Performing multicast communication in computer networks by using overlay routing

Abstract

An overlay protocol and system for allowing multicast routing in the Internet to be performed at the application level. The overlay protocol uses “native” Internet multicast and multicast routing protocols to route information, according to overlay routing tables. Overlay groups are mapped to native multicast groups to exploit native multicasting in regional or local forwarding domains. Use of the overlay protocol allows overlay distribution to be handled in a more intelligent and bandwidth-managed fashion. Overlay routers are placed at each of several local area networks, Internet service provider's point of presence, enterprise, or other cohesively-managed locations. The overlay computers are configured according to bandwidth and security policies, and perform application-level multicast distribution across the otherwise disjoint multicast networks by using the overlay routing. The result is an overlay multicast network that is effectively managed according to local network management policies. Application-level control can be applied to the transferred data at the overlay routers.

1 . An overlay routing processor for transferring information over a computer network, wherein the computer network has a native routing protocol the overlay routing processor comprising 
 instructions for associating computers on the network with a given overlay group;    instructions for determining whether received information is associated with the given overlay group; and    instructions for routing the received information to the computers associated with the given overlay group by using the native routing protocol.    
   
   
       2 . The overlay routing processor of  claim 1 , wherein the native routing protocol defines computers as members of native groups for purposes of routing information among members of a given native group, the overlay routing processor further comprising 
 instructions for identifying a specific native group as an efficient distribution channel for the given overlay group; and    wherein the instructions for routing include instructions for using the specific native group to perform the routing.    
   
   
       3 . The overlay routing processor of  claim 2 , wherein the instructions for identifying a specific native group include 
 instructions for using a hash function to perform the identification.    
   
   
       4 . The overlay routing processor of  claim 2 , wherein multiple overlay processors are coupled together over the network, the overlay routing processor further comprising 
 a data table accessed by the processor for defining peer relationships between overlay processors; and    wherein the instructions for routing include instructions for using the defined peer relationships between overlay processors to perform the routing.    
   
   
       5 . The overlay routing processor of  claim 1 , wherein an end-user computer is coupled to the network, wherein a first media information source is coupled to the network for sending media information to the network, the overlay routing processor further comprising 
 a data structure associating the media information with a first overlay channel identifier;    instructions for receiving a request from the end-user computer to receive the media information;    instructions for retrieving the first overlay channel identifier from the data structure and for associating the first overlay channel identifier with the request; and    instructions for routing all or a portion of the media information received by the overlay routing processor to the end-user computer.    
   
   
       6 . The overlay routing processor of  claim 5 , wherein a second media information source is coupled to the network for sending media information to the network, the overlay routing processor further comprising 
 instructions for indicating an error condition if a second overlay channel identifier associated with the second media information source is the same as the first overlay channel identifier.    
   
   
       7 . The overlay routing processor of  claim 2 , further comprising 
 instructions for associating a native group with an overlay group; and    instructions for changing the association between an overlay group and a native group.    
   
   
       8 . The overlay routing processor of  claim 7 , wherein the association between an overlay group and a native group includes defining a range of native multicast addresses.  
   
   
       9 . The overlay routing processor of  claim 8 , wherein the range of native multicast addresses is defined as an IP4 Class D address and a prefix length.  
   
   
       10 . The overlay routing processor of  claim 1 , further comprising 
 instructions for handling administrative scoping.    
   
   
       11 . The overlay routing processor of  claim 1 , further comprising 
 instructions for servicing plugin modules.    
   
   
       12 . The overlay routing processor of  claim 1 , further comprising 
 instructions for placing a limit on the number of transfers between computers for a given portion of information.    
   
   
       13 . The overlay routing processor of  claim 12 , wherein information is transferred between the computers in packets, the overlay routing processor further comprising 
 instructions for placing a “time-to-live” value in a field in a packet    
   
   
       14 . The overlay routing processor of  claim 1 , further comprising 
 instructions for preventing the transfer of information between predetermined computers.    
   
   
       15 . The overlay routing processor of  claim 14 , wherein one or more computers are identified by an address, the overlay routing processor further comprising 
 using the address to prevent the transfer of information between predetermined computers.    
   
   
       16 . A routing device in a computer network, the device comprising 
 instructions for detecting a client request for content information from a client computer;    instructions that identify a processor for handling the client request;    instructions that obtain communication information from the processor;    instructions that transmit the communication information to the client computer, wherein the communication information provides the client computer with a preferred way to communicate with the routing processor.    
   
   
       17 . The server of  claim 16 , wherein the instructions that identify a processor include 
 instructions that provide a uniform resource locator to the client computer.    
   
   
       18 . The server of  claim 17 , wherein the instructions that identify a processor include 
 instructions that provide an overlay address corresponding to the content information to the client computer.    
   
   
       19 . A device in a computer network, the device comprising 
 instructions that detect a client request for content information from a client computer;    instructions that identify a processor for handling the client request;    instructions that obtain a communication resource from the processor to be used to facilitate transfer of information between the client computer and the processor;    instructions that transmit the communication information to the client computer, wherein the communication information provides the client computer with a preferred way to communicate with the processor;    instructions that obtain from the identified processor a communication resource to allow transfer of information between the client computer and the processor; and    instructions for transferring information about the communication resource to the client computer.    
   
   
       20 . The device of  claim 19 , wherein the communication resource is a port identifier.  
   
   
       21 . A method for performing overlay routing in a computer network, the computer network including multiple computers coupled to allow information transfer over the computer network, the computer network having a native routing protocol, the method comprising the following 
 associating computers on the network with a given overlay group;    determining whether received information is associated with the given overlay group; and    routing the received information to the computers associated with the given overlay group by using the native routing protocol.    
   
   
       22 . A computer-readable media programmed with instructions for performing overlay routing in a computer network, the computer network including multiple computers coupled to allow information transfer over the computer network, the computer network having a native routing protocol, the instructions including 
 instructions for associating computers on the network with a given overlay group;    instructions for determining whether received information is associated with the given overlay group; and    instructions for routing the received information to the computers associated with the given overlay group by using the native routing protocol