Phy bandwidth estimation from backpressure patterns

Abstract

The present invention provides a system and method of determining available bandwidth at a physical layer (PHY) device at a server on a broadband network. A link layer controller of a master administrator adaptively polls a PHY device over a set of time intervals. During polling, the controller places a PHY device's address on a line of a bus and awaits a response from the PHY device. Based upon the response from the PHY device, the administrator can determine whether the PHY device has available bandwidth. The link layer controller uses this information to recalculate its polling scheme to better make use of the available bandwidth over the shared transmission medium to which each PHY device in the network is attached.

1 . A method for determining available bandwidth at a physical layer (PHY) device at a network administration server, the method comprising the steps of:
 polling by a controller said PHY device at predetermined time intervals;   receiving at said administrator a series of responses from said PHY device; and   determining available bandwidth at said PHY device based upon said responses.   
   
   
       2 . The method of  claim 1 , wherein said polling comprises transmitting an inquiry as to the status of an incoming packet buffer of said PHY device. 
   
   
       3 . The method of  claim 2 , wherein said responses from said PHY device are indicative of the current status of said incoming packet buffer. 
   
   
       4 . The method of  claim 1  further comprising the steps of:
 comparing said responses to determine an optimized time interval; and   polling said PHY device at said optimized time interval.   
   
   
       5 . The method of  claim 4 , wherein said optimized time interval is determined based upon the current performance level of said PHY device. 
   
   
       6 . The method of  claim 5 , wherein said performance level of said PHY device is determined from the available bandwidth at said PHY device. 
   
   
       7 . The method of  claim 6 , wherein said PHY device is attached to a common bus shared with a plurality of other PHY devices. 
   
   
       8 . The method of  claim 7 , wherein said PHY device and said plurality of other PHY devices are ports for connecting nodes of a broadband network. 
   
   
       9 . A system for determining available bandwidth at a physical layer (PHY) device at a network administration server comprising:
 a controller for polling said PHY device at predetermined time intervals;   a PHY device operably connected to said administrator for responding to said polling with a series of responses; and   a response measurement unit for receiving said responses from said PHY device and determining available bandwidth at said PHY device based upon said responses.   
   
   
       10 . The system of  claim 9 , wherein said polling comprises transmitting an inquiry as to the status of an incoming packet buffer of said PHY device. 
   
   
       11 . The system of  claim 10 , wherein said responses from said PHY device are indicative of the current status of said incoming packet buffer. 
   
   
       12 . The system of  claim 9  wherein said response measurement unit is further programmed to compare said responses to determine an optimized time interval and instruct said administrator to poll said PHY device at said optimized time interval. 
   
   
       13 . The system of  claim 12 , wherein said optimized time interval is determined based upon the current performance level of said PHY device. 
   
   
       14 . The system of  claim 13 , wherein said performance level of said PHY device is determined from the available bandwidth at said PHY device. 
   
   
       15 . The system of  claim 14 , wherein said PHY device is attached to a common bus shared with a plurality of other PHY devices. 
   
   
       16 . The system of  claim 15 , wherein said PHY device and said plurality of other PHY devices are ports for connecting nodes of a broadband network.