Method and system for reducing congestion in connection-oriented packet networks having digital subscriber line access

• US 6,388,990 B1
• Filed: 12/18/1998
• Issued: 05/14/2002
• Est. Priority Date: 12/18/1998
• Status: Expired due to Fees

• Current Assignee: Megapath Group, Inc. (US Telepacific Holdings Corporation)
• Original Assignee: Covad Communications Company
• Inventors: Wetzel, Gregory F.
• Primary Examiner(s): Yao, Kwang Bin
• Assistant Examiner(s): Harper, Kevin C.
• Application Number:
  US09/216,081
• Time in Patent Office: 1,243 Days
• Field of Search: 370/483, 370/420, 370/468, 370/522, 370/525, 370/229, 370/230, 370/232, 370/233, 370/235, 370/236, 370/351, 370/352, 370/353, 370/354, 370/400, 370/401, 370/465, 370/355, 370/357, 370/395.65, 370/395.1, 375/219, 375/220, 375/222
• US Class Current: 370/230
• CPC Class Codes: H04L 12/2854 Wide area networks, e.g. public data networks
• CPC Class Codes: H04L 12/4608 LAN interconnection over ATM networks
• CPC Class Codes: H04L 2012/5632 Bandwidth allocation
• CPC Class Codes: H04M 11/062 using different frequency bands for speech and other data
• CPC Class Codes: H04Q 11/0478 Provisions for broadband connections

Abstract

A method and system for provisioning remote user data access over digital subscriber lines (DSL'"'"'s) through connection-oriented packet networks is described. According to a preferred embodiment, DSL terminal units are directed to train at a rate that is not substantially greater than the subscribed data rate, thereby avoiding network congestion due to data rate mismatches between the DSL connection and a corresponding permanent virtual circuit (PVC) channel through the connection-oriented packet network. According to another preferred embodiment, the DSL units are directed to test for the maximum trainable data rate before settling to the subscribed data rate, and to communicate this information to a network operations center computer, thereby allowing the maximum allowable DSL data rate to be compared to actual client traffic usage patterns and to the client'"'"'s subscribed data rate. According to another preferred embodiment, in the event that the maximum trainable rate lies substantially below the subscribed data rate, the network operations center automatically re-provisions the permanent virtual circuit (PVC) channel through the connection-oriented packet network to a corresponding lower level, thereby conserving network resources.

Claims

1. A method for provisioning a data connection between a client and a destination over a dedicated network having a digital subscriber line portion and a connection-oriented packet network portion, comprising the steps of:

receiving a subscribed data rate for the digital subscriber line;

provisioning a permanent virtual circuit channel across said connection-oriented packet network portion, said permanent virtual circuit channel being provisioned at a data rate corresponding to said subscribed data rate for the digital subscriber line; and

instructing said digital subscriber line portion to train at a data rate not substantially greater than said subscribed data rate for the digital subscriber line, said digital subscriber line portion being capable of training at one of a plurality of data speed increments not aligned with said subscribed data rate, said trained data rate being selected to correspond to one of the lowest data speed increment greater than said subscribed data rate and the greatest data speed increment less than said subscribed data rate;

whereby congestion between said digital subscriber line portion and said connection-oriented packet network portion due to data rate mismatch therebetween is substantially avoided.

2. The method of claim 1, said permanent virtual circuit channel being an ATM channel, said trained data rate allowing for the possibility of a marginal congestion condition upon the occurrence of data bursts between said subscribed data rate and said trained data rate, wherein said ATM channel is provisioned using relaxed congestion reduction parameters that curb the numbers of ATM cells discarded upon the occurrence of said marginal congestion condition.

3. The method of claim 1, said digital subscriber line portion comprising a client digital subscriber line terminal unit, a central office digital subscriber line terminal unit, and a copper facility therebetween, said method further comprising the steps of:

instructing said central office digital subscriber line terminal unit to test for a maximum trainable rate between said central office digital subscriber line terminal unit and said client digital subscriber line terminal unit; and

transmitting information related to said maximum trainable rate from said central office digital subscriber line terminal unit to a network operation center.

4. The method of claim 3, further comprising the step of, at said network operation center, recording said information related to said maximum trainable rate in a database, said database being configured to store current and historical maximum trainable rates for a plurality of client digital subscriber lines.

5. A method for provisioning a data connection between a client and a destination over a dedicated network having a digital subscriber line portion and a connection-oriented packet network portion, comprising the steps of:

receiving a subscribed data rate;

determining a maximum trainable rate of said digital subscriber line portion;

provisioning a permanent virtual circuit channel across said connection-oriented packet network portion at said subscribed data rate if said maximum trainable rate is greater or equal to than said subscribed data rate;

provisioning a permanent virtual circuit channel across said connection-oriented packet network portion at a data rate corresponding to said maximum trainable rate if said maximum trainable rate is less than said subscribed data rate, thereby releasing bandwidth for other permanent virtual circuit channels on said connection-oriented packet network that would have been unused had said permanent virtual circuit channel been provisioned at said subscribed data rate.

6. The method of claim 5, further comprising the step of instructing said digital subscriber line portion to train at a data rate not substantially greater than said subscribed data rate if said maximum trainable rate is greater or equal to than said subscribed data rate, whereby congestion between said digital subscriber line portion and said connection-oriented packet network portion due to data rate mismatch therebetween is substantially avoided.

7. The method of claim 6, further comprising the step of instructing said digital subscriber line portion to train at a data rate equal to said maximum trainable rate if said maximum trainable rate is less than said subscribed data rate.

8. The method of claim 7, further comprising the step of transmitting information related to said maximum trainable rate to a network operation center.

9. The method of claim 8, further comprising the steps of

enabling said digital subscriber line portion and said permanent virtual channel for activating said data connection; and

monitoring said digital subscriber line portion for detecting if said digital subscriber line portion has reset.

10. The method of claim 9, wherein if said digital subscriber line portion has reset, performing the steps of:

determining a subsequent maximum trainable rate of said digital subscriber line portion;

transmitting information related to said subsequent maximum trainable rate to said network operation center; and

if said subsequent maximum trainable rate is equal to the prior maximum trainable rate, instructing said digital subscriber line portion to train at a data rate equal to said prior maximum trainable rate.

11. The method of claim 10, wherein if said subsequent maximum trainable rate is different than the prior maximum trainable rate, performing the steps of:

reprovisioning said permanent virtual circuit channel across said connection-oriented packet network portion at said subscribed data rate if said subsequent maximum trainable rate is greater or equal to than said subscribed data rate; and

reprovisioning said permanent virtual circuit channel across said connection-oriented packet network portion at a data rate corresponding to said subsequent maximum trainable rate if said subsequent maximum trainable rate is less than said subscribed data rate, thereby releasing bandwidth for other permanent virtual circuit channels on said connection-oriented packet network that would have been unused had said permanent virtual circuit channel been provisioned at said subscribed data rate.

12. A method for provisioning a permanent data connection between a client premises and a destination over an ATM network that includes an xDSL link to the client premises, comprising the steps of:

receiving a subscribed data rate;

installing a remote DSL terminal unit at the client premises;

installing a Central Office (“

CO”

) DSL terminal unit at a central office near said client premises and establishing a wired connection between the remote DSL terminal unit and the CO DSL terminal unit, said CO DSL terminal unit being capable of training at one of a plurality of data speed increments not aligned with said subscribed data rate, said trained data rate being selected to correspond to one of the lowest data speed increment greater than said subscribed data rate and the greatest data speed increment less than said subscribed data rate;

at a network operations center, provisioning an ATM channel between said CO DSL terminal unit and an ATM network switch near said destination, said ATM being provisioned at the subscribed rate;

installing a data link between the CO DSL terminal unit and the network operations center;

instructing said CO DSL terminal unit to test for a maximum trainable rate between said CO DSL terminal unit and said remote DSL terminal unit;

transmitting information related to said maximum trainable rate from said CO DSL terminal unit to the network operations center; and

activating said xDSL link and said ATM channel, wherein said activating said xDSL link comprises instructing said digital subscriber line portion to train at a data rate not substantially greater than said subscribed data rate, whereby congestion between said digital subscriber line portion and said connection-oriented packet network portion due to data rate mismatch therebetween is substantially avoided;

whereby said network operations center is capable of monitoring the status of said xDSL link using said data link to said CO DSL terminal unit.

13. The method of claim 12, said selected trained data rate causing the possibility of a marginal congestion condition upon the occurrence of data bursts between said subscribed data rate and said trained data rate, wherein said ATM channel is provisioned using relaxed congestion reduction parameters that curb the numbers of ATM cells discarded upon the occurrence of said marginal congestion condition.

14. The method of claim 13, wherein upon a detection of a resetting of the CO DSL terminal unit, further steps are performed comprising the steps of:

determining a subsequent maximum trainable rate of said digital subscriber line portion;

transmitting information related to said subsequent maximum trainable rate to said network operation center;

if said subsequent maximum trainable rate is equal to the prior maximum trainable rate, instructing said digital subscriber line portion to train at a data rate equal to said prior maximum trainable rate;

if said subsequent maximum trainable rate is different from the prior maximum trainable rate, performing the steps of;

reprovisioning a permanent virtual circuit channel across said connection-oriented packet network portion at said subscribed data rate if said subsequent maximum trainable rate is greater or equal to than said subscribed data rate;

reprovisioning a permanent virtual circuit channel across said connection-oriented packet network portion at a data rate corresponding to said subsequent maximum trainable rate if said subsequent maximum trainable rate is less than said subscribed data rate, thereby releasing bandwidth for other permanent virtual circuit channels on said connection-oriented packet network that would have been unused had said permanent virtual circuit channel been provisioned at said subscribed data rate;

instructing said digital subscriber line portion to train at a data rate not substantially greater than said subscribed data rate if said subsequent maximum trainable rate is greater or equal to than said subscribed data rate; and

instructing said digital subscriber line portion to train at a data rate equal to said subsequent maximum trainable rate if said subsequent maximum trainable rate is substantially less than said subscribed data rate.

15. The method of claim 12, further comprising the step of, at said network operation center, recording said information related to said maximum trainable rate in a database, said database being configured to store current and historical maximum trainable rates for a plurality of client digital subscriber lines.