Dynamic allocation of a set of addresses to router RF modem for individual assignment to hosts

• US 6,405,253 B1
• Filed: 11/09/2000
• Issued: 06/11/2002
• Est. Priority Date: 01/17/1997
• Status: Expired due to Term

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Scientific-Atlanta Incorporated (Cisco Systems, Inc.)
• Inventors: Hrastar, Scott E., Schutte, Mark E.
• Primary Examiner(s): Kim, Kenneth S.
• Application Number:
  US09/710,382
• Time in Patent Office: 579 Days
• Field of Search: 370/397, 370/399, 370/409, 709/228, 709/242, 709/245
• US Class Current: 709/228
• CPC Class Codes: H04H 20/79 using downlink of the CATV systems, e.g. audio broadcast via CATV network
• CPC Class Codes: H04H 60/84 which are fixed telephone networks
• 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 12/2863 Arrangements for combining access network resources elements, e.g. channel bonding modem pooling H04L25/14; routing of packets H04L45/00; multichannel or multilink protocols H04L69/14
• CPC Class Codes: H04L 12/2872 Termination of subscriber connections
• CPC Class Codes: H04L 12/2874 Processing of data for distribution to the subscribers
• CPC Class Codes: H04L 12/5692 Selection among different networks
• CPC Class Codes: H04L 2101/604 Address structures or formats
• CPC Class Codes: H04L 2101/622 Layer-2 addresses, e.g. medium access control [MAC] addresses
• CPC Class Codes: H04L 41/0213 Standardised network management protocols, e.g. simple network management protocol [SNMP]
• CPC Class Codes: H04L 41/0663 Performing the actions predefined by failover planning, e.g. switching to standby network elements
• CPC Class Codes: H04L 41/0677 Localisation of faults
• CPC Class Codes: H04L 61/50 Address allocation
• 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: H04L 61/5061 Pools of addresses
• CPC Class Codes: H04L 63/08 for authentication of entities cryptographic mechanisms or cryptographic arrangements for entity authentication H04L9/32
• CPC Class Codes: H04L 69/40 for recovering from a failure of a protocol instance or entity, e.g. service redundancy protocols, protocol state redundancy or protocol service redirection management of faults, events, alarms or notifications in data switching networks H04L41/06
• CPC Class Codes: H04L 9/40 Network security protocols
• CPC Class Codes: H04N 21/25816 : involving client authentication restricting access to computer systems by authenticating users using a predetermined code G06F21/33; cryptographic authentication protocols H04L9/32; networks authentication protocols H04L63/08; authentication in wireless network security H04W12/06
• CPC Class Codes: H04N 21/42676 : for modulating an analogue carrier signal to encode digital information or demodulating it to decode digital information, e.g. ADSL or cable modem
• 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 7/17309 : Transmission or handling of upstream communications

Abstract

An asymmetrical network for coupling customer-premises Internet hosts such as personal computers to the Internet. The head end of a CATV system has a high-bandwidth connection to the Internet. The down link connecting the personal computers to the Internet is the cables provided by the CATV system; the up link is a telephone connection to the head end. A router is connected to the down link by means of an RF modem, to the up link by means of an analog modern, and to a LAN which is connected to the Pcs. The router routes IP packets for the hosts that are received on the CATV cable to the hosts via the LAN; it routes IP packets from the hosts that are destined for the Internet to the head end via the telephone line. The asymmetrical network conserves IP addresses and addresses on the CATV cable by dynamically allocating the IP addresses for an RF modem'"'"'s hosts and an address on the CATV cable for the RF modem in response to a request made by the RF modem via the telephone line. It further saves IP addresses by assigning a non-unique IP address to the router for use inside the LAN. When the CATV system fails, the asymmetrical network automatically begins to use the telephone line as both the up link and the down link, and when the CATV system is restored, the asymmetrical network automatically returns to using the CATV cable as the down link and the telephone line as the up link. A further feature of the asymmetrical network is that the head end components and the RF modem have IP addresses, so that standard TCP/IP protocols can be used to control the asymmetrical network.

Claims

1. A method employed in at least one server of managing the allocation of a set of addresses to an RF modem, the method comprising the steps performed in the at least one server of:

receiving at least one first packet from the RF modem;

determining a number of addresses to allocate to the RF modem based upon information on a plurality of addresses and upon information in the at least one first packet, the number of addresses being at least two;

allocating a set of addresses for the RF modem, the set of addresses comprising the number of addresses determined in the determining step, the set of addresses comprising at least two addresses; and

communicating the set of addresses to the RF modem with at least one second packet, the RF modem capable of assigning each address of the set of addresses to at least one host.

2. The method of claim 1, wherein the information in the at least one first packet comprises the number of addresses to be allocated.

3. The method of claim 1, further comprising the step of maintaining the information on the plurality of addresses, the plurality of addresses comprising allocated addresses and unallocated addresses, the information on the plurality of addresses comprising information on which addresses of the plurality of addresses are allocated addresses and which addresses of the plurality of addresses are unallocated addresses.

4. The method of claim 3, wherein the allocating step changes the information on the plurality of addresses so that the set of addresses for the RF modem is added to the allocated addresses and removed from the unallocated addresses.

5. The method of claim 4, wherein the at least one first packet comprises identifying information for the RF modem that is allocated the set of addresses.

6. The method of claim 5, further comprising the steps of:

maintaining the identifying information for the RF modem; and

associating the identifying information for the RF modem with the set of addresses added to the allocated addresses.

7. The method of claim 6, further comprising the steps of:

ascertaining that the set of addresses is no longer used by the RF modem; and

deallocating the set of addresses by changing the information on the plurality of addresses so that the set of addresses is removed from the allocated addresses and added to the unallocated addresses.

8. The method of claim 7, further comprising the step of disassociating the identifying information for the RF modem from the set of addresses removed from the allocated addressed and added to the unallocated addresses.

9. The method of claim 7, wherein the ascertaining step further comprises receiving at least one third packet from the RF modem, the at least one third packet comprising the identifying information for the RF modem.

10. The method of claim 9, wherein the at least one third packet is received from the RF modem as a result of the RF modem determining that the at least one host is finished with an assignment of an address from the set of addresses.

11. The method of claim 7, wherein the set of addresses and the plurality of addresses both comprise logical addresses.

12. The method of claim 11, wherein the logical addresses are Internet Protocol (IP) addresses.

13. The method of claim 12, wherein the at least one first packet and the at least one second packet conform to a Dynamic Host Configuration Protocol (DHCP).

14. A method employed in an RF modem for obtaining a set of addresses from at least one server, the method comprising the steps performed in the RF modem of:

sending at least one first packet to the at least one server;

receiving at least one second packet from the at least one server, the at least one second packet comprising a set of addresses allocated by the at least one server based upon information on a plurality of addresses and upon information in the at least one first packet, the set of addresses comprising at least two addresses; and

assigning a first address from the set of addresses to at least one host.

15. The method of claim 14, wherein the information on the plurality of addresses is maintained by the at least one server, the plurality of addresses comprising allocated addresses and unallocated addresses, the information on the plurality of addresses comprising information on which addresses of the plurality of addresses are allocated addresses and which addresses of the plurality of addresses are unallocated addresses.

16. The method of claim 14, wherein the at least one first packet comprises identifying information for the RF modem that is allocated the set of addresses.

17. The method of claim 14, wherein the information in the at least one first packet comprises a number specifying how many addresses are to be allocated by the server.

18. The method of claim 14, further comprising the steps of:

determining that each address of the set of addresses is no longer used by at least one host; and

communicating at least one third packet to the at least one server, the at least one third packet comprising identifying information for the RF modem.

19. The method of claim 18, wherein the set of addresses and the plurality of addresses both comprise logical addresses.

20. The method of claim 19, wherein the logical addresses are IP addresses.

21. The method of claim 20, wherein at least one first packet and the at least one second packet conform to a Dynamic Host Configuration Protocol (DHCP).

22. The method of claim 14, wherein the assigning step further comprises the steps of:

receiving a request from the at least on host for an address assignment;

selecting the first address from the set of addresses; and

sending a response to the at least one host, the response comprising the first address as a fulfillment of the request for address assignment.

23. The method of claim 22, wherein the first address is a logical address.

24. The method of claim 23, wherein the logical address is an IP address.

25. The method of claim 24, wherein the request and response conform to a Dynamic Host Configuration Protocol (DHCP).