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Title:
DISTRIBUTION POINT UNIT
Document Type and Number:
WIPO Patent Application WO/2018/039703
Kind Code:
A1
Abstract:
The present invention is concerned with a distribution point unit (100) comprising a housing means containing: an input for receiving power (260); one or more ports (180A-180D) each suitable for receiving a twisted pair copper wire; a DSL interface (150) for each port, configured to transmit and receive data to and from the twisted pair copper wire; a cable modem (200) having a port for receiving a coaxial cable for communicative coupling to a CMTS; and a channel (130) between the DSL interface and cable modem configured to communicate data therebetween.

Inventors:
WILKINS RYAN (AU)
STEIGER DENNIS (AU)
ANDIS JAMES (AU)
Application Number:
PCT/AU2017/050278
Publication Date:
March 08, 2018
Filing Date:
March 31, 2017
Export Citation:
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Assignee:
NBN CO LTD (AU)
International Classes:
H04L12/00; H04M3/00; H04M7/00; H04M19/00
Domestic Patent References:
WO2016026688A12016-02-25
Foreign References:
US20140314412A12014-10-23
Other References:
KACKER, A. ET AL.: "Review of nbn's network selection methodology and the efficiency and prudency of the design of its FTTN, FTTB and HFC networks", April 2016 (2016-04-01), XP055592426, Retrieved from the Internet
BROADBAND FORUM: "Architecture and Requirements for Fiber to the Distribution Point", TECHNICAL REPORT, TR -301, August 2015 (2015-08-01), XP055471493, Retrieved from the Internet [retrieved on 20170606]
See also references of EP 3507971A4
Attorney, Agent or Firm:
ALLENS PATENT & TRADE MARK ATTORNEYS (AU)
Download PDF:
Claims:
Claims:

1. A distribution point unit comprising a housing means containing: an input for receiving power; one or more ports each suitable for receiving a twisted pair copper wire; a DSL interface for each port, configured to transmit and receive data to and from the twisted pair copper wire; a cable modem having a port for receiving a coaxial cable for communicative coupling to a CMTS; and a channel between the DSL interface and cable modem configured to communicate data therebetween.

2. A distribution point unit according to claim 1 , wherein the input for receiving power is the one or more ports suitable for receiving a twisted pair copper wire, wherein power is delivered to the distribution point unit over the twisted pair copper wire/s.

3. A distribution point unit according to claim 2, wherein the distribution point unit utilises a power optimisation arrangement in which power is drawn from one or more devices connected to ports.

4. A distribution point unit according to claim 3, wherein the power optimisation arrangement includes a balancing arrangement by which the drawn power is balanced between devices connected to ports.

5. A distribution point unit according to claim 1 , wherein the input for receiving power is the port for receiving the coaxial cable, wherein power is delivered to the distribution point unit over the coaxial cable.

6. A distribution point unit according to any preceding claim including a plurality of physical cable modems.

7. A distribution point unit according to any preceding claim, wherein the distribution point unit is configurable to create a connectivity tunnel with a CMTS and to assign an identifier to the connectivity tunnel, the connectivity tunnel serving as an identified channel for data communication between the DPU and the CMTS.

8. A distribution point unit according to claim 7, wherein the distribution point unit is configurable to create a separate connectivity tunnel for each device connected to a port, and to assign an identifier to each connectivity tunnel, wherein each connectivity tunnel serves as an identified channel for data communication between each device and the CMTS.

9. A distribution point unit according to claim 7 or claim 8, wherein the distribution point unit is configurable to map upstream and downstream data flows to the individual connectivity tunnels.

10. A distribution point unit according to any one of claims 7 to 9, wherein the connectivity tunnel is a virtual cable modem or a Layer 2 VPN.

1 1. A distribution point unit according to any one of claims 7 to 9, wherein the distribution point unit includes an embedded router with an IP address, wherein the connectivity tunnel is an IP tunnel that is identified by the IP address.

12. A distribution point unit according to claim 1 1 , wherein the distribution point unit is configurable to create a single IP tunnel.

13. A distribution point unit according to claim 1 1 , wherein the distribution point unit is configurable to create a separate IP tunnel for each device connected to a port, wherein the created IP tunnels serve as identified channels for data packet communication with the distribution point unit.

14. A distribution point unit according to claim 7, wherein the distribution point unit is configurable to create a single connectivity tunnel for all devices connected to ports, assign an identifier to the connectivity tunnel, and to direct data entering the DPU to the appropriate port by reference to unique tags contained in the data stream.

15. A distribution point unit according to claim 14, wherein the tag takes the form of a C-tag.

16. A distribution point unit according to claim 14 or claim 15, wherein the tag is assigned to individual Ethernet frames entering the distribution point unit.

17. A distribution point unit according to any preceding claim, wherein the distribution point unit is configurable to process incoming data packets for the purpose of prioritisation.

18. A distribution point unit according to claim 17, wherein the processing involves applying a prioritisation tag to the incoming data packets.

19. A distribution point unit according to claim 17 or claim 18, wherein the distribution point unit is configurable to process incoming data packets that have been mapped to a service flow applicable to a QoS/Traffic Class.

20. A distribution point unit according to claim 19, wherein the cable modem is configurable to process incoming data in the form of tagged 802.1 Q Ethernet frames.

21. A distribution point unit according to any preceding claim, wherein the channel between the DSL interface and cable modem includes a virtual Ethernet channel.

22. A method for providing broadband access to customer premises equipment, the method comprising the steps of: establishing a DSL connection between the customer premises equipment and a unit located externally to the customer premises equipment; establishing a DOCSIS connection between the unit and a CMTS; establishing a separate connectivity tunnel on the unit for each established DSL connection; assigning an identifier to the connectivity tunnel, the connectivity tunnel serving as an identified channel for data communication between the DPU and the CMTS; and using the or each connectivity tunnel to communicate data between the or each DSL connection and the CMTS.

23. A method for providing broadband access to customer premises equipment, the method comprising the steps of: establishing a DSL connection between the customer premises equipment and a unit located externally to the customer premises equipment; establishing a DOCSIS connection between the unit and a CMTS; establishing a single connectivity tunnel on the unit for all of the established DSL connections; assigning an identifier to the connectivity tunnel, the connectivity tunnel serving as an identified channel for data communication between the DPU and the CMTS; and directing data received from the CMTS to the appropriate DSL connection by reference to a unique tag included in the received data.

24. A method according to claim 22 or claim 23, wherein the connectivity tunnel is a Layer 2 VPN.

25. A method according to claim 22 or claim 23, wherein the unit includes an embedded router with an IP address and the connectivity tunnel is an IP tunnel.

Description:
Distribution point unit

Field of the invention

[0001] The present invention relates to a distribution point unit. More particularly, the present invention is concerned with an integrated distribution point unit deployable in an access network to a broadband telecommunications network.

[0002] Any discussion of documents, acts, materials, devices, articles and the like in this specification is included solely for the purpose of providing a context for the present invention. It is not suggested or represented that any of these matters formed part of the prior art base or were common general knowledge in the field relevant to the present invention as it existed in Australia or elsewhere before the priority date of each claim of this application.

Background of the invention

[0003] Cost-effectively rolling out a telecommunications network to deliver faster and/or more reliable broadband services to every residential and business premises in a country the size of Australia (with around 10 million residential and business premises) involves many and varied challenges. A critical consideration for such a network is the provision of access infrastructure to connect the network endpoint at each premises to the edge of the telecommunications service provider's core network. For fixed networks, access infrastructure currently takes the form of the ubiquitous twisted pair copper wires that run from each premises to a local telephone exchange. Broadband services are delivered over twisted pair copper wires by modems that implement one or more of the various forms of digital subscriber line (DSL) technology.

[0004] Broadband services can also be provided to premises over hybrid fibre coaxial (HFC) networks. Such networks were constructed in Australian cities during the early 1990s primarily for delivering broadcast cable television, and are comprised of a coaxial cable section and an optical fibre section. The coaxial cable section is a shared cable that runs throughout the serviced area, with each individual premises connecting to the cable through a purpose built lead-in. The optical fibre section of an HFC network runs from a cable distribution facility (or 'headend') to a number of optical nodes that are distributed throughout the service area. The broadcast signal is converted from optical to electrical form at the optical node whereupon it is transmitted onto the coaxial cable for delivery to the connected premises. Broadband services are delivered over HFC networks through cable modems that connect to cable modem termination systems (CMTS) that are installed at the headend. Cable modems typically implement the Data over Cable Interface Specification (DOCSIS). The current specification, DOCSIS 3.1 , supports up to l OGbps downstream and 1 Gbps upstream of network capacity.

[0005] Usually, a separate cable modem is provided at each premises, although United States Patent No. 7,007,296 describes a signal distribution system in which a single cable modem is shared amongst a number of premises. The shared cable modem is housed in a unit that is located outside of the serviced premises such as on a pole on in a below-ground cabinet. Each serviced premises connects to the unit through a separate coaxial cable or combined coaxial cable/twisted pair drop line. A second coaxial cable connects the unit to an optical node of an HFC network so that cable television signals can be delivered to the serviced premises through the connecting drop lines. The second coaxial cable is also coupled to the shared cable modem, that is in turn coupled to an Ethernet switch or DSL concentrator. This allows downstream DOCSIS data arriving on the cable to be demodulated by the shared cable modem into suitably formatted packets and directed to the Ethernet switch/DSL concentrator for delivery to the appropriate drop line. Upstream traffic is managed by directing packets arriving on the drop lines through the Ethernet switch/DSL concentrator and on to the shared cable modem at which they are modulated into DOCSIS data for delivery on the second coaxial cable to the headend.

[0006] In the absence of cost and timing considerations, faster broadband services could be provided by entirely replacing the existing access infrastructure (i.e twisted pair or coaxial cable) with an optical fibre network that reaches directly into each premises. Such a connection methodology is known as 'Fibre to the Premises' (FTTP). FTTP encompasses 'Fibre to the Home' (FTTH), in which the optical fibre reaches the boundary of a detached premises such as a box on the outside wall of a home, and 'Fibre to the Building' (FTTB), in which the optical fibre reaches the communications room of a multiple dwelling with existing technology being used connect to each individual apartment.

[0007] However, completely replacing the existing access infrastructure with optical fibre is simply not practical or feasible in most instances from a cost and/or timing perspective. It would be advantageous to provide improved or at least equivalent broadband access in a way that re-uses this existing access infrastructure.

Summary of the Invention

[0008] According to a first aspect of the present invention there is provided a distribution point unit comprising a housing means containing: an input for receiving power; one or more ports each suitable for receiving a twisted pair copper wire; a DSL interface for each port, configured to transmit and receive data to and from the twisted pair copper wire; a cable modem having a port for receiving a coaxial cable for

communicative coupling to a CMTS; and a channel between the DSL interface and cable modem configured to communicate data therebetween.

[0009] In broad terms, the present invention provides an integrated distribution point unit (DPU) that is operable to connect a twisted pair copper telephone line to a cable modem and thus to a CMTS of an HFC network.

Connecting a twisted pair copper network to an HFC network in this way allows end users to benefit from a faster and/or more reliable data network (in the form of an HFC network), but also enables network operators to leverage existing copper wire lead-ins to provide this improved service. In the Australian context, only a fraction of the premises that are 'passed' by the coaxial cable section of existing HFC networks have the necessary lead-in to actually connect to the network. This is in marked contrast to the lead-ins to the twisted pair copper network that are installed in almost 100% of premises. The present invention leverages this near- ubiquitous infrastructure to connect premises to HFC networks, while avoiding the costs, delays and disruptions to end users associated with constructing new coaxial cable lead-ins or repairing faulty lead-ins.

[0010] The present invention, by interfacing two formerly distinct networks, creates a new type of access network comprising twisted pair copper and coaxial cable. At least in preferred embodiments, the present invention from the perspective of network operators and end users is able to replicate a Fibre to the Node (FTTN) service.

[001 1] Accommodating the components of the invention in a housing allows for low cost/high volume unit manufacture, so that one device can serve as few as four individual premises. The unit can also be located in close proximity (typically within 100 meters or less) to each premises. This allows the maximum data transmission speed to be extracted from the copper cable. The approach also exploits the superior transmission speed and resistance to interference of coaxial cable over longer distances.

[0012] Another benefit of preferred embodiments of the present invention lies in its ability to be powered from a non-utility source, or in other words the DPU can be powered through either the twisted copper or coaxial cable that is connected to the unit. Drawing power from one of the communication lines into the device obviates the need to locate the DPU in close proximity to a separate power source.

[0013] Drawing power from the twisted pair copper typically requires installation of a reverse power feeding (RPF) device in the End User Premises which provides power to the DPU over the same copper pair used to provide the service. Reverse power feeding may be suitably provided as defined in ETSI TR 102629. [0014] Embodiments of the invention that are powered through the copper cable preferably utilise a power optimisation arrangement in which the power can be drawn from one or more of the devices connected to ports.

[0015] Preferably, the power optimisation arrangement includes an balancing arrangement by which the drawn power is balanced between devices connected to ports.

[0016] Alternatively or additionally, the DPU can be forward-powered over a connected coaxial cable. As would be understood by those skilled in the art, coaxial cable distribution networks carry varying voltages (typically between 48V- 90V) for powering connected active devices such as line amplifiers, line extenders and optical nodes. This same power source can be harnessed to provide total or partial power requirements of the DPU.

[0017] Alternatively or additionally, the DPU can be powered directly from a local source such as utility power, battery, off-grid solar, micro-grid solutions and combinations thereof.

[0018] Typically, the present invention includes a single physical cable modem, however according to other embodiments a plurality of physical cable modems are provided.

[0019] Preferably, the DPU is configurable to create a connectivity tunnel with a CMTS and to assign an identifier to the connectivity tunnel, the connectivity tunnel serving as an identified channel for data communication between the DPU and the CMTS.

[0020] According to preferred embodiments, the DPU is configurable to create a separate connectivity tunnel for each device connected to a port, and to assign an identifier to each connectivity tunnel, wherein each connectivity tunnel serves as an identified channel for data communication between each device and the CMTS.

[0021] Typically, the DPU is configured to map upstream and downstream data flows to the individual connectivity tunnels. [0022] According to certain embodiments, the connectivity tunnel is a Layer 2 VPN.

[0023] According to other embodiments, the DPU includes an embedded router with an IP address, wherein the connectivity tunnel is an IP tunnel that is identified by the IP address. A single IP tunnel can be created for the DPU or a separate IP tunnel can be created for each device connected to a port. These IP tunnels serve as identified channels for data packet communication with the DPU.

[0024] According to an alternative embodiment of the invention, the DPU is configurable to create a single connectivity tunnel for all devices connected to ports, assign an identifier to the connectivity tunnel, and to direct data entering the DPU to the appropriate port by reference to unique tags contained in the data stream. Typically, the tag takes the form of a C-tag. According to preferred embodiments, the tag is assigned to individual Ethernet frames entering the DPU. The connectivity tunnel may include a virtual cable modem or a Layer 2 VPN. The connectivity tunnel may also include an IP tunnel, wherein the DPU is further configured to direct data flowing into the DPU by reference to unique tags contained in the data stream.

[0025] According to other embodiments, the DPU is configured to create a single connectivity tunnel for two or more of the ports.

[0026] According to preferred embodiments, the DPU is configurable to process incoming data packets for the purpose of prioritisation. The processing typically involves applying a prioritisation tag to the incoming data packets.

[0027] Preferably, the DPU is configured to process incoming data packets that have been mapped to a service flow applicable to a QoS/Traffic Class.

Optimally, the cable modem is configured to process incoming data in the form of tagged 802.1 Q Ethernet frames. Typically, the cable modem is configured to process incoming data that has been aggregated and classified.

[0028] Typically, the channel between the DSL interface and cable modem includes a virtual Ethernet channel. [0029] Optionally, the DPU is configurable to open a management channel that is suitable to permit remote management of the cable modem.

[0030] Alternatively, the DPU is configured to run a PMA client that is suitable to permit remote management of the cable modem by a PMA server.

[0031] According to a second aspect of the present invention there is provided a method for providing broadband access to customer premises equipment, the method comprising the steps of: establishing a DSL connection between the customer premises equipment and a unit located externally to the customer premises equipment; establishing a DOCSIS connection between the unit and a CMTS; establishing a separate connectivity tunnel on the unit for each established DSL connection; assigning an identifier to the connectivity tunnel, the connectivity tunnel serving as an identified channel for data communication between the DPU and the CMTS; and using the or each connectivity tunnel to communicate data between the or each DSL connection and the CMTS.

[0032] Preferably, the connectivity tunnel is a Layer 2 VPN.

[0033] Alternatively, the unit includes an embedded router with an IP address and the connectivity tunnel is an IP tunnel.

[0034] According to a third aspect of the present invention there is provided a method for providing broadband access to customer premises equipment, the method comprising the steps of: establishing a DSL connection between the customer premises equipment and a unit located externally to the customer premises equipment; establishing a DOCSIS connection between the unit and a CMTS; establishing a single connectivity tunnel on the unit for all of the established DSL connections; assigning an identifier to the connectivity tunnel, the connectivity tunnel serving as an identified channel for data communication between the DPU and the CMTS; and directing data received from the CMTS to the appropriate DSL connection by reference to a unique tag included in the received data.

[0035] Preferably, the connectivity tunnel is a Layer 2 VPN.

[0036] Alternatively, the unit includes an embedded router with an IP address and the connectivity tunnel is an IP tunnel.

Brief description of the drawings

[0037] By way of non-limiting examples, embodiments of the present invention will be described by reference to the attached drawings, in which:

Figure 1 is a high level schematic illustration of a distribution point unit according to the invention;

Figures 2 to 4 illustrate a variety of installation environments for distribution point units according to the invention;

Figure 5 is a schematic illustration of an embodiment of a distribution point unit according to the invention having a plurality of virtual cable modem instances;

Figure 6 is a schematic illustration of an embodiment of a distribution point unit according to the invention having a plurality of physical cable modem instances; Figure 7 is a schematic illustration of an embodiment of a distribution point unit according to the invention having a plurality of layer 2 VPNs with unique service flows;

Figure 8 is a schematic illustration of an embodiment of a distribution point unit according to the invention having a single layer 2 VPN with multiple service flows;

Figure 9 is a schematic illustration of an embodiment of a distribution point unit according to the invention having a single layer 2 VPN with shared service flows;

Figure 10 is a schematic illustration of an embodiment of a distribution point unit according to the invention utilising an IP tunnelling protocol with unique tunnels; and

Figure 1 1 is a is a schematic illustration of an embodiment of a distribution point unit according to the invention utilising an IP tunnelling protocol with a shared tunnel.

Detailed description of the drawings

[0038] Unless otherwise required by the context, the following acronyms and abbreviations are used in this specification, for both known systems and features of the present invention:

Distribution Point describes a physical location in the access network where physical connectivity for individual End User premises and services are broken out from the higher density shared cables for the purpose of crossing the End User Premises property boundary and providing physical service connectivity to the End User Premises.

Distribution Point Unit' or 'DPU' refers to a powered device that is designed to be typically located at or in a Distribution Point; delivers broadband services into the premises over a twisted copper pair in the existing copper lead-in cable; is powered either by the HFC cable network or from the premises over the same copper pair used to carry service into the premises; and connects back towards the Point of Interconnect (POI) via an HFC solution.

Multi-port DPU is used to describe a device that when connected to a single coaxial endpoint of an HFC network can provide multiple independent broadband services over multiple, separate copper lead-ins towards End User premises.

DPU System means an integrated technology system (being a combination of network and communications and computing hardware, firmware and software) compliant with both HFC and DSL interface specifications.

Co-axial to the Distribution Point' or 'Coax DPU' describes the network architecture that supports the application of DPU Systems and all supporting components which enable the delivery of services between an HFC network and existing twisted copper pair lead-ins.

Lead-in is used to describe the physical connection entering the End User's property for the purpose of connecting the End User Premises to the access network.

RPF or Reverse Power Feeder is used to describe the equipment used to provide power to the DPU, such as defined in ETSI TR102 629, nominally located in the End User Premises.

EMS is used as an abbreviation for Element Management System which is a software platform used to support remote management of active network equipment, and present management interfaces to operational support systems.

DSL refers to any physical digital modulation type imposed or applied over twisted pair copper wire including generic DSL technology and VDSL.

VDSL refers to VDSL2 unless the context provides otherwise.

UNI-DSL refers to an interface presented at the end-user premises. NTD or 'Network Termination Device' refers to a powered device located at the End User Premises for providing access to a broadband telecommunications network via one or more user network interface ports.

The terms end user traffic, user traffic and service traffic are used interchangeably.

End User refers to an end user of a broadband telecommunications network. The End User may be a consumer (typically for home broadband access) or business for a business grade product. The physical location of the service termination or boundary point used by the End User for accessing the service is termed the End User Premises. The physical location of the service termination and network boundary point used by providers of broadband services to End Users is called the Point Of Interconnect or POI.

The term Copper Access Network or CAN is used to describe an existing copper plant connecting an Exchange and End User Premises. The terms Exchange, Central Office and CO are used interchangeably.

Upstream or Return Path refers to the direction from the End User towards a core (typically Ethernet Aggregation) network.

Downstream or Forward Path refers to the direction towards the End User

Premises.

CPE is used to describe Customer Premises Equipment that is wholly the responsibility of an End User and/or of a provider of broadband services to End Users. A service may terminate on the CPE (for example a VDSL modem) however the details of particular items of CPE do not form part of the present invention and will thus not be described in detail beyond a description of an interface that is presented to CPE by embodiments of the present invention

NSI refers to a Network Side Interface, which is the interface of a CMTS towards an Aggregation or Core network. DOCSIS is an acronym for Data over Cable Service Interface Specification.

DOCSIS is an internationally recognised standard that permits high speed data transfer over existing cable TV systems used by cable operators to provide broadband access to their customers through a cable modem. DOCSIS 3.1 is the current specification published in 2013. It supports up to 10Gbps downstream and 1 Gbps upstream of network capacity.

Connectivity Tunnel refers to a data communications channel between a CMTS or headend and a DPU. Connectivity Tunnels may be created by any suitable means including BSoD, L2VPN, Generic Router Encapsulation and L2TPv3.

User traffic flows refer to traffic originating from or communicated to end users. User traffic flows are identified and marked for QoS by a user traffic flow tag (or 'C tag').

BSoD L2VPN is an acronym for Business Services over DOCSIS via Layer 2 Virtual Private Networks released in 2006. L2VPN provides a virtual connection at the OSI Layer 2 level between customer sites using Layer 2 protocols to facilitate the use of business applications services over DOCSIS. Such business services include subscriber identification insertion, C-tag processing, L2 and NSI encapsulation. VPNs can be point to point via Ethernet over cable, or point to multipoint, as in the case of LANs. A set of LANs and the L2 Forwarders between them that enable hosts attached to the LANs to communicate with Layer 2 Protocol Data Units (L2PDUs) or data packets. A single L2VPN forwards L2PDU data packets based only on the Destination MAC (DMAC) address of the L2PDU, transparent to any IP or other Layer 3 address. A cable operator administrative domain supports multiple L2VPNs, one for each subscriber enterprise to which Transparent LAN Service is offered.

CM is an abbreviation for Cable Modem. A cable modem is a peripheral device that modulates and demodulates an analog signal to encode and decode digital information that is transmitted providing bi-directional high bandwidth access and data communication via radio frequency channels using HFC architecture. CMTS is an abbreviation for Cable Modem Termination System. It is located at the cable television system headend or distribution hub, which provides

complementary functionality to the cable modems to enable data connectivity to a wide-area network.

Channel refers to the frequency spectrum occupied by a signal. Usually specified by centre frequency and bandwidth parameters.

Physical (PHY) Layer refers to Layer 1 in the Open System Interconnection (OSI) architecture; the layer that provides services to transmit bits or groups of bits over a transmission link between open systems and which entails electrical, mechanical and handshaking procedures.

Customer Premises Equipment refers to the equipment at the end user's premises. It may be provided by the end user or the service provider.

Service Flow or SF is a MAC-layer transport service which provides unidirectional transport of packets from the upper layer service entity to the RF and shapes, polices, and prioritizes traffic according to QoS traffic parameters defined for the Flow.

Quality of Service (QoS) refers to the ability to classify, mark and prioritise end user traffic such that applications receive appropriate network resources to ensure that any required service functionality is achieved.

MAC Domain refers to a subcomponent of the CMTS that provides data forwarding services to a set of downstream and upstream channels.

Media Access Control Address is the "built-in" hardware address of a device connected to a shared medium.

[0039] Turning to Figure 1 , an embodiment of a DPU 100 is shown in a high level schematic illustration. DPU 100 includes a DSL interface 150 (or VDSL Block) that provides a DSL connection to End User Premises. VDSL Block 150 is capable of being provisioned with an IP address to allow for remote management and configuration. VDSL Block 150 further supports re-initialization to allow specific VDSL ports (and only that specific port) to revert to a suitable default configuration.

[0040] DSL interface 150 can be remotely managed and operated such as by enabling or disabling the DSL layer. This can be either independently controlled or linked to a DOCSIS 3.x interface port state. Remote operational management can be achieved through a Persistent Management Agent (PMA) implemented as a PMA client on DPU 100. The PMA client is suitably in communication with a PMA Server located elsewhere on a DPU EMS Network Subnet using the NETCONF (IETF RFC 6241) network management protocol.

[0041] A cable modem 200 (or DOCSIS Block) is incorporated into DPU 100 to connect the unit to an HFC Outside Plant. Power is suppled to DPU by way of a power unit 250. Power unit 250 can be implemented in a variety of manners, but preferably by way of a Reverse Power Feed 260 that draws power over one or more of the VDSL lines entering the DPU. Alternatively, DPU 100 can be powered through the HFC Plant via a Line Power Supply 270.

[0042] VDSL Block 150 includes multiple ports 160A-160D, each suitable to receive a copper pair telephone wire 180A-180D. Any convenient number of ports can be provided in VDSL Block 150.

[0043] DOCSIS Block 200 includes an RF port 220 for receiving a coaxial cable 230. A communications channel in the form of a virtual Ethernet 130 extends between VDSL Block 150 and cable modem 200.

[0044] DPUs 100 according to the invention can be installed in a wide variety of installation environments, including:

• Single Dwelling Units (SDUs) which do not have readily available

accessibility to HFC Outside plant;

• Single Dwelling Units (SDUs) where there is no physical capacity available on the HFC Outside Plant.

• Single Dwelling units (SDUs) with missing or blocked cable lead-ins

requiring costly and time consuming remediation; and • Multi-Dwelling Units (MDUs) that do not have existing HFC lead-ins and backbone infrastructure.

[0045] More specifically, DPUs 100 can be 'proactively' installed in areas that are planned to be served by HFC, however for reasons including a lack of HFC street plant, lack of readily available capacity to serve local premises, or collapsed or blocked lead-ins, the service is not achievable. DPU's installed in such environments enable providers of broadband services to offer End Users an appropriate product set and CPE suitable to connect to a DPU as opposed to other access technologies such as HFC. Depending on the area and location, DPU can be housed in an environmentally hardened casing or one more suited to an indoor installation.

[0046] As illustrated in Figure 2, for SDUs 300A-300D that are within an HFC footprint, DPUs 100 can be installed when there is no HFC plant or infrastructure available to a premises or group of premises. For example, due to sub-division or new housing development in areas beyond the original HFC rollout. In this scenario, SDUs can be rapidly and cost effectively made serviceable by utilising existing copper pair lead-ins.

[0047] As illustrated in Figure 3, for MDUs 350 that are within an HFC footprint, a DPU 100 can be proactively installed when there is no HFC lead-in and/or backbone to each premises within the MDU complex 350. In this scenario MDU complexes 350 with multiple apartments can be rapidly and cost effectively made serviceable by utilising existing copper pair lead-ins. Typically, the copper pairs within the MDU converge at a central point within the building such as a central communications cabinet or centralised MDF (Main Distribution Frame).

[0048] As illustrated in Figure 4, a 'reactive' DPU installation scenario occurs when the technology serving a particular premises needs to be changed to a DPU connection methodology from another access technology (such as HFC) due to intervening events. A prime example for the application of a DPU in these circumstances is where problematic or collapsed (broken) lead-ins are discovered during an inspection. A blocked lead-in occurs when an installation technician cannot use the existing coaxial lead-in conduit due to physical or logistical obstructions.

[0049] In these 'reactive' DPU installation cases, a multi-port DPU provides a timely and cost effective method for providing lead-in connectivity for premises with blocked cable access.

[0050] Turning to Figure 5, a more detailed description of a multi-port DPU 100 follows. DPU provides an independent broadband service to an End User via each DSL port 160A-160D (i.e four services in total). DPU 100 includes a single physical cable modem 200 that implements a unique connectivity tunnel -in the form of virtual cable modems 210A-210D-for each DSL port 160A-160D. DPU 100 also creates a corresponding instance of a layer 2 Virtual Private Network (VPN) 225A-225D for each virtual cable modem.

[0051] An alternative embodiment is illustrated in Figure 6 in which DPU 100 includes a plurality of physical cable modems 215A-215D. Each physical cable modem implements a separate layer 225A-225D.

[0052] A further alternative embodiment is illustrated in Figure 7, which shows a single physical cable modem 200 creating a plurality of connectivity tunnels in the form of Virtual LANS 217A-217D and corresponding layer 2 VPNs 225A-225D.

[0053] Each layer 2 VPN 225A-225D is a transparent point-to-point VPN and can be implemented by any convenient means, including Business Services over DOCSIS. The layer 2 VPNs are not limited to any specific tunnelling protocols.

[0054] In the embodiments illustrated in Figures 5 to 7, user traffic flows between the End Users and broadband service providers via the DPU 100 and a CMTS 400 where a connection is made to an Ethernet aggregation network (not shown).

[0055] The layer 2 VPNs 225A-225D uniquely identify each customer's broadband connection. This is implemented in the broadband service provider's network (upstream of the Internal Network to Network Interface l-NNI) through a suitable VLAN tagging system. A VLAN tagging system that utilises outer 'S-tags' (service tags) and inner C-tags (customer tags) is shown in Figures 5 to 7. In the illustrated embodiment, all four End Users have selected a different service provider for broadband services. It may be that all four end users select the same broadband service provider in which case there may be a single broadband service provider connection present at the l-NNI interface.

[0056] DPU 100 has the inherent flexibility to implement a number of traffic classes (TC-1 and TC-4) that are distinguished in capability and performance.

[0057] Ethernet frames are passed between cable modem 200 and VDSL block 150 over virtual Ethernet 130.

[0058] Another embodiment is illustrated in Figure 8, which is suitable for implementations of the invention using CMTS 400 that maps cable modem MAC addresses to Layer 2 VPNs, rather than mapping service flows to Layer 2 VPNs. As such, such CMTS 400 supports only a single Layer 2 VPN 225 per cable modem, rather than multiple Layer 2 VPNs.

[0059] In the embodiment illustrated in Figure 8, end user traffic arriving at the l-NNI is tagged with inner C-tags for each End User but with a common outer S-Tag. Upon arriving at CMTS 400, the outer S-tag is discarded and the data packets are directed to the appropriate DPU 100, before then being directed to the appropriate port of DSL block 150 on the basis of the C-tag. As with the embodiments illustrated in Figures 5 to 7, communication between the cable modem and DSL interface is over a virtual Ethernet 130.

[0060] In the embodiment illustrated in Figure 9, DPU 100 implements a scheme in which users share service flows for the various traffic classes (TC-1 and TC-4). More specifically, traffic is aggregated, classified, and mapped to service flows applicable to the relevant QoS/Traffic Class. To better support multiple end users, the bandwidth capacity of the service flows can be increased over that of a standard HFC service.

[0061] A further alternative embodiment is illustrated in Figure 10, in which Layer 3 IP tunnelling is utilised to implement connectivity tunnels rather than Layer 2 VPNs. DPU includes an embedded router (eRouter) device 320 that presents an IP address for each of the DSL ports 160A-160D. These IP addresses serve as one endpoint of an IP tunnel 330A-330D, with the other endpoint being established upstream at CMTS 400 or within an aggregation network. End user traffic is communicated transparently via each IP tunnel 330A-330D through CMTS 400, DOCIS Block 200 and eRouter 320. At eRouter 320, the end user traffic flows are directed to the correct port 160A-160D of DSL block 150 on the basis of the C tag.

[0062] An alternative methodology for an IP-tunnel-based implementation is illustrated in Figure 1 1. Rather than presenting a separate IP address and associated IP tunnel for each DSL port, eRouter 320 presents a single IP address that is used as an endpoint of a single IP tunnel 330. This single IP tunnel 330 is used to carry traffic destined or originating from any DSL port 160A-160D. It is necessary for eRouter 320 to consult the C-tag on the data units arriving at tunnel 330 in order to direct them to the appropriate DSL port 160A-160D.

[0063] A combination of approaches can be adopted, whereby virtual (Layer 2 or Layer 3) networks are used to carry traffic for one or more of the DSL ports. For example, in a 4-port embodiment, two Layer 2 VPNs or IP tunnels can be created to each carry the traffic for two of the DSL ports.

[0064] In general, Quality-Of-Service (QoS) is addressed either using a Layer 3 Differentiated Services Code Point (DSCP) field or a Layer 2 PCP field within the VLAN header. For upstream traffic from the End User, if the DSCP field is used, incoming end user traffic is tagged with the appropriate identifier (typically VLAN) associated with the DSL port. PCP bits within the VLAN header are defined based on this DSCP field. This results in a DSCP to QoS mapping.

[0065] In the case of a Layer 2 field, incoming user traffic in the form of Ethernet frames, then based on the provisioned services of the end user associated with the DSL port, the VLAN Identifier and PCP bits within the VLAN header are defined.

[0066] If the traffic from the end user has no DSCP or CoS marking, then a default class of service (i.e a default VLAN header with PCP bits) may be applied depending on the provisioned services. In this way, the VLAN header is used to both to identify traffic associated with an end user and also to provide Quality-of- Service (prioritisation of traffic). [0067] DOCSIS Block 200 manages buffers for the End User connections to ensure levels of service are maintained under normal loads as well as when experiencing traffic bursts

[0068] Each DSL port is capable of supporting multiple MAC source addresses. The network operator may learn one or more MAC source addresses detected at ingress to the UNI-DSL, based upon ingress service frames. A MAC address ageing function ensures that any obsolete MAC addresses are removed from the active list, after a period of 300 seconds.

[0069] The DOCSIS Block 200 subsystem includes a Cable Modem (CM) instance. Each CM is provisioned an IPv6 management address by the HFC EMS as part of the standard DOCSIS 3.0 Cable Modem registration process.

[0070] In relation to the treatment of Ethernet user traffic, CMTS 400 essentially performs Layer 2 forwarding and VLAN encapsulation. More specifically, CMTS 400 maps tagged Ethernet frames on the NSI to specific BSoDs/VLANs. As part of the initial cable modem registration, CMTS 400 learns the MAC address of the cable modem, as well as the associated Layer 2 VPN and service flows.

[0071] VDSL Block 150 provides a direct pass through for the Ethernet frames, performing the Layer 1 conversion required to interface with DOCSIS Block subsystem 200. VDSL Block subsystem 150 has minimum latency;

implements a single FIFO queue on the upstream and downstream of each VDSL port and does not modify the Ethernet frames sent from the End User.

[0072] It is to be understood that, throughout the description and claims of the specification, the word "comprise" and variations of the word, such as

"comprising" and "comprises", is not intended to exclude other additives, components, integers or steps.




 
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