Introduction
10BaseS is an innovative technology that enables the use of Ethernet over existing, unconditioned, telephone-grade wire (copper twisted pair). The technology allows Ethernet LAN transmissions to coexist with either POTS (Plain Old Telephone
Service), ISDN, or advanced PBX (Private Branch Exchange)
signaling services over the same pair of ordinary copper wires. 10BaseS technology uses the newest coding and digital modulation techniques from the DSL world in conjunction with Ethernet, the most popular LAN protocol. A 10BaseS system provides a point-to point transmission that can deliver a symmetrical, full duplex, raw data rate of 11.25 Mbps over distances of up to 1 Mile (1.6 km). This easily provides a net 10 Mbps, in each direction. Products utilizing 10BaseS technology are simple to install and interface easily with any existing Ethernet solution, to meet all present and future needs of enterprise managers, property managers, and consumers. The 10BaseS system is targeted at the following market segments:
• Hospitality
Hotels, hospitals, convention centers and even airports have in recent years started employing on-premises servers offering office services (fax, email, etc.), video-on-demand, high-speed multi-user network games, and other recreational services. The 10BaseS system overcomes standard 10BaseT distance limitation and delivers voice, video, and Internet access simultaneously with ordinary telephone service based on existing telephone grade wire infrastructure.
• Business and Campus LAN extension (multiple build-ings/locations)
Multi-building and multi-LAN businesses often have the need to interconnect facilities/ locations separated by a distance longer than the standard Ethernet limitation. The corporations’ tele-phone-grade wire infrastructure, if properly outfitted, will al-low the connection of standard 10BaseT Ethernet LANs at a rate of 10 Mbps without disrupting active voice and PBX ser-vices. This market has grown enormously in recent years and there is an unprecedented anticipation for LAN extension solu-tions that offer a long-term cost-effective solution such as 10BaseS.
10
BaseS: Ethernet
transport over standard
twisted pair wire
Wilfried Brachschoss
Vice-president, Communication & Peripherals, Asia Pacific Infineon Technologies Asia Pacific Pte Ltd.
• Residential Multiple Dwelling Units
Apartment complexes, dormitories and other MDU owners seek to offer advanced recreational and professional services to their tenants such as Internet access, video-on-demand, personal web-hosting and similar applications. These services can now be provided through a single, high-speed point of service. Employing 10BaseS will allow 10BaseT compatible network access to each apartment/unit over the installed telephone-grade wiring.
• Specialized applications – Surveillance Services, Control Centers
Employing 10BaseS will allow 10BaseT Ethernet data access to each location over the installed telephone-grade wiring. Facilities which use video cameras for surveillance or remote control and monitoring such as Metro or subway systems, malls, and others can benefit from this cost-effective high-speed solution.
Technology Overview
10BaseS was developed as a solution to the outpouring demand for high speed LAN connectivity extension. The concept was to utilize the existing telephone-grade wire infrastructure using the most popular LAN network technology, Ethernet, with the newest coding and modulation techniques used in the DSL in-dustry. The emerging technology, 10BaseS, combines the best of both of them.
To understand 10BaseS it is necessary to understand DSL and the simplicity of Ethernet.
DSL Copper Access Technologies
Telecommunications networks regard analog modem signals as plain voice signals. The signal goes through a filtering process in its path from the subscriber’s premises to the Central Office and vice versa. This signal filtering, however, limits data transfer rates across the voice-grade lines to 56 Kbps when using current modem technology’s sophisticated modulation techniques. In practice, they usually only reach transmission rates of 36.6 Kbps over a common telephone-grade wire.
Voice-grade telephone lines are filtered at the local central office to pass frequencies in the range of 300 Hz to 3.3 KHz, allowing signals from multiple voice-grade lines to be digitized and multiplexed together for transmission across the PTSN’s switched digital links. In the U.S. additional 3.3 KHz loading coils, on the telephone lines, limit the analog modem capabili-ties even more.
Analog modems’ advantage is their simplicity of operation and the fact that they can be utilized on any existing telephone-grade wire, at nearly 600 million locations. However, the band-width limitations of voice-grade lines do not come from the telephone-grade wires – they come from the core network. Without filters, telephone-grade wires could conduct frequen-cies all the way into the Megahertz regions. This is where DSL technology comes in.
DSL – “Digital Subscriber Line”
DSL technology extends the bandwidth by a significant factor while still using the same analog voice-grade twisted pair copper wiring. DSL uses the newest and most advanced coding and modulation techniques in order to transmit the highest pos-sible bit-rates. There are several variants of DSL technology, supporting different rates and distances, and targeting diverse applications.
HDSL – “High-Bit-Rate Digital Subscriber Line”
HDSL serves as a full or fractional T1 or E1 modem over twisted pair copper lines and does not require a COAX or fiber link. It uses a relatively small amount of bandwidth and requires repeaters to reach all customers with full rate. SDSL, a variant of HDSL, uses more advanced modulation techniques, supports both voice and data, and transmits up to 1.544 Mbps or 2.048 Mbps. The distances supported by HDSL/SDSL over a 24-gauge line reach up to 12,000 feet. Typical applications include PBX network connections, digital loop carrier systems, Internet POPs (Point of Presence), servers, and private data networks. HDSL/ SDSL is the most mature of the xDSL technologies and can be used today for applications such as Internet access and remote LAN access.
ADSL – “Asymmetric Digital Subscriber Line”
ADSL was developed for the commodity market, specifically for ATM networks. The Telecom companies’ ADSL units are targeted to reside in the Central Office and to support dis-tances up to 6 km (20,000 ft), while the end-unit resides at the customer’s premises. The ADSL standard, based on DMT tech-nology, has defined several service rate/distance combinations, reaching up to 8 Mbps in the downstream direction and up to 1 Mbps upstream. Typical deployments provide between 1-2 Mbps downstream
ADSL supports only POTS and ISDN on the same line, thus requiring telephone companies tohave a POTS splitter, large in size, to handle existing voice services. Various companies are currently developing solutions that enable ADSL to coexist with ISDN. Unfortunately, ADSL is very complex, somewhat ex-pensive to install, and consumes a lot of power (about 5 Watts per line).
G.Lite – “Universal ADSL”
Universal ADSL is focused on providing a mass market version of ADSL, which is a scaled-down version of full rate ADSL with fewer complexities and less overall requirements at a tradeoff for speed. The Universal ADSL Working Group
(UAWG) played a significant role in the rapid development of the G.Lite standard, which was officially sanctioned by the ITU. G.Lite supports up to 1.5 Mbps in the downstream direction to a distance of up to 3.5 km, but requires installation of a special signal “splitter” to separate voice and data. G.lite does not co-exist with ISDN on the same line. Its devices must be con-nected to every phone jack in the home.
VDSL -“Very-high-data-rate Digital Subscriber Line”
While no approved standard exists yet for VDSL, several groups including ANSI, ETSI, ITU and FSAN are currently working on this issue. VDSL is targeted at supporting shorter distances than ADSL with higher bit-rates: Up to 51 Mbps at 300 meters (1,000 ft), and up to 13 Mbps at 1.5 km (4,500 feet). It can be either symmetric or asymmetric.
The ETSI, ITU and FSAN organizations are standardizing QAM modulation for VDSL applications due to the fact that VDSL is directed at shorter distances. In many ways, VDSL QAM is simpler than ADSL DMT, even though it is ten times faster. VDSL is targeted at point-to-point and point-to-multi-point environments. VDSL supports POTS or ISDN on the same line, and can work in an environment with heavy interference from ISDN, HDSL and ADSL. The splitter is implemented with passive filtering, and it can be easily implemented in a small, low cost design because of VDSL’s high frequency band utili-zation. The splitter separates the POTS or ISDN signals from the data signals, and may even be eliminated from certain designs.
Disadvantages
Communicating high-speed data using DSL technology is still a challenge. Enabling high-speed data communication over a bundle of twisted pairs requires that the local loop infrastruc-ture (currently used for POTS) be ready for those rates. Inter-ference is one of the major problems facing high-speed DSL technology. The power required for the transmission of a high-speed signal must also be considered because it creates addi-tional FEXT (Far End Cross Talk) and NEXT (Near End Cross
Talk) interference. Ethernet
Ethernet is the most popular protocol for the Local Area Network (LAN). The IEEE 802.3 Committee formalized the standard in the late 1980’s. Ethernet technology is mature, in-expensive, and well understood. Industry estimates indicate that over 40 million Ethernet nodes had been installed worldwide as of 1994. The widespread popularity of Ethernet ensures a massive market and competitively priced Ethernet equipment. Since the acceptance of the first Ethernet standard, the specifi-cations and the rights to build Ethernet technology have been made easily available to everyone. This availability, combined with the ease of use and robustness of the Ethernet system, created the large Ethernet market and are another reason that Ethernet is so widely implemented in the computer industry. The vast majority of computer vendors today equip their prod-ucts with 10 Mbps Ethernet interfaces, making it possible to link all types of computers with an Ethernet LAN. Each Ethernet enabled computer is known as a network station or node, and operates independently of all other stations on the network. There is no central controller. All stations attached to an Ethernet are connected to a shared signaling system, called the medium. Ethernet signals are transmitted serially, one bit at a time, over the shared signaling channel to every attached station.
The medium access control mechanism is based on a system called Carrier Sense Multiple Access with Collision Detection (CSMA/CD). To send data, a station first listens to the channel. When the channel is idle the station transmits its data in the form of an Ethernet frame. After each frame transmission, all stations on the network must contend equally for the next frame transmission opportunity. This ensures that access to the net-work channel is fair, and that no single station can lock out the other stations. Access to the shared channel is determined by the medium access control (MAC) mechanism embedded in the Ethernet interface located in each station.
Disadvantages
Ethernet’s CSMA/CD mechanism is a half-duplex system, which requires each station on the network to stop transmit-ting, and wait for a short time before transmitting again. This reduces the total bandwidth available for data delivery. There is no guaranty that a station will receive the full bandwidth re-quired for transmission. For this reason, most of the Ethernet products developed over the last few years support full duplex Ethernet, allowing 10 Mbps bi-directional communication but requiring a point-to-point environment.
10BaseS™ Technology
The 10BaseS system provides an extension to the IEEE 802.3 compliant 10BaseT Ethernet standard network. It combines the most innovative DSL modulation technologies with thepopular standard Ethernet technology. 10BaseS provides simple and standard LAN connectivity and extension over ex-isting telephone wire infrastructure, while boasting several com-petitive advantages.
The 10BaseS system provides a point-to-point link that can deliver half or full duplex 10BaseT Ethernet at the full 10 Mbps data rate. It supports transmission of POTS or ISDN or PBX signaling simultaneously with data over the standard telephone-grade wire infrastructure.
Modulation
The system employs Quadrature Amplitude Modulation (QAM). QAM modulation uses both signal amplitude and phase to de-fine each symbol. 10BaseS uses the most sophisticated QAM technology with various QAM modulations (256, QAM-128, QAM-64, QAM-32, QAM-16, QAM-8 and QAM-4). A specific modulation is chosen according to the line specifica-tion and the rate definispecifica-tion. 10BaseS is designed to support multi-QAM in order to achieve performance as close to the physical limit as possible, while maintaining low cost and low power. 10BaseS has higher capacity than both DMT TDD and regular QAM, when comparing capacity calculations (the calculation of physical capacity limitations).
Frequency Domain
10BaseS facilitates the transport of symmetrical bi-directional data over unshielded, copper twisted pair telephone wires origi-nally intended for the frequency band between 300 Hz and 3.4 KHz. The system employs Frequency Division Duplexing (FDD) to separate the downstream channel, the upstream channel, and POTS, ISDN, or PBX signaling services, in the frequency domain. This enables service providers to overlay 10BaseS on existing POTS, ISDN, or PBX signaling services without disruption. Both 10BaseS and POTS/ISDN/PBX services may be transmitted over the same line without inter-fering with each other.
Errors and Interference
Ethernet data is encapsulated onto a continuous stream of cells in a proprietary scheme. The system applies a self-synchroniz-ing scrambler mechanism to this continuous, non-bursty data cell stream. The scrambler is initialized to a random value pro-viding better de-correlation of the transmitted signals, and thus better FEXT performance when transmitted through a multi-pair copper cable. sophisticated Reed-Solomon (RS) error correction code is also applied to the data stream, providing strong error detection and recovery capabilities. Upon recep-tion, the Ethernet data is reassembled from the error free cell stream.
Bandwidth
10BaseS technology operates at a continuous raw symmetrical bi-directional data rate of 11.25 Mbps. This allows transport of Ethernet data at the full standard line rate of 10 Mbps, in full duplex. The transport overhead does not reduce the Ethernet bandwidth and the system may thus be used totally transpar-ently in a 10 Mbps Ethernet network.
Topography
The 10BaseS system is essentially a point-to-point communi-cation system. The core data pump is a blind modem, capable of supporting point-to-multi-point transmission systems. Op-eration in the point-to-point arrangement avoids the need for the collision detection scheme by frequency separation of the downstream from the upstream and at the same time supports full duplex operation. The physical Ethernet interface is a stan-dard RJ-45 socket. The user may connect stanstan-dard 10BaseT equipment, such as an Ethernet switch or an Ethernet NIC card, to the 10BaseS equipment using standard Ethernet cables.
10BaseS key features
• Standard 10 Mbps Ethernet over regular twisted pair cop-per wire
• Distances of up to 1 Mile (1.6 km) at full duplex 10 Mbps • Simultaneous data and POTS ,ISDN or PBX signaling
services over the same line
• Utilizes the most advanced multi-QAM modulation tech-niques
• Minimum interference with other wire pairs and other ser-vices
• Full duplex point-to-point transmission • Longer distances can be reached at lower rates
• Low power implementation, minimum heat dissipation issues
• Supports testing and management capabilities
Network Applications
The 10BaseS system takes advantage of the nearly unlimited potential of existing telephone wire infrastructure to deliver popular high-speed data access to greater distances. It does so by coupling the industry–standard Ethernet with the innovative 10BaseS technology. 10BaseS provides a point-to point link that can handle half or full duplex 10BaseT at the full 10 Mbps data rate and supports POTS or ISDN or PBX signaling simul-taneously with data. Following are examples of network appli-cation of 10BaseS in some target markets:
• Hospitality Access – hotels, hospitals, convention centers and airports
• Business LAN extension - SOHO (Small Office - Home
• Campus and school network connection and extension • Residential Internet Access [MDU – Multiple Dwelling
Units]
• Specialized applications such as surveillance and remote control
Hospitality Access
Using the existing telephone infrastructure, 10BaseS can bring full speed 10BaseT Ethernet to every telephone extension in a hospitality facility. Ethernet connectivity can be brought to each room in a hotel or hospital, to every telephone extension on the exhibition floor of a convention center and to the conference rooms of such facilities. Ethernet Access can even be offered in telephone booths and travel lounges at airports. Internet access, Virtual LAN connectivity with home offices and video conferencing are services that can be offered once this Ethernet connectivity is available, as well as locally hosted web sites, video-on-demand, and other recreational services. These ser-vices are provided without any interference to the existing telephone functionality.
A 10BaseS network is essentially an Ethernet network with an extended range on each 10BaseS segment. A local network backbone is usually connected through routers and firewalls to the Internet. Local servers handle billing and access control to the networking facilities. Multi-port 10BaseS switches can be up-linked into the local backbone Ethernet network with high-speed 100BaseT or 1000BaseT connections. The 10BaseS ports of the 10BaseS switches are connected through splitters to the telephone infrastructure. Up to 1 mile away, at the end of each telephone line, another splitter can be fitted to separate out the POTS/ ISDN/PBX signaling from the 10BaseS signals. This splitter can be built-in to the 10BaseS End-user unit. The tele-phone is then connected to a standard RJ-45 jack on the End-user unit. Appropriate software running on central servers, such as IPort from ATCOM, manages the user connections, such as enabling Internet access, and handling billing issues. The installation depicted in the following figure is typical of the hospitality market.
The advantage of 10BaseS is the use of existing telephone-grade wire infrastructure. There is no need to re-wire the facil-ity with Ethernet grade cables, saving the cost of rewiring and the possible loss of revenue while areas are shut down for lay-ing wires. The 10 Mbps 10BaseT rate can be delivered to dis-tances that neither standard 10BaseT Ethernet nor any other technology available in the market today can achieve.
Business LAN Extension
The business environment presents several situations in which 10BaseS can be utilized for LAN extension. The rising de-mand for more office space and the inadequate availability of physically near premises are just some of the causes for many corporations distributed locations. It may only be on a different floor in the building or even in a nearby building. With 10BaseS, this physical separation is no longer an obstacle for the Busi-ness LAN. Current solutions like frame-relay and T-1 line ser-vices are expensive and are no mach in data rate for the 10 Mbps of 10BaseT Ethernet.
Branch offices are also in need of communication with their corporate offices. Connecting the LAN directly would be the easiest and cheapest way to accomplish direct communication with corporate databases and executives. Branches that are within 1 mile of their corporate offices can benefit from a 10BaseS connection over existing telephone lines that may be leased from the local Telephone Company at much lower rates than Frame-Relay or T-1 service.
The SOHO (Small Office Home Office) market is defined by two major segments: income-generating, home-based busi-nesses and Home workers - corporate employees who work at home at least part time. The access requirements of these two segments differ slightly –Home workers will have a single con-nection to the corporate office, whereas home-based businesses will typically have a LAN connection.
The solution for all of these situations is the same - a 10BaseS connection using existing copper infrastructure. The require-ment for business LAN access may include bridging and addi-tional features such as VLAN, tunneling and addiaddi-tional encryp-tion and authenticaencryp-tion for security. These features can all be supplied over a 10BaseS link since it presents a standard 10BaseT Ethernet connection. A 10BaseS unit will reside on both sides of the link. Additional hardware such as switches, routers, and encryption hardware may easily be added to the network structure and can provide their additional features.
Campus Network Connection and Extension
In a campus environment 10BaseS can be used to provide 10 Mbps Ethernet connections between campus buildings, replacing current T1 connections. In this environment, 10BaseS can use the existing telephone-grade wires already in place be-tween the buildings. In schools, classrooms can be connected to computer science labs and to centrally located servers.
Fig.1: Typical Hospitality 10BaseS Network
Residential Internet Access (MDU)
10BaseS can bring full 10 Mbps network connectivity to resi-dential users in apartment complexes and dormitories. Most MDU owners or operators usually contract for high-speed T1 or frame-relay Internet access to a central location. They may also offer locally hosted recreational services, such as video-on-demand and high-speed multi-user games. This latter appli-cation requires a 10BaseS End-user unit in each apartment that signs up for service. It’s a simple plugandplay installation -the user just connects his PC E-thernet card to -the 10BaseS unit. 10BaseS switching units can be installed in the basement along with the telephone equipment, using Fast Ethernet links to up-link to the Internet router and local servers.
Surveillance and Remote Control applications
In remote monitoring and surveillance applications, there is a need to transmit information from remote locations, such as video cameras, to a central location (control room). Control information may also need to be sent back to the remote equip-ment. 10BaseS can be used over existing telephone wires to provide this type of connectivity, using standard Ethernet to transmit the data. Using 10BaseS eliminates the need to re-wire with special cables, and allows the use of standard software and hardware developed for connectivity over the LAN environment.
Competitive Analysis
This section will compare 10BaseS technology to some other high-speed technologies available on the market.
Cable Modems
Cable modems offer a dedicated service over a shared media. While cable modems have greater downstream bandwidth ca-pabilities (up to 30 Mbps), that bandwidth is shared among all users on a line, and will therefore vary, perhaps dramatically, as more users in a neighborhood get online at the same time. Cable modems are also affected by ingress noise on the up-stream path. Due to cable TV infrastructure topology, its ability to deliver two-way communications is not clear. It is estimated that cable operators will have to make large investments in in-frastructure to support two-way service for a large customer base.
Cable infrastructure is largely targeted toward the residential community. In order to provide data networking services to the business environment the cable infrastructure must be extended to cover the business environment. Serving a large and diverse user base (i.e., residential and business users) will enable cable operators to spread costs over a greater number of users and offer flexible pricing options.
10BaseS advantages over cable modems are:
• Two-way transmission - 10BaseS supports point to point full duplex communication at 10 Mbps, as compared to shared 30 Mbps, in which bandwidth varies with the num-ber of users logged on.
• Cost-effectiveness – 10BaseS uses the existing telephone-grade wire infrastructure, no further investment is required. For cable modems, more investment is needed to extend existing infrastructure.
• Widespread availability - Telephone infrastructure is in-stalled everywhere while cable TV’s infrastructure is lim-ited to residential areas.
• Security – 10Base-S is a point-to-point link, therefore all data transfer is secure. On the other hand, some cable modem systems still do not encrypt/filter traffic within the local cable loop.
• Choice of ISPs - Cable TV lines do not have ‘common-carrier’ status as do phone lines.
DSL Technologies
Several alternatives exist for creating DSLs (Digital
Subscriber Loops). All use telephone-grade wires to transfer
data between the home and the telephone central office. Suffi-cient bandwidth is provided to support interactive data and video services. All DSL technologies rely on banks of digital signal processors and transceivers at both ends of the line to process the transmission signals, thus communicating data between the home or office and the telephone company’s services. In the near future telephone companies will be able to offer affordable advanced data services over DSL.
Data Rates
ADSL is an increasingly interesting option. ADSL is a high-speed asymmetrical DSL alternative that can provide a down-stream data rate of up to 8 Mbps with a return data rate of up to 1 Mbps over a single twisted pair. ADSL speeds vary based on the quality of the link and the equipment used. In practice, with real-life loops, equipment placed in the field typically achieved rates far lower than the quoted maximum. CDSL and G.Lite advertise speeds in the 1–1.5 Mbps downstream, 128–384 Kbps upstream range. 10BaseS is based on the emerging VDSL stan-dard delivering full duplex symmetrical 10 Mbps data trans-mission. No other standard DSL technology can reach this rate.
Fig. 3: Typical School or Campus 10BaseS Network Extension
Fig. 4: Residential Internet Access
Distances
The maximum range of ADSL is limited to 5.5 km (18,000 feet). HDSL uses two half-duplex pairs to provide service in both directions, for up to 3.6 km (12,000 feet). CDSL and G.lite operate at 6 km (20,000 feet). VDSL modems are limited to 1.5 km (4,500 feet) at full rate, yet, they can reach longer distance at somewhat lower rates.
10BaseS operates at distances of up to 1 Mile (1.6 km) with-out lowering the 10 Mbps data rate. It is possible, though, to extend the distance limit of 10BaseS by reducing the data rate.
Voice and Data
ADSL and VDSL are designed to coexist on the same telephone-grade infrastructure with POTS or ISDN. Data transmitted by 10BaseS on telephone-grade wire does not interfere with the POTS or ISDN signals either. At both ends of the connection a splitter is used to separate voice from data.
The splitter is implemented through the usage of passive frequency filtering. The VDSL splitter can be easily imple-mented in a small, low cost design because of its high frequency band utilization. 10BaseS uses a splitter design similar to VDSL, which is substantially lower in cost than the ADSL splitter.
Protocols
HDSL, ADSL, CDSL, G.lite and VDSL aim to provide ATM cell as well as packet based protocol interfaces. This allows products to take advantage of ATM features. Nevertheless, to transport Ethernet packets these products require appropriate conversion logic, which will reduce their performance and increase their power consumption and complexity.
10BaseS was designed specifically for the transport of Ethernet. It offers a built-in Ethernet interface eliminating the need for any “conversion”. Building an Ethernet switch with 10BaseS ports is a straightforward process that utilizes only Ethernet technology.
Privacy and Security
HDSL, ADSL, G.lite and VDSL are all full duplex point-to-point connections. The only way to “listen” in on them would be to physically connect to the transmission line, demodulate the signals and decode the data.
10BaseS is also a full duplex point-to-point secure connec-tion. Listening in on the 10BaseS transmissions involves physi-cally connecting to the line, demodulating the signals and de-coding the data. If required, additional standard encryption and security protocols can easily be employed as 10BaseS has stan-dard Ethernet interfaces at the ends.
EtherLoop™ Technology
EtherLoop technology was developed by Elastic Networks, an independent unit of Nortel, to provide high-speed Internet access and/or LAN connectivity over standard POTS twisted pair wire. EtherLoop uses concepts of DSL technologies and Ethernet packet delivery algorithms to provide a high-speed solution.
Voice and Data
EtherLoop uses a range of frequencies from 30 kHz up to approximately 3 MHz in high quality installations. EtherLoop offers voice and Ethernet services simultaneously.
Data Rates and Distances
EtherLoop offers speeds of up to 6 Mbps over loops of up to 1 km (3,000 ft). Greater distances can be reached (up to 7 km or 21 Kft) but with much lower data rates. Data is transmitted only in half duplex.
10BaseS can reach a symmetrical full duplex speed of 10 Mbps over a 1Mile (1.6 km) of twisted pair wire.
Protocols and Interference
EtherLoop utilizes burst technology to reduce interference prob-lems and to simplify the transport of Ethernet data. EtherLoop is a half-duplex connection allowing only one transmitter to be active at a time. When there is traffic in both directions, the line must be shared and total bandwidth is divided between the trans-mitters. EtherLoop employs only the error checking and retrans-mission mechanisms of standard Ethernet to overcome the noise and interference that appear in local loops and the regular tele-phone infrastructure.
10BaseS is a full duplex point-to-point technology. It offers the ability to support full duplex Ethernet transmissions with no loss in performance. This feature lets the user take full ad-vantage of the now standard full duplex Ethernet equipment. 10BaseS uses a scrambler followed by sophisticated Reed-Solomon forward error correction algorithms to suppress noise and interference. Advanced equalization algorithms are also used to handle interference, line distortions, and Cross talk. Minimum power is used for transmission, reducing the inter-ference that 10BaseS generates to a minimum.
HomeRun™ Technology
HomeRun technology was developed by Tut Systems Inc. to provide home networking capabilities over standard POTS twisted pair wire together with voice services. HomeRun is similar to EtherLoop in its use of DSL type technologies and Ethernet packet delivery algorithms.
Tut’s products are based on the use of its HomeRun™ pro-prietary technology. They operate up to distances of 150m (500 feet), allowing data rates of up to 1 Mbps.
HomeRun” is quite similar to EtherLoop” and therefore compares similarly to 10BaseS.
10BaseS advantages in comparison are:
• Higher data rate of 10 Mbps, as compared to rates of up to 1 Mbps.
• Full duplex (two-way) communications at 10 Mbps, no bridging and no lowering of data rate due to bi-directional traffic, as compared with half duplex service of its coun-terparts.
• Strong Reed-Solomon encoding algorithms and scram-bling, in contrast to weak error detection based on Ethernet CRC.
• Strong error detection/correction capabilities of the Reed-Solomon algorithms, as com-pared to retransmission in case of error detection, reducing overall bandwidth. • Continuous, reduced-power transmissions, as compared
to bursty transmissions that generate additional noise and interference to the environment.
• Same bundle coexistance with ADSL. 10BaseS operates in a frequency band and power output that can coexist with ADSL in the same bundle of telephone wires. 10BaseS is not affected by ADSL nor does it affect ADSL. Both Etherloop and HomeRun can not coexist with ADSL in the same bundle.
Conclusion
10BaseS technology was developed by Savan Communications to answer customers’ immediate needs for high-speed access. Development and implementation of 10BaseS technology has been guided by the emerging VDSL standards. The telecom partners recommendations and their noise and interference models in the FSAN, the DAVIC, the ETSI and ANSI VDSL standards committees, and the QAM VDSL Coalition have been used in the design process.
10BaseS offers standard Ethernet capabilities over existing telephone-grade wire coexisting simultaneously with POTS, ISDN, or advanced PBX signaling. 10BaseS technology is the combination of the best from the two worlds of VDSL and Ethernet. It provides full duplex 10 Mbps 10BaseT Ethernet over the telephone-grade wire infrastructure, up to distances of 1 Mile (1.6 km). No other technology available in the market today can offer such high-speed transmission over copper lines to similar distances.
10BaseS is the easiest, most cost effective solution for LAN connectivity and extension today.
Author’s contact details
Wilfried Brachschoss
Infineon Technologies Asia Pacific Pte Ltd. 302 Level 3 Festival Walk
80 Tat Chee Avenue Kowloon Tong, Hong Kong Phone: (852) 2898 0430 Fax: (852) 2587 9296
