Network address assignment in a passive optical network

• US 7,525,980 B2
• Filed: 08/03/2004
• Issued: 04/28/2009
• Est. Priority Date: 05/09/2002
• Status: Expired due to Term

• Current Assignee: Calix Incorporated
• Original Assignee: Calix Networks Incorporated (Calix Incorporated)
• Inventors: Koch, Christopher D, Johnson, Milton J
• Primary Examiner(s): Chan; Wing F
• Assistant Examiner(s): Duong; Duc T
• Application Number:
  US10/910,523
• Publication Number:
  US 20050018681A1
• Time in Patent Office: 1,729 Days
• Field of Search: 370/400, 370/401, 370419-421, 370/463, 370/475, 370/754, 709/220, 709/226, 709/245
• US Class Current: 370/420
• CPC Class Codes: H04L 61/5014 using dynamic host configuration protocol [DHCP] or bootstrap protocol [BOOTP]
• CPC Class Codes: H04L 61/5061 Pools of addresses
• CPC Class Codes: H04L 61/59 using proxies for addressing

Abstract

Assignment of network addresses, e.g., IP addresses, to network nodes in a passive optical network (PON) may involve assignment of IP addresses within a common subnet scope to network nodes coupled to different optical fiber links and different interface modules in the PON. In this manner, excessive waste of IP addresses can be avoided. Instead of assigning an entire subnet scope of addresses to the nodes coupled to a single optical fiber link, a common subnet can be allocated across a PON having multiple, independent interfaces, increasing the number of subnet IP addresses that are actually used. Accordingly, the IP address space within a subnet scope can be distributed more efficiently. In addition to conserving IP addresses, the number of subnets allocated by ISPs can be reduced, along with the significant expense incurred by ISPs in reserving and maintaining multiple class C subnets.

Claims

1. A passive optical network comprising:

a first group of network nodes coupled to a first optical fiber link;

a second group of network nodes coupled to a second optical fiber link;

a first DHCP server that assigns Internet Protocol (IP) addresses within a first common subnet scope to at least some of the network nodes in the first group and at least some of the network nodes in the second group; and

a second DHCP server that assigns IP addresses of a second common subnet scope to at least some of the network nodes in the first group and at least some network nodes in the second group, wherein the second common subnet scope is different from the first common subnet scope.

2. The passive optical network of claim 1, further comprising:

a first interface module that transmits information to the first group of nodes via the first optical fiber link; and

a second interface module that transmits information to the second group of nodes via the second optical fiber link.

3. The passive optical network of claim 2, wherein the first interface module includes an address resolution protocol (ARP) agent that generates proxy ARP requests for the first group of network nodes to determine IP addresses for network nodes in the second group of network nodes.

4. The passive optical network of claim 3, further comprising a router that directs information to and from the first interface module and the second interface module, wherein the router includes an ARP cache storing IP addresses for network nodes in the first and second groups of network modes.

5. The passive optical network of claim 4, wherein the first interface module includes an ARP cache storing IP addresses for network nodes in the first group of network nodes, and the second interface module includes an ARP cache storing IP addresses in the second group of network nodes.

6. The passive optical network of claim 1, wherein the first DHCP server is associated with a first network service provider and the second DHCP server is associated with a second network service provider.

7. The passive optical network of claim 6, wherein each of the first and second network service providers is an Internet service provider.

8. The passive optical network of claim 1, wherein the common subnet scope includes 255 IP addresses and the number of network nodes in each of the first and second groups is less than 255.

9. A method comprising:

assigning, with a first dynamic host configuration protocol (DHCP) server, Internet Protocol (IP) addresses to at least some network nodes of a first group of network nodes coupled to a first optical fiber link;

assigning, with the first DHCP server, IP addresses to at least some network nodes of a second group of network nodes coupled to a second optical fiber link, wherein at least some of the IP addresses assigned to the network nodes in the first group by the first DHCP server and at least some of the IP addresses assigned to the network nodes in the second group by the first DHCP server are within a first common subnet scope;

assigning, with a second DHCP server, IP addresses to at least some of the network nodes in the first group of network nodes; and

assigning, with the second DHCP server, IP addresses to at least some of the network nodes of the second group, wherein at least some of the IP addresses assigned to at least some of the network nodes in the first group by the second DHCP server and at least some of the IP addresses assigned to the network nodes in the second group by the second DHCP server are within a second common subnet scope different from the first common subnet scope.

10. The method of claim 9, further comprising:

generating first DHCP proxy requests for the first group of network nodes via a first DHCP relay agent; and

generating second DHCP proxy requests for the second group of network nodes via a second DHCP relay agent;

wherein assigning IP addresses comprises assigning IP addresses to the network nodes in the first and second groups with the first and second DHCP servers in response to the first and second DHCP proxy requests.

11. The method of claim 9, wherein the first DHCP server is associated with a first network service provider and the second DHCP server is associated with a second network service provider.

12. The method of claim 11, wherein each of the first and second network service providers is an Internet service provider.

13. The method of claim 9, wherein the common subnet scope includes 255 IP addresses and the number of network nodes in each the first and second groups is less than 255.

14. The method of claim 9, further comprising generating proxy address resolution protocol (ARP) requests for the first group of network nodes to determine IP addresses for network nodes in the second group of network nodes.

15. The method of claim 9, wherein the information includes voice, video and data packets.

16. A passive optical network (PON) interface that is coupled to a group of network nodes via an optical fiber link, the PON interface comprising:

a computer-readable medium containing a data structure that maps a first network node of the group of network nodes to a first dynamic host configuration protocol (DHCP) server and maps a second network node of tbe group of network nodes to a second DHCP server; and

a relay agent to receive a DHCP request for an assignment of a network address from one of the first and second network nodes, map the request to the respective one of the DHCP servers that is associated with the node in accordance with the data structure, select an appropriate link for communicating the request to the respective DHCP server that is associated with the node, and communicate the request to the respective DHCP server that is associated with the node on the selected link.

17. A method comprising:

receiving, with a passive optical network (PON) interface that is coupled to a group of network nodes via an optical fiber link, a request for an assignment of a network address from one of the network nodes, wherein the PON interface couples to a plurality of dynamic host configuration protocol (DHCP) servers via a plurality of links;

accessing a data structure that associates a first portion of the network nodes of the group to a first DHCP server of the plurality of DHCP servers and associates a second portion of the network nodes of the group to a second DHCP server of the plurality of DHCP servers;

mapping the request to one of the plurality of DHCP servers that is associated with the node in accordance with the data structure;

selecting one of the plurality of links for communicating with the one of the plurality of the DHCP servers that is associated with the node; and

communicating a DHCP proxy request to the one of the plurality of the DHCP servers that is associated with the node on the selected link.