Broadband system with topology discovery

• US 20020075814A1
• Filed: 09/13/2001
• Published: 06/20/2002
• Est. Priority Date: 09/22/2000
• Status: Active Grant

• Current Assignee: Ciena Corporation
• Original Assignee: PhyFlex Networks, Inc. (Ciena Corporation)
• Inventors: Gupta, Dev V., Dravida, Subrahmanyam, Rege, Kiran, Tandon, Manas, Desai, Gautam, Dorbala, Prasad, Jayadevan, Anoop, Dikshitulu, Sitaram
• Granted Patent: US 7,139,247 B2
• Time in Patent Office: Days
• US Class Current: 370/255
• CPC Class Codes: H04L 12/2801 Broadband local area networks
• 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 12/2872 Termination of subscriber connections
• CPC Class Codes: H04L 12/2876 Handling of subscriber policies group policies management H04L41/0893
• CPC Class Codes: H04L 12/4641 Virtual LANs, VLANs, e.g. virtual private networks [VPN] LAN interconnection over a bridge based backbone H04L12/462; encapsulation techniques H04L12/4633; routing of packets H04L45/00; packet switches H04L49/00; virtual private networks for security H04L63/0272
• CPC Class Codes: H04L 2012/5605 Fibre
• CPC Class Codes: H04L 2012/5606 Metallic
• CPC Class Codes: H04L 2012/561 Star, e.g. cross-connect, concentrator, subscriber group equipment, remote electronics
• CPC Class Codes: H04L 2012/5651 Priority, marking, classes
• CPC Class Codes: H04L 2012/5679 Arbitration or scheduling
• CPC Class Codes: H04L 41/0853 by actively collecting configuration information or by backing up configuration information
• CPC Class Codes: H04L 41/12 Discovery or management of network topologies
• CPC Class Codes: H04L 41/5003 Managing SLA; Interaction between SLA and QoS
• CPC Class Codes: H04L 45/02 Topology update or discovery
• CPC Class Codes: H04L 45/026 Details of "hello" or keep-alive messages
• CPC Class Codes: H04L 47/10 Flow control; Congestion control
• CPC Class Codes: H04L 47/15 in relation to multipoint traffic arrangements for broadcast or multicast in data networks H04L12/18
• CPC Class Codes: H04L 47/20 Traffic policing
• CPC Class Codes: H04L 47/24 Traffic characterised by specific attributes, e.g. priority or QoS
• CPC Class Codes: H04L 47/2416 : Real-time traffic
• CPC Class Codes: H04L 47/2425 : for supporting services specification, e.g. SLA
• CPC Class Codes: H04L 47/2441 : relying on flow classification, e.g. using integrated services [IntServ]
• CPC Class Codes: H04L 47/2491 : Mapping quality of service [QoS] requirements between different networks
• CPC Class Codes: H04L 47/32 : by discarding or delaying data units, e.g. packets or frames
• CPC Class Codes: H04L 47/70 : Admission control; Resource allocation
• CPC Class Codes: H04L 47/724 : at intermediate nodes, e.g. resource reservation protocol [RSVP]
• CPC Class Codes: H04L 47/788 : Autonomous allocation of resources
• CPC Class Codes: H04L 47/801 : Real time traffic
• CPC Class Codes: H04L 47/805 : QOS or priority aware
• CPC Class Codes: H04L 47/822 : Collecting or measuring resource availability data
• CPC Class Codes: H04L 47/829 : Topology based
• CPC Class Codes: H04L 61/5007 : Internet protocol [IP] addresses
• CPC Class Codes: H04L 61/5014 : using dynamic host configuration protocol [DHCP] or bootstrap protocol [BOOTP]
• CPC Class Codes: H04N 21/6118 : involving cable transmission, e.g. using a cable modem
• CPC Class Codes: H04N 21/6168 : involving cable transmission, e.g. using a cable modem
• CPC Class Codes: H04N 7/10 : Adaptations for transmission by electrical cable H04N7/12 takes precedence
• CPC Class Codes: H04N 7/17309 : Transmission or handling of upstream communications
• CPC Class Codes: H04Q 3/0045 : involving hybrid, i.e. a mixture of public and private, or multi-vendor systems

Abstract

Hybrid fiber/coax networks employ the existing cable plant used for cable TV and transmit data signals in a frequency bandwidth above that which is used for cable TV. As this cable plant was deployed in a tree and branch topology, data transmissions may be susceptible to noise, variable transmission loss and frequency dispersion, particularly in the upstream direction. Further, due to the tree and branch topology, homes at the far end of the network experience much greater loss than do the homes that are near to the headend/ONU. The present system, which uses point-to-point data links between intelligent network elements located in the feeder/distribution network to provide reliable, secure, bi-directional broadband access. Digital signals are terminated at the intelligent network elements, switched and regenerated for transmission across additional upstream or downstream data links as needed to connect a home to a headend or router. The intelligent network elements can be co-located with or replace the standard network elements to take advantage of existing network configurations. The standard network elements can be selectively replaced by the intelligent network elements in an incremental approach. A method of discovering the network topology includes sending a message from one of the network elements on a transmission path to a topology server, the message including information identifying the one network element. At each intermediate network element in the transmission path, information identifying each intermediate network element is appended to the message. In this manner, the data links are made over relatively short runs of coax cable, which can provide greater bandwidth than the typical end-to-end feeder/distribution connection between a home and the headend or optical network unit.

Claims

1. In a network having plural network elements, a method of discovering the network topology comprising:

sending a first message from one of the network elements on a transmission path to a topology server, the first message including information identifying the one network element;

at each intermediate network element in the transmission path, appending to the first message information identifying each intermediate network element.

2. The method of claim 1 wherein the information identifying each network element in the first message includes MAC address and physical port information for each corresponding network element.

3. The method of claim 1 wherein the first message comprises a DHCPDISCOVER message including an options field having the information identifying each network element in the transmission path.

4. The method of claim 1 further comprising sending a second message from the topology server to the one network element, the second message including a routing ID for the one network element.

5. The method of claim 4 wherein the second message comprises a DHCPOFFER message.

6. The method of claim 1 further comprising sending a third message from the one network element to the topology server periodically, the third message including information identifying the one network element.

7. The method of claim 6 wherein the third message comprises a DHCPINFORM message including an options field having the information identifying each network element in the transmission path.

8. The method of claim 1 wherein the plural network elements are interconnected using point-to-point data links over a tree and branch network.

9. A system comprising:

a topology server; and

plural network elements, at least one network element operable to send a first message from one of the network elements on a transmission path to the topology server, the first message including information identifying the one network element;

each intermediate network element in the transmission path operable to append to the first message information identifying each intermediate network element.

10. The system of claim 9 wherein the information identifying each network element in the first message includes MAC address and physical port information for each corresponding network element.

11. The system of claim 9 wherein the first message comprises a DHCPDISCOVER message including an options field having the information identifying each network element in the transmission path.

12. The system of claim 9 wherein the topology server is operable to send a second message to the one network element, the second message including a routing ID for the one network element.

13. The system of claim 12 wherein the second message comprises a DHCPOFFER message.

14. The system of claim 9 wherein the one network element is further operable to send a third message to the topology server periodically, the third message including information identifying the one network element.

15. The system of claim 14 wherein the third message comprises a DHCPINFORM message including an options field having the information identifying each network element in the transmission path.

16. The system of claim 9 wherein the plural network elements are interconnected using point-to-point data links over a tree and branch network.

17. In a network having plural network elements, a computer program product including computer program code for discovering the network topology comprising:

computer program code for sending a first message from one of the network elements on a transmission path to a topology server, the first message including information identifying the one network element;

at each intermediate network element in the transmission path, computer program code for appending to the first message information identifying each intermediate network element.

18. In a network having plural network elements, a computer data signal having program code for discovering the network topology comprising:

program code for sending a first message from one of the network elements on a transmission path to a topology server, the first message including information identifying the one network element;

at each intermediate network element in the transmission path, program code for appending to the first message information identifying each intermediate network element.

19. In a network having plural network elements, apparatus for discovering the network topology comprising:

means for sending a first message from one of the network elements on a transmission path to a topology server, the first message including information identifying the one network element;

at each intermediate network element in the transmission path, means for appending to the first message information identifying each intermediate network element.