Multiplex communications – Data flow congestion prevention or control – Control of data admission to the network
Reexamination Certificate
1998-12-18
2002-05-14
Yao, Kwang Bin (Department: 2664)
Multiplex communications
Data flow congestion prevention or control
Control of data admission to the network
C370S355000
Reexamination Certificate
active
06388990
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to the field of digital communications. In particular, the present invention relates to an optimal method for provisioning a high-speed data connection between a user and a destination over a connection-oriented packet network having digital subscriber line access to the user premises.
BACKGROUND OF THE INVENTION
With the explosive growth of the Internet and with the increasing desirability of telecommuting, the need for more reliable and higher speed data access over the “last mile” to homes and small businesses has become apparent. In particular, it has become desirable to provide high-speed data communications (1) between remote users, such as users at homes or small businesses, and corporate networks for telecommuting purposes, and (2) between remote users and the Internet. A traditional method of remote user access, and still the most common, involves the use of two-wire modems, such as V.90 modems, to establish a dial-up connection between the remote user and their company's dial-in server, or between the remote user and their Internet Service Provider (ISP). Although still having certain cost advantages, the traditional dial-up modem has many practical disadvantages including dial-up delay and including a limited data access rate, which is currently 56 Kbps for V.90 modems.
FIG. 1
shows a block diagram of an emerging technology and service solution that provides numerous advantages over traditional remote access methods.
FIG. 1
shows a connection-oriented packet network
100
for providing a connection between a remote user and a destination where a DSL (Digital Subscriber Line) link is used to access the remote user premises. As used herein, “remote user” indicates a customer at a home, small business, or other location whose primary method of data connection to the outside world is through ordinary telephone system “last mile” copper connections to the telephone company central office (CO).
As known in the art, connection-oriented protocols rely on end-to-end connections through virtual circuits. The virtual circuits are either Permanent Virtual Circuits (PVC's) that are permanently “nailed up”, or Switched Virtual Circuits (SVC's) that are established on a per-call basis. In a connection-oriented protocol, successive packets travel from the source to the destination over the same path, whereas for connectionless protocols each individual packet finds its own way through the network to its destination. Examples of connection-oriented protocols include Asynchronous Transfer Mode (ATM), Frame Relay, and X.25 Virtual Circuit Mode. Examples of connectionless protocols include the Internet Protocol (IP), X.25 Datagram Mode, and SMDS (Switched Multimegabit Data Service).
From a connectivity and throughput perspective relevant to the remote access network of
FIG. 1
, the newer connection-oriented protocols such as Frame Relay and ATM are advantageous for reasons including (a) higher data rates over the newer and more reliable hardware that is now available, as compared to connectionless lower-level protocols, and (b) the opportunity to define specific grades of service, such as CIR (Committed Information Rate) for Frame Relay and QoS (Quality of Service) metrics for ATM. See generally McDysan and Spohn, ATM:
Theory and Application, Signature Edition,
McGraw-Hill Series on Computer Communications (1998), the contents of which are hereby incorporated by reference into the present disclosure.
As known in the art, DSL technology affords the opportunity to establish high bit rate access over ordinary copper lines between remote user premises and the telephone company CO. DSL technology has been described as creating high-speed “dumb pipes” over ordinary copper lines, allowing high bandwidth to remote users at reduced cost. See K. Taylor, “Converting Copper: How xDSL Paves the Way for ATM”, in Gadecki and Heckart, ATM . . . , IDG Books Worldwide (1997) at pp. 91-93. The contents of the Gadecki and Keckart text are are hereby incorporated by reference into the present disclosure.
DSL technology, often named xDSL technology, comes in several different variations. High Bit Rate DSL (HDSL) is the oldest DSL technology, which arose from problems in transmitting T
1
(1.544 Mbps) over long copper loops, offers symmetric (same speed both ways) data rates up to 1.544 Mbps in a 4-wire implementation, and up to 768 Kbps in 2-wire implementations. Symmetric DSL (SDSL) offers, in a single 2-wire implementation, a symmetric data rate of up to 1.1 Mbps and even 1.544 Mbps in light of recent improvements. Asymmetric DSL (ADSL) offers, in a single 2-wire implementation, the combination of a high-speed downstream channel that can deliver a one-way downstream rate of 1.5-8 Mbps to the remote user, along with a duplex channel that can deliver a symmetric data rate of up to 640 Kbps. Other types of DSL services have emerged including Rate Adaptive DSL (RADSL), ISDN DSL (IDSL), and Very High-Speed DSL (VDSL). See generally Chen, DSL:
Simulation Techniques and Standards Development for Digital Subscriber Line Systems,
MacMillan Technology Series (1998), the contents of which are hereby incorporated by reference into the present disclosure.
As shown in
FIG. 1
, the connection-oriented packet network
100
provides connectivity between a remote user or client premise
102
, such as a home or small business, and a corporate LAN
104
. Alternatively, or in conjunction therewith, the connection-oriented packet network
100
provides connectivity between the client premise
102
and the Internet
106
via ISP
108
. As used herein, for simplicity and clarity of disclosure, the remote user is denoted as the “client” of the remote data access service. It is to be appreciated that the “customer” of the remote data access service of
FIG. 1
, i.e. the party that requests the service and pays the service invoices, may actually be the client, the client's employer, the ISP, or a different party depending on bundling, reselling, or other business and marketing factors. Unless otherwise indicated herein, and for purposes of clarity of disclosure and not by way of limitation, the “client” shall correspond to a single entity at the remote user premise who requests, uses, and pays the remote data access service of FIG.
1
.
In the case of the corporate LAN
104
as the destination, the connection-oriented packet network
100
provides a permanent virtual circuit (PVC) between the client premise
102
and the corporate LAN
104
. Physically, (1) a DSL link
110
is provided between the client premise
102
to the CO
112
, (2) a standard Time Division Multiplexed (TDM) link
114
(e.g., DS-
3
or STS-
3
c
) is provided between the CO
112
to an ATM network switch
116
of an ATM Network
118
, (3) facilities of ATM Network
118
are provided between ATM network switch
116
and an ATM network switch
120
near the corporate LAN
104
, and (4) a standard TDM link
122
(e.g., DS-
1
or DS-
3
) is provided between ATM network switch
120
and the corporate LAN
104
. The DSL link
110
is provisioned between (a) a remote DSL terminal unit
132
such as a DSL modem at the client premise
102
, and (b) a CO DSL terminal unit
134
such as a DSL Access Multiplexer at the CO
112
. The TDM link
122
between ATM network switch
120
and the corporate LAN
104
terminates at a router
107
at the corporate site.
Using the above facilities, in
FIG. 1
an ATM circuit is provisioned between remote DSL terminal unit
132
and router
107
, traversing the DSL link
110
, the CO DSL terminal unit
134
, the TDM link
114
, the ATM switch
116
, the ATM Network
118
, the ATM switch
120
, and the TDM link
122
. For purposes of disclosing features and advantages of the preferred embodiments infra, the portion of the ATM circuit between the remote DSL terminal unit
132
and the CO DSL terminal unit
134
may be referred to as a digital subscriber line portion, while the portion of the ATM circuit between the CO DSL terminal unit
134
and the router
Covad Communications Company
Harper Kevin C.
Kuo Jung-hua
Yao Kwang Bin
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