CA2546118C - Multicasting method and apparatus - Google Patents

Abstract

A scalable architecture is disclosed for delivery of real-time information over a communications network. Embedded into the architecture is a control mechanism (10) that provides for the management and administration (60) of users (40) who are to receive the real-time information. A user (40) chooses to tune in or tune out a particular channel, but does not choose the time at which the channel distributes its information. Advantageously, interactive (two-way) information can be incorporated into the system, multiple streams of information can be integrated for delivery to a user (40), and certain portions of the information being delivered can be tailored to the individual user (40).

Description

ML)LTICASTING METHOD AND APPARATUS
i. Fieid of the iaventioa . ...This relates to a method and apparatus for.providing' .
audio and/or visual communicatio~r .services, ..in real-time, to a multiplicity of identif cable, users ~ -on a communications network, such as the Internet. In a preferred embodiment, the,invention monitors which users~are receiving signals on which one of . a~ plurality of channels and modifies the :content io .of at' least . some .signals .in response thereto., A particular .
application is to provide services akin~to multi-channel radio or television with commercial programming content adjusted in accordance with the identity of the individual user.

2. Eackgrouad of the Iaveatioa Systems such as the Internet typically are point-o-point (or unicast) .,systems in which .a message, is~ converted into a series of addressed packets that, are~routed .from a 2o.source.node through a plurality of routers~to a~destination node. In most communication protocols the~packet~.includes a header that contains'the addresses of the source and the destination nodes~as well as a sequence.number that '.
specifies the packet's order in the message:__ , In.general, these systems do not have the .capability of broadcasting a message from.a source node..to all the other nodes in the network~because such~a capability is rarely of much~use and could easily overload the nettaork.~
however, there are situations where it is desirable for. one.
node to communicate with some subset of all~the~nodee~. For example, multi-party conferencing capability, analogous to that.found in~the public telephone system and broadcasting to a limited number of nodes, is of considerable interest to users of packet-switched networks. To satisfy such demands, packets destined for several recipients have been encapsulated in a unicast packet and forwarded from a source to a point in a network where the~packets have been replicated and-forwarded on to all desired recipients. This technique is known as IP Multicasting and the network over which such packets are routed. is referred~to as the Multicast Backbone or MBONE.- More recently, routers~.have becoae 5:avai.lable that can route the.multicast addresses (class D
addresses) , provided for .in communication protocols such a~
.TCp~IP and UDP/IP. A multicast address is essentially.aii address for a group of host computers who have indicatedw.
~. their desire to participate-in that-group. Thus, a multicast to packet can'be routed from a source node through a plurality of multicast routers (or mrouters) to one ~or. more devices receiving thc~-multicast packets.. From theta the packet is.
distributed to all the~host computers that are members of the -multicast group: . - . .
l5 ~ ~ . These techniques ha'ire been used to provide on the Internet~audio and video conferencing as well ae radio-like broadcasting to groups of interested parties. 8eo, for example, K. Savetz.et 81'. MBON~' Multicastina Tomorrow~s Internet (TDG Books.WorldWide Inc:, 1996). .
Z0 ~ Further~details concerning technical aspects of multicasting may be found in the. Internet documents Request for Comments (RFC) 1112 and 1458, which are reproduced at Appendices A and B of the Savetz book and in D.P. Brutaman et "MBONE provides Audio and Video Across the Internet,"
Z5 IEEE Comx~uter, Vol. 2T, No. -4, pp. 30-36 (April 1994), -Citation of the foregoing documents is.not to~be construed as an.admission that any of such documents is ,a -prior art publication relative to the present invention.-3. summary of the Invention .The present invention is a scalable architecture for delivery of real-time. information. over a communications network. Embedded into the architecture is a control 35 mechanism that provides for the management and administxation of users who are to receive the real-tune information.
- 2 '~

In the preferred embodiment, the information being delivered is high-quality audio. However, it could.also 'be video, graphics, text or. any other, type of information that can be transmitted over.a digital. network. This information s is delivered in real-time to any number of widely distributed.
users. ~ It is rear-tame .in .that for a given channel of information, approximately the~same information is. being sent at approximately the same time to everyone who is.enabled to receive, the information. .
l0 ; . Preferably', there are multiple' chanriels~ of information available simultaneously to be delivered. to users, each channel consisting of an independent.stxeam of information. A user~~chooses to tune in or~tune out's particular channel, but does not choose the time~.at which the 15 channel distributes its information. .Advantageously, , interactive (two-way) information.~can.be incorporated into the system, multiple streams of information can be integrated for delivery to a user, and certain portions..ol,tDo.
information being delivered can. be tailored to the individual 20 user.

4. Erief Description of tb~ DrapiaQ .
These and other objects, features and.advantages of our invention will be more readily apparent from the 25 following Detailed Description of a Preferred E~abodiment of our invention in which: ' Fig. 1 is a schematic diagram depicting ~an, overview of the system of the present invention;
Fig. 2 is a schematic diagram~depicting the network 30 control center for the system of_.Fig. 1f:
Fig. 3 is a schematic~diagram depicting a unicast distribution structure;
Fig. 4 is a schematic diagram depicting a multicast distribution structure; .
55 Fig. 5-is a schematic diagram depicting. the connection.between the media server and the user in the system of Fig. 1;
_ 3 _ Figs. 6-l7. are timing diagrams that depict various aspects of the operation of the system of Fig. 1; and Figs. 18 and 19 depict the user interface.for control of the system of: Fig. 1:
g Where the same reference numerals appear,in multiple drawings, the numerals refer to the same or corresponding structure in such drawings.

5. Detailed Description of the Preferred Embodiment to ~ Referring to Fig. 1, the system of the present invention comprises a Network Control Center 10, a plurality of Primary servers 20, Media Servers 30, Users 40 and Control Servers 50 and an Administration Server 60. The servers are interconnected by a~communications network, which in. the 15 preferred embodiment is the~global connected internetwork known as~.the Internet. The NetworkwControl Center 10 is the source of the information being distributed. It receives audio feeds from satellite,~'oYer the air broadcast'or in other ways and processes this information for delivery over 2o the network on multiple channels of information., This processing consists of optionally recording the information for future broadcast and dynamically inserting paid commercial advertisements.
For each channel of information, there is a~Primary 25 Server 20. that receives the stream of information from the Network Control Center 10 and compresses the information steam to allow for more efficient transmission. The Primary.
Servers 20 are directly connected. to the network.
. ~ The Primary Servers forward information via the 30 network to a number of Media Servers 30. There may be a .
large number of Media Servers~and in fact there may be many levels of Media Servers. For example, a Media Server that receives a stream of information from a Primary Server may forward that stream via the network to another Media Server 35 that~then forwards it to a User 40: This multilevel hierarchical structure is described in more detail below.

. The topology of the Internet dictates the ideal placement of Media Servers, the fan-out of each. Media Server and. the nur~iber of ~~ levels of Media Servers between the Primary -vServer and Users. For example, the Media Servers that~feed from a Primary Server might be -placed at major 'poirits of presence (POPS) of each of the large Internet service.
prov.iders.. These Media Servers might also be placed-near clouds'that serve as high bandwidth-exchange. points between the major.carriers. Similarly, Media Servers that-feed to Users might be placed ~on or close to networks . that= have. a large-number of subacriberg to minimize the distance and number of data streams being transmitted.
Control Servers 50 are responsible for keeping-track of which Users_ are~listening.to which channels and for -i5 directing the Media Servers to start and stop stteairis of information to those Users. The Control-Servers are~also responsible for handling other interactions among~th~ various components of the system.as will be described in-more~detail below. Each Control~server is responsible for. managing a 20 cluster'of Media Servers; and each,Media Server is~managed by a single Control Server-at any given time: As a result, the Control Servers are distributed throughout the Internet, preferably~located close to the Media Servers.
The Administration server 60 is responsible for 25 registering new Users; authenticating Users Who want'to log.' onto-the system, and maintaining audit logs for how many Users'are listening~to which channels~and at which times.
Maintaining audit logs and,. gathering statistics~are features critical to monitoring the delivery of paid commercial '.
30 messages as well as for other purposes. For example, .for purposes of assessing copyright royalties, the audit logs.can record the number of listeners for each musical or. video selection-that is distributed by the system. Another application is to determine the percentage of listeners who 85 are interested in listening to a particular musical selection.
by determining how many listen~to the entire selection and how many turn it off.
.. 5 . -The system of the present invention.can be .
considered a distribution architecture integrated with a -control:architecture. The distribution architecture, handles scalable real-time delivery of information.to any number of Users on a.packet switched network, such as the Internet.
The control architecture-represents.a~second scalable system integrated with the distribution architecture for managing and administering-the delivery of that information. .-.The remainder of this description is divided into i0 three~sections. In the next section the distrib_utiorl architecture will-be described in ~nore'detail. ~ Following that,. the control architecture' will be.described. In the third section the User interface will be illustrated.
I. Distribution Architecture The distribution architecture provides-for'tha delivery of real-time information to any number of Users distributed throughout a network. Ais will be described in detail below, the distribution architecture~is scalable to allow for efficient delivery of multiple simultaneous infor~nation~ channels in real-tine to a large number of Users.
In the preferred embodiment, the information that is being distributed consists of high-quality audio iii' addition to other information'. It should be appreciated that - the basic architecture and other general principles set forth herein would-also apply to the delivery of video, graphics, text or any other'type of information that can be delivered over a digital network. In addition; it should be -appreciated that an information-stream can consist of audio with supplemental information such as text and graphic images and commands to control software running on the User s computer. - , -The source of information in the preferred embodiment is the Network Control Center 10, depicted in'the schematic diagram of Fig. 2. Control Centers of this type of design are-available from Broadcast Electronics, Inc, and are similar to what would be found in a conventional radio , station serving multiple frequencies.
Referring to Fig. 2, the incoming signal can be received in a variety of ways such as from a satellite, over-the-air broadcast, cable or hard disk. It is then processed by Receiver/Decoder 110, which decodes the signal and provides an incoming audio stream. Routing Switcher 120 is responsible for routing the incoming audio feed from the Receiver to either Delay Recording Workstation 140 or to one of the Playback/Control Workstations 130. Real-time insertion of paid commercial advertising takes place at the Playback/Control Workstations and the resulting integrated audio stream is delivered to the Primary Servers. The Delay Recording Workstation is responsible for recording an incoming broadcast so that it can be played back at a later time.
Supervisory Workstation 150 is responsible for managing and controlling the Playback/Control Workstations, Delay Recording Workstations and other computers as may be connected to the local area network within the Network Control Center. Production Workstation 160 and AudioVAULT-NFS Server 170 are used to manipulate audio samples, such as commercial messages for use by the Playback/Control Workstations. The audio being delivered can consist of syndicated Tv or radio programs, such as would be received over satellite or cable and delivered as described above.
These can be delivered live and/or played back at~a later time. It is also possible for the delivery of information, such as music, to take place from information that is all 3o stored locally such as on a hard disk. A new play list and its associated music data can then be downloaded periodically to update the channel. Additionally, it is possible to deliver commercial-free programming, for example public service announcements or label-specific music.
In the preferred embodiment the Primary Servers are responsible for compressing the audio stream using an advanced perceptual technique developed and licensed by AT&T

Corp. and Lucent Technologies, Inc. This highly . -sophisticated algorithm is used to maximize the benefit of the bandwidth available. Advantageously, two bitrates are available, a first rate of approximately 20Kbps and a second rate of approximately 56Kbps. Using the perceptual technique, the quality of the first rate is similar to FM
monaural (with a sampling rate of approximately 22,000 16-bit samples per second) and the second rate is close to CD
quality stereo (with a sampling rate of approximately 32,000 16-bit samples in stereo each second). The signals at the two different bitrates comprise two different audio channels and thus require two different compression processes.
The computational requirements of compressing an audio stream in real time using techniques such as the advanced perceptual technique are approximately 100% of a Pentium-Pro 2o0Mhz computer and the computational requirements of decompressing an audio stream in real time are approximately 30% of a Pentium 75Mhz computer. Future improvements and/or changes to the algorithm could significantly change these requirements. For the present, a dedicated computer is required within the Primary Server to compress the audio stream. The decompression process takes place on end Users computers and preferably would use only a portion of the computers computational requirements, allowing the computers to be used for other tasks while they are processing the audio stream.
It is important to appreciate that the compression and decompression techniques employed by the present invention are not critical to the overall operation of the system and the advantages obtained therefrom could be obtained with other compression methodologies.
Advantageously, the identity of the compression technique used can be encoded into the audio stream in the packet header. This makes it possible to identify to the receiver the nature of the decompression algorithm to use; and thereby make it possible for the computer within the Primary Server _ g _ to select an optimum compression algorithm depending on the .
nature of the audio stream to be compressed. ' The remainder of the distribution 'architecture ' .
comprises the multilevel hierarchy of data transmission 5 originating at the Primary Server 20 and terminating at the Users 40 as shown',in Figure.3. In the preferred embodiment, the network is the global connected Internet. It can also include private networks that are~connected to the Internet and it could be implemented on any packet switched .network, 1.0 cable'=modem-based or satellite-based cable system.. It is possible that certain links within the overall system, for example, the link between~the Primary Server and the first level of Media Servers, are private data links that carry '~.
~orily data associated with this.system. This could also be 15 true of other data transmission.paths in the distribution architecture. . The User receiving ;the information preferably can be anyone who has access to the Internet.with~sufficient bandwidth to receive the resulting audio data.
. It should be appreciated that the distribution architecture of .the present inveintion~ provides !o=
scalability. Using such a structure, any numbet~ of Users, and as widely distributed as necessary, can be accommodated.
In the preferred embodiment, the fan-out at each level ,o!
Media Server (given~the state of technology today) is on the,.
25 order of ten, but the same structure could be applieil~with other fan-outs. The location and fan-out of the. Media.
Servers is chosen to minimize overall iietwork~bandwidth consumed.
The-flow of information from Primary Server ~0 30 through network to User 40 is based on the delivery of.a~
continuous sequence~of individual pieces of information, or packets. Thus the distribution~architecture implements a.
form of multicast packet delivery to a group. The group iti this case is the set of all Users who are listening to a ' 35 given channel at a given time. Group membership is dynamic;
users can start and stop listewing~to a channel at any time:

Multicasting can be implemented in a variety of ways, any or_all of'which can be used~in the present invention. In the preferred embodiment, the Media Servers receive unicast packet,stieams and they then duplicate these streams into more unicast streams to other Media Servers that are in the membership .group for that stream. The lowest level Media servers use hardware broadcast, multicast and/or unicast to reach all Users served by that~Media Server.
iD If the Media Server is. directly connected.~to~tha same physical network as the User, hardware broadcast~or multi~cast can be used to transmit the packet .stream, to alb Users listening at that time on.that network. In this case the Media Servers can translate the incoming packets into.
broadcast or multicast packets for transmission on the local network:.. only a single packet is transmitted at-a=tine.on the local network,and any computer directly connected to the local network can receive that packet. Hardware multicast'is . built~into most networks and it is lower~~iw overall overhead 2o than hardware broadcast since computers not interested in a transmission do not have to process the'packets. In the case that a Media Server is serving a User who is not on the same physical network,' a unicast trawsmissiow is used to reach that User, which requires.a.separate packet transmission for each User so connected. In~the preferred embpdiment, the.
assignment of Users to. Media Servers is done using control transactions among the User 4d; Control Servers 50, and Administration Server 60. This system will be described~more fully in the following section.
3o Multicasting can also be implemented within ttie~
Internet at the IP level using~IP class D addresses and tha IGMP group controh protocol. Fig. 4 illustrates how the multilevel hierarchical distribution architecture would . __ operate using IP multicast delivery. Under this system, a 35~packet is transmitted With.a multicast address for a destination and each router,maintains group membership lists for each interface that it is connected to and will forward packets across the Internet to other routers such that all ~~~~
Users within the~global group eventually receive a copy of~
the_packet. Unless and until all routers Within the Internet understand multicasting in this way, it is necessary~to supplement it with IP,tunneling in which multicast packets are encapsulated in unicast.packets-and routed by unicast routers to multicast routers. The present invention can .
~~and will be able to take advantage of IP multicasting as i~
becomes widely available. Each channel of information would be given its own class D address and the Media Server~would then simply transmit packetslusing the appropriate IP
destination address. In this case no Media Servers would.be . used as this function would be accomplished~by the.routers in.~
use~to store and forward other IP packets. ~ .
Thus it can be appreciated that the implementation . of the multicast delivery structure can be implemented using.
a combination of IP unicast, IP multicast and hardware multicast or any other system that provides for distributed delivery of information .to a specific group o~ destinations.
It is expected that special relationships with Intexnet . providers will be established so~that delivery of. the audio steams can take place with~a guaranteed.bandwidth and iW the most efficient way possible.
In the preferred embodiment, packets of information for distribution use the UDP protocol under IP rather.than the TCP protocol. TCP provides for reliable stream delivery but at the cost~of retransmission and delays. For real-time information, it is usually more appropriate to use.UDP since~.~
the information is.time critical and low latency is more ,-important that reliability. Since TCP is a point-to-point protocol, it is incompatible with IP multicasting. ~IiowevAr TCP could be used on the IP unicast links between Media , Servers that are.expec.ted to have very low packet loss.. In order to handle out of order;"lost, duplicate and corrupted packets, the UDP packets are serialized.' In the preferred embodiment the size of the audio packets.being transmitted is variable and can change on a . packet by packet'basis. It is expected that when using compression schemes that have a fixed bit rate, .such as ADPCM, a.ll packets.for that'stream~would be the same size.
Alternatively when~:using a variable.bit rate compression s algorithm, ityis expected that packet. size would vary so'as-to~establish approximately the same amount of time for each sample... For example, if~ each packet corresponds .to a ~20 millisecond segment of speech, this could, correspond to.100 bytes during onetime period and 200.bytes during another. .
l0 Additionally, the Media Server'may choose to dynamically wary the packet size to accommodate~changes in network.conditions.
Since the resulting playback of audio infor~ation~
is sensitive to packet loss and network congestion, software .running on the various computers that, make up this system 15 monitors the ongoing situation and adapt to it in the beat possible way: This may. involve using different Media Servers and/or lowering the data rate to the User. For example, similar to analog dynamic signal quality negotiation present in many analog radio ,receivers,~,the User. software may request Z0 a lower bitrate until the~situation 3s improved...Also, note that .the audio information being delivered to the User is p=eferabl~..,interle.aved.,so that. a contiguous segment ~of the audio stream is distributed for transmission over several ~.
packets. As a result, the loss of one packet'is spread out 25 over multiple audio'samples and causes minimal degradation in audio.-.Advantageously, a small degree of redundancy may be incorporated'within the audio stream to further guard against"
packet loss. . ~ ~ ' Preferably, there are two bitrate options available 30 to the User foi audio delivery.,.. These axe approximately 2oRbps for standard audio and.approximately 56Rbps~for high quality audio. Thus, a 28.8Kbps modem connection over"an analog phone line is sufficient, to. listen to standard audio broadcasts. To listen to high quality audio, an ISDN .
35 connection to the Internet is required, or some other connection with greater than 56Rbps bandwidth. It should be appreciated that higher. bandwidths are ~currel~tly ~ becoming available to end Users. In particular the use of cable modems and residential fiber networks are enhancing the bandwidths available to Users and thus making broadcasts of higher bitrates more practical.
In addition to the content of the audio channel being delivered, it is also possible to deliver out of band of side-bar information such as graphics, images and text.
This side-bar information is synchronized with the audio channel. This may only involve small increases in bandwidth requirements, such as 1-2Kbps. For example a music program could deliver images of an album cover, the text of song lyrics, or URLs for use by a Web browser. The User can preferably choose to have the side-bar information show up automatically or be hidden. It is also possible to incorporate two-way interaction into the system, such that for example Users can participate in a global chat session during the audio broadcast. These and other details are explained in more detail below under the description of the User interface.
The delivery of paid commercial advertising information is an important aspect of the present invention.
Advertising may be incorporated into the audio stream within the Network Control Center as described above. It may also be incorporated into the audio stream at the User level, or at some intermediate point in the distribution architecture.
In addition, the side-bar information discussed above can also include advertising content. Fig. 5 illustrates the provision to the User of two separate streams 32, 34 of packets, one of which may be used for advertising. In this case the insertion of the stream of commercial advertising into the non-commercial stream occurs on the User's computer. Fig. 5 also illustrates packet stream 36, which identifies the User to the system. This enables the system to monitor which Users are listening to which channels and also allows the system to vary, for example, the advertising content delivered to a User.

One advantage of this alternative is to allow ~ targeted commercial delivery based on the individual User.
That is, an individual User would receive the main audio feed plus a particular advertising stream unique to his demographic group. Note that the advertising stream typically is lower in overall bitrate and generally does not require real-time delivery, thus lowering the overall load on the network. For example, the advertising stream could be delivered to the User in advance of the regular programming, stored in a buffer in the User's computer and inserted into the stream of regular programming upon receipt of a cueing signal embedded in the stream of regular programming. Thus, a substantial number of targeted groups, perhaps 10 or 100 or even more could be accommodated without an impractical increase in network load.
II. Control Architecture The control architecture described in this section is responsible for managing and administering the Users who are receiving the information being delivered by the distribution architecture described in the previous section.
The control architecture handles new User registration, User login, the starting and stopping of audio streams and the monitoring of ongoing transmissions. The control architecture is scalable just as is the distribution architecture so that any number of Users can be managed.
This section describes the control protocol, which consists of the format and sequence of control messages that are exchanged among Users, Control Servers, Media Servers, Primary Servers and the Administration Server. These messages are in the form of objects, which have specific data formats. Objects are exchanged preferably using the TCP
protocol although other options are possible. Below we describe the sequence of objects passed among the various computers and detail the internal structure of each object.

The major objects used in the present embodiment of the invention are set forth in Table 1. For each object, Table 1 provides a brief description of its function, identification of the names of the fields in the object, their types and a brief description of their function.
Channel Activation Object Contains information used for channel activationldeactivation. It is sent to to Media and Primary Servers to tell them to carry or stop carrying a specific channel. Media Servers get the channel from another server in the system hierarchy and Primary Servers get and encode the feed fmm the actual input soulnee.
Field Name Field Type Remarks 15 Token Security Token Object Moniker Moniker Object unique channel identifier Activate Int action flag (activate/deaetivate) Compress?ype Int type of compression to rise Xost Host Object host carrying the channel Channel Guide Object Contains analytical and descriptive information for an item requested that is uniquely ident<'fied by a moniker. It is usually the reply to a Channel Guide Request object.
Field Name >a5eld Type Remarks a 5 Token Security Token Object Type Int type of content Result the content data itself Channel Guide Request Object Conveys a request for analytical and descriptive inforntation about an 3 o item uniquely identt~ed by the contained moniker. The reply is in the form of a Channel Guide object.
Field Name Field Type Remarks Token Security Token Object inherited from base class Type Int type of content Moniker Moniker Object unique identifier Table 1 (continued) -Host Object Encapsulates the attributes of a networked computer related to the operation or services it offers or requests.
Field Name Field Type Remarks Token Security Token Object HostName String computer name and domain PortNumber Int port number for service DisplayNartet String descriptive computer name 1 o Login Information Object E~.capsulates the name and password by which a User is known to the sysrem.
Field Name Field Type Remarks Token Security Token Object Login String User's systera login name Password String User's system password (possibly encrypted) Media Control Interface (MCI) Request Object 2 o Encapsulates a multimedia control command, such as play and stop, and any extra information that may be necessary to perform the requested service.
Field Name Field Type Remarks Token Security Token Object 2 5 Command Int multimedia command String String command-specific extra info Moniker Object A moniker encapsulates the name of an object or process with the intelligence necessary to work with that name. In other words, it 3 o provides naming and binding services. The Moniker Object is used in the system for unique ident~~cation of various components, parts or features, such as a channel, a directory, or a computer list.
~3eld Name Field lope Remarks Token Security Token Object 3 5 ~ Sag unique string identifier DisplayName String User-readable name Table I (rnntinued) -Ping Object Ping is the name given to the "Are-You Alive?" operation useful in determining if a specific computer is up and running. This object is used in the system when a server has to be queried for its operational status. It can also provide timing information for statistical purposes and quality of service evaluations.
Field Name Field Type Remarks Token Security Token Object Date Date system date Mme Time system dme Protocol list Object Encapsulates a general purpose collection object.
Field Name Field Type Remarks Token Security Token Objxt Type Int type of object list Result Message Object 2 o Acts as the acknowledgment for a requested service successfully carried that out or reports errors that occur in the system during a clientlserver transaction.
Field Name Fyeld Type Remarks Token Security Token Object 2 5 ~t Int result code Messagt String message corresponding to code Security Token Object Contains the authorization key for a transaction. The key must be validated before any service is performed.
Field Name Field Type Remarks ID String authorization key/transaction 1D.

Table 1 (continued) ~ . ' ..,.
Server Activation Object Contains information used in the server activationldeactivation process.
Used for announcement as well as command purposes (e.g., a server can notcfy the administration database that is now activated or a server can be instructed to manage someone else).
Field Name Field Type Remarks Token Security Token Object Active Int action flag (activate/deactivate) Managt Int control flag (manage/associate) ~,pt 1nt server type Host Host Object host to be controlled Server List Request Object Encapsulates a request for a list of available server resources for an identified service (e.g., a request for a list of Control Servers for a specified channel).
Field Name Field Type Remarks Token Security Token Objax Type Int type of service Moniker Moniker Object content/channel unique identifier Z 0 Host Host Object local host information Statistics Object Contains system-related information that can be used by load balancing algorithms and for statistical purposes.
2 5 Field Name Field Type Remarks Token ~ Security Token Object Load Int load on the system Threads lnt number of threads running Users Int number of Users being Uptime Int serviced 3 0 NumberManaged Int amount of time running NumberAssociated Int number of managed servers number of associated servers Statistics Request Object Encapsulates a request for system-related information that can be used by load balancing algorithms and statistical purposes.
Field Name Field 'lope Remarks Token Security Token Object Load Int request flag (onloff) Threads lnt request flag (on/off) Users Int request flag (on/off) Uptime int request flag (on/off) NumberManaged Int request flag (on/of~

NumberAssociated Int request flag (on/off) User Object Users and Servers use this object to register themselves with the administration database. They provide the information for subsequent logins (name, password) and other system-related info. The end Users -provide personal, demographic, and system-related information.
Field Name Field Type Remarks Token Security Token Object Login Login Information login information(natne, Object password) FirstName String User's first name LastNamt String User's last name 2 0 T itle String User's job title Company String User's employer Addressl String User's home street address Address2 String User's address extra Qity String city, village State String state, province or foreign country ZipCode String zip or postal code Age ~ String User's age Gender String User's gender PhoneNumher String telephone number FarNumber String fax number Email String email address Dunographics Dictionary market-targeting extra User info Sysremlnfo Dictionary system-related information Ta6k 1 (rnntinue~d) . Version Object All components of the system use this object to report their versioning information to the party they transact with in order to use a protocol they both understand. They are also given the chance to update themselves if a newer version exists.
Field Name Fiefd Type Remarks Token Security Token Object Major Int . major protocol version number Minor Int minor protocol version number Type Int sender type Client Version client version information Unlike traditional protocols based on state computers, the control protocol of the present invention is a light-weight, stateless protocol comprising simple sequences of objects. It is light-weight in that in most sequences only two objects are involved in the transaction and after a sequence is completed the connection can be reused. It is also stateless in that the server maintains no information about the client. Every transaction is handled independently of the previous ones. States exist in the lower levels, for example within the TtrP layer, to express logical states of a network connection but they are not actually part of the control protocol. .
In the preferred embodiment, the software running on the Control Servers, Media Servers and Primary Servers is programmed for Windows NT and UNIX environment using the OLE
environment. In addition, COM interfaces are used between components. The Rogue Wave system is used to transfer objects between the applications running on the various computers. The software running on the User computer is preferably programmed for a Windows 32-bit environment, so it will run on a Windows 95 or windows NT computer.
Alternatively, Macintosh and UNIX environments can be accommodated by other User software.
The basic process of a control transaction consists of a version sequence followed by one or more protocol sequences. The version sequence starts after the computer -initiating the transaction, the client, has established a connection with the computer completing the transaction, the server. The client sends a Version Object (deffined in Table 1) and in~response the server then sends back its own Version Object. This version sequence is used so that both client and server are aware of the version numbers of the software they are using. If a version number is older than expected, either client or server can choose to conform to the previous version or abort the transaction, depending on its needs and capabilities. If a version number is newer than expected, in most cases the current transaction can be completed since the software systems are designed to be fully backward compatible with previous versions. Additionally, in the case that the i5 server of the transaction is the Administration Server, the client receives information about what the latest version number is and thus the client can be informed that a software update is needed. The process of handling automatic updating of User software is described more fully below.
After the version sequence, one or more protocol sequences occur in which other objects are exchanged between client and server. When a particular protocol sequence is completed, another independent protocol sequence can be serviced. The protocol sequences that are part of the control architecture of the present invention are summarized in Table 2 and described below in conjunction with Figures 6-1?.

summary of Protocol Sequencea intro '- ~n : ::...,. . ..:.::
eyuen pent ~ . .:::
Se . .. .. ..:: . . eets t ange n'~' ~

User RegistrationUser Administration Version Object and Login User Object (see Fig. Channel Guide Object 6) User Login User Administration Version Object (sue Fig, Login Information Object n Channel Guide Object Channel PlayUser Administration Version Object (see Figs Server List Object Sa, 8B, 8C) Control Version Object Server List Object Media Version Objxt MCI Objects -OPEN/PLAY/STOP/CLOSE

Ping Objects (TCP connection stays open) Token ValidationControl or AdministrationVersion Object or (see Figs. Media or Control Security Token Object 9A, 9B) Primary Server Media or AdministrationVersioa Object 2 RegistrationControl User Object 5 and Login Server Activation Object i (see Fig.
10) Server LoginMedia or AdministrationVersion Object (see Fig. Control Login Objod 11) Server Activation Object Control ServerAdministration Control Version Object Activation Server Activation Objxt (see Fig.
II 12) I
II

;:.:: .;. :.::,:,:~::: - , ; , ::.; .. ",..;,;;:::..,.::::.::~.>.:.:;:' . .:... ...., urn:. ~a a .. ~
ontro a uenee.1..'I lyl Ub, t:xch 1....
. gent .. erxex...<<x:...:.~ :.. ... .
,..._..::...:.:::,>::.,..::.:::. . ~.,.::::: , cts.. .
.::....-..:....:::..::.:.:....:, ..... .......... .
1::.. .. .. .::::::........:........:",~,.,.:....................... ......
:.....,..::, ..... ,...,..,.,.............. ......., ".
... . .... . .:,:.:;.: .:,.w......,Y,,".::,.._ \ .". :.. __ ..:...:.:..v:\L::a.... .~~,a ::...py:gss :\..:::.:::.:::.,:::v?..:,w:...:.:_ ..~\,y .~..:..: ;.l::s.

Media Semr Control Media Version Objetx Activation Server Activation Object (see Fig. Ping Objecxs ' 13) (TCP connection stays open) Control ChannelAdministration Control Version Object Activation Channel Activation Object (see Fig.
14) Media ChannelControl Media (open TCP connexion) Activation Cham~el Activation Objecxs (see Fig.
1~

Distribution Media Media or Version Objecx Activation Primary MCI Objects -(~ Fig. 16) OPEN/PLAY/STOP/CLOSE

. Ping Objects I

(TCP conaecdon stays opt) Statistics Administration Control Version Object Request or (see Fig. Media Statistics Object 17) The User registration and login sequences are the processes by which a new User registers with the system, logs in and retrieves programming information. The channel play sequence takes place when a User asks to listen to a particular channel. The token validation sequence is used to verify that a computer requesting a service is authorized to do so. The Server registration, login and activation sequences are used by Control and Media Servers when they become active. The Control Server and Media Server activation sequences are used to manage the Control and Media Servers. The control channel, media channel and distribution activation sequences are used to cause a channel to be distributed to a Media Server. Finally, the statistics request is used for administrative purposes.

. Fig. 6 illustrates the User registration and logic sequence in more detail. This sequence.takes place~after the User has installed the User software on his/her computer.. It is expected, that the User will , download the software from the Internet and.then invoke it, which in the preferred embodiment will use the Windows Wi-zard~interface:. This will guide tho.
User through the installation process including filling out the. registration fork which we will describe more ~ fully in ' the next section. After the User has selected a na~na and l0 password and selected the option~to register, the Uee= ~. : .
computer opens a TCP connection to the~Administratioil Server.
Advantageously, the full domain name of~the Administration Se=ver is. embedded into the User software,'although it could be discovered in other-ways: The User,and Administratios~~l Server then exchange'version objects with the Administration .
Server as described above. If the version numbexs vdeet expectations, the User sends a User Object to the 1.
Administration Server. The format of.tha User Object is shown ~in. Table 1. Once the' Admini~stration Server receives Z0 the User object, it verifies that..the information, is filled in properly and that the selected User.name.is uniquei.~~ I!
the user object is invalid for any reason, the Administration Server returirs'a Result Message Object with a. coda indicating the reason. The format of the Result Message Object is,showp Z5 in Table i. If the User information is valid, the . ' Administration,Server updates the global database of Use=.
names and passwords and then generates a security tokeri for that User. This security token is then returned to the User.
inn a Result Message Object. ~ . ~ . .
5p .Upon receiving the Result Message Object, the User saves the security token for future use. This. token is an identifier that allows the User to request seivices from the Administratioir Server and~other computers within the overall' system. The security~token is aot saved permanently.or 95 registered on the~User computer. Normally, the User software then immediately sends a Channel.Guide Request Object to the Administration Server and a Channel Guide Object is returned..

The format of 'these objects is also shown in Tabls.i. Note . that in principle, this, is a separate transaction and could take~place in a separate TCP connection to the Administration Server. In particular; once the User has registered and 5 logged iri, he/she can request the Channel Guide Object again since it may have been updated since the previous,request.~
~At this point. the TCP connection to the Adiainistration'~aeiver is closed.
The process of User registration only neads'to~taks to'place once~.for each User. However anyone can bra-register at any time, even after the software has'been installed. In particular, it is expeoted~that if multiple persons.use a computer, each~person will register and obtain his/hor own User name and pa~ss~orh..~If the registration process is. not i5 completed successfully, the User software sayea the ~' registration infonriation and asks~the Ueer if he/she .would like to try again the next time'the software is invoked.
since the security.~toksn is not permansntly~saved by the Uservsoftware,, it ie lost when the. User software .is Z0 closed, and the security token'must''again bo_ratrieved tree the Administration server the next time 'the year wants to use the systea.. . This. process .is the purpose of the ,login sequence illustrated in Fig. .7. This sequencra is used ~if a .
User has already registered and needs~only to retrieva~a 35 valid secu~~ty, token. In this, case. the sequence consists of the User s sending a Login.~Information Object to the .
Administration server. The~Administration serve= than queries the User database to validate the logit~ nay and password. If the loqin name and password are~.corract, than a 5o security token~is returned to the User. Normally the receipt of the security token will immediately be followed by a channel information request sequence, just .as in tho registration sequence described previously.
The control sequence that takes place when a.User 35 initiates a channel play operation i~s~illustrated in Figs.
8A, 88 and 8C. First the User software~requests a Control server List from the Administration server, l~ota that the Server List Request Object, illustrated in Table l.contains~-a . channel identifier. The Administration Server generates a sorted list of Control Servers based on overall system load and the location of the User on the network and returns this list to the User using a Protocol List Object. Once the Control Server List is returned to the User, the Administration Server is no longer needed and the TCP
connection is closed.
The User software then searches the list of Control Servers and opens a TCP connection to the first host listed.
If that host computer does not respond, then the next Control Server on the list is tested and so forth in succession.
Upon obtaining a response from a Control Server, the User software uses a Server List Request object to requests a i5 Media Server List from the Control Server. If the Control Server is too busy to service the User, it returns a Result Message Object so indicating and the User software tries the next Control Server on the list. However, in the likely scenario that the Control Server is able to handle the User's request, a sorted list of Media Servers is generated and returned to the User computer using a Protocol List Object.
The TCP connection to the Control Server is then closed by the User software.
At this point the User software initiates a TCP
connection to the first Media Server on the list provided by the Control Server. As in the previous case, it attempts to connect to the first host on the list and if unsuccessful tries the next hosts in succession. Once the Version Objects are exchanged, the User software sends an MCI Request Object to the Media Server. An MCI Request Object can be used for four basic commands: OPEN, PLAY, STOP and CLOSE. The User software must first send an OPEN command for the desired channel. If the returned Result Message Object indicates success, the User software then sends a PLAY command.
When the Media Server receives a valid PLAY
command, it initiates the delivery of audio information to the User as described in the previous section. Note that this could be in the form of broadcast, multicast or unicast ~ packets to a specific UDP port. The TCP connection through which the MCI Request Objects were sent stays open during the audio play operation. In addition, Ping Objects are sent to the User on a periodic basis to verify that the computer is still working and active. When the User software receives a Ping object, it simply returns it. The Media Server uses the Ping Objects to measure round trip time and also to determine when a User's computer has terminated abnormally. In that case the audio stream is terminated.
In the case of normal termination of the audio stream, the User makes an explicit selection to stop and this causes a STOP command to be sent to the Media Server in an MCI Request Object. The Media Server then terminates the audio stream to that User. When the User closes the application software or selects another channel to play, the User. software will send a CLOSE command to the Media Server in an MCI Request Object and the TCP connection is closed.
The initiation of the audio stream by the Media Server causes a log entry to be generated and sent' to the Administration Server. This information is important so that the Administration Server can update its database to indicate which Users are listening to which channels. The security token is used to identify the User initiating the audio stream. Additionally, when the audio stream is terminated to any User, another log message is generated and sent to the Administration Server.
Fig. 9A illustrates the process by which security tokens are validated. The Administration Server is the only server that can validate a security token. Thus, when a User requests services from a Control Server or from a Media Server, that server must go back to the Administration Server with a token validation sequence. However, Control Servers and Media Servers are allowed to cache validations of security tokens so that they do not have to validate tokens repeatedly once they have validated it the first time. In the case where a Media Server receives a request, the token will be validated with the Control Serves that is managing, that Media server. Fig. 98 identifies the various token validation scenarios. , .. , :.
Fig. 10 illustrates the process by which a neW
5'Server is registered. This process .is similar to_new User registration. It~.~is expected, however, that the serve=
installation will be through a Web interface rather than a . Wizard. The Administration Server, upon receiving a User .
Object from a Media Server or .Control Server, validates the .User ~name~ and password and generates a. security token just as in the case of User~registration. Normally the Serve= then immediately sends back a server Activation object indicating that it is ready to be used as a system resource. Once this process has.been.completed, the TCP connection to the ~~ i5 Administration Server is closed.
If a Media Server or control server that has sent a ' Server Activation Object to the Administration Server~becomes inactive, it will send another Server Activation obiect indicating this condition. In~the case of a Media Serves, this object is sent to.the managing Control Server. ~In~the case of a 'Control Server, this object sent to: the Administration server. As in..the case of User:registration, Media Server and Control server registration needs~only~taka place once per computer. However, if the computer is,' ~ .
restarted, the server must login and again retrieve a , security token. This~is the server login and activation sequence shown in Figure 11. ' ~ . . .
once a Control Server has indicated to the Administration,server that it is ready, the Administration Server can activate that Control Server'by sending the~~~
control server a Server Activation object as illustrated in Fig. 12. This is e~separate transaction and i$ used to tall the control Server which Media Servers it~is supposed to . __ manage. Recall that a Control Server and a number of Media 55 severs fore a cluster- of_ Media Servers. The single control Server that manages that cluster~must be given a list of host computers corresponding to the Media Servers in that cluster.

The process by which a Control Server activates the Media Servers.that it manages is~illustrated in Fig. l3'. The Control Server sends a Server Activation Object to'the Media . Server indicating that it is responsible for channel 5 management. This TCP connection between the Control Server .
and. the Media server stays open during the time that both servers are active. The Control server periodically sends Ping Objects to the Media Server.across this open TCP
connection to verify that the Media Server is~ still ,running.
i0 ~ ~ Fig.' 14 illustrates _the process by which a~-giver .
channel is activated by the Administration Server. The .
Administration Server opens,a connection to a Control Server that its wishes. to have carry a given channel and~provido a Channel Activation Object. This object indicates.to the i5 Control. server which Media or Primary server the Control Server should direct its Media Servers to get the feed from.
At this~point the Control Server is said to be carrying that channel and it will.~.ba a valid host on a list of Control Servers requested by a Chaiu~al Play sequence. .
Zp ~ Ffg: 15 illustsates what. happens when-~a Control Server needs to provide a channel. First it sends.s~Channel Activation Object to one of the Media.Servers that it manages across the,operi TCP connection~described previously. This .
object indicates to the Media Server that it should start 25 receiving the channel identified and from where it should receive it. . ~ ~ .
'. In Fibs. 16A and 168 depict how the Media Sei vat requests distribution .o! an audio channel from another, Media server or from a Primary server. This sequence is much the 30 .same as that~~in which a User requests the distribution of audio information..from 'a Media server. ~ Note that a Media Server receives a single incoming stream for each channel 'that it is carrying and then redistributes this stream to all Users~or other Media Servers that request it.
3s Ffnally, Fig. 19 illustrates the statistics request sequence. This~sequence is used by the Administration Server to gather information_from the Media Servers and control Servers in order to manage the overall system. It can use this infonaation to detect failures and to balance~load as the dynamic.conditions change. As indicated above, it can also~use this information to monitor which:Users are ~. ~ ~5 listening to which channel'or whether Users stop listening~to ~a channel,at any time, such~.as~during the play of a particnl-ar song. 'It can. also use this information to~ control . ~the.advertising, content that is~downioaded to'a.particular User in advance of receipt'of regular audio programming 1o and/or monitor the delivery.of advertising to the Users.
' The control architecture described in this section is scalable to handle any number of Users. Note that the' User registration process only~happens.once for each .
subscriber and~the login process.only happens.once per i5 sessioxi~ These .interactions, whichrequire: th0 Administration Server, ~ are e3cpected, to constitute, a .. very small ' ' percentage :of the overall system .band~ridth. ~ If the Administration Server. were to becoione a bottleneck, however, ~it would 'be possible to duplicate it and to have the database ,2o it maintains distributed and automatically.updated to g~iarantee consistency., ~ _ . .
They. Control Servers are ~ d~ist=ibuted throughout the ' network and can handle the lower level . interactions ~~iith the 'Users and the Media Servers. A single Cont=ol:Server.can 25 handle preferably on the order of ten Media Servers up to several hundred Users. The bitrate among the Users, the control Servers and~the Media~servers is expected to be-small.
in comparison to the audio transmission bitrate. The Ping Objects~normally only involve'the User and the nearest Media 30 Server. They, are also. low in overhead since thex are small and only get transmitted infrequently.
III. User Interface The User interface is provided by. the client application 35 runniag~on an individual computer.and its associated' graphical interface. In the preferred embodiment the User interface~is available for 32-bit Windows (95.and NT), Macintosh ans UNIX platforms. Preferably anyone on the Internet can freely download a copy of the client software and install it in their computer.
Figure 18 illustrates the main User screen in the preferred embodiment. The screen is composed of three sections: channel guide (upper left frame), program guide (upper right frame), and multimedia frame (lower half of screen). The channel guide lists, as a tree hierarchy, the channels that are available from the system. The User selects a channel from the list of those displayed on the channel guide. The program guide provides information pertaining to the channel selected. This information can be a detailed schedule of the programming that has played or will be playing on the channel selected. Additionally, other relevant information will be displayed in this frame, for example, a notice regarding an upcoming special event on another channel. The multimedia frame provides an integrated web browser that displays information via a series of tabbed sections.
The information contained in the channel guide, program guide, and the tabs of the multimedia frame is dynamically transmitted to the client. For example, if a new channel begins operation, the client application can immediately display it as being available. Furthermore, the tabs displayed can be specifically relevant depending on what song is playing. For example, tabs displaying the album cover, information on the artist, song lyrics, tour dates can be displayed. Additionally, as shown in the example in figure 18, a tab can be available allowing the User to place an order for the CD or allowing the User to participate in a chat session related to the channel.
Figure 19 illustrates the key pull-down menus available in the main User screen in the preferred embodiment. Table 3 provides a description of each of the functions available through the pull down menus, as shown in figure 19.

As~will be apparent to those skilled in the art, w numerous modifications may be made.within the spirit and scope of the invention.
~ ' Tables 3 Pull-Do~rn Menn~ Functionr Menu Menu sub.-Choice Descrzpt on .~

choice . . , . . . . ~ ..
~ .

Fi t Login A
ows the. User to og n to . ~ the system. . . . .

to ' ~gou A ows the User o ogou ~

. ~ from the systea. - " -. . ' Register -Brings wp-a is og so a the User can register with the system f or the f irst time:

Close Minimizes a screen..
' ~

Ed Copy A ows a User to popy a .

, selection on ~to- ~tha clipboard. ' Properties A ows a User se ' various properties.

Au o I Play - Beg ns playiag~ a se ec channel. .' ~

~ s op s ops p ay ng. a se ecte .

2D . .
channel.

Mute "'' Stops t a p ay ng o au o ' . Vio~ .. Too Bar Disp ay or h a a too (providing'acceBS to pull-down menu functions).

s atus Bar 'Disp ay or h a a status bar . nonaally situated .'at . ~ bottom of the screen.

We D sp ay or hi a a too Bar .~ . section that provides access ~ ~

to the web browser functions. ' xe p Help Topics Brings up a lisp o~ ava a ,. ~ online help topic.

. ou .... Displays summary information ' regarding this application, such as versioa number, copy-right information, and so on.

_f

Claims (131)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A system for streaming a continuous sequence of individual pieces of information over a communications network to a group of users that selected a particular channel, the system comprising:
at least one server adapted to transmit the continuous sequence of individual pieces of information at approximately a same time to each user in the group that selected the particular channel, wherein the individual pieces of information include audio information;
an application that generates a user interface screen adapted to allow a user to initiate a purchase of a product, the user interface screen including:
a channel guide that includes a list of available channels of audio, and a program guide that provides information relating to the particular channel;
and at least one server adapted to maintain an audit log that records data indicative of at least one of:
how many users listened to the particular channel, or times at which the users listened to the particular channel.

2. The system of claim 1, wherein membership in the group of users is dynamic.

3. The system of claim 1, wherein a user in the group can start and stop listening to the particular channel at any time.

4. The system of claim 1, wherein the application is a client application that is configured to be downloaded over the communications network and installed on user computers.

5. The system of claim 1, wherein the product is a CD that is relevant to the audio information being transmitted.

6. The system of claim 1, wherein the user interface screen includes a link to facilitate the purchase.

7. The system of claim 1, wherein the product is relevant to the audio information that is being transmitted.

8. The system of claim 1, wherein the audit log records data indicative of how many users listened to the particular channel and times at which the users listened to the particular channel.

9. The system of claim 1, wherein the user interface screen is adapted to allow a user in the group to initiate two-way interaction with at least one other user in the group.

10. The system of claim 9, wherein the two-way interaction allows the user and the at least one other user to chat.

11. The system of claim 9, wherein the two-way interaction allows the user and the at least one other user to chat about the particular channel.

12. The system of claim 9, wherein the user interface screen includes a link to facilitate the two-way interaction during transmission of the audio information.

13. The system of claim 1, wherein the user interface screen is adapted to allow a display of tour dates.

14. The system of claim 1, wherein the user interface screen further includes information selected from the group consisting of an album cover, artist information, song lyrics, and tour dates.

15. The system of claim 1, wherein the information provided in the program guide relates to audio information that will be playing on the particular channel.

16. The system of claim 1, wherein the information provided in the program guide is dynamically transmitted to the application.

17. The system of claim 1, wherein the available channels include at least one of music, talk radio, news, special events, concerts, sports broadcasts, or corporate announcements.

18. The system of claim 1, wherein the available channels include channels featuring different types of music.

19. The system of claim 1, further comprising at least one server adapted to control routing of the individual pieces of information in response to selection signals received from the users.

20. The system of claim 19, further comprising multiple servers to transmit the continuous sequence of individual pieces of information at approximately the same time to each user in the group, wherein the multiple servers that transmit the information are configured to be scalable so that any number of users can receive the audio information.

21. The system of claim 1, further comprising multiple servers to control routing of the individual pieces of information in response to selection signals received from the users, wherein the multiple servers that control the routing are configured to be scalable so that any number of users can receive the audio information.

22. The system of claim 1, wherein the audit log records data indicative of how many users listened to the particular channel and data indicative of how many users are stored in a database.

23. The system of claim 1, further comprising at least one server adapted to send advertising information to at least one of the users in the group.

24. The system of claim 23, wherein the advertising information includes content that is varied.

25. The system of claim 24, wherein the content is varied based on demographics.

26. The system of claim 24, wherein the content is varied based on the particular channel.

27. The system of claim 23, wherein the advertising information is incorporated into the continuous sequence of individual pieces of information.

28. The system of claim 23, wherein the advertising information is incorporated into a separate stream of information, and the separate stream is transmitted before the audio information and stored in a memory of a computer operated by a user in the group and then inserted into the audio information upon receipt of a cueing signal by the computer.

29. The system of claim 1, wherein the audio associated with each of the available channels comprises an independent continuous sequence of information.

30. The system of claim 1, wherein the user interface screen is adapted to allow a user to play, stop and mute the audio information.

31. A method for streaming a continuous sequence of individual pieces of information over a communications network to a group of users that selected a particular channel, comprising the steps of:

transmitting the continuous sequence of individual pieces of information at approximately a same time to each user in the group that selected the particular channel, wherein the individual pieces of information include audio information;

providing an application that generates a user interface screen adapted to allow a user to initiate a purchase of a product, the user interface screen including:
a channel guide that includes a list of available channels of audio, and a program guide that provides information relating to the particular channel;
and maintaining an audit log that records data indicative of at least one of:
how many users listened to the particular channel, or times at which the users listened to the particular channel.

32. The method of claim 31, wherein the product is a CD that is relevant to the audio information being transmitted.

33. The method of claim 31, wherein the audit log records data indicative of how many users listened to the particular channel and the times at which the users listened to the particular channel.

34. The method of claim 33, further comprising storing in a database data indicative of how many users listened to the particular channel.

35. The method of claim 31, wherein the user interface screen is adapted to allow a user to chat with at least one other user in the group.

36. The method of claim 31, wherein the user interface includes information selected from the group consisting of an album cover, artist information, song lyrics, and tour dates.

37. The method of claim 31, wherein the available channels include channels featuring different types of music, and the user interface screen is adapted to allow a user to play, stop and mute the audio information.

38. The method of claim 31, further comprising controlling routing of the individual pieces of information in response to selection signals received from the users.

39. The method of claim 31, further comprising transmitting advertising information to at least one of the users in the group.

40. The method of claim 39, wherein the advertising information includes content that is varied.

41. A method for making available a plurality of media streams, wherein each of the media streams comprises an independent continuous sequence of individual pieces of information, comprising the steps of:
transmitting the media streams, wherein a particular media stream of the media streams is transmitted at approximately a same time to a group, wherein the group comprises a set of all users that selected the particular media stream;

providing an application that generates a user interface screen including:

a channel guide that includes a list of available media streams, and side-bar information containing data selected from the group consisting of graphics, images and text; and maintaining a database that includes data indicative of at least one of:
the media streams selected by the users, how many users listened to the selected media streams, or times at which users listened to the selected media streams.

42. The method of claim 41, wherein the media streams include different types of music, and the user interface screen is adapted to allow a user to play, stop and mute the music.

43. The method of claim 42, wherein the side-bar information is synchronized with the different types of music and includes images relating to an album cover and artist information.

44. The method of claim 41, further comprising providing a plurality of servers that are adapted to transmit the plurality of media streams.

45. The method of claim 44, further comprising selecting one or more of the plurality of servers to transmit the media streams in response to selection signals received from the users.

46. The method of claim 41, wherein the side-bar information relates to an album cover.

47. The method of claim 41, wherein the side-bar information relates to artist information.

48. The method of claim 41, wherein the side-bar information relates to tour dates.

49. The method of claim 41, wherein the side-bar information relates to song lyrics.

50. The method of claim 41, wherein the side-bar information relates to a URL.

51. The method of claim 45, wherein the user interface screen is adapted to allow a user to initiate a purchase of a product.

52. The method of claim 51, wherein the product is a CD that is relevant to at least one of the plurality of media streams being transmitted.

53. The method of claim 41, wherein the user interface screen is adapted to allow a user to initiate two-way interaction that allows users to chat.

54. The method of claim 41, further comprising transmitting advertising information to at least one of the users in the group.

55. The method of claim 54, wherein the advertising information includes content that is varied.

56. A system for streaming a continuous sequence of individual pieces of audio information over a communications network to a group of users that selected a particular channel, the system comprising:

at least one server adapted to transmit the continuous sequence of individual pieces of audio information at approximately a same time to each user in the group that selected the particular channel;
at least one server adapted to maintain an audit log that records data indicative of how many users listened to the particular channel;

a client application that generates a user interface screen including:

a channel guide that includes a list of available channels of audio, wherein the available channels include channels featuring different types of music, a program guide that provides information relating to the particular channel, and a frame adapted to allow a user to initiate a purchase of a product.

57. The system of claim 56, wherein the client application is configured to be downloaded over the communications network and installed on user computers.

58. The system of claim 56, wherein a user in the group can start and stop listening to the particular channel at any time.

59. The system of claim 58, wherein the product is a CD that is relevant to the audio information being transmitted.

60. The system of claim 56, wherein the user interface screen is adapted to allow a user to initiate two-way interaction that allows users to chat, and the user interface screen is further adapted to allow the user to play, stop and mute the audio information.

61. The system of claim 56, wherein the user interface screen further includes information selected from the group consisting of an album cover, artist information, song lyrics, and tour dates.

62. The system of claim 56, further comprising at least one server adapted to control routing of the individual pieces of audio information in response to selection signals received from the users.

63. The system of claim 56, wherein data indicative of how many users are stored in a database.

64. The system of claim 56, further comprising at least one server adapted to send advertising information to the users.

65. The system of claim 64, wherein the advertising information includes content that is varied.

66. A system for streaming a continuous sequence of individual pieces of audio information over a communications network to a group of users that selected a particular channel, the system comprising:
a plurality of servers adapted to transmit the continuous sequence of individual pieces of audio information at approximately a same time to each user in the group that selected the particular channel;
at least one server adapted to maintain an audit log that records data indicative of how many users listened to the particular channel, wherein the data are stored in a database;

a client application that generates a user interface screen including:
a channel guide that includes a list of available channels of audio, wherein the available channels include channels featuring different types of music, side-bar information containing data selected from the group consisting of an album cover, artist information and a URL, and a frame adapted to allow a user to initiate a purchase of a product.

67. The system of claim 66, wherein the client application is configured to be downloaded over the communications network and installed on user computers.

68. The system of claim 66, wherein the side-bar information is synchronized with the audio information.

69. The system of claim 66, wherein the side-bar information includes data regarding the album cover, the artist information, and the URL.

70. The system of claim 66, wherein the product is a CD that is relevant to the audio information being transmitted.

71. The system of claim 66, wherein the user interface screen is adapted to allow a user to initiate two-way interaction for users to chat.

72. The system of claim 66, further comprising at least one server adapted to select one or more of the plurality of servers to transmit the audio information in response to selection signals received from the users.

73. The system of claim 72, wherein the plurality of servers are configured to be scalable so that any number of users can receive the audio information.

74. The system of claim 66, further comprising at least one server adapted to send advertising information to the users.

75. A system for streaming multiple channels of audio information over a communications network, the system comprising:
a plurality of servers adapted to transmit the multiple channels of audio information, each channel including an independent continuous sequence of individual pieces of information and said plurality of servers configured so that the audio information for a particular channel of the multiple channels is transmitted at approximately a same time to a group, wherein the group comprises a set of all users that selected the particular channel;

at least one server adapted to route the audio information by selecting one or more of the plurality of servers in response to selection signals received from the users;
a client application that generates a user interface screen including:
a channel guide that includes a list of the multiple channels of audio information, wherein the multiple channels include channels featuring different types of music, a program guide that provides information relating to a selected channel, and a frame adapted to allow a user to initiate a purchase of a CD that is relevant to the audio information being transmitted.

76. The system of claim 75, wherein a user can select any of the multiple channels and can start and stop listening to the particular channel at any time.

77. The system of claim 75, wherein the product that may be purchased is relevant to the audio information that is being transmitted.

78. The system of claim 75, wherein the user interface screen is adapted to allow a user to initiate two-way interaction that allows users to chat.

79. The system of claim 75,wherein the user interface screen further includes information selected from the group consisting of an album cover, artist information, song lyrics, and tour dates, and the user interface screen is further adapted to allow the user to play, stop and mute the audio information.

80. The system of claim 75, wherein the plurality of servers are configured to be scalable so that any number of users can receive the audio information.

81. The system of claim 80, further comprising at least one server adapted to send advertising information to the users.

82. The system of claim 81, wherein the advertising information includes content that is varied.

83. A system for streaming audio information over a communications network, the system comprising:

multiple channels of audio information, each channel of the multiple channels including an independent continuous sequence of individual pieces of information;
at least one server adapted to transmit the audio information of each channel, said server configured so that the audio information for a particular channel of the multiple channels is transmitted at approximately a same time to a group, wherein the group comprises a set of all users that selected the particular channel;
an application that generates a user interface screen adapted to allow a user to initiate a purchase of a product, the user interface screen including:
a channel guide that includes a list of the multiple channels available to the user, wherein the channels include different types of music, and a program guide that provides information relating to a channel selected by the user; and at least one server adapted to maintain an audit log that records data indicative of at least one of:
the channels selected by the users, how many users listened to the selected channels, or times at which users listened to the selected channels.

84. The system of claim 83, wherein a user can select any of the multiple channels and can start and stop listening to the selected channel at any time.

85. The system of claim 83, wherein the product is a CD that is relevant to the audio information being transmitted.

86. The system of claim 83,wherein the audit log records data indicative of the channels selected by the users, how many users listened to the selected channels, and the times at which users listened to the selected channels.

87. The system of claim 83, wherein the user interface screen is adapted to allow a user to initiate two-way interaction that allows the users to chat.

88. The system of claim 87, wherein the user interface screen further includes information selected from the group consisting of an album cover, artist information, song lyrics, and tour dates, and the user interface screen is further adapted to allow the user to play, stop and mute the audio information.

89. The system of claim 87, wherein the audio information is transmitted by a plurality of servers that are configured to be scalable so that any number of users can receive the audio information.

90. The system of claim 89, further comprising at least one server adapted to select one or more of the plurality of servers in response to selection signals received from the users.

91. The system of claim 90, wherein data indicative of how many users are stored in a database, and data indicative of the channels selected by the users are stored in the database.

92. The system of claim 90, further comprising at least one server adapted to send advertising information to the users.

93. The system of claim 92, wherein the advertising information includes content that is varied.

94. A system for streaming audio information over a communications network, the system comprising:
multiple channels of audio information, each channel of the multiple channels including an independent continuous sequence of individual pieces of information;
at least one server adapted to transmit the audio information of each channel, said server configured so that the audio information for a particular channel of the multiple channels is transmitted at approximately a same time to a group comprising a set of all users that selected the particular channel;

an application that generates a user interface screen adapted to allow a user to initiate a purchase of a CD that is relevant to the audio information being transmitted, the user interface screen including:
a channel guide that includes a list of the multiple channels available to the user, wherein the channels include different types of music, and a program guide that provides information relating to a channel selected by the user; and at least one server adapted to route the individual pieces of information in response to selection signals received from the users.

95. The system of claim 94, wherein a user can select any of the multiple channels and can start and stop listening to the selected channel at any time.

96. The system of claim 94, wherein the user interface screen is adapted to allow a user to initiate two-way interaction that allows the users to chat.

97. The system of claim 96, wherein the user interface screen further includes information selected from the group consisting of an album cover, artist information, song lyrics, and tour dates.

98. The system of claim 96, further comprising at least one server adapted to send advertising information to the users.

99. The system of claim 98, wherein the advertising information includes content that is varied.

100. The system of claim 96, wherein the audio information is transmitted by a plurality of servers that are configured to be scalable so that any number of users can receive the audio information.

101. A system for streaming a continuous sequence of individual pieces of audio information over a communications network to a group of users that selected a particular channel, the system comprising:
at least one server adapted to transmit the continuous sequence of individual pieces of audio information at approximately a same time to each user in the group that selected the particular channel;

an application that generates a user interface screen adapted to allow a user to initiate two-way interaction allowing the user to chat and further adapted to allow the user to initiate a purchase of a CD that is relevant to the audio information being transmitted, the user interface screen including:
a channel guide that includes a list of available channels of audio information, wherein the channels include different types of music, and a program guide that provides information relating to the particular channel;

and at least one server adapted to maintain an audit log that records data indicative of at least one of:
how many users listened to the particular channel, or times at which users listened to the particular channel.

102. The system of claim 101, wherein the user interface screen further includes information selected from the group consisting of an album cover, artist information, song lyrics, and tour dates.

103. The system of claim 101, further comprising at least one server adapted to control routing of the individual pieces of audio information in response to selection signals received from the users.

104. The system of claim 101, further comprising at least one server adapted to send advertising information to the users.

105. The system of claim 104, wherein the advertising information includes content that is varied.

106. A system for streaming a continuous sequence of individual pieces of audio information over a communications network to a group of users that selected a particular channel, the system comprising:
at least one server adapted to transmit the continuous sequence of individual pieces of audio information at approximately a same time to each user in the group that selected the particular channel;
an application that generates a user interface screen adapted to allow a user in the group to initiate two-way interaction allowing the user to chat and further adapted to allow the user to initiate a purchase of a CD that is relevant to the audio information being transmitted, the user interface screen including:
a channel guide that includes a list of available channels of audio information, wherein the channels include different types of music, and a program guide that provides information relating to the particular channel;
and at least one server adapted to route the individual pieces of audio information in response to selection signals received from the users.

107. The system of claim 106, wherein the user interface screen further includes information selected from the group consisting of an album cover, artist information, song lyrics, and tour dates, and wherein a user in the group can start and stop listening to the particular channel at any time.

108. The system of claim 107, wherein the audio information is transmitted by a plurality of servers that are configured to be scalable so that any number of users can receive the audio information.

109. The system of claim 107, further comprising at least one server adapted to send advertising information to the users.

110. The system of claim 109, wherein the advertising information includes content that is varied.

111. A system for streaming audio over a communications network, the system comprising:
at least one server configured to transmit a continuous sequence of packets containing audio information, wherein the continuous sequence of packets is transmitted at approximately a same time to each of multiple user computers;

a software application configured to be loaded onto each of the user computers, wherein the software application contains instructions for generating a user interface comprising:

a channel guide that includes a list of available channels of audio information, and a program guide that provides program information for at least one of the available channels; and at least one server configured to record which user computers received the audio information, which of the available channels were received, or times at which any of the available channels were received.

112. The system of claim 111, wherein the user interface further comprises an order placing feature that allows users of the multiple user computers to place an order for a product.

113. The system of claim 111, wherein the user interface further comprises a two-way interaction feature that allows users of the multiple user computers to participate in a chat session.

114. A method for streaming audio over a communications network, comprising the steps of:
transmitting a continuous sequence of packets containing audio information, wherein the continuous sequence of packets is transmitted at approximately a same time to each of multiple user computers;

providing a software application configured to be loaded onto each of the user computers, wherein the software application contains instructions for generating a user interface comprising:

a channel guide that includes a list of available channels of audio information, and a program guide that provides program information for at least one of the available channels; and generating a database that includes data indicative of how many user computers received the audio information, which of the available channels were received, or times at which any of the available channels were received.

115. The method of claim 114, wherein the user interface further comprises an order placing feature that allows users of the multiple user computers to place an order for a product.

116. The method of claim 114, wherein the user interface further comprises a two-way interaction feature that allows users of the multiple user computers to participate in a chat session.

117. A system for streaming multiple channels of audio information over a communications network, the system comprising:

a plurality of first servers configured to transmit the multiple channels of audio information, each channel including an independent continuous sequence of packets containing audio information, where said plurality of first servers are configured so that the audio information for a particular channel is transmitted at approximately a same time to each of multiple user computers that requested the particular channel;
at least one second server adapted to route the audio information to the user computers through selected first servers of said plurality of first servers in response to selection signals received from the user computers; and a software application configured to be loaded onto each of the user computers, wherein the software application contains instructions for generating a user interface comprising:

an order placing feature that allows users of the multiple user computers to place an order for a CD that is relevant to the audio information being transmitted, a channel guide that includes a list of the multiple channels, wherein the multiple channels include channels featuring different types of music, and a program guide that provides program information relating to a particular channel of the multiple channels.

118. The system of claim 117, wherein the user interface further comprises a two-way interaction feature that allows users of the multiple user computers to participate in a chat session.

119. A system for streaming a continuous sequence of packets of audio information over a communications network, the system comprising:

at least one server configured to transmit the packets at approximately a same time to each of multiple user computers;

a software application configured to be loaded onto each of the user computers, wherein the software application contains instructions for generating a user interface comprising:

an order placing feature that allows users of the multiple user computers to place an order for a CD that is relevant to the audio information, a two-way interaction feature that allows users of the multiple user computers to participate in a chat session, a channel guide that includes a list of available channels of audio information, and a program guide that provides program information for at least one of the available channels; and at least one server configured to record which user computers received the audio information, which of the available channels were received, or times at which any of the available channels were received.

120. The system of claim 119, further comprising at least one server adapted to route the packets in response to selection signals received from the user computers.

121. A system for streaming audio information over a communications network, the system comprising:
multiple channels of audio information, each channel of the multiple channels including an independent continuous sequence of individual pieces of information;
at least one server adapted to transmit the audio information of each channel, said server configured so that the audio information for a particular channel of the multiple channels is transmitted at approximately a same time to a group comprising a set of all users that selected the particular channel;

an application that generates at least one user interface screen adapted to allow a user to initiate a purchase of a product; and at least one server adapted to maintain an audit log that records data indicative of at least one of:

the channels selected by the users, how many users listened to the selected channels, or times at which users listened to the selected channels.

122. The system of claim 121, wherein a user can select any of the multiple channels and can start and stop listening to the selected channel at any time.

123. The system of claim 121, wherein the product that may be purchased is relevant to the audio information that is being transmitted.

124. The system of claim 121, wherein the at least one user interface screen is adapted to allow a user to initiate two-way interaction that allows the users to chat.

125. The system of claim 121, further comprising at least one server adapted to send advertising information to the users.

126. A system for streaming audio information over a communications network, the system comprising:
multiple channels of audio information, each channel of the multiple channels including an independent continuous sequence of individual pieces of information;

at least one server adapted to transmit the audio information of each channel, said server configured so that the audio information for a particular channel of the multiple channels is transmitted at approximately a same time to a group comprising a set of all users that selected the particular channel;

an application that generates at least one user interface screen adapted to allow a user to initiate a purchase of a CD that is relevant to the audio information being transmitted; and at least one server adapted to route the individual pieces of information in response to selection signals received from the users.

127. The system of claim 126, wherein a user can select any of the multiple channels and can start and stop listening to the selected channel at any time.

128. The system of claim 126, wherein the at least one user interface screen is adapted to allow a user to initiate two-way interaction that allows the users to chat.

129. The system of claim 126, further comprising at least one server adapted to send advertising information to the users.

130. The system of claim 126, wherein the audio information is transmitted by a plurality of servers that are configured to be scalable so that any number of users can receive the audio information.

131. The system of claim 130, wherein the at least one server adapted to route selects one or more of the plurality of servers in response to the selection signals received from the users.