The Advantages of DS2 for Networked Entertainment

The advantages of DS2 for Networked Entertainment - 1

The advantages of DS2 for Networked Entertainment

Lance Watson

Design of Systems on Silicon, S.A. (DS2)

April 18, 2006

Abstract

This paper considers the advantages of DS2 200 Mbps powerline communications technology for networked entertainment. Over the last couple of years, the digital home- a home where electronic devices communicate and interact has emerged as the key driver for the electronics industry. For the first time the way in which products communicate is as important as the features that they support. Most industry analysts agree that the key differentiator for new consumer products over the coming years will be their ability to network. This paper makes a comparative analysis of the available technologies for home networking and in particular considers the advantages offered by the DS2 200 Mbps powerline technology especially in terms of whole home coverage, QoS and speed.

This information applies for the following operating systems:
Microsoft Windows Server™ “Longhorn”
Microsoft Windows Vista™
Microsoft Windows Server 2003
Microsoft Windows XP
Microsoft Windows 2000

Contents

The Rise of the Digital Home

Options for Home Networking

Communications Media

Technologies for Home Networking

Data Rate Performance

Home Network Coverage

Coverage for HPNA and CoAX based solutions.

Class of Service and Quality of Service

Leadership, Maturity, Performance and Availability

Standards and Coexistence

Network Security

Author's Disclaimer and Copyright: Copyright (c) 2006, Design of Systems on Silicon, S.A. (DS2).

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The Rise of the Digital Home

Over the last couple of years, the digital home- a home where electronic devices communicate and interact has emerged as the key driver for the electronics industry. For the first time the way in which products communicate is as important as the features that they support. Most industry analysts agree that the key differentiator for new consumer products over the coming years will be their ability to network:

According to Paul Jackson of Forrester Research, “The digital home — a single networking environment that allows a household to control and share entertainment, communications, and applications — will liberate consumer experiences from technology shackles. Killer applications will include video distribution, flexible storage, and enriched voice communication. But an explosion in functionality will lead to an explosion in control complexity. A universal, voice-enabled browser will solve this UI complexity and give the digital home mass appeal.”

"As home networking matures globally, the key will be to explore not just the adoption of home networking but the intensity of home networking usage. Various regions in the world will go through different stages of intensity, ranging from simply sharing a broadband connection to multimedia networking of consumer electronics to whole home automation," said Jonathan Gaw, research manager for IDCs Consumer Markets: Home Networking program.

Options for Home Networking

Communications Media

The choice for Home Networking is limited by the communications mediums available. One simple option is Ethernet cabling, where so-called CAT-5 cables are run around the home, but drilling holes in the walls and finding spaces for these cables is not an easy task in existing homes, and can be an expensive option for new homes. The alternates to CAT5 can be broadly separated into: wireless communications technologies which use the 2.4GHz and 5.4GHz radio frequency bands, coaxial home cabling which is used for distributing analog TV signals around the home, telephone cabling which provides multiple phone sockets around the home and use of the existing electrical cables to carry the data signals.

The options available for communications media for home networking are summarized in the table below, along with the 3 key selection criteria: the market phase for each of the solutions, the availability of outlets to provide whole home coverage and the potential causes for interference.

Medium / Market Phase / Av. US Outlets per Home / Potential for Interference
Ethernet Cabling / Commodity / None / None
Wireless / Commodity / No Outlets needed / Microwave Ovens
Coax / Embryonic / 3.5 / TV, Satellite Control
Powerline / Extended / 30 to 50 / Power Supplies
Phone Line / Extended / 3 / Telephones, xDSL

Technologies for Home Networking

Performance and availability vary greatly among the technologies available for the different media. The table below compares the relative merits of each of these technologies in terms of the available data rate, coverage and quality of service capabilities.

Protocol / Wireless / Power Lines / Coaxial Cabling / Telephone Cable
Ethernet / No / No / No / No
802.11g /  / No / No / No
Homeplug Turbo / No /  /  / 
HPNA 3.0 / No / No /  / 
MoCA / No / No /  / No
DS2 200Mbps / No /  /  / 

Data rate is the most obvious limiting factor for many types of service; for example if a technology cannot support a 20Mbps data stream, it will not be able to support streaming of High Definition TV. Beyond raw data rate, another key factor is coverage: all technologies are limited in some way by range. For example some wireless technologies have limits on distance and the obstacles that they can pass for a particular data rate, limiting them to a single room for media transmission. DS2 200Mbps technology on the other hand is capable of providing high speed streaming capabilities throughout the whole home.

Qualities of service (QoS) capabilities also have an important impact on the types of applications and services that can be provided. Deterministic QoS to ensure that data bandwidth can be guaranteed for any particular application is a great advantage, especially when there is heavy channel loading. Lack of deterministic QoS means that high priority services such as audio and video streaming can have their service level affected by lower priority traffic such as internet browsing. The QoS standards support is also critical. as it indicates the ease with which the technology can be integrated with existing applications.

Technology / Max Phy Rate / 6Mbps+ / 12Mbps+ / 19Mbps+ / 50Mbps+ / 90Mbps+ / OFDM Carriers / Deterministic QoS / QoS Standard
Ethernet / 100 /  /  /  /  /  / No / No / 802.1d An. H.2
802.11b / 11 / 1 room / No / No / No / No / No / No / 802.11e
802.11g / 54 / 2 walls / 1 room / 1 room / No / No / 54 / No / 802.11e
802.11a / 54 / 1.5 wall / 1 room / 1 room / No / No / 54 / No / 802.11e
HomePlug 1.0 / 14 / No / No / No / No / No / 84 / No / HomePlug QoS
Homeplug w. Turbo / 85 /  /  / % / No / No / 84 / No / HomePlug QoS
HPNA 2.0 / 32 / % / No / No / No / No / No / VoHPNA only
HPNA 3.0 / 128 /  /  /  /  /  / Yes / HPNA3 QoS
DS2 200Mbps : powerline / 200 /  /  /  /  / % / 1536 / Yes / 802.1d*
DS2 200Mbps : phone and coax / 200 /  /  /  /  /  / 1536 / Yes / 802.1d*

*See later in this document for DS2 class of service extensions to

Data Rate Performance

As mentioned earlier in this White Paper, the overall data rate requirement for different applications varies greatly. The extent to which different technologies can respond to the requirements of these applications depends on the data rate that they can provide.

Technology data rate capabilities are usually quoted in terms of the maximum physical data available, that is to say the speed with which the technology transmits binary data onto the channel. Whilst this provides a basic means of comparing different technologies, it does not take into account the fact that not all the data transmitted is actually used by the application. In all cases extra data must be transmitted for synchronization, error correction, flow control and network management, which reduces the proportion of useful “application” data that can be transmitted onto the channel, by a factor of 20 to 40%. In addition it should be born in mind the fact that the quoted maximum physical data rate for all technologies is that achieved under ideal conditions. In the section on coverage we will discuss the real world data rates that can be achieved in typical conditions. Despite all these caveats on comparing physical data rates, for simplicity’s sake the number is the most often used for communicating technology capabilities, where DS2 can claim a far high speed than any wireless technology or any other technology for powerline or phone cables.

By looking at the different “usage scenarios” for the digital home, it is relatively straightforward to calculate the levels of data rate that will be required for the digital home. It is easy to conclude that technologies which cannot consistently provide data bandwidths in the range 35 to 55 Mbps will not be able to fulfill the needs of the digital home.

Application / Two person family / Four person family / Six person family with children
App. Rate Mbps / App. Rate Mbps / App. Rate Mbps
HDTV Home Theater / 12-27.8 / 12-27.8 / 12-27.8
SDTV / 3-7 / 9-21
Home Theater Audio / 5.4 / 5.4
CD Audio / 1.6
Phone-VoIP / 0.16 / 0.16
Print out / 1
Control home devices / 0.04
Visual phone / 1
Caching TV program / 12
IP Data / 4 / 4
Total / 34.5-44.4 / 41.616-47.416 / 40.6-58.4

Home Network Coverage

To provide consumers with a problem free, out of the box experience, it is not enough to provide a high enough data rate for any particular application. It is important to provide coverage, which provides the required data bandwidth in a high percentage of potential connections throughout the whole home.

The diagram above shows the application data rate achieved in an independent test undertaken by C’t magazine (the raw results can be seen on the next page)

The wireless system only achieves 10Mbps in 52% of cases, which means that only half of the home can be covered with a 10Mbps service. This makes it evident that video service with the best standard wireless solution available today is not a possibility.

A little better, the Homeplug 85Mbps Turbo solution can more or less guarantee a 10Mbps application bandwidth, but 20Mbps coverage for HDTV or multiple media services is patchy and 30Mbps is only possible in rare occasions.

For a true digital home, complete coverage at data rates anticipated in the usage scenarios mentioned earlier in this document, the only option is DS2 200Mbps technology, which can achieve 20Mbps in 100% of cases, 30Mbps in 96% of cases, 40Mbps in 91% of cases and 50Mbps in 68% of cases.

Coverage for HPNA and CoAX based solutions.

For HPNA and Coax based solutions, home coverage is limited by the availability of telephone sockets and coax outlets. Whilst for Powerline technology, the availability of electricity outlets is estimated at 30-50 around the home. for telephone and coaxial-based solutions, the average US home has only 3 to 3.5 sockets each for coax and telephony. Whilst DS2 200Mbps is the only technology which can support digital home level data rates over telephone wires, power cables and coaxial cable, it is worthwhile analyzing the impact of coverage implied by the shortage of phone sockets and coaxial outlets in the home. If we assume that the maximum comfortable length of cable to connect a device is 2m long, the floor area connectivity for a single adapter can be calculated as a semicircle with radius of 2m from the outlet. For a 150m2 home with 3.5 outlets the coverage is only 22m2 or 14% of the home. The analysis is the same for both coax and telephony.

Class of Service and Quality of Service

Quality of service denotes the ability of a communication technology to differentiate traffic into different types and prioritize its transmission over the network. It is critical for ensuring the correct transmission of services where performance characteristics such as bandwidth (in the case of video) and latency (in the case of voice over IP) need to be preserved in the presence of other traffic. Without quality of service a low priority transmission such as that for web browsing, could interrupt video and audio transmissions dramatically reducing performance. This is generally experienced by the end-user as the appearance of pixelisation (macro-blocks) in the case of video transmission and sound glitches in the case of audio.

The different types of traffic are normally identified by special tags defined by standards such as IEEE802.1d type of service flag, which assumes a different value depending on the type of traffic. DS2 200Mbps technology extends this concept by implementing a programmable service classifier allowing any part of an Ethernet packet to be used to identify its priority level. This is very powerful because it means that it can adapt to traffic, which has not been tagged according to the IEEE protocol

Beyond the prioritization of different Quality of Service levels, some technologies, such as DS2 200Mbps, support class of service (CoS) capabilities. This means that different traffic types can be associated with Service Level Agreements (SLAs), which determine the required bandwidth, latency and jitter, for a video stream, for example the minimum data rate will be strictly maintained, and for a VoIP call, the latency and Jitter are controlled.

The table below shows the QoS and CoS capabilities of the different available technologies.

Service Classifier / Deterministic
QoS / QoS
Priorities / Class of Service SLAs
HomePlug 1.0/ Turbo / No / No / 8 / No
802.11 / No / No / 4 / No
HPNA 3.0 / No / Yes / 8 / No
DS2 200Mbps / Yes / Yes / 8 / 4

Leadership, Maturity, Performance and Availability

Selecting a networking technology is not only a technical consideration but other factors should be considered such as the level of leadership provided by the technology provider. New and untested technologies can provide nasty surprises for unwary adopters. DS2 has an enviable track record as the industry leader in home networking technology. The diagram above shows how DS2 chip sets have been consistently available with higher performance than competing technology providers such as Intellon, indicated in the chart. Consider the following facts:

• DS2 has always been the first company to provide the key features demanded by the home networking market
• 200Mbps capability
• TDMA MAC for Deterministic Class of Service
• PLC technology which is suitable for In Home and Access Networking
• DS2 chip sets have consistently provided 2 to 3 times the performance of other solutions
• No alternative technology provider provides such a complete feature set including
• Class of service capabilities
• Programmable class of service capabilities
• DS2 is the only technology supplier to provide both Access and Home Networking

DS2 is the only technology provider to supply an application programming interface (API) to allow developers to extend chip-set functionality

Standards and Coexistence

DS2, in cooperation with the Universal Powerline Organization provides the most compliant coexistent solutions on the market. The main philosophy behind the UPA is to provide a standardized approach to coexistent technologies on the powerline medium. The UPA has published an open specification for power-line coexistence, which allows any technology to use the powerline without impeding other technologies from using the same technology at the same time. DS2 is actively developing specifications for home networking technologies in collaboration with the UPA for international standardization organizations such as the IEEE and ETSI. The table below compares the standardization efforts of the different technology providers.

Technology / Specification
Effort By / Specification Type / Technology Providers / Standardization Effort
HomePlug 1.0 / HomePlug / Closed Specification / Intellon (95%)
Corinex (5%) / Submissions to IEEE, ETSI
HomePlug Turbo / HomePlug / Proprietary (Intellon) / Intellon / None
UPA / UPA / Open specification Dec 2005 (Opera, ) / DS2 / Submissions to IEE, ETSI
HPNA 3 / HPNA / Closed Specification / Copper Gate (95%)
MoCA / MoCA / Closed Specification / No silicon available

Network Security

Concerns about the safe guarding of personal data, digital rights management, and protection against malicious hackers make network security a key issue for any home networking technology. To evaluate the security of any system all the points of vulnerability should be taken into consideration:

• Medium Vulnerability: How easy is it to access the medium – obviously it is far harder to tap in to fiber optic cables than into wireless signals

• Encoding: (How easy is it to decode the transmitted physical signal) PSK and FSK signaling is very easy to decode, Multi-bit per carrier OFDM, however has a unique channel transfer function which is only present at the transmission and reception points of the signal making it is almost impossible to tap the signal.

• LAN isolation: How easy is it to access the basic management transmissions of the LAN? If the technology provides a LAN isolation mechanism, the task of entering the network is much more difficult because it is impossible to use standard hardware to get clues about what the possible encryption keys are.

• Static or Dynamic Encryption Keys. Most home networking technologies use 56 bit DES encryption with static keys. DS2 on the other hand uses dynamic keys so that the encryption changes for every transmission. This means that it even If a hacker manages to crack a key, he can only decrypt a small amount of data, and then he has to start over and crack the key for the next transmission.

• Key and Payload Encryption Key Lengths: Encryption keys can be “cracked”, using special search techniques. A 56bit key will take a few hours to crack on a home computer. The 3DES technique, which is the only static key used in DS2 technology is encrypted with a 168bit key. Cracking such a key requires 5x1033 times more effort than a 56 bit key, so it would take longer than the age of the universe to break the encryption system.

• Hardware/Software encryption. Some technologies use software to perform encryption tasks. This means that the data rates for encrypted data can be slower than those for unencrypted transmissions. DS2 encryption is fully implemented in hardware ensuring that encryption has no effect on data rate.

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The table below summarizes the encryption capabilities of a number of home networking technologies.