Method of using routing protocols to reroute packets during a link failure
First Claim
1. An improved first router that routes packets according to their logical network addresses, the first router being connected between a first link, a second bidirectional link, and a third link and ordinarily receiving packets addressed to a host on the third link via the first link, the improvement comprising:
- a first link failure detector for detecting a failure in the first link; and
a routing protocol message provider which responds to a detected failure by sending a sequence of routing protocol messages on the second bidirectional link, the sequence being responded to by a second router that is accessible via the second bidirectional link and that ordinarily routes packets addressed to the host via the first link, the second router responding to the sequence by routing those packets via the second bidirectional link.
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0 Petitions
Accused Products
Abstract
The preferred embodiment of the present invention is 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. The invention includes: a cable television link failure detector connected to the cable television link; a message generator connected to the cable television link failure detector, where the message generator is configured to generate at least one message responsive to the cable television link failure detector; and a message transmitter connected to the message generator, where the 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.
17 Citations
42 Claims
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1. An improved first router that routes packets according to their logical network addresses, the first router being connected between a first link, a second bidirectional link, and a third link and ordinarily receiving packets addressed to a host on the third link via the first link, the improvement comprising:
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a first link failure detector for detecting a failure in the first link; and
a routing protocol message provider which responds to a detected failure by sending a sequence of routing protocol messages on the second bidirectional link, the sequence being responded to by a second router that is accessible via the second bidirectional link and that ordinarily routes packets addressed to the host via the first link, the second router responding to the sequence by routing those packets via the second bidirectional link. - View Dependent Claims (2)
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3. 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 link and a second link, said method comprising steps of:
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routing data through the first link from the second router to the first router;
detecting, at the first router, a failure of the first link from the second router to the first router;
generating at least one message at the first router responsive to detecting the failure of the first link;
transmitting the at least one message from the first router to the second router through the second link; and
routing data through the second link from the second router to the first router responsive to receiving the at least one message from the first router along the second link. - View Dependent Claims (4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. 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:
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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; and
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. - View Dependent Claims (15, 16)
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17. 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:
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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; and
routing data from the second router to the first router through the second communication path, responsive to changing at least one table. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29)
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30. A method for communicating data to an RF modem from a CATV head end, wherein the RF modem and the CATV head end are connected by an first communication path and a second communication path, the method comprising the steps performed in the RF modem of:
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receiving data communicated from the CATV head end to the RF modem over the first communication path;
determining that the first communication path has failed;
notifying the CATV head end to communicate data from the CATV head end to the RF modem over the second communication path; and
receiving data communicated from the CATV head end to the RF modem over the second communication path. - View Dependent Claims (31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42)
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Specification