Method and apparatus for automatically detecting virtual circuit settings and encapsulation types in a DSL network

• US 20040052263A1
• Filed: 09/18/2002
• Published: 03/18/2004
• Est. Priority Date: 09/18/2002
• Status: Active Grant

• Current Assignee: Ikanos Communications Incorporated (Qualcomm, Inc.)
• Original Assignee: Conexant Systems Incorporated (Synaptics Incorporated)
• Inventors: Xu, Haibo
• Granted Patent: US 7,489,693 B2
• Time in Patent Office: Days
• US Class Current: 370/399
• CPC Class Codes: H04L 12/2856 Access arrangements, e.g. Internet access asynchronous transfer mode networks H04L12/5601; broadband local area networks H04L12/2801; optical access or distribution networks H04Q11/0067; access to open networks H04L12/5691; digital subscriber line end-user equipment and bit-level processing of data on a PSTN-based network H04M11/00; home network gateways H04L12/2834; wireless access networks H04W
• CPC Class Codes: H04L 12/2859 Point-to-point connection between the data network and the subscribers encapsulation H04L12/4633; virtual LANs H04L12/4641; routing of packets H04L45/00
• CPC Class Codes: H04L 12/2889 Multiservice, e.g. MSAN
• CPC Class Codes: H04L 12/5601 Transfer mode dependent, e.g. ATM
• CPC Class Codes: H04L 2012/5615 Network termination, e.g. NT1, NT2, PBX
• CPC Class Codes: H04L 2012/5617 Virtual LANs; Emulation of LANs
• CPC Class Codes: H04L 2012/5625 Operations, administration and maintenance [OAM]
• CPC Class Codes: H04L 2012/5672 Multiplexing, e.g. coding, scrambling
• CPC Class Codes: H04L 69/16 Implementation or adaptation of Internet protocol [IP], of transmission control protocol [TCP] or of user datagram protocol [UDP]
• CPC Class Codes: H04L 69/168 specially adapted for link layer protocols, e.g. asynchronous transfer mode [ATM], synchronous optical network [SONET] or point-to-point protocol [PPP]
• CPC Class Codes: H04L 69/24 Negotiation of communication capabilities
• CPC Class Codes: H04M 11/062 using different frequency bands for speech and other data

Abstract

Automatic detection of the virtual circuit setting and encapsulation type of a DSL line. A DSL modem determines the correct virtual path identifier (VPI) and virtual channel identifier (VCI) by sending OAM loopback requests to different VPI/VCI pairs until a valid loopback reply is received. PPPoA encapsulation is detected when a valid reply is received to a PPP LCP configuration request or echo request. PPPoE encapsulation is detected when a valid reply is received to a PPP LCP termination request or a PPPoE discovery offer (a PADO packet) is received in response to a PPPoE discovery initiation request (a PADI packet).

Claims

1. A method for determining the correct virtual circuit settings for a DSL modem comprising:

choosing a virtual circuit setting;

sending a loopback request over the chosen virtual circuit setting;

if a reply to the loopback request is received, storing the chosen virtual circuit setting as the correct virtual circuit setting; and

if a reply to the loopback request is not received, choosing different virtual circuit settings and sending loopback requests until a reply is received.

2. A method as claimed in claim 1, wherein the virtual circuit settings comprise a virtual path identifier (VPI) and a virtual channel identifier (VCI).

3. A method as claimed in claim 2, wherein the VPI and VCI settings are chosen a group of pre-identified potentially correct virtual circuit settings.

4. A method as claimed in claim 2, wherein the loopback request is an OAM loopback cell.

5. A method as claimed in claim 4, wherein the VPI and VCI fields of the loopback cell are set to the chosen VPI and VCI.

6. A method as claimed in claim 5, wherein the reply to the loopback request comprises a replica of the sent OAM loopback cell containing the chosen VPI and VCI.

7. A method as claimed in claim 1, wherein the method is carried out by software residing in a DSL modem.

8. A method for determining whether a DSL line is using PPPoA encapsulation comprising:

sending a PPP/LCP configure-request packet;

if a reply to the sent configure-request packet is received, storing the encapsulation type as PPPoA;

sending a PPP/LCP echo-request packet; and

if a reply to the sent echo-request packet is received, storing the encapsulation type as PPPoA.

9. A method as claimed in claim 8, wherein the reply to the configure-request packet is a PPP/LCP configure-ack packet, configure-nak packet or configure-reject packet.

10. A method as claimed in claim 8, wherein the reply to the echo-request packet is a PPP/LCP echo-reply packet.

11. A method as claimed in claim 8, wherein configure-request and echo-request packets are sent rapidly and alternately for a pre-determined time period or until a reply to either a configure-request packet or echo-request packet is received.

12. A method as claimed in claim 8, wherein the method is carried out by software residing in a DSL modem.

13. A method for determining whether a DSL line is using PPPoE encapsulation comprising:

executing a PPPoE fast connect recovery command;

if a reply to the fast connect recovery command is received, storing the encapsulation type as PPPoE;

sending a PPPoE discovery stage PADI packet; and

if a reply to the sent PADI packet is received, storing the encapsulation type as PPPoE.

14. A method as claimed in claim 13, wherein the PPPoE fast connect recovery command comprises:

retrieving stored information about the most recent line connection; and

sending a line termination request using the most recent line connection.

15. A method as claimed in claim 14, wherein the line termination request comprises a PPP/LCP terminate-request packet.

16. A method as claimed in claim 14, wherein the line termination request comprises a PPPoE PADT packet.

17. A method as claimed in claim 14, wherein the line termination request comprises a PPP/LCP terminate-request packet and a PPPoE PADT packet.

18. A method as claimed in claim 15, wherein the reply to the fast connect recovery command comprises a PPP/LCP terminate-ack packet.

19. A method as claimed in claim 17, wherein the reply to the fast connect recovery command comprises a PPP/LCP terminate packet.

20. A method as claimed in claim 13, wherein the method is carried-out by software residing in a DSL modem.

21. A computer readable medium having computer executable instructions for automatically detecting the correct DSL virtual circuit setting and encapsulation type by performing steps comprising:

detecting the correct virtual circuit setting by sending loopback requests over different virtual circuit settings until a valid loopback reply is received;

detecting PPPoA encapsulation by receiving a reply to a PPP/LCP configuration request or echo request; and

detecting PPPoE encapsulation by receiving a reply to a PPP/LCP termination request or a PPPoE discovery initiation request.

22. A DSL modem comprising a computer readable medium as claimed in claim 21.

23. A DSL modem comprising:

means for automatically detecting the correct virtual circuit settings when the modem is connected to a DSL line; and

means for automatically detecting the encapsulation type being used on the DSL line.

24. A DSL modem as claimed in claim 23, wherein the means for detecting the correct virtual circuit settings comprises sending loopback requests over different virtual circuits until a valid loopback reply is received.

25. A DSL modem as claimed in claim 23, wherein PPPoA encapsulation is detected by receiving a valid reply to PPP/LCP configuration request.

26. A DSL modem as claimed in claim 25, wherein PPPoA encapsulation is also detected by receiving a valid reply to a PPP/LCP echo request.

27. A DSL modem as claimed in claim 23, wherein PPPoE encapsulation is detected by receiving a valid reply to a PPPoE discovery initiation request.

28. A DSL modem as claimed in claim 27, wherein PPPoE encapsulation is also detected by receiving a valid reply to a PPP/LCP termination request.

29. Operating software for a DSL modem comprising:

computer executable instructions for detecting the correct virtual circuit settings of a connected DSL line by sending loopback requests over different virtual circuits until a valid loopback reply is received.

30. Operating software for a DSL modem comprising:

computer executable instructions for determining that the encapsulation type being used by a connected DSL line is PPPoA when a valid reply is received in response to a PPP/LCP configuration or echo request; and

for determining that the encapsulation type is PPPoE when a valid reply is received in response to a PPPoE discovery initiation request or a PPP/LCP termination request.