MiniMAC implementation of a distributed cable modem termination system (CMTS) architecture

• US 7,551,610 B2
• Filed: 08/27/2002
• Issued: 06/23/2009
• Est. Priority Date: 08/27/2002
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Broadcom Corporation (Broadcom, Inc.)
• Inventors: Burrell, Paul E, Danzig, Joel I, Cummings, Scott A
• Primary Examiner(s): Mills; Donald L
• Application Number:
  US10/228,194
• Publication Number:
  US 20040045032A1
• Time in Patent Office: 2,492 Days
• Field of Search: 370/389, 370/390, 370/392, 370/400, 370/432, 370465-468, 370352-356, 375/138, 375/144, 375147-149, 709/220, 709/223, 709/226
• US Class Current: 370/354
• CPC Class Codes: H04L 12/2801 Broadband local area networks

Abstract

A miniMAC implementation of a distributed CMTS in a hybrid fiber/coaxial (HFC) plant. The distributed CMTS comprises at least one network layer, at least one media access layer, and one or more physical layers. The at least one media access layer includes one or more miniMAC layers. The one or more miniMAC layers are remotely located from a remaining part of the at least one media access layer. The at least one network layer, the remaining part of the at least one media access layer, the one or more miniMAC layers, and the one or more physical layers each function as separate modules, enabling each layer to be in separate component locations of the HFC plant, yet having the at least one network layer connected to the remaining part of the at least one media access layer, the at least one media access layer connected to each of the one or more miniMAC layers, and each of the one or more physical layers connected to each of the one or more miniMAC layers. The one or more miniMAC layers are located in close proximity to the one or more physical layers in the HFC plant. The one or more miniMAC layers convert digital bit streams into packets and maintain timing constraints between the one or more miniMAC layers and the one or more physical layers.

Claims

1. A distributed cable modem termination system in a hybrid fiber/coaxial (HFC) plant, comprising:

at least one network layer;

one or more physical layers,

at least one media access layer, wherein said at least one media access layer comprises;

one or more miniMAC layers comprising (i) circuitry required to convert digital bit streams into packets and vice versa, and (ii) means for remotely coupling to a remaining part of said at least one media access layer which is structurally separate from said one or more miniMAC layers; and

the remaining part of said at least one media access layer which is structurally separate from said one or more miniMAC layers;

wherein;

said one or more miniMAC layers are remotely located from the remaining part of said at least one media access layer;

said one or more miniMAC layers are remotely coupled to the remaining part of the at least one media access layer; and

said one or more miniMAC layers and the remaining part of the at least one media access layer are configured to jointly operate as the at least one media access layer;

wherein said at least one network layer, said remaining part of said at least one media access layer, said one or more miniMAC layers, and said one or more physical layers are dispersed throughout said HFC plant in a modular fashion, enabling each dispersed layer to be in separate locations of said HFC plant, yet having said at least one network layer connected to said remaining part of said at least one media access layer, said at least one dispersed remaining part of said at least one dispersed media access layer connected to each of said one or more dispersed miniMAC layers, and each of said one or more dispersed physical layers connected to each of said one or more dispersed miniMAC layers;

wherein said one or more dispersed miniMAC layers are located in close proximity to said one or more dispersed physical layers in said HFC plant, said one or more dispersed miniMAC layers maintaining timing constraints between said one or more dispersed miniMAC layers and said one or more dispersed physical layers;

wherein each dispersed layer is isolated from at least one other layer; and

wherein said at least one dispersed network layer, said at least one dispersed remaining part of said dispersed media access control layer, said one or more dispersed miniMAC layers, and said one or more dispersed physical layers are configured to operate collectively as a cable modem termination system.

2. The distributed cable modem termination system of claim 1, wherein said at least one dispersed network layer and said dispersed remaining part of said at least one dispersed media access layer are located in a fiber portion of said HFC plant and said one or more dispersed miniMAC layers and said one or more dispersed physical layers are located in a coaxial portion of said HFC plant to increase bandwidth allocations to one or more cable modems.

3. The distributed cable modem termination system of claim 1, wherein said at least one dispersed network layer and said dispersed remaining part of said at least one dispersed media access layer are located in a headend of said HFC plant and said one or more dispersed miniMAC layers and said one or more dispersed physical layers are located in a coaxial portion of said HFC plant to increase bandwidth allocations to one or more cable modems.

4. The distributed cable modem termination system of claim 1, wherein each of said one or more dispersed miniMAC layers and each of said one or more dispersed physical layers are co-located in said HFC plant.

5. The distributed cable modem termination system of claim 1, wherein said at least one dispersed network layer and said dispersed remaining part of said at least one dispersed media access layer are placed in hubs of said fiber portion of said HFC plant and said one or more dispersed miniMAC layers and said one or more dispersed physical layers are placed in one or more fiber nodes of said HFC plant to increase bandwidth allocations to one or more cable modems.

6. The distributed cable modem termination system of claim 1, wherein said at least one dispersed network layer and said dispersed remaining part of said at least one dispersed media access layer are placed in hubs of said fiber portion of said HFC plant, said one or more dispersed miniMAC layers are placed in said fiber nodes of said HFC plant, and said one or more dispersed physical layers are placed in one or more post fiber nodes of said HFC plant to increase bandwidth allocations to one or more cable modems.

7. The distributed cable modem termination system of claim 1, wherein said at least one dispersed network layer is placed in a headend and said dispersed remaining part of said at least one dispersed media access layer is placed in a hub of said fiber portion of said HFC plant, and said one or more dispersed miniMAC layers and said one or more dispersed physical layers are co-located in one or more fiber nodes or in one or more post fiber nodes of said HFC plant to increase bandwidth allocations to one or more cable modems.

8. The distributed cable modem termination system of claim 1, wherein said at least one dispersed network layer and said dispersed remaining part of said at least one dispersed media access layer are co-located in a headend or a hub of said fiber portion of said HFC plant and said one or more dispersed miniMAC layers and said one or more dispersed physical layers are co-located in one or more fiber nodes or in one or more post fiber nodes of said HFC plant to increase bandwidth allocations to one or more cable modems.

9. The distributed cable modem termination system of claim 1, wherein said at least one dispersed network layer is placed in one of said headend and said hub in a fiber portion of said HFC plant.

10. The distributed cable modem termination system of claim 1, wherein one of said one or more dispersed miniMAC layers are co-located with one of said one or more physical layers in each fiber node of said HFC plant.

11. The distributed cable modem termination system of claim 1, wherein one of said one or more dispersed miniMAC layers are co-located with one of said one or more physical layers in each post fiber node of said HFC plant.

12. The distributed cable modem termination system of claim 1, wherein one of said one or more dispersed miniMAC layers are placed in each fiber node of said HFC plant and each of said dispersed physical layers is placed in each post fiber node of said HFC plant.

13. The distributed cable modem termination system of claim 1, wherein said dispersed remaining part of said at least one dispersed media access layer is placed in one of said headend and said hub in a fiber portion of said HFC plant.

14. A miniMAC layer of a media access control (MAC) layer in a distributed cable modem termination system (CMTS), comprising:

circuitry required to convert digital bit streams into packets and vice versa; and

means for remotely coupling to a remaining part of the MAC layer which is structurally separate from said miniMAC layer and in a dispersed location from said miniMAC layer;

wherein;

the miniMAC layer is configured to operate while structurally isolated from the remaining part of the MAC layer; and

while remotely coupled to the remaining part of the MAC layer, the miniMAC layer is configured to jointly operate with the remaining part of the MAC layer, wherein the combination of the miniMAC layer and the remaining part of the MAC layer function equivalently to a MAC layer.

15. The miniMAC layer of claim 14, wherein the circuitry required to convert digital bit streams into packets and vice versa comprises:

an upstream interface for buffering bit streams received from a physical layer of the CMTS;

a network interface for converting the buffered bit streams from the upstream interface into a packet interface;

a map processor configured to receive packets categorized as maps from the network interface, wherein the maps are used to allocate bandwidth to cable modems in the CMTS for upstream transmissions; and

a downstream interface for receiving the packets categorized as maps from the map processor and for receiving all remaining packets from the network interface, wherein the downstream interface converts each packet into bit streams for transmission to the physical layer.

16. The miniMAC layer of claim 14, wherein the means for coupling the circuitry required to convert digital bit streams into packets and vice versa to the remaining part of the MAC layer comprises a digital network interface.

17. The miniMAC layer of claim 16, wherein the digital network interface is configured to:

receive a packet from the circuitry required to convert digital bit streams into packets and vice versa in a packet format used by the circuitry required to convert digital bit streams into packets and vice versa, and convert the packet into a packet format used by an exterior network coupled to the distributed CMTS; and

receive a packet in the packet format used by the exterior network and convert the packet to the packet format used by the circuitry required to convert digital bit streams into packets and vice versa.

18. The miniMAC layer of claim 15, wherein said map processor sends said maps to said upstream interface to enable said upstream interface to identify which of said cable modems in said cable modem system sent said stream of bits.

19. The miniMAC layer of claim 14, wherein said miniMAC layer further comprises interfacing circuitry to maintain timing constraints between said miniMAC layer and a physical layer in said distributed CMTS.

20. The miniMAC layer of claim 14, wherein said miniMAC layer is in close proximity to a physical layer in said distributed CMTS.

21. The miniMAC layer of claim 14, wherein said miniMAC layer enables a physical layer to be positioned deep into a hybrid fiber/coax plant, closer to a plurality of cable modems to increase bandwidth allocations to said plurality of cable modems.