Transcript Document

Joint Meeting May 21, 2001
OCCS and OC ComSigSoc
Home Networking
Residential Gateway
Dwight Borses
Member of the Technical Staff
Field Applications Engineer
Irvine Field Sales Office
1
Outline of Talk (as Advertised)
-- Residential Gateways ( Broadband to the home ) are the
main reason for home networking.
-- Popular physical media for connecting the gateway to the
rest of the home: phone line, power line, and Wireless.
-- Technical issues involved in high-data rate transmission
over above media. In all three cases, the same spreadspectrum modulation technique has been adopted.
-- Comparison of the data rate, cost, reliability, etc. of the
three choices of media.
2
Topics Under Discussion
•
•
•
•
•
•
Basic definitions of a Gateway
Value to Consumer & Service Provider
Connectivity options
Protocols
Software
Interfaces
3
A gateway MUST…
• What it is: A Residential Gateway is a bridge
between media.
– Media can be networks, interfaces, or even
data formats.
• What it does: A gateway enables the exchange
of data between devices.
4
A gateway CAN…
• Gateways CAN include many other optional features…
– Data, Video, Audio Servers
– Additional user interfaces (CRT, TV out)
– Extra software (Applications, games)
– Fax Server
– Print Server
– Data vault
…as long as they don’t limit the primary gateway function!
• These are NON-ESSENTIAL features, and may even
reduce the true value of the gateway, by impacting
system MTBF, configuration, throughput, etc.
5
Impact of added features
• Each added feature carries a burden
– Hardware component
– Software component
– Configuration component
– Management component
– System MTBF impact
6
Why do I want one?
• Few people ‘want’ a gateway
– Let’s see…juice, eggs, gateway, toothpaste…
• Many people NEED gateways
– Secure access to the Web
– Multiple devices need to communicate
– Multiple network types used in the home
– Sharing connections to the outside world
– Consolidation of data transport into/out from the home
• Not NEEDED if you only have one device in the home
(exception: gateways that split multiple functions
coming to/from the home, such as voice (telephone)
and data (Web access).
7
Value to the Consumer
•
•
•
•
Secure connections to the Internet (firewall)
Secure telecommuting (VPN)
Sharing of broadband Internet access
Seamless connectivity for ALL in-home devices, across
ALL network types
• Easy to setup and use
– Automatic configuration
– Remote feature management
– Automatic updates
• Security and Safety
– Remote monitoring of intrusion and fire alarms
• Home Automation
– Controlling devices in the home locally and remotely
8
Value to the Service Provider
• Consolidate delivery of services to the home
– Telephony
– Internet access
– Audio / Video content
• Enable new services
– Remote monitoring and control for Utilities
and alarms (meter reading, power managing,
security services)
– On-demand feature expansion (additional
phone lines, faster data access, movie rental)
• Reduced on-site service (no truck rolls)
9
Requirements for Gateways
•
•
•
•
Always on
High MTBF
Self diagnosing (not fault tolerant – fault ‘aware’)
Expandable
– Point-of-manufacture expansion (fixed, internal)
– Consumer expansion (hot pluggable, external)
• Quiet, non-obtrusive
• Cost effective at a system level (BOM cost doesn’t
necessarily = system cost)
• Network agnostic
– The gateway should support any interface the customer chooses
– The customer shouldn’t be restricted by an enabling device!
10
Problems with Gateways
• No single standard
• Many proposed standards
• Gateways don’t play well together
–
–
–
–
DHCP server / client configuration
DNS server / client configuration
May interfere with Discovery services
‘gateway behind a gateway’ hard to remotely manage
–
–
–
–
–
Automatic, remote, or simple non-technical setup
Fault ‘aware’
Automatic recovery from transient faults
Automatic ‘fail-over’ for lifeline services (POTS)
Hot plug external expansion
• Must be consumer friendly (nearly foolproof)
11
Firewalls
• Why
– Same reasons as the lock on your front door
• How
– Gateway monitors all traffic from WAN
– Allows client requests to pass from LAN to
WAN
– Allows server responses to pass into LAN
– Ignores requests that originate on WAN,
unless the request can be authenticated
12
VPN –Virtual Private
Network
• What is it?
– A method for securely exchanging data across
unsecure networks
• How does it work?
– Gateways on both ends agree on encryption key
– Each IP that is destined for the private network is
encrypted
– Then the encrypted packet is encapsulated within
an unencrypted IP packet, and sent across the
Internet to the other gateway
13
Connections to the Outside
• Common for most Broadband connections:
– Always on ( or < 2 second ‘connect’)
– High data rates
– Not intrusive (doesn’t consume a resource
(e.g. phone line))
– Enables new usage models for Internet
• Streaming audio / video
• Highly interactive gaming
• Remote security / monitoring
14
Connections to the Outside
• DSL (ADSL, G.lite, IDSL, SDSL,VDSL)
– ADSL
• 1 Mbps up/ 8 Mbps down, 500 Kbps typ.
• Operates up to 18k ft. from CO
– G.lite
• 512 Kbps up, 1.5 Mbps down
• Splitterless (potential for consumer install)
– SDSL
• Symmetric up/down speed, up to 3 Mbps
– IDSL
• Uses ISDN coding, 144 Kbps, symmetric
– VDSL
• 2.5 –10 Mbps up, 30 –42 Mbps down
• Operates up to 4500 ft. from CO
• Protocol is ATM (data link layer) for all DSL
15
Connections to the Outside
• Cable
– DOCSIS compliance testing improves
interoperability
– 3-10 Mbps up / 27-56 Mbps down, 3 Mbps typ.
(varies)
– Protocol is 802.2 (data link layer of Ethernet)
• ISDN
– Digital service (requires ‘adapter’ to use
analog phones in the home)
– 2B(data) + 1D(signalling) = 128Kbps
(64k/channel)
16
Connections to the Outside
• Fixed Wireless (terrestrial)
– Wide range of speeds: 128Kbps to 2Mbps
– Transceiver and antenna mounted on house
• 2-way Satellite
– Similar to satellite TV, except box also contains
transmitter
– Speeds 256Kbps – 2Mbps (not verified)
– Possible latency issues may affect voice services,
since RTT is ~0.5 seconds!
• FTTH (Fiber To The Home) & FTTC (Fiber To The Curb)
– In trials in US (infancy)
– Single delivery point for all home services (telephone,
data, cable TV, etc)
17
Connections on the Inside
Existing wires (No New Wires)
– Telephone wiring
• HPNA
– Rev 1.0 is ~1Mbps ethernet
– Rev 2.0 is ~10 Mbps, with QoS enhancements
– Electrical wiring Why A Powerline Bus....Because Its Everywhere!
• HomePlug
– Estimated 20Mbps
• X10
– Old, one-way (no ack) 50bps protocol
• Lonworks Power Line Interface
– 5.4Kbps
– Protocol, devices, SW, controlled by Echelon
• CEBus
– 7Kbps, using CAL protocol
18
Powerline Technology
• Most pervasive medium with multiple outlets in
every room
– Cost effective
– Availability worldwide
– Easy to adopt by consumers
– Easy to install
– Utilizes existing power source for
communications
19
CEBus® Standard's
Powerline Carrier Technology
• Uses the home's 120v, 60 cycle, electrical wiring to
transport messages between household devices.
• Uses Spread Spectrum technology to overcome
communication impediments found within the home's
electrical powerline.
– Spreads its signal over a range from 100Hz to 400Hz during each bit
in the packet.
– Instead of frequency hopping or direct sequence spreading, CEBus
sweeps through a range of frequencies as it istransmitted.
20
HomePlug
• The HomePlug PHY uses orthogonal frequency division
multiplexing (OFDM) as the basic transmission technique.
• HomePlug uses OFDM in a burst mode rather than in
continuous mode.
• HomePlug technology also uses concatenated Viterbi and
Reed Solomon FEC with interleaving for payload data, and
turbo product coding (TPC) for sensitive control data fields.
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Connections Inside
• New wires required
– Ethernet
• 10/100/1000 Mbps (Apple)
• It’s ethernet, need I say more?
– IEEE 1394
• 400Mbps – 3.2Gbps(rev b)
• Used primarily for video & storage (today)
• Supports peer – peer transactions
– Lonworks twisted pair transceivers (obscure)
– RS485 (obscure)
22
Connections Inside
• Wireless
– 802.11a/b
• 802.11b widely available today
– 11Mbps, stepping to 5.5, 2, and 1Mbps
– 2.4GHz, DSSS
– Apple AirPort
• 802.11a available 2H/01
– 54Mbps
– Shares MAC w/ 802.11b
• MAC currently under revision to add QoS &
higher security (802.11e)
23
Connections Inside
• Wireless
– Bluetooth
• PAN, not LAN!!
– 1 master, 7 active slaves, 256 sync’d devices
• Short range (10m) IRDA-like theme
• Will be ubiquitous, if low $$ achieved
• 2.4GHz, FHSS
– HomeRF
• 1.0 is 1Mbps (now)
• 2.0 is 10Mbps (soon)
• Has support for voice channels
• Too late! Loses to 802.11
• 2.4GHz, FHSS
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Connections Inside
• Wireless
– DECT
• Originally designed for cordless telephones
• Being (ill)extended to other LAN-like functions
• 1.8GHz (2.4GHz in US)
• TDMA, up to 12 voice slots
• 552Kbps max., using all slots
• Speed enhancements proposed
• Good for voice, loses to 802.11 or Bluetooth for
data
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Protocol Soup – OSI Layers
Layer Name
7 Application
6
Purpose
Programs that use data
2
Presentation Data is extracted, formatted,
decrypted
Session
Defines period during which
data can be exchanged
Transport
Moving the data
Network
Sending packets on the
network
Data link
Format of the data frame
1
Physical
5
4
3
Protocols
HTTP, FTP,
Telnet,SNMP,
DNS, DHCP
ASCII, EBCDIC
TCP, UDP
IP,ARP
Ethernet, X.25,
PPP, ATM
Electrical signaling conventions 802.3, RS232,
DSL
26
Protocol Soup
• General info:
– PPP (Point to Point Protocol)
• Commonly used for dialup connections
• Now being used in broadband networks, since the
dialup model is well understood
– IP is a ‘best effort’ service (no guarantees)
– UDP is simplest, but only ‘best effort’
– TCP is most complex, most reliable
• Connection oriented, reliable (error checking)
• Handshake ‘acks’ to open connection, send data,
close connection
– Multiple levels of encapsulation make the job of
sending data over a network easier (use what is
already proven to work), at the expense of efficiency.
27
Voice Services: Introduction
• Large interest in using the gateway to provide digital
voice services to the home
• Quality of Service (QoS) is THE largest factor for
providing these services to the gateway
• Voice services consist of two basic parts:
– Voice data: digitized, sometimes compressed, has
strict requirements on minimum bandwidth and
maximum jitter / latency
– Signaling information: Provides network with
necessary information to initiate and terminate the
call.
• Designed to utilize existing networks (Internet, or PSTN
[POTS and PANS] –Public Switched Telephone
Network)
28
Voice Services: Introduction
• The standards for Voice over broadband
networks:
– cVoDSL - channelized Voice over DSL
– VoATM - Voice over ATM
– VoMBN - Voice over Multiservice Broadband
Networks, or VoIP - Voice over IP
• All attempt to allow for mixed data/voice traffic
across same interface
• There is a separate standard for digitized voice
over analog modem (over POTS line)
29
Voice Services: Differences
• VoIP
– Most forward-looking standard, since all data is contained
within standard IP packets
– Utilizes resilient nature of Internet to route traffic
– Currently, QoS is not toll quality across Internet, since
existing protocols do not provide prioritization of
isochronous (real time) data over asynchronous (bulk)
data.
– Quality should improve when IPv6 is deployed
– Of greatest interest to non-telco service providers, as it
provides means of supplying telephony services to the
home without needing to access existing telephone
network (PSTN) infrastructure
– VoIP is feasible today on closed networks
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Operating Systems
• No ‘best’ gateway OS
• We (NSC)are OS agnostic
• All the usual suspects…
– Microsoft (many flavors)
– Linux (many flavors)
– QNX (RTOS)
– Wind River (RTOS)
– CP/M (just kidding…)
31
Gateway Architectures
Some basic gateway types:
• Non-expandable (network processor based)
– Lowest initial cost
– Difficult to integrate with other gateways
• Full-featured
– High initial cost
– Lower cost per interface, due to integration at time of
manufacture
• Configurable, expandable
– Low initial cost
– Can function as single gateway for all interfaces
– Most versatile, feature set fits exact customer needs
32
Gateway Architectures
• Internal low cost, popular, Interfaces:
– PCI
– IDE
– USB
– LPC
• External SW friendly, hot-pluggable Interfaces:
– USB
– 1394
– 10/100baseT Ethernet
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Gateway Architectures
MFG
Expansion USB
(Internal)
MFG
Expansion PCI
(Internal)
Core
Internal
External
Expansion Compute Engine Expansion
Interfaces
Interfaces
(X86)
MFG
Expansion LPC
(Internal)
IDE
OS/Application
storage
User
Expansion
USB Modules
(External)
User
Expansion
1394 Modules
(External)
Clocks
System
microcontroller
PWR regulation
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Pieces We (NSC)Have
• Compute engine
– Several classes of processors
• GX/55XX
• SCx200
• CR16
• Interface Components
• 1394
• Networking Components
– MacPhyter 10/100 Ethernet
– HPNA 1.0
– Bluetooth (in development)
– 802.11a (in development)
– HomeRF (RF portion)
• All the supporting functionality (power management regulation, environment monitoring) for a complete
system
35
And people that have ‘em…
HPNA
Cable
Manufacturer 802.11b 2.0 HomePlug V.90 ADSL Modem 802.11a Processors Ethernet HomeRF Bluetooth
National
rev 1.0
x
x
x RF only
x
Agere
x (MAC) x
x
Analog Devices
x
x
x
Atmel
x (MAC)
x
Broadcom
x
x
Conexant
x
x
x
x
x
X
Globespan
x
Intersil
x
Intel
x
x
x
x
Motorola
x
x
x
x
x
TI
x
x
x
x
Virata
x
Voice
Comments
x
x
x
Philips RF
Positioned
as
Competitor
x
Silabs RF
x
x
Large share
x
x
x
x
36
Thank You!
Q&A
37