U.S. patent application number 10/463088 was filed with the patent office on 2004-12-23 for addressable fiber node.
Invention is credited to Gould, Kenneth, Williams, Christopher Pierce.
Application Number | 20040261119 10/463088 |
Document ID | / |
Family ID | 33517038 |
Filed Date | 2004-12-23 |
United States Patent
Application |
20040261119 |
Kind Code |
A1 |
Williams, Christopher Pierce ;
et al. |
December 23, 2004 |
Addressable fiber node
Abstract
A system and method for providing a hybrid fiber network (HFN)
means to identify a fiber node by a unique address. An addressing
module is installed in proximity to, or collocated with, a fiber
node. The addressing module comprises an addressing module
identifier that associates the addressing module with a particular
fiber node. Network parameter values are received from the fiber
node by the addressing module and reported to a reporting
station.
Inventors: |
Williams, Christopher Pierce;
(Potomac Falls, VA) ; Gould, Kenneth; (Oakton,
VA) |
Correspondence
Address: |
ROBERTS ABOKHAIR & MARDULA
SUITE 1000
11800 SUNRISE VALLEY DRIVE
RESTON
VA
20191
US
|
Family ID: |
33517038 |
Appl. No.: |
10/463088 |
Filed: |
June 17, 2003 |
Current U.S.
Class: |
725/129 ;
348/E7.07; 348/E7.094; 725/119 |
Current CPC
Class: |
H04N 7/22 20130101; H04N
7/17309 20130101; H04N 21/6168 20130101; H04N 21/6118 20130101;
H04N 21/42684 20130101 |
Class at
Publication: |
725/129 ;
725/119 |
International
Class: |
H04N 007/173 |
Claims
What is claimed is:
1. An addressing module for a fiber node deployed in a hybrid fiber
network (HFN), the addressing module comprising: a first interface
for connecting the addressing module to the fiber node on its
subscriber side; a second interface for connecting the addressing
module to one or more test points of the fiber node; and a logic
module internal to the addressing module adapted to: receive an
addressing module identifier from the HFN, wherein the addressing
module identifier associates the addressing module with the fiber
node; receive from the one or more test points one or more network
parameter values related to the performance of the HFN; and send
the one or more network parameter values to a reporting station in
association with the addressing module identifier.
2. The addressing module for a fiber node deployed in a HFN as in
claim 1, wherein the one or more a network parameters comprise at
least one of a cable modem bandwidth parameter, a peak bandwidth
demand parameter, an optical power parameter, a digitally modulated
signal level parameter, analog video signal quality parameter, and
RF Carrier Power parameter, an RF noise power parameter, a signal
to noise parameter, an average noise power parameter, a carrier to
noise parameter, a composite second order parameter, a composite
triple beat parameter, a cross modulation parameter, a hum
parameter, a laser clipping parameter, an optical signal modulation
index parameter, a phase parameter, a group delay parameter, a
composite intermodulation noise parameter, a return loss parameter,
a coherent disturbances peak to valley parameter, a video to analog
delta measurement parameter, a differential gain and phase
parameter, an analog color parameter, and a fiber node operational
status parameter.
3. The addressing module as in claim 1, wherein the one or more
network parameter values related to the performance of the are in
analog form and wherein the logic module is further adapted to
convert each of the one or more analog network parameter values to
a digital network parameter value.
4. The addressing module of claim 1, wherein the logic module is
further adapted to: receive a configuration file from the HFN; and
configure the addressing module according to the configuration
file.
5. The addressing module as in claim 1, wherein the logic module is
further adapted to: receive an instruction from a reporting
station; and select one or more network value parameters based on
the instruction.
6. The addressing module as in claim 1, wherein the logic module
further comprises a media access controller (MAC) having a MAC
address and wherein the addressing module identifier is the MAC
address.
7. The addressing module as in claim 1, wherein the reporting
station is a cable modem termination system (CMTS).
8. The addressing module as in claim 1, wherein the reporting
station is a network device.
9. The addressing module as in claim 1, wherein the HFN is
DOCSIS-compliant.
10. A method for addressing a fiber node in a hybrid fiber network
(HFN), the method comprising: associating a fiber node with an
addressing module having an addressing module identifier;
registering the addressing module identifier with the HFN in
association with the fiber node; receiving at the addressing module
a status indicator of the fiber node; and reporting the status
indicator to a reporting station.
11. The method for addressing a fiber node in a HFN as in claim 10,
wherein the addressing module further comprises a media access
controller (MAC) having a MAC address and wherein the addressing
module identifier is the MAC address.
12. The method for addressing a fiber node in a HFN as in claim 10,
wherein the reporting station is a cable modem termination system
(CMTS).
13. The method for addressing a fiber node in a HFN as in claim 10,
wherein the reporting station is a network device.
14. The method for addressing a fiber node in a HFN as in claim 10,
wherein the status indicator is selected from the group consisting
of operating normally, operating abnormally, and inoperable.
15. The method for addressing a fiber node in a HFN as in claim 10,
wherein the HFN is DOCSIS-compliant.
16. A method for collecting parameter values in a communication
path between a cable head end and a subscriber on a
DOCSIS-compliant hybrid fiber network (HFN), wherein the HFN
comprises an addressing module associated with a fiber node via an
addressing module identifier and wherein the method comprises:
measuring one or more parameter values at the fiber node associated
with the addressing module; receiving the one or more parameter
values at the addressing module; and reporting the one or more
parameter values to a reporting station in association with the
addressing module id.
17. The method for collecting parameter values in a communication
path between a cable head end and a subscriber on a HFN as in claim
16, wherein the one or more parameter values is at least one of a
cable modem bandwidth parameter, a peak bandwidth demand parameter,
an optical power parameter, a digitally modulated signal level
parameter, analog video signal quality parameter, and RF Carrier
Power parameter, an RF noise power parameter, a signal to noise
parameter, an average noise power parameter, a carrier to noise
parameter, a composite second order parameter, a composite triple
beat parameter, a cross modulation parameter, a hum parameter, a
laser clipping parameter, an optical signal modulation index
parameter, a phase parameter, a group delay parameter, a composite
intermodulation noise parameter, a return loss parameter, a
coherent disturbances peak to valley parameter, a video to analog
delta measurement parameter, a differential gain and phase
parameter, an analog color parameter, and a fiber node operational
status parameter.
18. The method for collecting parameter values in a communication
path between a cable head end and a subscriber on a HFN as in claim
16, wherein the addressing module further comprises a media access
controller (MAC) having a MAC address and the addressing module
identifier comprises the MAC address.
19. The method for collecting parameter values in a communication
path between a cable head end and a subscriber on a HFN as in claim
16, wherein the reporting station is a cable modem termination
system (CMTS).
20. The method for collecting parameter values in a communication
path between a cable head end and a subscriber on a HFN as in claim
16, wherein the reporting station is a network device.
21. The method for collecting parameter values in a communication
path between a cable head end and a subscriber on a HFN as in claim
16, wherein the HFN is DOCSIS-compliant.
Description
FIELD OF INVENTION
[0001] The present invention relates generally to the field of
hybrid fiber-coax (HFC) networks. More particularly, the present
invention permits an HFC cable network to identify a fiber node by
a unique address.
BACKGROUND OF INVENTION
[0002] Wired broadband communication systems increasingly rely on
fiber optical cables (fiber) for data transport. In the cable
television environment, the network uses both fiber and coax
(referred to as a "Hybrid Fiber-Coax" or "HFC" network). The
signals run in fiber-optical cables from the cable head end to
junctions near the subscriber (the "downstream" direction). At that
point, the signal is converted from optical transmission over fiber
to RF transmission over coaxial cables that run to a number of
subscriber premises. These junctions are referred to as fiber
nodes. Communications from the subscriber premises to the cable
head end (the "upstream direction") are sent over coax to the fiber
node where the signal is converted from an RF signal to an optical
signal. The optical signal is then sent over fiber to the cable
head end.
[0003] Access to the cable network's data service is provided
through a cable modem (CM). Increasingly, CMs are required to
comply with an industry standard referred to as the "Data Over
Cable Service Interface Specification" or DOCSIS. DOCSIS provides a
set of standards and a certifying authority by which cable
companies can achieve cross-platform functionality in Internet
delivery. A DOCSIS-compliant cable network comprises a cable modem
termination system (CMTS) that forms the interface to an Internet
service provider (ISP) and exchanges digital signals with cable
modems on a cable network.
[0004] Referring to FIG. 1, a block diagram of a DOCSIS-compliant
HFC network is illustrated. In a DOCSIS HFC network, fiber node 105
is connected to CM FN1.sub.i 101 and CM FN1.sub.n 102 and fiber
node 110 is connected to CM FN2.sub.i 103 and CM FN2.sub.n 104.
Fiber nodes 105 and 110 communicate in the upstream direction with
an upstream port 125 of a CMTS 120. A downstream port 150 on the
CMTS 120 communicates in the downstream direction with the CM
FN1.sub.i 101, CM FN1.sub.n 102, CM FN2.sub.i 103, and CM FN2.sub.n
104 through fiber nodes 105 and 110.
[0005] Communication between the CMTS 120 and fiber nodes 105 and
110 in both the upstream and downstream direction is over a fiber
network. Communication between the fiber nodes 105 and 110 and
their respective CMs is over coaxial cable.
[0006] Each time a CM is powered on (or booted), the CM registers
with an upstream port on the CMTS. As an element of this
registration process, the Media Access Control (MAC) address of the
CM is communicated to the CMTS. Using the MAC address, the CMTS
associates each CM with an upstream port on the CMTS to which the
CM is connected.
[0007] In contrast to CMs, fiber nodes are not addressable today,
and as a result, they are an invisible component on the HFC
network. That is, while fiber nodes are connected to a CMTS, the
CMTS cannot communicate directly with the fiber node. Since the
fiber node represents a physical domain in the HFC plant, it is
valuable to associate that domain with the logical domain in a
network. Currently, information about the health and configuration
of a fiber node is obtained from the HFC plant engineers
responsible for configuring and maintaining the HFC.
[0008] Fiber nodes vary in configuration and are described in terms
of the segmentation of the receivers in the forward (downstream)
direction and transmitters in the reverse (upstream) directions.
The segmentation of the node is a design consideration that is
determined in part by the volume and nature of the subscriber
traffic anticipated by the cable service provider.
[0009] By making the fiber node addressable, diagnostic information
from the fiber node about the HFC plant can be reported in
real-time to the CMTS. In addition, the number of subscribers
connected to a fiber node is determinable in real-time by the CMTS.
These data would be valuable in determining the demand on upstream
ports of a CMTS and in managing available bandwidth and the most
efficient segmentation of each fiber node. As new services are
deployed (e.g., voice over IP), the need to manage the downstream
network is even more critical to efficient management of network
resources. Determining the capacity per node--per port in real-time
would be invaluable in provisioning new customers and scaling for
the future.
[0010] For example, when deploying voice over using the Internet
protocol (VoIP) it is necessary for a multi-system cable operator
(MSO) to accurately estimate the number of phone calls that a
single upstream CMTS port may experience so as not to exceed the
call capacity of the port. By determining the number of fiber nodes
that can be served by a single upstream CMTS port (the "upstream
channel combining ratio"), and the number of homes-passed per fiber
node (a measure of potential subscribers), an MSO is able to assess
how many "homes passed" are connected to that CMTS port. Knowledge
of the volume of calls passing through a fiber node in "real time"
would allow the MSO to determine when adjustments to the upstream
combining ratio would be appropriate. The information would also be
helpful in better focusing marketing and sales initiatives within a
particular neighborhood by providing the MSO with information about
unused capacity.
[0011] Making the fiber node addressable would also improve the
ability of the network operator to diagnose and remedy network
problems. In the case where there are problems on a DOCSIS CMTS
upstream port, being able to associate that port with a fiber node
would allow the operator to track the symptoms back to a specific
area, identify what fiber node(s) are affected by the problem, and
enhance the ability to dispatch technicians to the appropriate
location.
[0012] U.S. Patent Application 2002/0136203 by Lira et al. (the
"Lira Application"), teaches integrating the functionality of a
CMTS into the fiber node. The integrated CMTS/fiber node includes a
MAC layer that presumably allows the integrated CMTS/fiber node to
be addressable. While the integrated CMTS/fiber node appears to
offer some of the benefits of an addressable fiber node, the
solution of the Lira Application introduces other problems. By
distributing the CMTS functionality closer to the end devices
(CMs), the number of CMTS rises to the number of fiber nodes on the
network thus increasing the probability of CMTS failure and making
maintenance more difficult. Additionally, incorporating the CMTS
into the HFC plant exposes these sensitive electronics to the
elements and provides more opportunity for tampering. (In a typical
a typical HFC network, the CMTS is located at a hub site, which
site is environmentally controlled and secure.) Finally, in order
to provide an addressable fiber node using the approach described
in the Lira Application, current networks would have to be
redesigned.
[0013] What is needed is a means of addressing existing and new
fiber nodes in an HFC network and obtaining from the fiber node
information about signal levels and other characteristics of the
cable plant without increasing maintenance risks or modifying the
architecture of existing networks. It would also be useful to be
able to determine the traffic volume being handled by a fiber node
to determine the demand on an upstream CMTS port and to permit
adjustment of the upstream combining ratio would need to be
made.
SUMMARY OF INVENTION
[0014] An embodiment of the present invention is an addressable
fiber node in an HFC network. The fiber node is made addressable by
connecting a fiber node to an addressing module. This connection
can be made on the subscriber side of the fiber node or by
connecting the addressing module to a bi-directional test port
associated with subscriber side of the fiber node. In another
embodiment of the present invention the addressing module is
integrated into the fiber node.
[0015] It is an aspect of the present invention to add addressing
capability to the existing fiber node in a non-obtrusive
manner.
[0016] It is another aspect of the present invention to connect an
addressing module to the test port of an existing fiber node.
[0017] It is a further aspect of the present invention to connect
an addressing module to the subscriber side of an existing fiber
node.
[0018] It is still another aspect of the present invention to
register fiber nodes with a CMTS.
[0019] It is another aspect of the present invention to integrate
an addressing module into a fiber node.
[0020] It is yet another aspect of the present invention to obtain
fiber node and network information from an addressable fiber
node.
[0021] It is a further aspect of the present invention to determine
the traffic volume passing through fiber nodes.
[0022] It is still an aspect of the present invention to isolate
problems within fiber nodes and in the network downstream from
fiber nodes.
[0023] It is another aspect of the present invention to determine
the signal level at a fiber node.
[0024] It is yet another aspect of the present invention to assess
characteristics of an HFC network.
[0025] It is still another aspect of the present invention to
assess the performance of devices comprising the physical plant of
an HFC network.
[0026] These and other aspects of the present invention will become
apparent from a review of the general and detailed descriptions
that follow.
[0027] An embodiment of the present invention is an addressable
fiber node in a HFC network. The HFC network may, for example, be a
DOCSIS-compliant network. However, this is not meant as a
limitation. The fiber node is made addressable by connecting the
fiber node to an addressing module. In this embodiment of the
present invention, the fiber node is connected to an addressing
module that has a unique addressing module identifier that
associates the module with a particular fiber node. The addressing
module identifier is reported to the CMTS using a registration
process that is analogous to the process used by CMs to register
with the CMTS. In another embodiment of the present invention the
addressing module identifier of the addressing module is the MAC
address of the addressing module. However, the present invention is
not so limited. As would be apparent to those skilled in the art of
the present invention, any system of addressing that performs the
role of the unique addressing module identifier may be used without
departing from the scope of the present invention.
[0028] In another embodiment of the present invention the fiber
node/addressing module pair monitors the operating parameters of
the fiber node. By way of illustration, these parameters include
the bandwidth used by the cable modems associated with a particular
fiber node/addressing module pair, peak bandwidth demand, and other
signal-related data available from the test ports of the cable node
to which the address module is connected. Other parameters that may
be monitored in this way include the optical power, digitally
modulated signals (QPSK, QAM, FSK) levels, analog video signal
quality (depth of modulation, average power of carrier, audio
deviation), RF Carrier Power, RF noise power, signal to noise,
average noise power, carrier to noise, composite second order,
composite triple beat, cross modulation (XMOD), hum, laser
clipping, modulation index for the optical signal, phase or group
delay, composite intermodulation noise, return loss, coherent
disturbances (color phase, white level, video hum, video pass band
response) peak to valley, video to analog delta measurement,
differential gain and phase, and color measurements related to
analog (gain, slope, padding, equalization, AGC voltage, current,
impedance, transmission loss, ripple, frequency response variation,
adjacent channel measurements, ingress measurements, common path
distortion in upstream, optical dispersion, optical absorption,
optical reflection, optical refraction, power supply duty cycle,
and quasi sin wave duty cycle).
[0029] As will be apparent to those skilled in the art, the fiber
node/addressing module pair may monitor other operating parameters
without departing from the scope of the present invention. The
operating parameters gathered by the fiber node/addressing module
pair are reported to the CMTS for processing by network management
tools. In another embodiment of the present invention the
addressing module processes the operating parameters and reports
the processed data to the CMTS.
[0030] In yet another embodiment of the present invention, a voice
over Internet protocol (VoIP) phone number comprises an identifier
that is associated with a specific fiber node. The fiber
node/addressing module pair monitors downstream VoIP packets to
determine if the packets are for delivery to a call recipient on
connected to that fiber node. Packets that are not directed to call
recipients downstream from the fiber node are discarded.
BRIEF DESCRIPTION OF THE DRAWINGS
[0031] FIG. 1 illustrates a block diagram of a typical HFC network
with a fiber node that is not addressable.
[0032] FIG. 2 illustrates a block diagram of a typical fiber node
with an addressing module connected to a test port of the fiber
node and an addressing module connected to the subscriber side of
the fiber node according to an embodiment of the present
invention.
[0033] FIGS. 3A and 3B illustrate a block diagram of a fiber node
incorporating an addressing module in accordance with an embodiment
of the present invention.
[0034] FIG. 4 illustrates an addressing module according to an
embodiment of the present invention in which test ports on a fiber
node are connected to an addressing module.
[0035] FIG. 5 illustrates a block diagram of an addressing module
according to an embodiment of the present invention.
DETAILED DESCRIPTION OF THE PRESENT INVENTION
[0036] An embodiment of the present invention is a fiber node that
is addressable and thereby visible on an HFC network. In one
embodiment of the present invention a legacy fiber node is made
addressable using an addressing module that has a unique addressing
module identifier that associates the module with a particular
fiber node. The addressing module is connected to the legacy fiber
node via an RF-port on the subscriber side of the fiber node. In an
alternate embodiment of the present invention the addressing module
is connected to a test port on the fiber node.
[0037] Referring to FIG. 5, an addressing module according to an
embodiment of the present invention is illustrated. An addressing
module 500 is connected to the downstream side of a fiber node. The
signal is received by a diplex filter 525, which separates the
downstream signal (typically 54 MHz and above) from the upstream
signal (typically 42 MHz and below). A receiver 505 is connected to
the high frequency side ("H") of the diplex filter 525. The
downstream signal is an analog signal that has had information
encoded in it by varying both the amplitude and phase of the wave.
The receiver processes this signal through an analog-to-digital
(A/D) converter. The A/D converter takes the signal, which varies
in voltage, and turns it into a digital stream. The downstream
signal from receiver 505 is supplied to the addressing module logic
assembly 510 where the data content is processed through an error
correction module and then converted to an appropriate protocol
(such as 10baseT protocol) and sent to the fiber node interface
515. A transmitter 520 is connected to the low side ("L") of the
diplex filter 525. The transmitter converts the digital signals
from the fiber node interface to a modulated analog signal for
transmission to the head end.
[0038] Within the addressing module logic assembly 510 is a media
access controller (MAC). The MAC acts as the interface between the
hardware and software portions of the various network protocols.
Fiber node interface 515 permits the addressing module 500 to
connect to the various test ports of the fiber node, converts the
network metrics captured from the fiber node to digital signals,
and responds to queries sent to it.
[0039] FIG. 2 illustrates a fiber node 200 with an addressing
module 210 connected to a bi-directional test point 215 associated
with the subscriber side of the fiber node 200. In this embodiment
of the present invention the test port is used as a tap into the
downstream (coax) side of the fiber node. Also illustrated in FIG.
2 is an addressing module 220 connected to the cable exiting the
subscriber side of the fiber node 200. In this embodiment of the
present invention the addressing module 220 is connected as close
to the fiber node 200 as feasible. Both addressing modules 210 and
220 are DOCSIS compatible and adapted to register with port 125 on
CMTS 120 (see FIG. 1) in accordance with the initialization process
illustrated in FIG. 3.
[0040] Referring to FIGS. 3A and B, the initialization process of
an addressing module according to an embodiment of the present
invention is illustrated. The addressing module is initialized with
the CMTS through a series of handshakes that comprise an exchange
of data. The first procedure of provisioning is the initialization
of the cable modem through the transmission of synchronization data
from the CMTS.
[0041] Referring to FIG. 3A, the addressing module is powered on
300. It then scans the cable network for a downstream data channel
305 carrying a signal that the addressing module recognizes as
coming from the CMTS. The signal from the CMTS comprises an
instruction set used by the addressing module to communicate with
the CMTS.
[0042] The addressing module receives and implements the
instruction set 308. It then receives an upstream channel
descriptor (UCD) message 310 from the CMTS. The CMTS periodically
transmits this message to all addressing modules that it controls.
The UCD provides the parameters concerning available upstream
channels on which the addressing module may transmit. The
addressing module stores the channel IDs it receives and examines
each one until it finds a channel on which it can operate 315. If
successful 318, the addressing module receives another timing SYNC
message, extracts an upstream time stamp, and receives a bandwidth
allocation message that identifies the upstream transmit frequency
related to the selected channel 320. If a channel is not found, the
addressing module again receives a UCD message from the CMTS 310
and the process continues.
[0043] Following acquisition of the UCD, SYNC, and the upstream
transmit frequency, the addressing module is able to transmit to
the CMTS an insertion packet 325 called a "ranging request"
(RNG-REQ) that provides a service identification (SID) setting of
zero. The addressing module transmits data at the lowest possible
power and slowly increases it during each interval. If the RNG-REQ
successfully reaches its destination 330, the CMTS immediately
transmits a ranging response (RNG-RSP) 335 and assigns the
addressing module a new but temporary SID. The CMTS also sends
information to adjust the addressing module's timing, frequency and
transmit power level. If the RNG-REQ is not successful, the again
transmits an RNG-REQ to the CMTS 325 and the process continues.
[0044] The addressing module sends a dynamic host configuration
protocol (DHCP) request to the CMTS 340 for an Internet protocol
(IP) address and other parameters. The request includes the MAC
address of the addressing module. The IP address enables the
addressing module to establish its identity for receiving the
downstream data addressed to it and for transmitting data from a
known Internet address. The CMTS forwards the addressing module's
request for the IP address to an available DHCP server at the
headend. This server contains a database or pool of IP addresses
allocated to the Internet devices on the network. The DHCP server
responds through the CMTS with an IP address and other necessary
data 345. The addressing module extracts this data from the message
and immediately configures its IP parameters 350.
[0045] In an embodiment of the present invention, the MAC address
of the addressing module comprises an identifier that is unique to
addressing modules. By way of example and not as a limitation, the
first three bytes of the MAC address normally used to identify the
manufacturer of an addressable device comprise a code unique to
addressing modules. In this embodiment of the present invention the
DHCP assigns the addressing module an IP address from a block of
addresses reserved for addressing modules. Communications to and
from the addressing modules are regulated by permissions based on
the assigned IP address. The last three bytes of the MAC address of
the addressing module comprise a unique addressing module
identifier. The addressing module identifier is associated with a
particular fiber node input via a database. In an alternate
embodiment of the present invention the addressing module
identifier maps to a specific fiber node and a specific input on
that fiber node.
[0046] The addressing module makes a request for the current time
and date from one or more time-of-day (TOD) servers through the
CMTS 355. This ensures that the addressing module and the CMTS have
accurate time stamps that are attached to requests and responses
between the two devices. These "events" are routinely logged in the
network management system at the headend.
[0047] Referring to FIG. 3B, after the addressing module receives
its IP address and accurate time, the addressing module obtains
operational parameters (the "configuration file") from the CMTS 360
by downloading the data using the trivial file transfer protocol
(TFTP) from a TFTP server designated for addressing modules. After
downloading the file, the addressing module identifies the upstream
and downstream channels in the file. If one or both channels are
not the same ones on which it is currently operating 365, the
addressing module reinitializes its relationship with the CMTS
using the new upstream frequency found in the operational
parameters file 370. If the channels are not correct, the
addressing module again obtains operational parameters from the
CMTS 360 and the process continues.
[0048] The final step is for the addressing module to become
authorized to use the network for transmitting data. The addressing
module sends a registration request (REG-REQ) to the CMTS. This
REG-REQ includes the current service identification (SID), IP
address, operational parameters, upstream and downstream channel
IDs, time stamps, and other configuration settings 375. If the
information is accepted 380, the CMTS responds with a new SID and
completes the registration process 390. If the information is not
accepted, the addressing module sends a REG-REQ to the CMTS 375 and
the process continues.
[0049] In an embodiment of the present invention, the SID assigned
by the CMTS is unique to addressing modules. The CMTS determines
that the device sending the registration request is an addressing
module from the IP address incorporated into the message. (As
described previously, the IP address assigned to the addressing
module by the DHCP is also unique to addressing modules.)
[0050] In another embodiment of the present invention, the
addressing module monitors the traffic received at the fiber node
input to which the addressing module is connected. The traffic
information is logged and the information sent in the form of a
message to the CMTS.
[0051] FIG. 4 illustrates an addressing module according to an
embodiment of the present invention in which test points 415 and
420 on a fiber node 400 are connected to input ports on an
addressing module 410. The data available from the test ports is
monitored by the addressing module, logged, and sent to the CMTS.
By way of example and not as a limitation, the fiber node 400
comprises a Motorola Starline.RTM. Scalable Optical Node model
SG2440. Test points 415 and 420 permit monitoring a subscriber side
RF signal (comprising both upstream and downstream signals), a
downstream RF signal component, an upstream RF signal component, an
upstream transmitter input level, and a downstream transmitter
output level. In an embodiment of the present invention, the
addressing module 410 is adapted to receive these signals and to
processes them. In this embodiment of the present invention for
each of the monitored signals, the addressing module determines the
average and peak signal levels over a sampling period. These levels
are digitized sent to the CMTS for storage and evaluation.
[0052] In another embodiment of the present invention, the
addressing module 410 is adapted to monitor and receive other
parameters relating to the performance of the fiber node 400 and to
the signals that pass through the fiber node 400. By way of example
and not as a limitation, these parameters include the bandwidth
used by the cable modems associated with a particular fiber
node/addressing module pair, peak bandwidth demand, optical power,
digitally modulated signals (QPSK, QAM, FSK) levels, analog video
signal quality (depth of modulation, average power of carrier,
audio deviation), RF Carrier Power, RF noise power, signal to
noise, average noise power, carrier to noise, composite second
order, composite triple beat, cross modulation (XMOD), hum, laser
clipping, modulation index for the optical signal, phase or group
delay, composite intermodulation noise, return loss, coherent
disturbances (color phase, white level, video hum, video pass band
response) peak to valley, video to analog delta measurement,
differential gain and phase, and color measurements related to
analog (gain, slope, padding, equalization, AGC voltage, current,
impedance, transmission loss, ripple, frequency response variation,
adjacent channel measurements, ingress measurements, common path
distortion in upstream, optical dispersion, optical absorption,
optical reflection, optical refraction, power supply duty cycle,
and quasi sin wave duty cycle.
[0053] In another embodiment of the present invention, the
addressing module takes advantage of the ability of a
DOCSIS-compliant device to register IP addresses of devices
connected to it. In an embodiment of the present invention each
input port on the addressing module 410 is assigned an IP address,
which is then associated with the test point connected to it. The
addressing module receives these IP addresses during the
configuration process (see FIG. 3, 375). In this way, the CMTS may
poll the individual test ports of the fiber node 400.
[0054] In yet another embodiment of the present invention, a voice
over Internet protocol (VoIP) phone number comprises an identifier
that is associated with a specific fiber node. The fiber
node/addressing module pair monitors downstream VoIP packets to
determine if the packets are for delivery to a call recipient on
connected to that fiber node. Packets that are not directed to call
recipients downstream from the fiber node are discarded.
[0055] In an embodiment of the present invention, the configuration
file comprises an "IQ" parameter that determines a level of
monitoring and reporting the addressing module is capable of
performing or, alternatively, a level of monitoring and reporting
that address module is authorized to perform. By way of
illustration and not as a limitation, an IQ parameter value of "1"
indicates that the addressing module is capable/authorized to
answer a simple query (a ping). An IQ parameter value of 2
indicates that the addressing module is capable/authorized to
report network-related performance data. And an IQ parameter value
of 3 indicates that the addressing module is capable/authorized to
filter VoIP packets as previously described. As will be apparent to
those skilled in the art, other levels of capability and
authorization may be established for an addressing module without
departing from the scope of the present invention.
[0056] Where the addressing module is capable of performing a
higher level monitoring and reporting, the IQ parameter may be set
by loading a new configuration file into the addressing module.
[0057] A system and method for addressing a fiber node in an HFC
network has been disclosed. It will be understood by those skilled
in the art of the present invention may be embodied in other
specific forms, such as, but without limitation, a DOCSIS compliant
network, without departing from the scope of the invention
disclosed and that the examples and embodiments described herein
are in all respects illustrative and not restrictive. Those skilled
in the art of the present invention will recognize that other
embodiments using the concepts described herein are also
possible.
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