Method for a cable modem to rapidly switch to a backup CMTS

Abstract

A protection CMTS is available to immediately service a cable modem should that modem's service from a working CMTS fail for any reason. To speed the service transfer (cutover) from the working CMTS to the protection CMTS, the cable modem may preregister with the protection CMTS well before the cutover becomes necessary. The cable modem's registration with both the working CMTS and the protection CMTS preferably employs a single IP address, so that the cable modem need not obtain a new IP address during cutover. While the cable modem may register with both the working CMTS and the protection CMTS, the devices are designed or configured so that only the working CMTS injects a host route for the cable modem into the appropriate routing protocol. Only after cutover to the protection CMTS does the protection CMTS inject its host route.

What is claimed is: 
     
       1. A method implemented on a protection CMTS for providing redundancy for a cable network having a working CMTS that provides normal service to a cable modem and the protection CMTS which takes over service to the cable modem should service from the working CMTS become unavailable, the method comprising:
 (a) at least partially registering the cable modem with the protection CMTS prior to the working CMTS becoming unavailable; and 
 (b) assuming a protection state in which the protection CMTS can take over service of the cable modem should its service with the working CMTS become unavailable, 
 wherein the cable modem is informed of an upstream channel of the protection CMTS. 
 
     
     
       2. The method of  claim 1 , wherein registering comprises specifying at least one of a transmission power, a transmission time slot, and or a transmission frequency at which the cable modem is to communicate with the protection CMTS should the cable modem service with the working CMTS become unavailable. 
     
     
       3. The method of  claim 1 , wherein registering comprises specifying one or more parameters as specified by DOCSIS. 
     
     
       4. The method of  claim 1 , wherein registering comprises noting an IP address for the cable modem, which IP address is used in communications between the cable modem and the working CMTS. 
     
     
       5. The method of  claim 4 , wherein the protection CMTS obtains the cable modem IP address in a communication from the cable modem. 
     
     
       6. The method of  claim 4 , wherein the protection CMTS obtains the cable modem IP address in a communication from the working CMTS. 
     
     
       7. The method of  claim 1 , wherein the service provided to the cable modem includes telephony service. 
     
     
       8. The method of  claim 1 , wherein during the protection state, the protection CMTS periodically establishes communication with the cable modem. 
     
     
       9. The method of  claim 8 , wherein the communication includes instructions to the cable modem to adjust at least one of a transmission power and or a transmission frequency at which the cable modem is to communicate with the protection CMTS should service with the working CMTS become unavailable. 
     
     
       10. The method of  claim 1 , further comprising:
 (c) determining that the working CMTS's service to the cable modem has or will become unavailable; and 
 (d) taking over service to the cable modem. 
 
     
     
       11. A method implemented on a protection router for providing redundancy in a network having a working router that provides normal service to a host and the protection router which takes over service to the host should service from the working router become unavailable, the method comprising:
 (a) at least partially registering the host with the protection router prior to the working router becoming unavailable; and 
 (b) assuming a protection state in which the protection router can take over service of the host should its service with the working router become unavailable, wherein the service includes telephony service, 
 wherein the host is informed of an upstream channel of the protection router. 
 
     
     
       12. The method of claim  1  11, wherein the network is a wireless network. 
     
     
       13. A CMTS designed or configured to act as a protection CMTS for a cable network having a working CMTS that provides normal service to a cable modem and the protection CMTS which takes over service to the cable modem should the service from the working CMTS become unavailable, the CMTS comprising:
 (a) one or more processors; 
 (b) memory in communication with at least one of the one or more processors; and 
 (c) wherein at least one of the one or more processors are configured to store registration data for the cable modem in the memory, and wherein the CMTS is configured to not provide communication service to the cable modem unless the service from the working CMTS should become unavailable and wherein the CMTS is configured to store the registration data at a time prior to the working CMTS becoming unavailable, 
 wherein the cable modem is informed of an upstream channel of the CMTS. 
 
     
     
       14. The CMTS of  claim 13 , wherein the registration data includes at least one of a transmission power, transmission time slots, and or a transmission frequency at which the cable modem is to communicate with the protection CMTS should the cable modem service with the working CMTS become unavailable. 
     
     
       15. The CMTS of  claim 13 , wherein the processors and memory are configured to implement DOCSIS. 
     
     
       16. The CMTS of  claim 13 , wherein the registration data includes an IP address for the cable modem, which IP address is used in communications between the cable modem and the working CMTS. 
     
     
       17. The CMTS of  claim 13 , wherein the processors and memory are configured to periodically establish communication with the cable modem. 
     
     
       18. The CMTS of  claim 13 , wherein the CMTS is designed or configured to perform routing operations. 
     
     
       19. A computer program product comprising a machine readable medium on which is stored program instructions for a method implemented on a protection CMTS, the method providing redundancy for a cable network having a working CMTS that provides normal service to a cable modem and the protection CMTS which takes over service to the cable modem should the service from the working CMTS become unavailable, the program instructions comprising instructions for:
 (a) at least partially registering the cable modem with the protection CMTS prior to the working CMTS becoming unavailable; and 
 (b) assuming a protection state in which the protection CMTS can take over service of the cable modem should its service with the working CMTS become unavailable, 
 wherein the cable modem is informed of an upstream channel of the protection CMTS. 
 
     
     
       20. The computer program product of  claim 19 , wherein the instruction for registering requires specifying at least one of a transmission power, a transmission frequency, and or transmission time slots at which the cable modem is to communicate with the protection CMTS should the cable modem service with the working CMTS become unavailable. 
     
     
       21. The computer program product of  claim 19 , wherein the instructions for registering comprise operations compliant with DOCSIS. 
     
     
       22. The computer program product of  claim 19 , wherein the instructions for registering comprise instructions for noting an IP address for the cable modem, which IP address is used in communications between the cable modem and the working CMTS. 
     
     
       23. The computer program product of  claim 19 , further comprising instructions for periodically establishing communication with the cable modem which the protection CMTS is in the protection state. 
     
     
       24. The computer program product of  claim 19 , further comprising instructions for:
 (c) determining that the working CMTS's services to the cable modem has become unavailable; and 
 (d) taking over service to the cable modem. 
 
     
     
       25. A method implemented on a protection CMTS for providing redundancy for a cable network having a working CMTS that provides normal service to a cable modem and the protection CMTS which takes over service to the cable modem should service from the working CMTS become unavailable, the method comprising:
 (a) at least partially registering the cable modem with the protection CMTS prior to the working CMTS becoming unavailable; 
 (b) thereafter, determining that the working CMTS's service to the cable modem has become unavailable; and 
 (c) taking over service to the cable modem, 
 wherein the cable modem is informed of an upstream channel of the protection CMTS. 
 
     
     
       26. The method of  claim 25 , wherein taking over service comprises using registration parameters for the cable modem, which registration parameters were previously provided to the protection CMTS. 
     
     
       27. The method of  claim 26 , wherein the registration parameters include an IP address for the cable modem, which IP address is used in communications between the cable modem and the working CMTS. 
     
     
       28. The method of  claim 26 , wherein the registration parameters include at least one of a transmission power, a transmission frequency, and or transmission time slots at which the cable modem is to communicate with the protection CMTS should the cable modem service with the working CMTS become unavailable. 
     
     
       29. The method of  claim 25 , wherein the service provided to the cable modem includes telephony service. 
     
     
       30. The method of  claim 25 , wherein determining that the working CMTS's service to the cable modem has become unavailable comprises receiving a communication indicating such unavailability from at least one of the cable modem and or the working CMTS. 
     
     
       31. The method of  claim 25 , further comprising providing routing services to one or more cable modems in the cable network. 
     
     
       32. The method of  claim 30 , wherein the communication indicating unavailability is a downstream channel change request. 
     
     
       33. A cable modem designed or configured for use on a cable network having a first CMTS that provides normal service to a cable modern and a second CMTS which takes over service to the cable modem should the service from the first CMTS become unavailable, the cable modem comprising;
 (a) a cable network interface; and 
 (b) memory, 
 wherein the cable modem is configured to
 register with the first CMTS, 
 be informed of an upstream channel for the second to CMTS, 
 register with the second CMTS using the upstream channel for the second CMTS, and 
 store registration data obtained from the second CMTS. 
 
 
     
     
       34. The cable modem of  claim 33 , wherein the registration data further comprises an IP address that is used for communications through both the working CMTS and the protection CMTS. 
     
     
       35. The cable modem of  claim 33 , wherein the registration data includes (i) at least one of a transmission power, transmission time slots, and or a transmission frequency at which the cable modem is to communicate with the protection CMTS should the cable modem service with the working CMTS become unavailable, and (ii) similar transmission data for communication with the working CMTS. 
     
     
       36. The cable modem of  claim 33 , wherein the cable modem is designed or configured to implement DOCSIS. 
     
     
       37. The cable modem of  claim 36 , wherein the cable modem is designed or configured to send a channel change response in response to a downstream channel change request from the working CMTS. 
     
     
       38. A protection CMTS for providing redundancy for a cable network having a working CMTS that provides normal service to a cable modem, the protection CMTS taking over service to the cable modem should service from the working CMTS become unavailable, the protection CMTS comprising:
 (a) means for at least partially registering the cable modem with the protection CMTS prior to the working CMTS becoming unavailable; and 
 (b) means for, prior to the working CMTS becoming unavailable, assuming a protection state in which the protection CMTS can take over service of the cable modem should its service with the working CMTS become unavailable, 
 wherein the cable modem is informed of an upstream channel of the protection CMTS. 
 
     
     
       39. The method of  claim 1 , further comprising:
 after registration, but before the protection CMTS takes over, requesting that the cable modem change one or more parameters to optimize communication on a path between the protection CMTS and the cable modem. 
 
     
     
       40. The method of  claim 11 , further comprising:
 after registration, but before the protection router takes over, requesting that the cable modem change one or more parameters to optimize communication on a path between the protection router and the cable modem. 
 
     
     
       41. The cable modem of  claim 33 , wherein the cable modem is configured to be informed of the second CMTS's upstream charnel by the first CMTS. 
     
     
       42. The CMTS of claim 16, wherein at least one of the one or more processors of the CMTS is configured to obtain the cable modem IP address in a communication from the cable modem. 
     
     
       43. The CMTS of claim 16, wherein at least one of the one or more processors of the CMTS is configured to obtain the cable modem IP address in a communication from the working CMTS. 
     
     
       44. The CMTS of claim 13, wherein the service provided to the cable modem includes telephony service. 
     
     
       45. The CMTS of claim 17, wherein the communication includes instructions to the cable modem to adjust at least one of a transmission power or a transmission frequency at which the cable modem is to communicate with the protection CMTS should service with the working CMTS become unavailable. 
     
     
       46. The CMTS of claim 13, wherein at least one of the one or more processors are configured further to:
 determine that the working CMTS's service to the cable modem has or will become unavailable; and   take over service to the cable modem.   
     
     
       47. The CMTS of claim 13, wherein at least one of the one or more processors are configured further to:
 after registration, but before the protection CMTS takes over, request that the cable modem change one or more parameters to optimize communication on a path between the protection CMTS and the cable modem.   
     
     
       48. A CMTS designed or configured to act as a protection CMTS for a cable network having a working CMTS that provides normal service to a cable modem and the protection CMTS which takes over service to the cable modem should service from the working CMTS become unavailable, the CMTS comprising:
 one or more processors; and   memory in communication with at least one of the one or more processors;   wherein at least one of the one or more processors are configured to   (a) at least partially register the cable modem with the protection CMTS prior to the working CMTS becoming unavailable;   (b) thereafter, determine that the working CMTS's service to the cable modem has become unavailable; and   (c) take over service to the cable modem,   wherein the cable modem is informed of an upstream channel of the protection CMTS.   
     
     
       49. The CMTS of claim 48, wherein at least one of the one or more processors of the CMTS is configured to take over service by using registration parameters for the cable modem, which registration parameters were previously provided to the protection CMTS. 
     
     
       50. The CMTS of claim 49, wherein the registration parameters include an IP address for the cable modem, which IP address is used in communications between the cable modem and the working CMTS. 
     
     
       51. The CMTS of claim 49, wherein the registration parameters include at least one of a transmission power, a transmission frequency, or transmission time slots at which the cable modem is to communicate with the protection CMTS should the cable modem service with the working CMTS become unavailable. 
     
     
       52. The CMTS of claim 48, wherein the service provided to the cable modem includes telephony service. 
     
     
       53. The CMTS of claim 48, wherein at least one of the one or more processors of the CMTS is configured to determine that the working CMTS's service to the cable modem has become unavailable comprises receiving a communication indicating such unavailability from at least one of the cable modem or the working CMTS. 
     
     
       54. The CMTS of claim 53, wherein the communication indicating unavailability is a downstream channel change request. 
     
     
       55. The CMTS of claim 48, wherein at least one of the one or more processors are configured further to provide routing services to one or more cable modems in the cable network. 
     
     
       56. A method implemented on a cable modem designed or configured for use on a cable network having a first CMTS that provides normal service to a cable modem and a second CMTS which takes over service to the cable modem should the service from the first CMTS become unavailable, the method comprising:
 registering with the first CMTS;   receiving information about an upstream channel for the second CMTS;   registering with the second CMTS using the upstream channel for the second CMTS; and   storing registration data obtained from the second CMTS.   
     
     
       57. The method of claim 56, wherein the registration data includes an IP address that is used for communications through both the working CMTS and the protection CMTS. 
     
     
       58. The method of claim 56, wherein the registration data includes (i) at least one of a transmission power, transmission time slots, or a transmission frequency at which the cable modem is to communicate with the protection CMTS should the cable modem service with the working CMTS become unavailable, and (ii) similar transmission data for communication with the working CMTS. 
     
     
       59. The method of claim 56, wherein the cable modem is designed or configured to implement DOCSIS. 
     
     
       60. The method of claim 59, wherein the cable modem is designed or configured to send a channel change response in response to a downstream channel change request from the working CMTS. 
     
     
       61. The method of claim 56, wherein the cable modem is configured to be informed of the second CMTS's upstream channel by the first CMTS. 
     
     
       62. A computer program product comprising a machine readable medium on which is stored program instructions for a method implemented on a cable modem designed or configured for use on a cable network having a first CMTS that provides normal service to a cable modem and a second CMTS which takes over service to the cable modem should the service from the first CMTS become unavailable, the program instructions comprising instructions for:
 registering with the first CMTS,   receiving information about an upstream channel for the second CMTS,   registering with the second CMTS using the upstream channel for the second CMTS, and   storing registration data obtained from the second CMTS.   
     
     
       63. A cable modem designed or configured for use on a cable network having a first CMTS that provides normal service to a cable modem and a second CMTS which takes over service to the cable modem should the service from the first CMTS become unavailable, the cable modem comprising:
 means for registering with the first CMTS;   means for receiving information about an upstream channel for the second CMTS;   means for registering with the second CMTS using the upstream channel for the second CMTS; and   means for storing registration data obtained from the second CMTS.