ISO / IEC JTC1/ SC25 WG1
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N1139
WG1 (Brussels, Chen)1
Date: 2005, February 09
ISO/IEC JTC1 SC25 WG1
Interconnection of Information Technology Equipment
Home Electronic Systems
Title:
Unifying HomeGate and Interoperability Models
Source:
Abraham Y. Chen, US Expert, US TAG
Project:
01.03.02: 15045-2
Requested Action:
For consideration at the WG1 meeting to be held
2005 March 14 - 18
Distribution: P-, L-, O- Members of SC25 WG1
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1.
Introduction and Summary:
This document utilizes the HG (Half Gateway) and GL (Gateway Link) terminologies
introduced by WG1 N1045 and refined in WG1 N1079 as building blocks to analyse the
models used by HomeGate Project’s RG (Residential Gateway) in SC25 N1020 and
Interoperability Project’s CIS (Common Interoperability System) in WG1 N1058. It turns out
that these models are based on the same concept. They appear to be different because their
main focuses are on different angles. It is determined that a single concise model can be used
for both Projects with consistency.
With this established, a Proxy device between two disparate transmission technologies in
Figure 5 of WG1 N879A can be easily modelled as well. This assures that each HAN can be
developed and deployed as if it were on an isolated island, yet always ready to interoperate
with others, as long as each technology camp provides a Half -Proxy that bridges that
technology to the CIS.
An extension of this analysis suggests that WAN & HAN tasks can also be clearly demarked
avoiding much of the confusions in the current broadband deployment. Current industry
approaches make this division fuzzy, resulting in business advantages to product vendors but
causing much confusion and frustration to service providers and end -users.
Lastly, having served their purposes, the HG and GL terminologies can now be retired to
minimize the burden on memorizing too many terminologies.
2.
Basic Building Blocks
Figure 1 shows the basic concept of two HGs (Half Gateways) linked by a GL (Gateway Link)
serving as a gateway between two networks of any kind.
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GL
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HGI#1
HGI#2
#1GL
#2GL
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System #1
System #2
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Notes: A. “HGI” here stands for “Half Gateway Interface”.
B. “GL” (Gateway Link) is presented here as a point -to-point connection, but could be
a portion of a multi-drop bus.
Figure 1: Half Gateways with Gateway Link
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The “System #n” blocks in the above figure represent different networks (WAN, HAN & PAN)
of wide range of transmission technologies as shown in Figure 2 below from page #4 of WG1
N1045.
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The Diagnosis
Last-1000 Meters
WAN
Last-100 Meters
HAN
Last-10 Meters
PAN
(Wide Area Network)
(Home Area Network)
(Proximity Area Network)
Cable
ISDN
Optical
RF
xDSL
HomePNA
PLC
Wireless
10 Mbps
Cordless
Ethernet
Firewire
InfraRed
USB
100 Mbps
1000 Mbps
The bottleneck is here!
Firewire: IEEE 1394
HomePNA: Home Phoneline Network Alliance
ISDN: Integrated Service Digital Network
PLC: Power Line Carrier
RF: Radio Frequency
USB: Universal Serial Bus
xDSL: type "x" of Digital Subscriber Line
The confusion is here!
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Figure 2: Categories of Transmission Technologies
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If we recognize that all of these are either derived from Ethernet or having adapters of some
sort that convert respective technology and protocol to be Ethernet compatible, we can
proceed with a reference line that all HES networking systems a re “the same”. It follows that
the following derivation becomes straightforward.
2.
Current Models Used by HomeGate and Interoperability Projects
A. The CIS model shown in presentation Slide #7 of WG1 N1058 of Interoperability
project has been redrawn as Figure 3 of SC25 N1020 of HomeGate project:
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Abstract HES Language (AL)
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GIWF #1
GIWF #2
GIWF #3
GIWF #4
#1AL
#2AL
#3AL
#4AL
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System #1
System #3
System #2
System #4
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Figure 3—Common Interoperability System (CIS)
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B. The basic architecture of the HES-gateway including associated architectural
domains is shown in Figure 4. of SC25 N1020:
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Domain of HES-gateway
Domain of WAN
Domain of HAN
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WAN
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WAN
interface
module
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HESgateway
internal
bus
and
RGIP
HAN
interface
module
HAN
service
module
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Figure 4—HES-gateway Architectural Domains
3.
Analysis of Partitioning for Convergence
At the first glance, Figures 1, 3 and 4 look different from one another. On the other hand, if we
fold the WAN portion of Figure 4 to the same side o f the “RGIP” block as “HAN interface” plus
“Service” modules, and then rotate the entire picture 90 degrees clockwise, it becomes pretty
much the same as that of Figure 3. The only difference between Figures 1 & 3 is that Figure 1
is very simplistic. However, this is precisely the value of Figure 1. That is, its only two
components, HG & GL can be used as building blocks for Figures 3 and 4, if we can clarify
then associate the main purposes of each of these diagrams:
A.
The “HG” and “GL” used in Figure 1 are intended to present the architecture of
a network’s physical infrastructure. In terms of OSI 7 -Layer Model, it would be more
appropriate to classify this as “Layer 0” Model.
B.
The “AL” and “GIWF” in Figure 3 are used to represent CIS operations at the
Abstract Language level. This is above OSI Layer 7 (or a “collection” of certain Layers of the
7-Layer Model). So, it probably would be appropriate to call this model as “Layer 8”.
C.
The “WAN & HAN interface modules”, “Service modules” and “HES -gateway
internal bus and RGIP” blocks in Figure 4 attempt to address the “protocol stack” of RG which
belongs to the OSI 7-Layer Model. But, the keywords, “interface module” and “internal bus”
give a definitive impression that this model is also dealing with physic al hardware entities.
If we organize the current diagrams with these three partitions, we can get a clear and
consistent picture.
4.
Unified Model
The following is a set of three Residential Gateway models representing the three levels of
networking configurations / applications:
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A.
OSI Layer “0” Physical Infrastructure
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RGIB (Residential Gateway Internal Bus)
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HGI#1
HGI #2
HGI #3
HGI #4
#1RGIB
#2RGIB
#3RGIB
#4RGIB
System #2
System #3
System #4
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System #1
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Figure 5: OSI “Layer 0” Physical Infrastructure
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Note that:
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a.
RGIB can be used as a generic expression for interconnection within any
gateway device. It will include GL (Gateway Link) function, as well.
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b.
If we spell HGI out as HomeGate Interface, we do not need to expand HG out
to “Half Gateway” anymore. Also,
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c.
HGI could be either WGI or HGI representing WAN or HAN Gateway Interface
modules, respectively. (There is a bit “double” use of the “H” here.)
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B.
OSI Layers 1 – 7 Protocol Stack
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RGIP (Residential Gateway Internal Protocol)
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GIWP #1
GIWP #2
GIWP #3
GIWP #4
#1RGIP
#2RGIP
#3RGIP
#4RGIP
System #2
System #3
System #4
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System #1
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Figure 6—OSI Layers 1 – 7 Protocol Stack
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This is a RG model corresponding to conventional OSI 7 -Layer protocol stack modelling.
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C.
OSI Layer “8” Common Language Abstract System
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Abstract HES Language (AHL)
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GIWF #1
GIWF #2
GIWF #3
GIWF #4
#1AL
#2AL
#3AL
#4AL
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System #1
System #3
System #2
System #4
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Figure 7— OSI Layer “8” Abstract HES Language
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This is a model that shows how AHL is transmitted among different systems in CIS
environment.
5.
Specific Applications of the Model
With a model that unifies both Projects with respect to all OSI Layers, the following diagrams
will only present that of the infrastructure layer (Layer “0”). It would be used to house the
higher level (Layer 1 –7 and Layer 8) models. Also, the RGIB used below represents not only
that residing within the conventional definition of the centralized Residential Gateway, but
also those distributed via transmission technologies that can reach appreciable distance as
well as supporting multiple nodes.
A.
Simple Gateway
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RGIB
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1:1 Simple
RG
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WGI
HGI
#1RGIB
#2RGIB
WAN
System #1
HAN
System #2
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Figure 8: Simple Residential Gateway
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B.
Proxy Between Disparate HANs
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RGIB
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HalfProxy
Pair
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HGI#1
HGI#2
#1GL
#2GL
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HAN#1
System #1
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HAN#2
System #2
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Figure 9: Proxy Linking HAN Technologies
The RGIB here could be degenerated into internal wiring connection be tween the two half
Proxy circuitry. With this configuration, System #1 and System #2 can be independently
evolved as if they were on isolated islands. Consequently, there is no need to standardize any
of the technologies or protocols that may be used in an y of these Systems. With Proxies
defined, there is no more need for RGs with multiple HAN connections. Of course, this does
not preclude manufacturers from offering products with such configuration.
C.
Network Adapter
If there is only one System connected to RGIB, the last diagram becomes a model of conventional
Network Adapter between a HAN and a EUT (End User Terminal).
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HAN (RGIB)
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HGI#1
Network
Adapter
#1HAN
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EUT
(System #1)
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Figure 10: Network Adapter Model
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D.
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With sufficient speed, a HAN could be utilized to serve t he function of the Distributed RGIB, or
a “Backbone Bus” allowing multiple HANs be connected to it via one HGI each, as shown in
Figure 11 below.
Distributed RGIB
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Distributed RGIB
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HGI #1
HGI #2
HGI #3
HGI #4
#1AHS
#2AHS
#3AHS
#4AHS
WAN #1
System #1
HAN #1
System #2
HAN #2
System #3
EUT
System #4
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Figure 11: HES with Multi-HANs Built around a Distributed RGIB
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E.
Generic HES
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Combining these configurations, it becomes apparent that if a technology that is capable of providing
HAN functions is selected to also serve the RGIB function, a generic configuration shown in Figure 12
can be formed. This architecture supports a multiple-part HomeGate that is physically distributed,
without the need to identify / develop a special interconnection facility for extending the RGIB. With
this configuration, even a SG no longer need two part HGIs to reach a HAN, but just a single HGI
module as shown below as HGI #1.
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RG
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Distributed RGIB
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HGI #1
HGI #2
HGI #3
HGI #4
#1AHS
#2AHS
#3AHS
#4AHS
PAN #1
System #3
EUT/Service
System #4
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WAN #1
System #1
HAN #1
System #2
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Figure 12: Generic HES Model
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Conclusion: Utilizing the HG (Half Gateway) and GL (Gateway Link) concepts, the models
used by HomeGate and Interoperability Projects have been merged into a conc ise and
universal model. This helps to streamline and unify the presentations of these two Projects.
Not only all known variations of HES configurations can be represented by these two basic
building blocks, but also this identifies a clear position for WG 1 to take in terms of task and
responsibility divisions among HES networking technology providers.
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That is,
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A.
There is no more need to standardize any one of multitude of HAN technologies. All
that each need to do is to present a Half -Proxy from its own technology and protocol to
interoperate with the AHL (Abstract HES Language) over the physical RGIB recommended by
WG1. With such Proxy setup, respective technologies can enjoy independence from any
influence by others while promises to consumers the full i nteroperability with other similarly
qualified technologies.
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B.
The simplification and partitioning of the RG model clearly segregates responsibilities
between WAN and HAN by enabling simple diagnostic procedures, resulting in the definitive
consequence of applying traditional communication industry’s demarcation practices to
broadband field, eliminating much of the consumers’ and service providers’ confusion and
frustration to date.
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C.
Appendix A is a set of recommended diagrams to revise the current figur es in SC25
N1020 of HomeGate Project (ISO/IEC 15045-2).
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D.
Appendix B is a set of recommended diagrams to revise the current figures in WG1
N1114 of Interoperability Project (ISO/IEC 18012-2)
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APPENDIX A
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Recommended Diagrams for SC25 N1020 of ISO/IEC 15045 -2
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Physical HES- gateway
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RGIB
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WGI X
WGI Y
HGI A
HGI B
WAN Y
HAN A
HAN B
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WAN X
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Objects on
network
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Object on
network
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Logical
Figure 1 – Interoperating Networks
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Figure 2 – (No change)
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Abstract HES Language (AHL)
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GIWF #1
GIWF #2
GIWF #3
GIWF #4
#1AL
#2AL
#3AL
#4AL
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System #1
System #2
System #3
System #4
Figure 3—Common Interoperability System (CIS)
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Domain of HES-gateway
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RGIP on RGIB
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WAN
I/F module
HAN
I/F module
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WAN
HAN
Service
module
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Domain of WAN
Domain of HAN
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Figure 4 – HES-gateway Architectural Domains
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Distributed RGIB (utilizing HAN1)
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RG
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WGI
WGI
HGI
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WAN
WAN
HAN #1
Application(s)
HAN2
Application(s)
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Figure 5 – Half-gateway Model
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Figure 6 (No Change except possible legend updates)
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Figure 7 (No Change except possible legend updates)
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Figure 8 (No Change except possible legend updates)
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Figure 9 (No Change except possible legend updates)
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Figure 10 (No Change except possible legend updates)
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Figure 11 (Did not redraw this because the original “Protocol c Interface” is not clearly explained. That
is, whether the “Tunnel” path is physical or logical? Also, it is not clear what is the physical
“Interconnect”? If it is part of the “distributed RGIB” defined above, it is realizable with any HAN
technology that also serves as RGIB. See Figure 11 in the main text of this document.)
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Physical HES- gateway
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RGIB
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VDSL
/ATM
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MEPG2
/RF
Ethernet
I/F
VoIP
/POTS
PC
Phones
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VDSL
access
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TV
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Figure A. 1 – VDSL Scenario
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Physical HES- gateway
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RGIB
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DBS
receiver
VDSL
/ATM
MEPG2
/RF
Ethernet
I/F
VDSL
access
TV
PC
VoIP
/POTS
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DBS
dish
Phones
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Figure A. 2 – DBS/DSL Scenario
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Physical HES- gateway
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RGIB
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Digital
cable
decoder
DSL
/ATM
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MEPG2
/RF
Ethernet
I/F
CEBus
I/F
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Cable
drop
DSL
access
TV
set
PC
Meter,
energy
appliances
Energy
Management
Service
module
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Figure A. 3 – Cable/DSL/Energy Management CEBus Scenario
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Physical HES- gateway
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RGIB
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DSL
/ATM
IEEE 802.11
WiFi I/F
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DSL
access
Healthcare monitoring
Service module
Healthcare
appliances
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Figure A. 4 – Healthcare Management Suggestion
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Physical HES- gateway
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RGIB
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DSL
/ATM
HomePNA
I/F
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DSL access
(over POTS)
HomePNA over
POTS wiring
POTS phones
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HomePNA
bridge
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Ethernet
appliances
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Figure A. 5 – DSL/HomePNA Scenario
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APPENDIX B
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Recommended Diagrams for WG1 N1114 of ISO/IEC 18012 -2
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Physical
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RGIB
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Residential Gateway
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HGI A
HGI B
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Objects on
Network A
Network A
Network B
Objects on
Network B
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Logical
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Figure 1 – Two Interoperating Networks
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Interoperable Residential Gateway
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Object 1
RGIP
Object 2
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IGI
(IWF-A)
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IGI
(IWF-B)
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Object 1-A
Network A
Network B
Object 2-B
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Figure 2 – Application Interoperability Model
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Interoperable Residential Gateway
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Object 1
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Object 2
RGIP
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IGI
(IWF-A)
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IGI
(IWF-B)
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LightSwitch
Network A
Network B
LightLamp
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Figure A.1.1 – (Lighting Application Procedure)
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