede that. At the same time, any computer connected to the internet via an "end-user" link like Ethernet or 802.11 will receive 1500 byte packets.

Anyway sorry for over complicating, but if you ask an advanced question expect an advanced answer

He didn't ask an advanced question. He asked this: Is it sent in small pieces or does data constantly flow from the source to the viewer? If so, how large is each piece?

- Warren

 

[Anttech]

You did not define them in your response, so they might as well be undefined. I wouldn't expect anyone to go hunting for references all over the web just to make sense of your response. In general, it isn't a good idea to use acronyms or terms without first being sure that your audience knows what they mean.

Nope you are right I didnt define them the IETF did. Honestly I disagree with your stance on this. I hate been treated like an idiot, and would prefer to have correct information. But you are an admin and I am not so you win.

For your, or anyones references,
MPLS = Multi protocol Label Switching
SDH = Synchronous Digital Hierarchy (SONET = Synchronous Optical Network, I made an error in a previous acronym lol)
IP = Internet Protocol

Okay. I'll concede that. At the same time, any computer connected to the internet via an "end-user" link like Ethernet or 802.11 will receive 1500 byte packets.

By default, yeap, but nothing to do with the question.

He didn't ask an advanced question. He asked this: Is it sent in small pieces or does data constantly flow from the source to the viewer? If so, how large is each piece?

Ok I will concede that, it isn't an advanced question, but to attempt to give the correct answer you will need to get advanced. Because the whole concept revolves around Multicasting at layer 3 (IP addressing). You need an understanding of this to understand how video content is distributed, IMHO you cannot explain streaming video without touching on Multicasting.

 

[chroot]

You don't even need to consider delivery at all to understand the basic concept of packetized streaming video.

- Warren

 

[Anttech]

IMHO for video yes you do. If you just want to explain basic packetised transport of data (TCP/IP) then I guess not. But Streaming video (and sound like internet radio) is based around Multicasting, if it wasnt its development would have hit a brick wall a decade or so ago.

 

[Evo]

Anttech, things are different in the US. My company is one of the few (almost none) that allow free multicasting. There was a lawsuit filed by some large telco providers that wated to charge their end users for viewing multicast streams from another provider so the FCC is shutting down companies in the US that do multicast streaming. My largest multicast client was one of those recently.

I'm at work and don't have time to go into details, but Unicast is the predominat streaming format in the US, although it is bandwidth intensive.

 

[Anttech]

Interesting,

How on Earth could a Cable company unicast TV services to all clients, or are you only talking about Teleco's, (quad/triple play)?

It would mean that you would need (amount of users * BW to deliver content) amount of BW. Which would be way over the 10G max I would think.

 

[Evo]

I'm referring to streaming video over the internet.

 

[linux kid]

Why does Unicast still exist? I can't find it's advantage over Multicast.

@choot: I actually prefer advanced answers because i want all the details. If there is an acronym or word I don't understand, I just hold ALT and left click on the word (an firefox Answers.com extension). But you are right some people are left confused because they don't know any better.

 

[Evo]

Why does Unicast still exist? I can't find it's advantage over Multicast.

Unicast is better quality and easier to control quality, the drawback is that each unicast session sends a stream to a single user making viewing by multiple users very expensive.

The reason you don't see multicasting on the internet is that almost no internet providers in the US allow it because of the perceived revenue loss.

 

[Evo]

Only applicable on Ethernet... Transmission technology's care about Time Windows, and typically mupltiplex streams into 64K segments, for easier extraction. The Majority of Internet traffic (IP traffic) runs over these types of networks, its just inside the cloud from your perceptive. MPLS over SDH is an example, The IP is there but encapsulated inside MPLS and in turn encapsualted inside SDH (SONET for Amercians)

This has nothing to do with the OP's question. MPLS is a multi-location business wide area network. Sure you can do video over MPLS but this would only apply to a miniscule portion of BUSINESS customers.

Ok, you're going to force me to post this.

Q: What is multicast?

A: Multicast is an IP technology that allows for streams of data to be sent efficiently from one to many destinations. Instead of setting up separate unicast sessions for each destination, multicast will replicate packets at router hops where the path to different multicast group members diverges.

Q: Why would I want to use multicast?

A: Multicast is the best method of delivering the same data to multiple receivers at the same time. Servers send only one data stream, and on every link leading to all the receivers, there is only one copy of that data stream. Using unicast, the server must send a separate but identical data stream for each connected receiver. This results in a high server CPU load as well as increased network bandwidth demands at the server as a direct result of these redundant data streams. Broadcast would solve the problem of duplicated packets, but ends up flooding the entire network, even if only a few hosts wish to receive the data.

Q: Can you provide an example of using multicast vs. unicast?

A: Say that Company X wants to set up an Internet radio station. They plan to transmit a 28.8 kbps audio stream. If the company expects to have 100 people listening to their transmission at a given time, they will need to purchase two DS1 connections (3 Mbps) to provide the bandwidth necessary for this radio station to send this data via unicast. (100 separate connections x 28.8 kbps = 2.88 Mbps) This is highly inefficient, since all 100 sessions are replicated from the server to the Internet provider, and possibly additional duplication is occurring down the path.

Multicast, however, replicates the packets only as needed for only those destinations that wish to receive the information. Hosts must join a multicast group, signifying their desire to receive the data. A tree is built based on this information and replication of packets only occurs at points where the tree splits off in different directions. This removes the bottleneck around the server, and in this example, Company X would only need to have a 28.8k line in order to create their radio station. This solution is also more scalable. Whether it has one hundred or one million listeners, the server will only need to send a single 28k stream. With unicast, Company X would need to upgrade its bandwidth as the radio station becomes more popular and more people start to listen.

Q: What applications are best suited for multicast?

A: Many people associate multicast with multimedia as it is an excellent transmission method for multimedia. This can be an Internet radio broadcast, television broadcast, video conferencing, stock market tickers, slide presentations, etc. However, multicast is also suited to a large number of other applications. Such applications include file transfers to multiple locations, or dynamic web page updates. In the future, all unicast and broadcast applications may be suited for multicast. In fact, you can think of unicast as multicast with only one group member, and broadcast as multicast where everyone on the network has joined the multicast group.

Q: What software applications are there for multicast?

A: Several. Many popular streaming applications, such as Microsoft Windows MediaPlayer, Real Networks RealPlayer, and Apple QuickTime have multicast capabilities. Several other multicast-only applications are appearing, such as Cisco's IP/TV and Apple's MacTV.

Numerous applications were developed in conjunction with the MBone. The most widely used of these is SDR (session directory), which is a program that lists many of the multicast sessions occurring on the MBone. A host of helper applications are available for SDR, such as VIC (video), VAT and RAT (audio), WB (white board), and more. These applications are available for UNIX and Microsoft Windows platforms. Several other applications have been built as clones of these programs for other operating systems.

You can find many MBone applications for numerous platforms at the following site: <http://www.merit.edu/~mbone/index/titles.html> [Broken]

Q: What are the limitations of multicast?

A: Multicast has one major limitation. For multicast to work, every router between the recipient and the source must be multicast enabled. Since multicast is a relatively new technology, not all networks are multicast enabled. XXX is the first ISP to completely enable multicast technology natively across their backbone. As the technology is embraced, more router vendors and ISPs will enable multicast. The cost benefits to multicast and the increasing use of high bandwidth multimedia applications on the Internet suggest that multicast will be ubiquitous very soon.

Q: What is the MBONE?

A: The MBONE was an educational research project to test new multicast applications. Begun in 1992, the MBONE is a collection of networks tunneled together to support multicast. Today, the MBONE is still used for multicast research, as well as the source of many of today's multicast sessions.

Q: Can I still reach the MBONE with XXX?

A: Yes. XXX has a peering connection to the MBONE. You can send and receive multicast traffic to and from the MBONE.

Q: What do you mean when you say that XXX carries multicast traffic natively?

A: With the original MBONE, it was difficult to enable multicast because of the need for all routers in a path to be multicast enabled. To route multicast traffic, it was necessary to create tunnels, or specially designed paths, to carry multicast traffic. As technology has improved, router manufacturers and ISPs can enable more of their network to carry multicast traffic without the use of these tunnels. XXX has enabled all of our backbone routers to carry multicast traffic without the need of any tunnels.

Q: How is XXX's network designed for multicast?

A: Working with Cisco Systems, XXX has removed the need for tunnels and now routes multicast natively across all of our backbone routers. Along with our customer connections, XXX also has connections to the MBONE, as well as multicast peerings with several other ISPs.

Q: What multicast protocols does XXX use?

A: XXX routes multicast through its backbone with PIM-SM (Protocol Independent Multicast - Sparse Mode). This is a shared-tree protocol, creating multicast trees from a central core location, called a rendezvous point (RP). XXX has six RPs located geographically throughout our network. These six RPs share the same IP address, allowing our customers and peers to contact the nearest available RP (anycast RP).

RPs communicate with each other and RPs in other networks through MSDP (Multicast Source Discovery Protocol). Routing is provided with either static routes, or MBGP (Multicast extensions for Border Gateway Protocol).

Q: How does PIM-SM work?

A: PIM-SM is a multicast routing protocol belonging to the shared-tree family. It uses a rendezvous point (RP), which multicast sources use to register their sessions. Other hosts look to the RP to find out what multicast sessions are available. When a host wishes to join a multicast session, it sends a join request to its gateway router. That router then builds a path back to the RP (the collection of all of these paths is called the multicast forwarding tree). The path that is chosen is determined by the unicast routing protocol (such as IS-IS, OSPF, IGRP, EIGRP, or RIP) running on the router. Once traffic has been received from the source of the session, the tree can switch to provide the optimal path from the source to the host. PIM-SM is defined in RFC 2362.

Q: What exactly does an RP do?

A: An RP serves as a central point for multicast sessions. A source will register its session with an RP. This information is carried to other RPs through MSDP. When a host joins a multicast group, it first joins the group at the RP. Once the host has received traffic from the source, the host can switch to a tree rooted at the source.

Q: Do I need to have my own RP?

A: No. If you choose to, you can set up one of your own routers as an RP. However, XXX has six routers geographically dispersed to provide the same service.

Q: What protocols does my router need to run?

A: Your router will need to be able to run PIM-SM and IGMP. If you have a Cisco router, multicast functionality is available in almost all Cisco IOS versions 11.1 or later. We strongly recommend using version 12.0 or later for best performance and reliability. If you plan to use your own RP or run MBGP, we recommend the 12.0.xS series.

Q: How difficult is it to configure a router for native multicast?

A: While the protocols that make multicast work can be extremely complicated, configuring a router is very simple. The following is a very simplified sample configuration to show what is minimally needed to enable a router for native multicast. In this example, the router is homed only to XXX and is using XXX's RP.

ip multicast-routing
ip pim rp-address 144.232.187.198
ip pim accept-rp 144.232.187.198
!
int Ethernet0
ip pim sparse-mode
!
int Serial0
ip pim sparse-mode
Repeat for all interfaces through which multicast traffic should flow.
For further configuration examples, we strongly encourage you to visit <ftp://ftpeng.cisco.com/ipmulticast.html>.

Q: What if I don't have a Cisco router?

A: You will need to check with your router vendor to find out if multicast is an available option. Minimum requirements are the ability to support PIM-SM and IGMP. Performance will be improved if your router supports PIM-SM version 2.

Q: What is IGMP?

A: The Internet Group Management Protocol (IGMP) is a protocol that controls group membership individual hosts. This protocol only operates in a LAN setting, but is required if you wish to be able to join a multicast group on a host. IGMP is defined in RFC 2236.

Q: Do I need to have special addresses for multicast?

A: Multicast uses Class D addresses (224.0.0.0 through 239.255.255.255). These addresses can only be allocated through IANA.
Many applications have been provided with ranges of addresses for their use, and will dynamically assign a multicast address to sessions created using it. For instance, SDR will automatically assign a multicast address to your session, if you announce the session with SDR. More applications are expected to use this method of dynamically assigning multicast addresses in the future.

The 233.0.0.0/8 block has been set aside for multicast use for anyone with their own autonomous system number (ASN). The ASN can be written as a 16 bit binary number (left padded with zeros), and then inserted into the middle two octets of this address block. For example, XXX has AS 1239. Written in binary, this value is 0000010011010111. By inserting this value into the middle two octets of the 233.0.0.0/8 block, XXX can then use 233.4.215.0/24 for multicast sessions. Anyone with their own ASN can use this method to create a /24 block for multicast use.

The 239.0.0.0/8 block is administratively scoped for internal use only. You can use this block within your own network similar to the way that the 10.0.0.0/8, 172.16.0.0/12, and 192.168.0.0/16 are used.

If you decide that you require static multicast addresses and do not have your own ASN, you can request them from IANA at this site: <http://www.isi.edu/cgi-bin/iana/multicast.pl> [Broken]

Q: Where can I find out more information?

A: For more information about multicasting, you might want to check out the following sources:

Williamson, Beau. Developing IP Multicast Networks. Indianapolis, IN: Cisco Press. 2000.
Maufer, Thomas A. Deploying IP Multicast in the Enterprise. Upper Saddle River, NJ: Prentice Hill PTR. 1998.
The following RFC's and drafts contain useful information about multicast:
RFC 2236: Internet Group Management Protocol, Version 2
<ftp://ftp.isi.edu/in-notes/rfc2236.txt>
RFC 2283: Multiprotocol Extensions for BGP-4
<ftp://ftp.isi.edu/in-notes/rfc2283.txt>
RFC 2362: Protocol Independent Multicast-Sparse Mode (PIM-SM)
<ftp://ftp.isi.edu/in-notes/rfc2362.txt>
Multicast Source Discover Protocol (MSDP)
<http://www.ietf.org/internet-drafts/draft-ietf-msdp-spec-02.txt> [Broken]
The following sites also contain useful information about multicast:
<ftp://ftpeng.cisco.com/ipmulticast.html>
<http://www.3com.com/nsc/501303.html> [Broken]
<http://www.ipmulticast.com/> [Broken]

 

[Anttech]

Evo it would have been quicker if you just posted the link, why did I force you to post that?:


I know what multicasting is, I know how it works, and I know MPLS in depth, and no it isn't a business only technology. I work for a Telco, and we use it as a transport medium for the likes of YOU when you cross our AS to visit a www site located HERE, and in fact on our GSM network we use it for WAP, and G3 applications (Streaming Video to Mobile Phones via Multicasting).

Many Telco's use MPLS, in Fact MOST in Europe use it. MPLS over Fiber will be the NORM, as ATM dies...

Why does Unicast still exist? I can't find it's advantage over Multicast.

Look Multicasts, are unicasts up until you get close to the requestor. Thats the beauty of Multicasting. Unicasts is the bedrock of IP technology so most data movement is done with Unicasting.

I'm referring to streaming video over the internet.

Could you provide a link to this please? Cisco Stream Video content from there website for training and the likes all the time, I doubt they are breaking the law.

Unicast is better quality and easier to control quality, the drawback is that each unicast session sends a stream to a single user making viewing by multiple users very expensive.

Better quality? Why? As I already stated Unicasting is multicasting up till nearer the requestor. Quality of service can still be implemented with multicasting (within an Autonomus System [AS])The Quality is just as good. In fact I have been implementing a IPM monitoring tool using Cisco 2800 Routers, and HPov to First Application Test Multicasting and there is no quality degregration.

The reason you don't see multicasting on the internet is that almost no internet providers in the US allow it because of the perceived revenue loss.

What are you talking about?

http://www.multicasttech.com/status/

Multicast prefixes are on the up all the time. Perhaps your company has made a business desion not to allow Multicasting across its AS, but that doesn't mean anything about the legality of it, or the use of Class D IP address on the 'net. Anyway if it was illegal, you would not see Multicast prefixes in the BGP (border Gateway Protocol) Internet Routing Table, for example here You would also certainly not see Triple and Quadriple Play Teleco's in the USA. And I know for a fact you have them, as I have friends in the industry working for Quadruple play Teleco's in the States. (Quadriple play refers to the ability to deliever Voice & Video & Data with Mobility if required. In other words: TV, Phone, Internet services, and Mobile Phone services GSM.)

Go watch a webcast (live one preferably) and you will be joining a multicast.

http://www.igd.fhg.de/archive/1995_www95/mbone/webcast-doc.html [Broken]

 

[eapro]

Is it just me or are the names ironic?

Multicast: multicast conserves network bandwidth by sending a single stream of data
Unicast: unicast transmits separate video, audio, or text streams to each computer requesting data.

Source: Answers.com

either Answers has its head screwed on backwards or the world is just attracted to confusion.

 

[Anttech]

Neither, it makes perfect sense to me...

 

[eapro]

oh, I just got it. I observed it from the wrong perspective.

the names suggest that multicast consists of "multiple" different content in a stream.

and unicast carries a single "uni" type of content per stream requested.

it's clear now.

 

[Anttech]

Sorry it seems you didnt get it:

A multicast is a means to transmit 1 stream of data (same content) from 1 origin to multiple addresses.
A Unicast is a means to transmit 1 stream of data to 1 address

 

[Evo]

Evo it would have been quicker if you just posted the link, why did I force you to post that?

Becuase you don't seem to know how multicasting owrks over the internet.

I know MPLS in depth, and no it isn't a business only technology.

A telephone company is a business, small telephone companies are my clients. You don"t seem to understand how the backbone architecture is meaningless here. You're confusing people by throwing out meaningless information. I have been selling multicasting over the internet for years. I worked with our guys at Bell Labs developing the service when the other company I worked at decided to do a beta for a large international client of mine.

 

[Anttech]

Becuase you don't seem to know how multicasting owrks over the internet.

What gave you that impression?

You sell Multicast over the internet? Thats a new one, how does 1 sell that?

You were asserting that MPLS is only used with Buisness networks, I am saying you are wrong. It is used on the PUBLIC internet. If you like I will give you an IP address, and you can ping it, the icmp scho reply you get will have traveled across MPLS. 3rd tere Teleco's use it

 

[Anttech]

Oh and I wasnt throwing out meaningless information, the Transmissions medium, and the protocols used are very [
meaningful when you are talking about how frames are broken up. THAT was part of the OP.

Is it sent in small pieces or does data constantly flow from the source to the viewer? If so, how large is each piece?

I was explaining that it depends what protocol you use as to how this is achieved. Each different Layer 2 protocol, Transmissions protocol has a different way of breaking up frames.

 

[Evo]

You sell Multicast over the internet? Thats a new one, how does 1 sell that?

It's a product. It's not magic. How do you think people do multicasting? They have to buy a service.

You were asserting that MPLS is only used with Buisness networks, I am saying you are wrong. It is used on the PUBLIC internet. If you like I will give you an IP address, and you can ping it, the icmp scho reply you get will have traveled across MPLS. 3rd tere Teleco's use it

You are very confused. First, I said that it is a business product, businesses use it, the public would be their end users. The PUBLIC internet is owned by the backbone providers, they are BUSINESSES. A person sitting at home (end user) is not going to buy an MPLS network in order to send and view video. You are confusing the matter. You have your telco environment and you think it applies to everything, you're wrong. AT&T is a huge internet backbone provider and their backbone is ATM, my company's backbone is just native IP, I don't think any of the major IXC's in the US use MPLS for their backbone, we sell MPLS that we can provide *over* our IP backbone, but we don't use it for delivering internet to the public.

And we're derailing this thread.

 

[Anttech]

Evo, I think you are confused.

Multicasting is a protocol, not a product. I would buy a connection to the World Wide Web from a teleco (the service), then I would implement Multicasting on my own, with my own equiptment.

If however I deside to outsource my network to you, then I would expect you to provide multicasting for me, but it is not a product it is a function, or rather a protocol that is handled by routers. However that is irrelevant to what the OP was asking, or what I was talking about.

Just to recap:

We are talking about how Video is streamed: Multicasting.
We are talking about how data is broken up when traversing across Networks.


Implementing Multicasting to obtain Publically routed Multicasts is actually very easy, You need a router that has the Memory to withstand BGP, then you need to get a Class D address and Vola You can multicast, I don't need to buy the 'multicasting product' from At&t for that, I just need the correct IP addressing, and the appropriate hardware, and the ability to advertise my routes tothe public, via BGP.

You have your telco environment and you think it applies to everything, you're wrong. AT&T is a huge internet backbone provider and their backbone is ATM, my company's backbone is just native IP

Well that just shows that you don't know what MPLS is. Its a protocol that sits on Layer 2, actually between layer 2 and layer 3. and you ENCAPSULATE IP inside it. Backbones all use IP at layer 3 (Unless in some instances you are using OSI), but not at layer 2 because IP is NOT a layer 2 protocol. You can use IP over SONET as well, but at layer 2 it is a DIFFERNET protocol. On ATM backbone you still encapsulate IP inside ATM.

ATM is on the way out. I also work for a HUGE teleco company, and yes we do have ATM, but it is going away, as it is for most teleco's here in Europe, it doesn't surprise me that in the States you arent yet, because you are behind us in terms of technology used. The reason why ATM is going away is because cell switching is not needed anymore, for the very same reasons why x25 went away, and Frame Relay became the norm. I guess I don't need to explain to you the reasons why x25 is dead, or do I?

Anyway yes the thread has been a tad derailed

 

[Evo]

Evo, I think you are confused.

Multicasting is a protocol, not a product. I would buy a connection to the World Wide Web from a teleco (the service), then I would implement Multicasting on my own, with my own equiptment.

Shows how little you know. Multicasting is a protocal which is actually sold as a product to businesses by some of the larger ISP's. You send them the video stream and they do the rest, for a price. My new company is the only one that will take the unicast stream and multicast it for no additional charge. The problem (if you read the FAQ I posted) is that if the end user and all routers between the host server and the end user are not multicast enabled, the end user will not be able to view multicast. In the US, Multicasting is not widely used, Unicast is. It's a fight between the ISP's Verizon and AT&T refuse to enable it in their network. Verizon's VP of Technology claims it's not a viable technology, which isn't true. But he's slamming it because they don't have it, we do. "Elby said that Verizon has taken this approach because IP multicast technology is not ready to scale to the size needed to deliver broadcast services. Elby pointed out that Verizon's video-on-demand services are based on IP technology, because on-demand video can be delivered to a user via a single unicast stream. But multicast IP is a whole different story.

"Technically speaking, the problem is getting highly scaleable IP multicast. Nobody has ever built an IP multicast network on that scale before."

He wants the end user to pay to view video instead of being able to hit a website and view for free. This is all part of the much misunderstood "Network Neutrality" fight going on.

http://www.lightreading.com/document.asp?doc_id=85708

If however I deside to outsource my network to you, then I would expect you to provide multicasting for me, but it is not a product it is a function, or rather a protocol that is handled by routers.

It's both, it's a product which is sold, I know, I've sold it. Just because you aren't aware of that doesn't make it disappear. Just like MPLS, Frame Relay and ATM are all "products" that are sold.

We are talking about how Video is streamed: Multicasting.

Very, very limited in the US.

Implementing Multicasting to obtain Publically routed Multicasts is actually very easy, You need a router that has the Memory to withstand BGP, then you need to get a Class D address and Vola You can multicast, I don't need to buy the 'multicasting product' from At&t for that, I just need the correct IP addressing, and the appropriate hardware, and the ability to advertise my routes tothe public, via BGP.

Ah, you read my FAQ.

And then maybe a handful of people can view the stream, if you're lucky, because every router in the internet between your server and the end user must be multicast enabled, and almost none are.

Here is more information which will explain why multicasting is not being used. This project my client was working with is in Belgium.

"Despite this, public multicast connectivity is still virtually unavailable to normal Internet users. Most network operators simply did not enable this function towards their clients. Currently Internet multicast is only available to a very small number of - mostly professional – users. The result is that it is barely being used, and there is currently almost no interesting multicast content being distributed."

"Internet multicast technology is available world-wide, but is simply not enabled towards normal Internet users."

http://www.castgate.net/castgate.htm [Broken]

This would have provided a solution allowing non-multicast end users to view multicasting, but the FCC shut him down, companies like Verizon want their end users to pay to view even though my client is paying to stream it already. They complain that even though their customers pay for unlimited internet access, that they should pay EXTRA for viewing videos. They will not allow their wireless "unlimited" data users to download music or video, if you do and they notice (which from articles I've read is pretty often), they shut off your service. Nice, huh?

 

[Anttech]

Shows how little you know. Multicasting is a protocal which is actually sold as a product to businesses by some of the larger ISP's.

No it isn't Evo, Perhaps in the Sales department you attempt to package it as a product. But it isnt, as an Engineer I engineer these solutions, and I know how it works, and I know I don't need you to process streams for me, if I can get my hands on a class d public IP address, as I explained before, before I know for a fact most if not all Good ISP process Mcasts.

Ah, you read my FAQ.

Nope, I didnt need to, I am a ccnp (With ccie written) Network Engineer I eat this stuff for breakfast...

And then maybe a handful of people can view the stream, if you're lucky, because every router in the internet between your server and the end user must be multicast enabled, and almost none are.

So how on Earth does OSPF work then, over public networks? You are aware that OSPF uses well defined multicasts to select the DR and BDR's to create a tree routing table, guess you werent. As does EIGRP and RIP, and all Telco's use these protocols internally?

It's both, it's a product which is sold, I know, I've sold it. Just because you aren't aware of that doesn't make it disappear. Just like MPLS, Frame Relay and ATM are all "products" that are sold.

MPLS ATM can be sold as products, but multicast isn't a product, because multicasting is part of IP.. It is just a CLASS D ADDRESS. All you need to do is to enbale it globally on a router, and route class D prefixes via BGP if you want public streams, and any other multicasting protocol if you arent, like mospf.

Very, very limited in the US.

So the great firewall of the States is filtering out BGP Mcasts? This is just so wrong...
http://www.multicast-isp-list.com/index2002.html [Broken]
Ever heard of Level3? The Largest Tere 3 Data Teleco in the world?

Level 3


Level 3 currently provides multicast connectivity/transit and will run native pim sparse-mode, MSDP and mBGP to any customer on any Level 3 Internet interface.


Multicast connectivity is included part of the basic service offering for no extra charge.


There are no limitations imposed on the use of multicast.


Contact :


Just request it from your sales representative or call
1-877-2LEVEL3
(1-877-253-8353)

As for this link:

http://www.castgate.net/castgate.htm [Broken]

Note that the supplied information can be slightly out-dated, as the CastGate project is still evolving, and updates to the

I tend to think this is the problem. The information is outdated.
Verizon won't carry other Triple Play ISP's TV content, but that isn't the same as Public Mcasts, are you aware of that? You do know the difference between the two don't you? I think that is where you are confused. It is very easy to filter that stuff out without breaking the Mcast public routing table.

 

[Evo]

You only seem to understand technical specs, but you don't understand how or even if the services are being used. As a Sales Engineer, I have to understand BOTH. I know how the technology works in the real world.

The information is not outdated, this just happened last month.

Also, Level 3 is geared mainly towards businesses, not consumers (home users). You simply do not understand the issues around this. Just because something is "technically" feasible doesn't mean it is "usable". Many things that "could" be possible are blocked by legal and marketing reasons. Just because you read about something doesn't mean squat.

I know what can and cannot be done in the US, I design and sell data networks to telephone companies, ISP's (Level 3 was a client at my last job) and large corporate accounts. I "have to know" what works and what doesn't. So a remark like "if I get a class D address I can do multicasting", is ridiculous because you don't understand that almost no one will be able to receive the multicast. When you talk about things that you don't know about, you are misinforming people.

Verizon won't carry other Triple Play ISP's TV content, but that isn't the same as Public Mcasts, are you aware of that? You do know the difference between the two don't you? I think that is where you are confused. It is very easy to filter that stuff out without breaking the Mcast public routing table.

See, this is a perfect example of you not knowing what you're talking about, this has nothing to do with them multicast enabling their IP backbone so that end users can view multicasts via the internet.

You seem to be unable to understand the difference between multicasting over cable or Verizon's plan to offer it over fiber to a subscriber's premise (FiOS) and multicasting over the public internet. They are not the same.

 

[Anttech]

Sorry you think that: Initially I was too technical, now I just don't know what I am talking about.

Did you even look at the link I posted, regarding the level of Class D routing? Level 3 is the "main pipe" of the world... Since you understand the technical Aspect, how about the BGP routing prefixes I linked, what was you take on that? How do you explain it?

Routing Multicasts is transparent to Telco's its like routing Unicasts, as I explained before. It is the same thing, up till closer to the requestor, or rather up till what we call a Rendevous point for the Mcast group.

I know what the confusion is about here, you are talking about IPTV over dsl or whatever. IE you take B.T. as your Telco provider, but decide Orange has better TV so you want to receive this distribution, via IPTV streams. Yes that is blocked, but this isn't what I was talking about, and technically isn't really the same.

If you are going to 'rubbish' my technical knowledge on this subject, and my overall understanding of the does and donts of Multicasting then bring it on, please. But back it up, I am open ears to new ideas, but I think you have a misunderstanding of this subject.

PS why are you editing my posts?

 

[Anttech]

See, this is a perfect example of you not knowing what you're talking about, this has nothing to do with them multicast enabling their IP backbone so that end users can view multicasts via the internet.

You seem to be unable to understand the difference between multicasting over cable or Verizon's plan to offer it over fiber to a subscriber's premise (FiOS) and multicasting over the public internet. They are not the same.

What are you talking about? Amazing, I am attempting to explain to you they are different, and either you are building a strawman or we have a communication problem. As I have asked you to verify if you know the difference in several posts now!

 

[Evo]

Did you even look at the link I posted, regarding the level of Class D routing? Level 3 is the "main pipe" of the world...

Level 3 is a business to business only company in the US, they do not sell to non-business customers.

Routing Multicasts is transparent to Telco's its like routing Unicasts, as I explained before. It is the same thing, up till closer to the requestor, or rather up till what we call a Rendevous point for the Mcast group.

This has nothing to do with the Telco environment. To do multicasting to non-dedicated business internet users, you need to be on one of the 2-3 ISP's that offer multicasting to consumers, since these ISP's mainly only sell to businesses, there are very few consumers on these companies. If someone wants to view your video and they are on an ISP that isn't multicast enabled (the vast majority) the instant your ISP hands off to their ISP the multicast stops. You do understand hot potato routing?

I know what the confusion is about here, you are talking about IPTV over dsl or whatever.

Uhm, no. See you don't understand.

The OP is not a business, he is a consumer, as are the vast majority of anyone reading in this forum. Video on the internet is gaining popularity, but because of the multicast issue, popular sites like youtube actually use flash.

 

[Anttech]

BTW Some more food for thought, on whether Multicasting is 'allowed' or is in use across the Public internet. It is very easy to Tunnel a Class D address or rather a Multicast stream inside a Unicast stream, so in fact it can be tunneled across 'Hostile' Transport Teleco's.

One can use a GRE (simple Generic Router tunnel) to do this:

Outlined here:

http://www.cisco.com/en/US/tech/tk828/technologies_configuration_example09186a00801a5aa2.shtml

This means even if an 'Inbetween' Autonomous System does not allow Mcasts, it can still cross that AS.

 

[Anttech]

The OP is not a business, he is a consumer, as are the vast majority of anyone reading in this forum. Video on the internet is gaining popularity, but because of the multicast issue, popular sites like youtube actually use flash.

Youtube isn't Live. Its a recording that's the difference, and the reason why they wouldn't multicast.. You would never multicast that type of content!

Can you stop telling me I don't understand, when you are the one who keeps giving incorrect information. If you understood the reason why one uses multicasts, you certainly would not have mentioned youtube!

 

[Evo]

Youtube isn't Live. Its a recording that's the difference, and the reason why they wouldn't multicast..

True, but there is live video with the flash media server, but I'm not knowledgeable about the limitations.

I have a sneaking suspicion that the OP was really thinking of video such as youtube, google video, etc... which are not streaming video and we've been arguing this for nothing.

I think we've been on two different pages on the multicasting, I'm only talking about the streaming capabilities to consumers which here in the US has been virtually blocked by the big ISP's. I apologize for being terse.