Communication network and a method of regulating the transmission of data packets in a communication network

A communication network, comprising:

• a multitude of nodes for transmitting data packets between the network and a multitude of user stations and for routing the data packets around the network, the multitude of nodes including a root node, a multitude of leaf nodes and a multitude of intermediate nodes located between the root and leaf nodes;
• and
• a multitude of links interconnecting the nodes to transmit data packets and control signals therebetween, each of the links connecting together two of the nodes to transmit data packets and said control signals in first and second opposite directions between said two nodes, each of the nodes being connected to at least one of the links, and the links connecting the nodes together to form a spanning tree structure traversing each of the nodes of the network at least once, the spanning tree forming a multitude of branches extending between the root node and the leaf nodes, each of said branches including at least a plurality of the nodes arranged in sequence along the branch;
• wherein on each branch of the spanning tree, each node next to another node on the branch in a first direction comprises a parent of said another node;
• and each node next to another node in the branch in a second, opposite direction comprises a child of said another node;
• each of the nodes including means to start a two-phase control cycle,
• in a first phase of the control cycle, the root node transmits a first control signal over a part of the spanning tree;
• and in the first phase of the control cycle, each intermediate node of said part of the tree transmits the first control signal to each child node of said intermediate node after said each intermediate node receives the first control signal and a first corresponding predetermined condition is satisfied.
• the first control signal indicating to each of the nodes on said part of the tree a first number of data packets that each of the nodes on said part of the spanning tree is permitted to transmit in a corresponding time interval, and
• in a second phase of the control cycle, each of the tree transmits a second control signal to a selected one of the other nodes of the tree to indicate completion of the first phase of the cycle.

A communication network comprising:

• a multitude of nodes for transmitting data packets between the network and a multitude of user stations, and for routing the data packets around the network;
• and
• a multitude of links interconnecting the nodes to transmit data packets and first and second control signals therebetween, each of the links connecting together two of the nodes to transmit data packets and said control signals in first and second opposite directions between said two nodes, the links connecting the nodes together to form a spanning tree structure traversing each of the nodes of the network at least once, each of the nodes being connected to at least one of the links;
• each node including
• i) means to determine whether the first control signal has been transmitted to the node over a predetermined one of the links within a first corresponding time period;
• and (1) if the first control signal has been transmitted to the node over said predetermined one of the links within the first corresponding time period, to transmit the first control signal over each of the other links connected to the node, other than said predetermined one of the links, if the node has transmitted to each of said other links, during a second corresponding time period, either a respective predetermined number of data packets, or all data packets the node has to transmit to said each of said other links, and (2) if the first control signal has not been transmitted to the node over said predetermined one of the links within the first corresponding time period, to transmit the first control signal over all of the links connected to the node, and
• ii) means to determine whether the second control signal has been transmitted to the node over all but one of the links connected to the node within a third corresponding time period;
• and (1) if the second control signal has been transmitted to the node over all but said one of the links connected to the node during said third corresponding time period, to transmit the second control signal over said one of the links if the node has transmitted to said one of the links, during a fourth corresponding time period, either a predetermined number of data packets, or all data packets the node has to transmit to said one of the links, and (2) if the second control signal has not been transmitted to the node over all but one of the links connected to the node within the third corresponding time period, to transmit the first control signal over all of the links connected to the node.