IP subnet sharing technique implemented without using bridging or routing protocols

• US 7,174,376 B1
• Filed: 06/28/2002
• Issued: 02/06/2007
• Est. Priority Date: 06/28/2002
• Status: Expired due to Fees

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Daruwalla, Feisal Y.
• Primary Examiner(s): Najjar; Saleh
• Assistant Examiner(s): ISMAIL, SHAWKI SAIF
• Application Number:
  US10/187,035
• Time in Patent Office: 1,684 Days
• Field of Search: 709223-225, 709/227, 709/245, 709/249, 709/250, 709238-242, 370350-351, 370/401, 370/409
• 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 nodes being configured or designed to communicate with at least one of the plurality of intermediate network devices via at least one upstream channel and at least one downstream channel;

each of the plurality of intermediate network devices being configured or designed to communicate with the head end complex;

each of the plurality of intermediate network devices being associated with a first IP subnet;

each of the plurality of intermediate network devices having a unique IP address associated therewith, the method comprising;

(a) receiving a first data parcel, the first data parcel including first source address information and first destination address information;

(b) forwarding the first data parcel to the head end complex if at least the following conditions are satisfied;

(i) the first data parcel corresponds to an IP packet; and

(ii) the first destination address information does not match the first IP subnet;

(c) forwarding the first data parcel to an appropriate port if at least the following conditions are satisfied;

(i) the first data parcel corresponds to an IP packet;

(ii) the first destination address information matches the first IP subnet; and

(iii) a port binding associated with the destination address information is known; and

(d) generating an Address Resolution Protocol (ARP) request if at least the following conditions are satisfied;

(i) the first data parcel corresponds to an IP packet;

(ii) the first destination address information matches the first IP subnet; and

(iii) a port binding associated with the destination address information is not known.

2. The method of claim 1 further comprising:

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

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

3. The method of claim 1 wherein the sharing of the first IP subnet by the plurality of intermediate network devices is accomplished without using a route injection protocol.

4. The method of claim 1 wherein the sharing of the first IP subnet by the plurality of intermediate network devices is accomplished without using a binding protocol to share the first IP subnet among the plurality of intermediate network devices.

5. The method of claim 1 wherein the access network corresponds to a cable network;

and

wherein the plurality of intermediate network devices correspond to distributed cable modem termination systems.

6. A network device adapted to share 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 network devices;

each of the plurality of nodes being configured or designed to communicate with at least one of the plurality of network devices via at least one upstream channel and at least one downstream channel;

each of the plurality of network devices being configured or designed to communicate with the head end complex;

each of the plurality of network devices being associated with a first IP subnet;

each of the plurality of network devices having a unique IP address associated therewith;

the network device comprising;

at least one processor;

at least one interface configured or designed to provide a communication link to at least one other network device in the access network; and

memory;

the network device being configured or designed to;

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

(b) forward the first data parcel to the head end complex if at least the following conditions are satisfied;

(i) the first data parcel corresponds to an IP packet; and

(ii) the first destination address information does not match the first IP subnet;

(c) forward the first data parcel to an appropriate port if at least the following conditions are satisfied;

(i) the first data parcel corresponds to an IP packet;

(ii) the first destination address information matches the first IP subnet; and

(iii) a port binding associated with the destination address information is known; and

(d) generate an Address Resolution Protocol (ARP) request if at least the following conditions are satisfied;

(i) the first data parcel corresponds to an IP packet;

(ii) the first destination address information matches the first IP subnet; and

(iii) a port binding associated with the destination address information is not known.

7. The network device of claim 6 being further configured or designed to:

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

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

8. The network device of claim 6 wherein the sharing of the first IP subnet by the plurality of network devices is accomplished without using a route injection protocol.

9. The network device of claim 6 wherein the sharing of the first IP subnet by the plurality of network devices is accomplished without using a binding protocol to share the first IP subnet among the plurality of network devices.

10. The network device of claim 6 wherein the access network corresponds to a cable network;

and

wherein the plurality of network devices correspond to distributed cable modem termination systems.

11. A computer program product 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 nodes being configured or designed to communicate with at least one of the plurality of intermediate network devices via at least one upstream channel and at least one downstream channel;

each of the plurality of intermediate network devices being configured or designed to communicate with the head end complex;

each of the plurality of intermediate network devices being associated with a first IP subnet;

each of the plurality of intermediate network devices having a unique IP address associated therewith, the computer program product comprising;

a computer readable storage medium having computer readable code embodied therein, the computer readable code comprising;

(a) computer code for receiving a first data parcel, the first data parcel including first source address information and first destination address information;

(b) computer code for forwarding the first data parcel to the head end complex if at least the following conditions are satisfied;

(i) the first data parcel corresponds to an IP packet; and

(ii) the first destination address information does not match the first IP subnet;

(c) computer code for forwarding the first data parcel to an appropriate port if at least the following conditions are satisfied;

(i) the first data parcel corresponds to an IP packet;

(ii) the first destination address information matches the first IP subnet; and

(iii) a port binding associated with the destination address information is known; and

(d) computer code for generating an Address Resolution Protocol (ARP) request if at least the following conditions are satisfied;

(i) the first data parcel corresponds to an IP packet;

(ii) the first destination address information matches the first IP subnet; and

(iii) a port binding associated with the destination address information is not known.

12. The computer program product of claim 11 further comprising:

computer code for forwarding the first data parcel to an appropriate port if a MAC address binding associated with the destination address information is also known; and

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

13. The computer program product of claim 11 wherein the sharing of the first IP subnet by the plurality of intermediate network devices is accomplished without using a route injection protocol.

14. The computer program product of claim 11 wherein the sharing of the first IP subnet by the plurality of intermediate network devices is accomplished without using a binding protocol to share the first IP subnet among the plurality of intermediate network devices.

15. The computer program product of claim 11 wherein the access network corresponds to a cable network;

and

wherein the plurality of intermediate network devices correspond to distributed cable modem termination systems.

16. 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 nodes being configured or designed to communicate with at least one of the plurality of intermediate network devices via at least one upstream channel and at least one downstream channel;

each of the plurality of intermediate network devices being configured or designed to communicate with the head end complex;

each of the plurality of intermediate network devices being associated with a first IP subnet;

each of the plurality of intermediate network devices having a unique IP address associated therewith, the system comprising;

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

(b) means for forwarding the first data parcel to the head end complex if at least the following conditions are satisfied;

(i) the first data parcel corresponds to an IP packet; and

(ii) the first destination address information does not match the first IP subnet;

(c) means for forwarding the first data parcel to an appropriate port if at least the following conditions are satisfied;

(i) the first data parcel corresponds to an IP packet;

(ii) the first destination address information matches the first IP subnet; and

(iii) a port binding associated with the destination address information is known; and

(d) means for generating an Address Resolution Protocol (ARP) request if at least the following conditions are satisfied;

(i) the first data parcel corresponds to an IP packet;

(ii) the first destination address information matches the first IP subnet; and

(iii) a port binding associated with the destination address information is not known.

17. The system of claim 16 further comprising:

means for forwarding the first data parcel to an appropriate port if a MAC address binding associated with the destination address information is also known; and

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