US 5,471,474 A · Communications highway network system

Abstract

A communications highway network system for the interactive communication of digital and analog information that incorporates LAN, MAN, and CATV technology to provide an information pathway of metropolitan size that has a spanning tree topology. The system is multiple drop that operates according a network protocol. The network protocol is based on modified TDM techniques, compensation for round trip loop delay, dynamic allocation of time slots on the network bus, and global synchronization. The protocol also permits concatenation of data packets to reduce overhead. Access to the network bus is controlled by a system allocator operating according to the network protocol. The allocator may allocate network bus bandwidth to simultaneously provide three levels of service for the system nodes to access the network bus, namely, isochronous, demand-based dedicated, and contention bandwidth allocation. This allocation method incorporates fairness to give all nodes sufficient bus access opportunities.

Claims55

Dependent claims

A communications network for interactive communications among network users, comprising:

a network bus;
a plurality of system nodes connected to the network bus with each system node having a loop delay associated therewith;
a pacer connected to the network bus for providing timing signals thereon for synchronizing network bus access operations by the plurality of system nodes;
an allocator that is capable of substantially simultaneously allocating the plurality of system nodes access to a network bus bandwidth by a plurality of bus allocation methods according to a network bus protocol that is based on the network bus being segmented in a time domain into repeating periods, compensation by each system node of its loop delay before accessing the network bus to transmit data during a repeating period, dynamically allocating access to the network bus bandwidth according to the plurality of bus allocation methods, and timing signals from the pacer, with at least one of the bus allocation methods being based on system nodes accessing the network bus bandwidth according to this method being given a requested discrete portion of network bus bandwidth for a predetermined number of repeating periods for transmitting data on the network bus.

1 more element

A method for accessing a network bus bandwidth, comprising the steps of:

(A) generating timing signals on the network bus for synchronizing network bus access operations by a plurality of system nodes connected to the network bus;
(B) segmenting the network bus in a time domain into a plurality of repeating time periods;
(C) determining for each system node that system node's loop delay;
(D) each system node that seeks access to the network bus bandwidth according to a first network bus access method transmitting a request to an allocator for assignment of a discrete portion of the network bus bandwidth for a predetermined number of repeating periods in which the requesting system nodes may transmit data packets on the network;
(E) the allocator assigning the system nodes that requested assignment of a discrete portion of the network bandwidth at step (D) a discrete portion of the network bus bandwidth for a predetermined number of repeating periods until a total amount of network bus bandwidth assigned by the allocator equals a predetermined maximum bandwidth, and for any system nodes that the allocator rejects its request for access according to this first network bus access method because the predetermined maximum bandwidth is reached, then step (G);
(F) the system nodes assigned discrete portions of network bus bandwidth at step (E) transmitting data packets onto the network bus at a time up to an amount assigned by the allocator, with each of such system nodes commencing transmission of the data packets one loop delay before a time the allocator assigned for that system node for transmitting data packets on the network bus;
(G) continuously monitoring an amount of data packets on the network bus and a number of collisions of data packets on the network bus;
(H) allowing any of the plurality of system nodes to transmit at least one data packet on the network bus by a second network bus access method, with each of such system nodes using the second network bus access method commencing transmission of the at least one data packet one loop delay before a time block the allocator has assigned for such system nodes to transmit on the network bus and at least one deferral condition is met;
(I) the allocator accepting requests from any of the plurality of system nodes for discrete portions of a next repeating period to transmit at least one data packet on the network bus according to a third network bus access method;
and
(J) the allocator assigning a discrete portion of the network bus bandwidth of the next repeating period to each up to a predetermined number of the system nodes requesting access at step (I) to the network bus according to the third network bus access method, with each of such system nodes accessing this network bus according to the third network bus access method commencing transmission of the at least one data packet one loop delay before a time the allocator has assigned for each system node to transmit on the network bus.

8 more elements

A method for accessing a network bus bandwidth, comprising the steps of:

(A) generating timing signals on the network bus for synchronizing network bus access operations by a plurality of system nodes connected to the network bus;
(B) determining for each system node that system node's loop delay;
(C) segmenting the network bus in the time domain into repeating periods of predetermined length and dividing each of the repeating periods into a plurality of time slots, with each repeating period including a predetermined number of time slots for transmission of a timing signal generated at step (A), a predetermined number of time slots for system nodes to transmit data packets on the network bus based on the system nodes accessing the network bus according to a first network bus access method, a predetermined number of time slots for system nodes to transmit data packets on the network bus based on the system nodes accessing the network bus according to a second network bus access method, and a predetermined number of time slots for system nodes to transmit data packets on the network bus based on the system nodes accessing the network bus according to a third network bus access method;
(D) each system node seeking access to the network bus bandwidth according to the first network bus access method transmitting a request to an allocator for assignment of a discrete portion of the network bus bandwidth defined by the predetermined time slots set forth in step (C) for system nodes to access the network bus according to the first network bus access method;
(E) the allocator assigning each of the system nodes requesting a portion of the network bus bandwidth at step (D) a discrete portion of the network bus bandwidth until a total amount of network bus bandwidth assigned by the allocator equals the predetermined number of time slots set forth in step (C) for system nodes to access the network bus according to the first network bus access method, and for any system nodes that the allocator rejects its request for a discrete portion of the network bus bandwidth requested at step (D), then step (G);
(F) the system nodes assigned network bus bandwidth at step (E) transmitting data packets onto the network bus at a time up to an amount assigned by the allocator, with each of the system nodes commencing transmission of the data packets one loop delay before the time the allocator assigned for each system node to transmit on the network bus;
(G) continuously monitoring an amount of data packets on the network bus and a number of collisions of data packets on the network bus;
(H) allowing any of the plurality of system nodes to transmit at least one data packet on the network bus by the second network bus access method in the predetermined number of time slots set forth in step (C) for system nodes accessing the network bus according to the second network bus access method, with each of the system nodes using the second network bus access method commencing transmission of the at least one data packet one loop delay before the predetermined number of time slots set forth at step (C) for system nodes accessing the network bus according to the second network bus access method and at least one deferral condition is met;
(I) the allocator accepting requests from any of the plurality of system nodes for discrete portions of a next repeating period of the predetermined number of time slots set forth in step (C) for system nodes accessing the network bus according to the third network bus access method;
and
(J) the allocator assigning discrete portions of the next repeating period of the predetermined number of time slots set forth in step (C) for system nodes accessing the network bus according to the third network bus access method according to the requests at step (I), with each of such system nodes using the third network bus access method commencing transmission of at least one data packet one loop delay before a time the allocator has assigned for such system nodes to transmit data packets onto the network bus.

8 more elements

A method for allocating access to a network bus of a communications network having a plurality of system nodes, comprising the steps of:

segmenting a network bus bandwidth in a time domain into repeating periods;
partitioning each of the repeating periods of the network bus bandwidth into a predetermined amount of network bus bandwidth for each of a plurality of bus allocation methods;
dynamically allocating access by the system nodes to the network bus bandwidth according to the plurality of bus allocation methods, with the allocation of access by the system nodes to the network bus bandwidth according to a first bus allocation method including the steps of,
accepting requests from each system node seeking access to the network bus bandwidth according to the first bus allocation method for discrete portions of the network bus bandwidth, and
assigning to each of the system nodes that requested access to the network bus bandwidth according to the first bus allocation method a discrete portion of the network bus bandwidth until a total amount of the network bus bandwidth assigned equals the predetermined amount of network bus bandwidth partitioned for the first allocation method;
and
transmitting a transmit map update packet to the plurality of system nodes to control access to the network bus by the plurality of system nodes.

4 more elements

Dependencies are inferred from the claim text.

Communications highway network system

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Communications highway network system

Life of this patent

Abstract

Claims55