Traffic metering in data networks

Abstract

Methods and apparatus are provided for metering data packets having a plurality of different packet lengths in a data communications network. A token count T C is incremented at a token increment rate CIR subject to an upper limit CBS on the token count. On arrival of a packet of length L tokens, it is determined if both T C >0 and T C +n≧L, where n is a defined number of tokens. If so, the data packet is categorized as in profile and L tokens are subtracted from the token count T C . Otherwise the data packet is categorized out of profile. In some embodiments, n is set to a value in the range 0<n<(L max −1) where L max is the maximum length of data packets to be metered. In other embodiments, n is varied in the range 0≦n≦(L max −1) in dependence on at least one feedback signal indicating an operational condition in the network. The degree of conformance of the metering system is determined by the parameter n, whereby the conformance level can be tuned to particular multi-length packet environments.

1 . A method for metering data packets, having a plurality of different packet lengths, in a device of a data communications network, the method comprising: 
 incrementing a token count T C  at a token increment rate subject to an upper limit on the token count;    in response to receipt of a packet of length L tokens, determining if both T C >0 and T C +n≧L, where n is a defined number of tokens and 2<n<(L max −1) where L max  is the maximum length of data packets to be metered;    if so, marking the data packet as in profile and subtracting L tokens from the token count; and    if not, marking the data packet as out of profile.    
   
   
       2 . Apparatus for metering data packets, having a plurality of different packet lengths, in a data communications network, the apparatus comprising: 
 a token counter for maintaining a token count T C ; and    control logic configured to increment the token count T C  at a token increment rate subject to an upper limit on the token count in response to receipt of a packet of length L tokens, to determine if both T C >0 and T C +n≧L, where n is a defined number of tokens and 2<n<(L max −1) where L max  is the maximum length of data packets to be metered.    
   
   
       3 . Apparatus for processing data packets in a data communications network, the apparatus including a network device; and at least one meter for metering data packets processed by the device, said meter comprising a token counter for maintaining a token count T C ; and 
 control logic configured to increment the token count T C  at a token increment rate subject to an upper limit on the token count in response to receipt by the meter of a packet of length L tokens, to determine if both T C >0 and T C +n≧L, where n is a defined number of tokens and 2<n<(L max −1) where L max  is the maximum length of data packets to be metered.    
   
   
       4 . A data communications network comprising a plurality of network devices including at least one apparatus according to  claim 3 .  
   
   
       5 . A computer program product comprising a computer readable medium having embodied therein computer readable program code for causing a processor of a network device to perform a method for metering data packets having a plurality of different packet lengths, the computer readable program code including instructions for incrementing a token count T C  at a token increment rate subject to an upper limit on the token count; and 
 in response to receipt of a packet of length L tokens, determining if both T C >0 and T C +n≧L, where n is a defined number of tokens and 2<n<(L max −1) where L max  is the maximum length of data packets to be metered.    
   
   
       6 . The apparatus of  claim 2  further including if both conditions are met, to categorize the data packet as in profile and subtract L tokens from the token count; and 
 if not, to categorize the data packet as out of profile.    
   
   
       7 . The apparatus of  claim 3  further including if both conditions are met, to categorize the data packet as in profile and subtract L tokens from the token count; and 
 if not, to categorize the data packet as out of profile.    
   
   
       8 . The computer program product of  claim 5  further including instructions for categorizing the data packet as in profile and subtracting L tokens from the token count if both conditions are not met; and 
 instructions for categorizing the data packet as out of profile if not met.    
   
   
       9 . The method of  claim 1  further including stacking data packets so marked in a queue to await a next stage of predefined processing.  
   
   
       10 . The method of  claim 1  further including discarding from further processing data packets so marked as being out of profile.  
   
   
       11 . The method of  claim 10  further including stacking in a queue, data packets so marked as being in profile for further predefined processing.