System for testing the upstream channel of a cable network

Abstract

A system for testing a portion of a cable network provides a pattern generator, addresser, forward error corrector, and comparator. The system is particularly adapted to testing the upstream channel in a cable network. The pattern generator generates a test signal. The addresser addresses the signal to a known server and also instructs the known server to return the test signal to the test system. The forward error corrector corrects errors introduced in the test signal in transmission from the known server to the test system. The comparator then compares the returned test signal to the originally transmitted test signal to determine the performance of the back channel. Preferably, the comparator uses a bit error rate test to determine the performance of the back channel.

1 . A device for determining the performance of a portion of a network comprising:
 a transmitter for receiving transmitter transmitted signals back from a remote receiver, the transmitter including:
 a forward error corrector for correcting errors introduced into the transmitter transmitted signals from the remote receiver to the transmitter; and 
 a comparator coupled to the forward error corrector for comparing a transmitted signal and the transmitter transmitted signals from the remote receiver for determining the performance of the portion of the network from the remote receiver to the transmitter. 
   
   
   
       2 . The device of  claim 1  further comprising a pattern generator connected to the network. 
   
   
       3 . The device of  claim 1  wherein the network is a cable network. 
   
   
       4 . The device of  claim 3  wherein the portion of the cable network is a local area cable loop. 
   
   
       5 . The device of  claim 4  wherein the device is coupled to an upstream channel of the local area cable loop. 
   
   
       6 . The device of  claim 5  wherein the device is also coupled to a forward channel of the local area cable loop. 
   
   
       7 . The device of  claim 1  further comprising an addresser connected to the network. 
   
   
       8 . The device of  claim 5  further comprising an addresser connected to the network. 
   
   
       9 . The device of  claim 1  further comprising:
 a pattern generator coupled to the comparator; and   an addresser coupled to the pattern generator.   
   
   
       10 . The device of  claim 3  further comprising a cable modem termination system in the network. 
   
   
       11 . The device of  claim 9  wherein:
 the network is a cable network;   the portion of the network is a local area cable loop; and   the addresser is coupled to an upstream channel of the local area cable loop.   
   
   
       12 . A device for determining the performance of a portion of a network comprising:
 a transmitter for receiving transmitter transmitted signals back from a remote receiver, the transmitter including:
 circuitry for correcting errors for correcting errors introduced into the transmitter transmitted signal from the remote receiver to the transmitter; and 
 circuitry for comparing a transmitted signal and the transmitter transmitted signals from the remote receiver for determining the performance of the portion of the network from the remote receiver to the transmitter, the circuitry for comparing connected to the circuitry for correcting errors. 
   
   
   
       13 . The device of  claim 12  further comprising circuitry for generating the transmitted signal connected to the network. 
   
   
       14 . The device of  claim 12  wherein the network is a cable network. 
   
   
       15 . The device of  claim 14  wherein the portion of the cable network is a local area cable loop. 
   
   
       16 . The device of  claim 12  further comprising circuitry for addressing a signal to the remote receiver, the circuitry for addressing connected to the network. 
   
   
       17 . The device of  claim 16  wherein the destination is a cable modem termination system. 
   
   
       18 . A memory device for storing program instructions comprising:
 a transmitter for receiving transmitter transmitted signals back from a remote receiver, the transmitter including:   a forward error corrector for correcting errors introduced into the transmitter transmitted signals from the remote receiver to the transmitter; and   a comparator coupled to the forward error corrector for comparing a transmitted signal and the transmitter transmitted signals from the remote receiver for determining the performance of a portion of a network from the remote receiver to the transmitter.   
   
   
       19 . The memory device of  claim 18  further comprising program instructions for a pattern generator connected to the network. 
   
   
       20 . The memory device of  claim 19  further comprising program instructions for an addresser connected to the network. 
   
   
       21 . The memory device of  claim 18  further comprising program instructions for an addresser connected to the network.