	US 7,573,828 B2
	Fault isolation system and method
Neal Y. Nakamura, Honolulu, Hi. (US); and Earl M. Ishihara, Mililani, Hi. (US)
Assigned to Time Warner Cable, Inc., New York, N.Y. (US)
Filed on Jan. 31, 2008, as Appl. No. 12/23,078.
Application 12/023078 is a continuation of application No. 11/040391, filed on Jan. 21, 2005, granted, now 7,366,102.
Prior Publication US 2008/0117828 A1, May 22, 2008
This patent is subject to a terminal disclaimer.
Int. Cl. H04L 12/26 (2006.01)

U.S. Cl. 370—244 [370/250]

9 Claims

1. A system for isolating a fault in a cable network comprising:

a correlator, wherein the correlator comprises instructions for:

identifying non-responsive subscriber devices connected to the network through an active device;

obtaining a device identifier of the last active device through which each non-responsive subscriber device connects to the network, wherein the device identifier comprises:

a first character field comprising a hub identifier;

a second character field concatenated with the first character field, wherein the second character field comprises a node identifier;

subsequent character fields concatenated with the second character field, wherein a subsequent character field comprises a cascade number and wherein the value of the cascade number identifies a branch of the network relative to a device from which the branch emanates;

a first separator interposed into the device identifier before a subsequent character field indicative of a branch from a first level active device that terminates at a second level active device; and

a second separator interposed into the device identifier before a subsequent character field indicative of a branch from an active device that terminates at a passive device;

correlating the last active device identifiers associated with the non- responsive subscriber devices to identify a furthest upstream active device as a likely common cause of the non-responsiveness of the non-responsive subscriber devices.