System method and network for providing high speed remote access from any ...

1

SYSTEM METHOD AND NETWORK FOR
PROVIDING HIGH SPEED REMOTE
ACCESS FROM ANY LOCATION
CONNECTED BY A LOCAL LOOP TO A
CENTRAL OFFICE

This application is a continuation of application Ser. No. 09/252,354 filed on Feb. 17, 1999, now U.S. Pat. No. 6,028,867.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to telecommunication networks, and more specifically to a system, method, and network for providing high speed remote access from any location connected by a local loop to a central office.

2. Related Art

Remote access generally refers to the ability of a user to access a remote system using a local system (e.g., a personal computer). The remote system can be either a stand-alone system or a network of systems. Mainframe computers such as those available from International Business Machines is an example of a stand-alone system. A network connecting several systems such as printers, modems, servers, computer systems, telecommunication equipment, among others, is an example of a network of systems. Remote access is commonly referred to as internet access when a local system accesses a remote network of systems such as what it known as world-wide-web.

Remote access typically requires transferring digital data between a local system and a remote system. Several applications and/or services with varying degrees of complexity can be provided using the remote access feature. Electronic mail, web browsing, distributed database applications, and electronic commerce are examples of such applications and services.

There has been an increasing demand for higher bandwidth connections from locations such as homes and small businesses. The need for higher bandwidth from homes has been driven in some instances by tele-commuters (employees working from homes) who would like to enjoy similar response times from corporate computer resources as their in-office counterparts when transferring files, accessing data bases etc.

In addition, it is believed that the availability of higher bandwidth will drive the market to provide more multimedia applications over the remote access connections. Large bandwidth connections may allow small businesses to disseminate (e.g., by providing a web server locally) or receive more information quickly from external customers or companies.

One solution for providing high-bandwidth connections to homes and small business is to install fibre to every location of interest. Unfortunately, installation of fibre to every home and small business is expensive and time consuming, thereby making it unsuitable for immediate deployment.

Another solution which has been attempted is to provide high bandwidth connections over cable installed for broadcasting television programs. The physical media (cable) is shared by many users from different homes and businesses. Unfortunately, such sharing may lead to unpredictability in the bandwidth available to individual users because high usage by some users may leave very little bandwidth for the others. In addition, due to the shared nature of the underlying media, users may be concerned about security and privacy.

2

Yet another option is to use the physical connections already installed for providing voice telephone calls over the past several decades. Voice telephone calls have been typically provided over metallic (e.g., copper) pairs connecting

5 to homes (and small businesses). These physical connections are commonly referred to as local loops. The local loops originate at what is known as a "central office" in the United States Telecommunications industry.

Remote access using local loops overcomes at least the

1° disadvantages noted with reference to fibre and cable. That is, local loops have been already idled over the past several decades and they can be used immediately. In addition, each local loop is dedicated to a home or business, leading to less unpredictability in the bandwidth availability due to active

15 use by other users.

The local loops have been installed originally to provide connections to voice calls placed from telephone instruments in locations such as homes and offices. To provide connections for voice calls, the local loops terminating at

20 central offices are usually connected to a voice switch (e.g., 5ESS from Lucent Technologies, 600 Mountain Avenue, Murray Hill, N.J. 07974, USA, UL:www.lucent.com, Phone Number: 1-908-582-8500). A sequence of voice switches in tandem provides the basic connection for a voice call, with

25 the last voice switch in the sequence being connected to the target (destination) telephone instrument. In general, voices switches are expensive due to the requirement to provide different types of services (e.g., switched voice calls, 9-1-1 emergency calls etc.).

Attempts have been made in the industry to provide as high bandwidth as possible for remote access using the basic telecommunication infrastructure installed for voice calls. In a typical configuration, a home computer uses a modem to

35 communicate with a remote system. The modem converts digital data to be transmitted from the home computer into analog signals suitable for transmission over a local loop. A remote computer uses another modem to receive the analog signals and converts back the received analog signals into

4Q digital data using another modem. The data transfer occurs in the reverse direction (i.e., from remote computer to home computer) also to support the remote access.

Unfortunately, the bandwidth rates which can be supported on local loops used as switched voice lines (i.e., using

45 modems) is limited. Modems and remote access equipment supporting bandwidth as high as 56 Kbps (at least in one direction) have been available from companies such as 3COM corporation and Ascend Communications. Much higher bandwidth is believed to be hard to achieve on a

5Q single local loop, at least in a cost-effective manner through switched voice switches.

Bandwidth of the order of 56 Kbps may not be sufficient for some users at homes and for many small businesses. The remote access requirements for homes and small businesses

55 typically include availability of reasonably high speed remote access at a fairly low price for affordability. Users from these types of locations usually do not have the resources to invest in special equipment (e.g., a fibre line and associated equipment) for high bandwidth. Therefore, it may

go be an important requirement to provide high bandwidth over the local loops described briefly above.

To provide higher bandwidth to locations connected by local loops, a group of technologies commonly referred to as digital-subscriber-loop (DSL) technologies have evolved.

65 The DSL technologies only as applicable to the present invention are described here. For a detailed description of the various DSL technologies, the reader is referred to 3

"Residential Broadband", by George Abe, published by Cisco Press, ISBN: 1-57870-020-5, which is incorporated in its entirety herewith.

According to the DSL group of technologies, a local loop is generally dedicated for use with DSL technologies. Band- 5 width higher than that possible through modem based service can be provided using these group of technologies. The bandwidth which can be provided is typically limited by the distance, the media used to implement the physical connection, potential presence of factors causing noise, and 1° the signaling scheme chosen for the corresponding DSL technologies.

Of the DSL group of technologies, IDSL (DSL technology using basic ISDN signaling framework) can be used to provide bandwidth of 128 Kbps or 144 Kbps depending on 15 the type of IDSL implementation. All local loops to homes can be equipped to support the IDSL signaling scheme irrespective of the distance a home is from the central office. Therefore, every location connected with a local loop can usually be provided remote access with a bandwidth of 128 20 Kbps or 144 Kbps. However, 128 Kbps or 144 Kbps bandwidth may not be sufficient for many locations. For example, some users at homes or small businesses may need much more than the 128 Kbps or 144 Kbps bandwidth possible using IDSL technology. 25

Asymmetric DSL (ADSL) is another one of the DSL group of technologies, which allows such higher bandwidth connections. As an illustration, DMT-modulated ADSL technology can support bandwidth of 6.1 Mbps in the 3Q direction leaving the central office and 640 Kbps in the reverse direction. ADSL has the general requirements that a location connected with a local loop needs to be within 14,000 feet (approximately 3 miles) of the central office and that the local loop be a continuous metallic path (without 3J electronic transmission equipment) end-to-end (i.e., from home to central office) to a location.

Unfortunately, not all the locations (homes and businesses) meet both the requirements for ADSL. Some homes and businesses may be outside of the 3 mile range 40 from a central office. In some other situations, the underlying local loop may not have a metallic path end-to-end. For example, the metallic wires terminating at locations such as office buildings and apartment complexes ("multiple family dwellings") typically originate at a multiplexor commonly 45 known as digital loop carrier (DLC), and DLCs are connected to central offices through shared media as described briefly below with reference to an apartment complex including several apartments.

In a typical scenario, a DLC is placed within or close to 50 an apartment complex. The DLC is usually connected to the central office using fibre or two pairs of metallic wires. A bandwidth of at least Tl is generally provided between the DLC and the central office, and the data required to support connections to each telephone instrument in an apartment is 55 multiplexed on the provided bandwidth. In some scenarios, ADSL cannot be supported due to the limited bandwidth (e.g., Tl) available between DLCs and central offices. Even with the availability of substantial higher bandwidth between a central office and DLC, special hardware and/or go software may be required in the DLC. Such special hardware and/or software may not be available in many DLCs. Accordingly, it may not be possible to provide ADSL based connections to several apartments.

At least from the above, it should be appreciated that high 65 bandwidth connections may be provided using the DSL technologies. A provider may provide high bandwidth con

4

nections using either the IDSL technology alone or ADSL technology alone. The provision of high speed connection using only one of these technologies leads to several disadvantages. Some example disadvantages are noted below.

When the bandwidth is provided using only one of the DSL technologies, a service provider may not have the ability to provide high speed remote access to all locations connected to a central office by local loops. For example, a provider using only the ADSL technology may not be able to serve locations connected through DLCs and locations away from central offices by more than three miles due to reasons described above. On the other hand, a provider using only the IDSL technology may not be able to serve subscribers requiring bandwidth larger than 144 Kbps or 128 Kbps. As a result, the pool of potential subscribers is smaller than all the locations connected to a central office with local loops.

The smaller pool of potential subscribers in turn can lead to more disadvantages. For example, many large companies may be discouraged from subscribing to the service due to the unavailability of high speed remote access to all their employees. As a result, some large companies may not even subscribe to the service providers providing high speed remote access using only either ADSL or IDSL technology. Subscription by less companies generally leads to an even smaller pool of actual subscribers.

The cost of providing services is higher in such instances as 'economies of scale' may not be recognized due to the smaller pool of subscribers. Economy of scale refers to the generally understood notion in the telecommunications industry that the average cost to provide a given service to a large pool of consumers is less than the average cost to provide the same service to a smaller pool of consumers. The increased cost due to the small pool of actual subscribers may be unacceptable in some situations.

Therefore, what is needed is a cost-effective scheme to provide high speed remote access to any location connected to a central office.

SUMMARY OF THE INVENTION

The present invention enables high speed remote access to be provided to any location connected to a central office in a cost effective manner. Connections with a bandwidth of 128 Kbps or 144 Kbps can be provided to any location connected to a central office by a local loop. Connections with bandwidth much higher than 128 Kbps or 144 Kbps can optionally be provided to some of the locations. Connections with such high bandwidth are provided using shared equipment and transmission facilities, thereby enabling all the connections to be provided in a cost-effective manner.

A telecommunication network is employed to provide high speed remote access in accordance with the present invention. The telecommunication network includes access multiplexors and data switches. The access multiplexors are located in a central office and provide interfaces for local loops connected using IDSL technology and another DSL signaling technology. The IDSL signaling technology provides the 128 Kbps or 144 Kbps bandwidth. As the local loops to any location can be used with IDSL signaling, 128 Kbps or 144 Kbps bandwidth can be provided to any location. The another DSL (e.g., ADSL) technology can provide for much higher speed transfers.

In one embodiment, an access multiplexor having some modules for interfacing with local loops using ADSL technology and other modules for interfacing with local loops using IDSL technology is employed. The access multiplexor 5

receives packets on ADSL local loops as cells and IDSL local loops as frames. The multiplexor forwards the received data to the data switches.

The data switches deliver the data of the packets to a destination remote target. The destination remote target is 5 typically determined based on the address contents of the packets. The data switch may perform any conversions necessary (e.g., from cells to frames and vice versa) so that the data can be delivered using a shared communication bandwidth pipe. That is, the data in all packets can be 1Q delivered to a destination remote target using one shared pipe so that economies of scale can be realized. Data is transmitted in the reverse direction from the remote targets to the locations, enabling remote access connections to be established.

Therefore, the present invention enables high speed remote access connections to be provided in a cost effective manner. This is accomplished by providing interfaces using different DSL technologies supporting high bandwidth datapaths and delivering all data received on more than one DSL interfaces to a destination remote target using a shared 20 bandwidth pipe.

The present invention enables employees to telecommute by providing connections having a minimum bandwidth of 128 Kbps or 144 Kbps to all homes. 25

The present invention enables a bandwidth of 128 Kbps or 144 Kbps to be supported on the interface to any location connected to a central office. In addition, some of the locations can be provided even higher bandwidth. This is enabled by using IDSL technology in combination with 3Q other DSL technologies providing higher bandwidth.

The present invention can be used by any type of provider to provide high bandwidth remote access. That is, RBOCs such as Pac Bell and South Western Bell, Competitive Local Exchange Carriers such as Covad Communications, among 35 other types of providers can use the present invention to provide high speed remote access. This is because the equipment required in accordance with the present invention can be conveniently placed in different locations allowed by law under the present United States regulatory environment. 40

Further features and advantages of the invention, as well as the structure and operation of various embodiments of the invention, are described in detail below with reference to the accompanying drawings. In the drawings, like reference numbers generally indicate identical, functionally similar, 45 and/or structurally similar elements. The drawing in which an element first appears is indicated by the leftmost digit(s) in the corresponding reference number.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be described with reference to the accompanying drawings, wherein:

FIG. 1 is a block diagram of a telecommunications system illustrating the manner in which high speed remote access can be provided to any location connected to a central office 55 in accordance with the present invention;

FIG. 2 is a block diagram illustrating an example configuration at a home or a small business accessing a remote target using the high speed remote access provided in accordance with the present invention; 60

FIG. 3 is a block diagram illustrating an example configuration at a remote target accessed by locations connected to a central office in accordance with the present invention; and

FIG. 4 is a block diagram illustrating the manner in which 65 a telecommunications system can scale to serve large areas in accordance with the present invention; and

6

FIG. 5 is a flow chart illustrating a method for providing high speed remote access according to the present invention.

DETAILED DESCRIPTION OF THE
PREFERRED EMBODIMENTS

0. Definitions and Glossary of Terms

The following are the definitions of some of the terms

used in the present patent application.

Location: Entities such as homes and businesses connected to a central office by a local loop.

Central office: In the U.S. Telecommunication industry, a central office commonly refers to a place where local loops connecting to different locations originate.

Local loop: Physical connection providing connectivity to a central office from a location. Each local loop typically includes a metallic (e.g., copper) wire pair connecting to a location. The physical connection to a central office may include equipment such as repeaters and/or a digital loop carrier (DLC) in the connection path.

Target: A place where remote systems are placed and accessed by users at locations using telecommunication network and local loops.

IDSL Technology: One of the DSL technologies well known in the industry, typically implemented using ISDN signaling scheme. Present (as of May 1998) implementations of IDSL technology typically provide bandwidth of 128 Kbps or 144 Kbps depending on the type of implementation.

Shared bandwidth pipes: A bandwidth pipe which allows bandwidth to be shared for transmission of data from (or to) more than one location. Shared bandwidth pipes can be used internal to telecommunication network, and also to connect telecommunication network to targets.

Telecommunication network: Includes equipment to provide interfaces (IDSL and at least one another DSL technology) to local loops and switches the data bits between remote systems and locations (or computer systems at locations).

Access Multiplexor: A multiplexor interfacing with local loops to receive (and send) data from a location. Access multiplexor is referred to as DSL access multiplexor (DSLAM) when interfacing with lines using DSL technology.

Data Switch: Equipment which receives packets on one port and routes data onto another port, typically using the address information in the packets.

Packet: A sequence of bits identifiable as a group according to a pre-determined convention.

1. Overview and Discussion of the Present Invention The present invention is described with general reference

to telecommunications system 100 of FIG. 1. Telecommunications system 100 includes several locations 110-A through 110-E connected to access targets 160-A and 160-B by telecommunication network 170. Locations 110-A through 110-E are connected to telecommunication network 170 by local loops 117-A through 117-E respectively. Remote target 160-A is connected to telecommunication network 170 by line 176-A and remote target 160-B is connected to telecommunication network 170 by line 176-B.

In the description herein, locations 110-A through 110-E will be collectively or individually referred to by reference numeral 110 as will be clear from the context. Similarly, access targets 160-A and 160-B will collectively or individually be referred to by reference numeral 160, local loops 117-A through 117-E will be collectively or individually referred to by reference numeral 117, and lines 176-A and 176-B will be collectively or individually referred to by reference numeral 176.