Patent US3709042A successfully refreshed from Google Patents.
Patent US6301223B1 successfully refreshed from Google Patents.
US6301223B1
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of using routing protocols to reroute packets during a link failure
Assignee: Cisco Technology Inc
•
Filing: 1997-04-11
•
Granted: 2001-10-09
•
Expires: 2017-04-11
Abstract
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 modem, 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.
Inventors
- 👤 Scott E. Hrastar
- 👤 Todd A. Merrill
- 👤 Roy A. Bowcutt
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 18:19
CPC Classifications
H; H04; H04H; H04H20/00; H04H20/65; H04H20/76; H04H20/77; H04H20/78; H04H20/79; H04L; H04L12/00; H04L12/28; H04L12/2801; H04L12/2854; H04L12/2856; H04L12/2863; H04L12/2869; H04L12/287; H04L12/2872; H04L12/2874; H04L12/54; H04L12/56; H04L12/5691; H04L12/5692; H04L41/00; H04L41/02; H04L41/0213; H04L41/06; H04L41/0654; H04L41/0663; H04L41/0677; H04L61/00; H04L61/50; H04L61/5007; H04L61/5014; H04L61/5061; H04L63/00; H04L63/08; H04L69/00; H04L69/40; H04L9/00; H04L9/40; H04N; H04N21/00; H04N21/20; H04N21/25; H04N21/258; H04N21/25808; H04N21/25816; H04N21/40; H04N21/41; H04N21/426; H04N21/42676; H04N21/60; H04N21/61; H04N21/6106; H04N21/6118; H04N21/6156; H04N21/6168; H04N7/00; H04N7/16; H04N7/173; H04N7/17309; H04H60/00; H04H60/76; H04H60/81; H04H60/82; H04H60/83; H04H60/84; H04L2101/00; H04L2101/60; H04L2101/604; H04L2101/618; H04L2101/622
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
213 words
A cable modem apparatus for reliably providing a personal computer access to the Internet through a cable television link and a public switched telephone network link, said apparatus comprising: a cable television link failure detector connected to the cable television link; a message generator connected to said cable television link failure detector, wherein said message generator is configured to generate at least one message responsive to said cable television link failure detector detecting cable television link failures; a message transmitter connected to said message generator, wherein said message transmitter is configured to transmit the at least one message through the public switched telephone network link to cause Internet communications to be communicated to the personal computer through the public switch telephone network link; a failure ended message generator connected to said cable television link failure detector, wherein said failure ended message generator is configured to generate failure ended messages responsive to said cable television link failure detector detecting cable television link failure endings; and a failure ended message transmitter connected to said failure ended message generator, wherein said failure ended message transmitter is configured to transmit failure ended messages through the public switched telephone network link to cause Internet communications to again be communicated to the personal computer through the cable television link.
Claim 2
Dependent Claim
213 words
A cable modem apparatus for reliably providing a personal computer access to the Internet through a cable television link and a public switched telephone network link, said apparatus comprising: a cable television link failure detector connected to the cable television link; a message generator connected to said cable television link failure detector, wherein said message generator is configured to generate at least one message responsive to said cable television link failure detector detecting cable television link failures; a message transmitter connected to said message generator, wherein said message transmitter is configured to transmit the at least one message through the public switched telephone network link to cause Internet communications to be communicated to the personal computer through the public switch telephone network link; a failure ended message generator connected to said cable television link failure detector, wherein said failure ended message generator is configured to generate failure ended messages responsive to said cable television link failure detector detecting cable television link failure endings; and a failure ended message transmitter connected to said failure ended message generator, wherein said failure ended message transmitter is configured to transmit failure ended messages through the public switched telephone network link to cause Internet communications to again be communicated to the personal computer through the cable television link.
Claim 3
Dependent Claim
36 words
The apparatus of claim 1 , wherein the message generated responsive to said cable television link failure detector detecting cable television link failures also causes a suspension of Internet communications communicated through the cable television link.
Claim 4
Dependent Claim
107 words
The apparatus of claim 1 , wherein said message generator configured to generate at least one message responsive to said cable television link failure detector detecting cable television link failures is further configured to generate messages as long as said cable television link failure detector detects cable television link failures, and said message transmitter configured to transmit the at least one message through the public switched telephone network link to cause Internet communications to be communicated to the personal computer through the public switch telephone network link is further configured to transmit messages as long as said cable television link failure detector detects cable television link failures.
Claim 5
Independent Claim
189 words
A method for routing data communicated to a first router from a second router, wherein the first router and the second router are connected by a first communication path and a second communication path, said method comprising steps of: routing data from the second router to the first router through the first communication path; receiving at the second router at least one message through the second communication path; determining from the at least one message that the first communication path has failed; changing at least one routing table responsive to receiving the at least one message through the second communication path; routing data from the second router to the first router through the second communication path, responsive to changing at least one table; receiving at least one network status message through the second communication path; determining from the at least one network status message the first communication path is operative, changing the at least one routing table responsive to determining that the first communication path is operative; and routing data from the second router to the first router through the first communication path, responsive to changing the routing tables.
Claim 6
Independent Claim
189 words
A method for routing data communicated to a first router from a second router, wherein the first router and the second router are connected by a first communication path and a second communication path, said method comprising steps of: routing data from the second router to the first router through the first communication path; receiving at the second router at least one message through the second communication path; determining from the at least one message that the first communication path has failed; changing at least one routing table responsive to receiving the at least one message through the second communication path; routing data from the second router to the first router through the second communication path, responsive to changing at least one table; receiving at least one network status message through the second communication path; determining from the at least one network status message the first communication path is operative, changing the at least one routing table responsive to determining that the first communication path is operative; and routing data from the second router to the first router through the first communication path, responsive to changing the routing tables.
Claim 7
Dependent Claim
35 words
The method of claim 4 , wherein the step of routing data through the second communicating path includes the second router suspending attempts to route data to the first router through the first communication path.
Claim 8
Dependent Claim
18 words
The method of claim 4 , wherein the at least one message is transmitted from the first router.
Claim 9
Dependent Claim
18 words
The method of claim 4 , wherein the at least one message includes a network routing protocol packet.
Claim 10
Dependent Claim
17 words
The method of claim 4 , wherein the at least one message includes a SNMP trap packet.
Claim 11
Dependent Claim
16 words
The method of claim 4 , wherein the at least one message includes a RIP packet.
Claim 12
Dependent Claim
23 words
The method of claim 4 , wherein the at least one message includes a table of operative communication paths to the first router.
Claim 13
Dependent Claim
26 words
The method of claim 4 , wherein the at least one message includes a table of paths distinct from operative communication paths to the first router.
Claim 14
Dependent Claim
35 words
The method of claim 4 , wherein: the data includes IP packets including IP addresses; the first router being connected to at least one personal computer; and the second router being connected to the Internet.
Claim 15
Dependent Claim
27 words
The method of claim 4 , wherein: the first communication path is a cable television RF communication path; and the second communication path is a telephone line.
Claim 16
Dependent Claim
36 words
The method of claim 4 , further including the step of maintaining a routine table for the second router, wherein responsive to determining a change of status of the first communication path the table is changed.
Claim 17
Dependent Claim
25 words
The method of claim 4 , wherein the first communication path is a unidirectional path and wherein the second communication path is a bidirectional path.
Claim 18
Dependent Claim
185 words
An improved CATV head end apparatus for reliably providing a personal computer access to the Internet through a cable television path and a public switched telephone network path, said apparatus comprising: a local area network (LAN); a modem pool, said modem pool comprising a plurality of modems connected to the public switched telephone network path and to said LAN, wherein said modem pool maintains a first table of addresses; a router connected to said LAN and to the Internet, wherein said router maintains a second table of addresses and routes data according to said second table; and a CATV communication manager connected to said LAN, said communication manager formatting data and producing output, wherein said communication manager maintains a third table of addresses, wherein the second table of addresses maintained by the router is changed responsive to a message received by the router through the LAN responsive to failure of the cable television path to the personal computer, and wherein the router routes data addressed to the personal computer to the modem pool responsive to the change of the second table maintained by the router.
Claim 19
Dependent Claim
185 words
An improved CATV head end apparatus for reliably providing a personal computer access to the Internet through a cable television path and a public switched telephone network path, said apparatus comprising: a local area network (LAN); a modem pool, said modem pool comprising a plurality of modems connected to the public switched telephone network path and to said LAN, wherein said modem pool maintains a first table of addresses; a router connected to said LAN and to the Internet, wherein said router maintains a second table of addresses and routes data according to said second table; and a CATV communication manager connected to said LAN, said communication manager formatting data and producing output, wherein said communication manager maintains a third table of addresses, wherein the second table of addresses maintained by the router is changed responsive to a message received by the router through the LAN responsive to failure of the cable television path to the personal computer, and wherein the router routes data addressed to the personal computer to the modem pool responsive to the change of the second table maintained by the router.
Claim 20
Dependent Claim
138 words
The apparatus of claim 16 , further comprising: a plurality of modulators connected to said communication manager, said modulators digitally modulating the output from said communication manager; and a combiner connected to said plurality of modulators, said combiner combining all output from said modulators and outputting said combined output through said cable television path; and a network management server connected to said LAN, wherein said network management server maintains a fourth table of addresses, wherein responsive to a message received by the modem pool through the public switched telephone network path responsive to failure of the cable television path to the personal computer, the first table of addresses maintained by the modem pool is changed and a message responsive to failure of the cable television path to the personal computer is transmitted to the router through the LAN.
References Cited (Backward Citations)
US3985962A
Cited
US4528589A
Cited
US4207431A
Cited
US4186380A
Cited
US4361851A
Cited
US4536791A
Cited
US4475123A
Cited
US4823386A
Cited
US4491983A
Cited
US4577224A
Cited
US4633462A
Cited
US4601028A
Cited
US4672533A
Cited
US4757460A
Cited
US4641304A
Cited
US4771391A
Cited
US5050213A
Cited
US4907224A
Cited
US4804248A
Cited
US4858224A
Cited
US5195092A
Cited
US5208665A
Cited
US4912721A
Cited
US5012469A
Cited
US4980886A
Cited
US5157657A
Cited
US5113499A
Cited
US5014125A
Cited
US5136690A
Cited
US5181107A
Cited
US5553287A
Cited
US5131041A
Cited
US5155590A
Cited
US5142690A
Cited
US5251324A
Cited
US5235619A
Cited
US5483631A
Cited
US5185860A
Cited
US5276789A
Cited
US5226120A
Cited
US5423006A
Cited
US5166931A
Cited
US5504921A
Cited
US5436909A
Cited
US5261044A
Cited
US5295244A
Cited
US5159592A
Cited
US5239540A
Cited
US5287351A
Cited
US5327554A
Cited
US5166930A
Cited
US5295140A
Cited
US5278833A
Cited
US5303234A
Cited
US5471399A
Cited
US5347304A
Cited
US5404505A
Cited
US5594798A
Cited
US5517618A
Cited
US5333183A
Cited
US5214390A
Cited
US5271041A
Cited
US5515418A
Cited
US5604528A
Cited
US5517488A
Cited
US5612959A
Cited
US5440555A
Cited
US5892812A
Cited
US5361259A
Cited
US5535403A
Cited
US5384777A
Cited
US5706277A
Cited
US5390181A
Cited
US5701465A
Cited
US5521925A
Cited
US5481542A
Cited
US5905714A
Cited
US5423003A
Cited
US5808886A
Cited
US5533108A
Cited
US5608446A
Cited
US5534913A
Cited
US5473599A
Cited
US5644706A
Cited
US5535206A
Cited
US5808671A
Cited
US5654746A
Cited
US5572640A
Cited
US5768280A
Cited
US5515361A
Cited
US5517502A
Cited
US5884284A
Cited
US5710884A
Cited
US5859852A
Cited
US5586121A
Cited
US5818845A
Cited
US5828655A
Cited
US5737316A
Cited
US5675732A
Cited
US5650994A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2004-10-08 | 2005-04-09 | 2005-10-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2008-10-08 | 2009-04-09 | 2009-10-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2012-10-08 | 2013-04-09 | 2013-10-09 | $7700.00 | Window Closed / Lapsed |