IP subnet sharing technique implemented without using bridging or routing protocols

• US 7,895,312 B1
• Filed: 12/01/2006
• Issued: 02/22/2011
• Est. Priority Date: 06/28/2002
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Daruwalla, Feisal Y.
• Primary Examiner(s): ISMAIL, SHAWKI SAIF
• Application Number:
  US11/607,790
• Time in Patent Office: 1,544 Days
• Field of Search: 709/238, 709/223, 709/225, 709/245
• US Class Current: 709/223
• 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 12/2861 Point-to-multipoint connection from the data network to the subscribers
• CPC Class Codes: H04L 12/2874 Processing of data for distribution to the subscribers
• CPC Class Codes: H04L 61/103 across network layers, e.g. resolution of network layer into physical layer addresses or address resolution protocol [ARP]

Abstract

An IP subnet sharing technique is described which allows multiple network devices of an access network to share an IP subnet without the need for each network device to run complex routing protocols, or bridging protocols. Further, the multiple network devices are able to share an IP subnet without the need to subdivide the IP subnet into smaller groups.

Claims

1. A method for sharing a subnet of IP addresses among a plurality of network devices in an access network, the access network including a head end complex, a plurality of nodes, and a plurality of intermediate network devices, each of the plurality of intermediate network devices being associated with a first IP subnet, the method comprising:

configuring a first device of the plurality of intermediate network devices to handle data parcel traffic using a traffic handling protocol which allows the first device to share the first IP subnet with the plurality of intermediate network devices;

sharing the first IP subnet with the first device and the other plurality of intermediate network devices in a manner which does not utilize a route injection protocol;

sharing the first IP subnet with the first device and the other plurality of intermediate network devices in a manner which does not utilize a bridging protocol and;

sharing the first IP subnet with the first device and the other plurality of intermediate network devices without subdividing the first IP subnet into smaller subgroups;

wherein each of the plurality of intermediate network devices is a distributed cable modem termination system (DCMTS).

2. The method of claim 1 further comprising:

receiving, at the first device, a first data parcel, the first data parcel including first source address information and first destination address information; and

forwarding the first data parcel to the head end complex in response to determining that a first set of conditions has been satisfied.

3. The method of claim 1 further comprising:

receiving, at the first device, a first data parcel, the first data parcel including first source address information and first destination address information; and

forwarding the first data parcel to the head end complex in response to determining that a first set of conditions has been satisfied;

wherein the first set of conditions includes;

the first data parcel corresponds to an IP packet, and the first destination address information does not match the first IP subnet.

4. The method of claim 1 further comprising:

receiving, at the first device, a first data parcel, the first data parcel including first source address information and first destination address information; and

forwarding the first data parcel to an appropriate port in response to determining that a second set of conditions has been satisfied;

wherein the second set of conditions includes;

the first data parcel corresponds to an IP packet, the first destination address information matches the first IP subnet, and a port binding associated with the destination address information is known.

5. The method of claim 1 further comprising:

receiving, at the first device, a first data parcel, the first data parcel including first source address information and first destination address information; and

generating an Address Resolution Protocol (ARP) request in response to determining that a third set of conditions has been satisfied;

wherein the third set of conditions includes;

the first data parcel corresponds to an IP packet, the first destination address information matches the first IP subnet, and a port binding associated with the destination address information is not known.

6. The method of claim 1 further comprising:

receiving, at the first device, a first data parcel, the first data parcel including first source address information and first destination address information; and

generating an Address Resolution Protocol (ARP) request if the MAC address binding associated with the destination address information is not known.

7. The method of claim 1 further comprising:

communicating information between the first device and the head end complex using at least one shared access channel of the access network.

8. The method as recited in claim 1, wherein each of the plurality of nodes comprises a cable modem.

9. The method as recited in claim 1, wherein each of the plurality of nodes comprises a cable modem.

10. The method of claim 1 further comprising:

receiving, at the first device, a first data parcel, the first data parcel including first source address information and first destination address information; and

forwarding the first data parcel to an appropriate port if a MAC address binding associated with the destination address information is known.

11. A network device of a plurality of network devices of an access network, the access network including a head end complex, each of the plurality of intermediate network devices being associated with a first IP subnet, the network device comprising:

at least one processor;

at least one interface operable to provide a communication link to at least one other network device in the data network; and

a memory;

the network device being operable to;

handle data parcel traffic using a traffic handling protocol which allows the network device to share the first IP subnet with the plurality of intermediate network devices;

share the first IP subnet with the plurality network devices in a manner which does not utilize a route injection protocol;

share the first IP subnet with the plurality of network devices in a manner which does not utilize a bridging protocol and;

share the first IP subnet with the plurality of network devices without subdividing the first IP subnet into smaller subgroups;

wherein each of the plurality of intermediate network devices is a distributed cable modem termination system (DCMTS).

12. The network device of claim 11 being further operable to:

receive a first data parcel, the first data parcel including first source address information and first destination address information; and

forward the first data parcel to the head end complex in response to determining that a first set of conditions has been satisfied.

13. The network device of claim 11 being further operable to:

receive a first data parcel, the first data parcel including first source address information and first destination address information; and

forward the first data parcel to the head end complex in response to determining that a first set of conditions has been satisfied;

wherein the first set of conditions includes;

the first data parcel corresponds to an IP packet, and the first destination address information does not match the first IP subnet.

14. The network device of claim 11 being further operable to:

receive a first data parcel, the first data parcel including first source address information and first destination address information; and

forward the first data parcel to an appropriate port in response to determining that a second set of conditions has been satisfied;

wherein the second set of conditions includes;

the first data parcel corresponds to an IP packet, the first destination address information matches the first IP subnet, and a port binding associated with the destination address information is known.

15. The network device of claim 11 being further operable to:

receive a first data parcel, the first data parcel including first source address information and first destination address information; and

generate an Address Resolution Protocol (ARP) request in response to determining that a third set of conditions has been satisfied;

wherein the third set of conditions includes;

the first data parcel corresponds to an IP packet, the first destination address information matches the first IP subnet, and a port binding associated with the destination address information is not known.

16. The network device of claim 11 being further operable to:

receive a first data parcel, the first data parcel including first source address information and first destination address information; and

forward the first data parcel to an appropriate port if a MAC address binding associated with the destination address information is known.

17. The network device of claim 11 being further operable to:

communicate information between the network device and the head end complex using at least one shared access channel of the access network.

18. The network device of claim 11 wherein the access network corresponds to a cable network;

and

wherein each of the plurality of network devices is a different one of a plurality of distributed cable modem termination systems.

19. The network device of claim 11 being further operable to:

receive a first data parcel, the first data parcel including first source address information and first destination address information; and

generate an Address Resolution Protocol (ARP) request if the MAC address binding associated with the destination address information is not known.

20. A system for sharing a subnet of IP addresses among a plurality of network devices in an access network, the access network including a head end complex, a plurality of nodes, and a plurality of intermediate network devices, each of the plurality of intermediate network devices being associated with a first IP subnet, the system comprising:

means for configuring a first device of the plurality of intermediate network devices to handle data parcel traffic using a traffic handling protocol which allows the first device to share the first IP subnet with the plurality of intermediate network devices;

means for sharing the first IP subnet with the first device and the other plurality of intermediate network devices in a manner which does not utilize a route injection protocol;

means for sharing the first IP subnet with the first device and the other plurality of intermediate network devices in a manner which does not utilize a bridging protocol and;

means for sharing the first IP subnet with the first device and the other plurality of intermediate network devices without subdividing the first IP subnet into smaller subgroups;

wherein each of the plurality of intermediate network devices is a distributed cable modem termination system (DCMTS).

21. The system of claim 20 further comprising:

means for receiving, at the first device, a first data parcel, the first data parcel including first source address information and first destination address information;

means for forwarding the first data parcel to the head end complex in response to determining that a first set of conditions has been satisfied;

means for forwarding the first data parcel to an appropriate port in response to determining that a second set of conditions has been satisfied; and

means for generating an Address Resolution Protocol (ARP) request in response to determining that a third set of conditions has been satisfied.