Enhanced multicast network communications

Abstract

Methods, systems, apparatus, including computer programs encoded on computer storage media, for generating and routing modified multimedia data frames. In one aspect, the method includes maintaining, by a first network node, channel membership data that includes data indicating, for each channel of a plurality of channels, leaf node membership for a plurality of channels, and for each channel of the plurality of channels: determining, based on the channel membership data, the leaf nodes that are subscribed to access the channel, generating, based on the leaf nodes that are subscribed to access the channel, a modified multimedia data frame for the channel that includes (i) a hub node identifier, (ii) data that describes a destination address of each leaf node that is subscribed to access the channel and (iii) a payload, and transmitting, by the first network node, the generated modified multimedia data frame to a second network node.

What is claimed is: 
     
         1 . A method comprising:
 determining, by a data processing apparatus, one or more leaf nodes subscribed to access a given channel based on channel membership data including leaf node membership for a plurality of channels;   generating, by the data processing apparatus, based on the one or more leaf nodes subscribed to access the given channel, a modified multimedia data frame for the given channel, the modified multimedia data frame including:
 (i) a hub node identifier identifying a hub node that serves at least one of the one or more leaf nodes subscribed to access the given channel, 
 (ii) address data describing a destination address of each leaf node served by the hub node and subscribed to access the given channel, wherein at least a portion of the address data describes the destination address of each leaf node according to a bitmap in which each bit in the bit map identities a particular leaf node, the address data being an encoded bitmap of destination addresses; and 
 (iii) a payload; and 
   transmitting, by the data processing apparatus, the generated modified multimedia data frame from a first network node to a second network node.   
     
     
         2 . The method of  claim 1 , further comprising, in response to determining, by the data processing apparatus, that the one or more leaf nodes is/are not subscribed to access the given channel, not generating the modified multimedia data frame for the given channel. 
     
     
         3 . The method of  claim 1 ,
 wherein the modified multimedia data frame includes a unicast data frame comprising a MAC Header and a payload, and   wherein the MAC Header includes a destination address field.   
     
     
         4 . The method of  claim 3 , wherein generating the modified multimedia data frame comprises:
 encoding the destination address for each leaf node subscribed to access the given channel into the encoded bitmap of destination addresses; and   populating a destination address field with the encoded bitmap of destination addresses.   
     
     
         5 . The method of  claim 4 , further comprising:
 receiving, by the data processing apparatus, at the second network node at least one modified multimedia data frame;   identifying, by the data processing apparatus, based on the encoded bitmap of destination addresses, a number of subsequent network nodes that are a destination of the at least one modified multimedia data frame; and   in response to determining that the number of subsequent network nodes is greater than one network node, generating, by the data processing apparatus, a modified multimedia data frame that includes (i) subsequent address data describing a destination address of each of the subsequent network nodes and (ii) a copy of the payload.   
     
     
         6 . The method  claim 4 , further comprising:
 receiving, by the data processing apparatus, at the second network node at least one modified multimedia data frame;   identifying, by the data processing apparatus, based on the encoded bitmap of destination addresses, a number of subsequent network nodes that are a destination of the at least one modified multimedia data frame; and   in response to determining that the number of subsequent network nodes is equal to one network node, generating, by the data processing apparatus, a unicast data frame that includes (i) subsequent address data describing a destination address of the one subsequent network node and (ii) a copy of the payload.   
     
     
         7 . A system comprising:
 one or more data processing apparatuses; and   one or more storage devices in communication with the one or more data processing apparatuses, the one or more storage devices storing instructions that when executed on the one or more data processing apparatuses cause the one or more data processing apparatuses to perform operations comprising:
 determining one or more leaf nodes subscribed to access a given channel based on channel membership data including leaf node membership for a plurality of channels; 
 generating based on the one or more leaf nodes subscribed to access the given channel, a modified multimedia data frame for the given channel, the modified multimedia data frame including:
 (i) a hub node identifier identifying a hub node that serves at least one of the one or more leaf nodes subscribed to access the given channel; 
 (ii) address data describing a destination address of each leaf node served by the hub node and subscribed to access the given channel, wherein at least a portion of the address data describes the destination address of each leaf node according to a bitmap in which each bit in the bit map identifies a particular leaf node, the address data being an encoded bitmap of destination addresses; and 
 (iii) a payload; and 
 
 transmitting the generated modified multimedia data frame from a first network node to a second network node. 
   
     
     
         8 . The system of  claim 7 , wherein the operations further comprise, in response to determining that the one or more leaf nodes is/are not subscribed to access the given channel, not generating the modified multimedia data frame for the given channel. 
     
     
         9 . The system of  claim 7 ,
 wherein the modified multimedia data frame includes a unicast data frame comprising a MAC Header and a payload, and   wherein the MAC Header includes a destination address field.   
     
     
         10 . The system of  claim 9 , wherein generating the modified multimedia data frame comprises:
 encoding the destination address for each leaf node subscribed to access the given channel into the encoded bitmap of destination addresses; and   populating a destination address field with the encoded bitmap of destination addresses.   
     
     
         11 . The system of  claim 10 , wherein the operations further comprise:
 receiving, by the one or more data processing apparatuses, at the second network node at least one modified multimedia data frame;   identifying based on the encoded bitmap of destination addresses, a number of subsequent network nodes that are a destination of the at least one modified multimedia data frame; and   in response to determining that the number of subsequent network nodes is greater than one network node, generating a modified multimedia data frame that includes (i) subsequent address data describing a destination address of each of the subsequent network nodes and (ii) a copy of the payload.   
     
     
         12 . The system  claim 10 , wherein the operations further comprise:
 receiving, by the one or more data processing apparatuses, at the second network node at least one modified multimedia data frame;   identifying based on the encoded bitmap of destination addresses, a number of subsequent network nodes that are a destination of the at least one modified multimedia data frame; and   in response to determining that the number of subsequent network nodes is equal to one network node, generating a unicast data frame that includes (i) subsequent address data describing a destination address of the one subsequent network node and (ii) a copy of the payload.   
     
     
         14 . A non-transitory computer-readable storage device having stored thereon instructions, which, when executed by a data processing apparatus, cause the data processing apparatus to perform operations comprising:
 determining one or more leaf nodes subscribed to access a given channel based on channel membership data including leaf node membership for a plurality of channels;   generating based on the one or more leaf nodes subscribed to access the given channel, a modified multimedia data frame for the given channel, the modified multimedia data frame including:
 (i) a hub node identifier identifying a hub node that serves at least one of the one or more leaf nodes subscribed to access the given channel, 
 (ii) address data describing a destination address of each leaf node served by the hub node and subscribed to access the given channel, wherein at least a portion of the address data describes the destination address of each leaf node according to a bitmap in which each bit in the bit map identities a particular leaf node, the address data being an encoded bitmap of destination addresses; and 
 (iii) a payload; and 
   transmitting the generated modified multimedia data frame from a first network node to a second network node.   
     
     
         15 . The non-transitory computer-readable storage device of  claim 14 , wherein the operations further comprise, in response to determining that the one or more leaf nodes is/are not subscribed to access the given channel, not generating the modified multimedia data frame for the given channel. 
     
     
         16 . The non-transitory computer-readable storage device of  claim 14 ,
 wherein the modified multimedia data frame includes a unicast data frame comprising a MAC Header and a payload, and   wherein the MAC Header includes a destination address field.   
     
     
         17 . The non-transitory computer-readable storage device of  claim 16 , wherein generating the modified multimedia data frame comprises:
 encoding the destination address for each leaf node subscribed to access the given channel into the encoded bitmap of destination addresses, and   populating a destination address field with the encoded bitmap of destination addresses.   
     
     
         18 . The non-transitory computer-readable storage device of  claim 17 , wherein the operations further comprise:
 receiving, by the data processing apparatus, at the second network node at least one modified multimedia data frame;   identifying based on the encoded bitmap of destination addresses, a number of subsequent network nodes that are a destination of the at least one modified multimedia data frame; and   in response to determining that the number of subsequent network nodes is greater than one network node, generating a modified multimedia data frame that includes (i) subsequent address data describing a destination address of each of the subsequent network nodes and (ii) a copy of the payload.   
     
     
         19 . The non-transitory computer-readable storage device  claim 17 , wherein the operations further comprise:
 receiving, by the data processing apparatus, at the second network node at least one modified multimedia data frame;   identifying based on the encoded bitmap of destination addresses, a number of subsequent network nodes that are a destination of the at least one modified multimedia data frame, and   in response to determining that the number of subsequent network nodes is equal to one network node, generating a unicast data frame that includes (i) subsequent address data describing a destination address of the one subsequent network node and (ii) a copy of the payload.