Dynamic bandwidth estimation and adaptation in high speed packet switching networks
First Claim
1. A method of dynamically adapting access to a packet switching communication network comprising a plurality of nodes interconnected with transmission links source nodes and destination nodes for the transmission of digital traffics from source nodes to destination nodes, said method comprising the steps of:
- measuring the mean bit rate mn of signals from said source node;
controlling the flow of said traffics from said source node into the network by means of a leaky bucket control circuit;
measuring the loss probability δ
n of packets introduced into said network by said leaky bucket control circuit;
defining adaptation regions on the values of said simultaneous mean bit rate and loss probability measurements;
in response to a pair of said mean bit rate and loss probability measurements falling outside said adaptation regions, modifying the bandwidth allocated to a connection between said source node and said destination node;
wherein said step of defining adaptation regions comprises the step of;
determining boundaries on values of said mean bit rate mn and said packet loss probability ξ
n satisfying the relationships;
space="preserve" listing-type="equation">ξ
.sub.n =ξ
.sub.H,ξ
.sub.n =ξ
.sub.L,m.sub.n =γ
, where;
ξ
H, ξ
L are constants having an order of magnitude range of values around said loss probability measurements,ξ
L <
ξ
Hγ
is the amount of bandwidth allocated to the connectionand wherein said step of modifying the bandwidth allocated to the connection comprises the steps of;
increasing the amount of bandwidth γ
allocated when;
space="preserve" listing-type="equation">ξ
.sub.n >
ξ
.sub.Hdecreasing the amount of bandwidth γ
allocated when;
space="preserve" listing-type="equation">ξ
.sub.n <
ξ
.sub.L and m.sub.n <
γ
.
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Accused Products
Abstract
A system adapts access to a packet switching network. A dynamic bandwidth adaptation continuously monitors the mean bit rate of a signal source and the loss probability of a connection in the network. A filtering means removes noise from the mean bit rate and loss probabilty. A test means determine whether the values fall within a pre-defined acceptable adaptation region in a mean bit rate, loss probability plane. Triggering means initiate bandwidth adaptation procedures when the values fall outside of the region which in turn, initiate means for acquiring a new connection bandwidth, and determining new parameters for the adaptation mechanism.
74 Citations
9 Claims
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1. A method of dynamically adapting access to a packet switching communication network comprising a plurality of nodes interconnected with transmission links source nodes and destination nodes for the transmission of digital traffics from source nodes to destination nodes, said method comprising the steps of:
-
measuring the mean bit rate mn of signals from said source node; controlling the flow of said traffics from said source node into the network by means of a leaky bucket control circuit; measuring the loss probability δ
n of packets introduced into said network by said leaky bucket control circuit;defining adaptation regions on the values of said simultaneous mean bit rate and loss probability measurements; in response to a pair of said mean bit rate and loss probability measurements falling outside said adaptation regions, modifying the bandwidth allocated to a connection between said source node and said destination node; wherein said step of defining adaptation regions comprises the step of; determining boundaries on values of said mean bit rate mn and said packet loss probability ξ
n satisfying the relationships;
space="preserve" listing-type="equation">ξ
.sub.n =ξ
.sub.H,ξ
.sub.n =ξ
.sub.L,m.sub.n =γ
,where; ξ
H, ξ
L are constants having an order of magnitude range of values around said loss probability measurements,ξ
L <
ξ
Hγ
is the amount of bandwidth allocated to the connectionand wherein said step of modifying the bandwidth allocated to the connection comprises the steps of; increasing the amount of bandwidth γ
allocated when;
space="preserve" listing-type="equation">ξ
.sub.n >
ξ
.sub.Hdecreasing the amount of bandwidth γ
allocated when;
space="preserve" listing-type="equation">ξ
.sub.n <
ξ
.sub.L and m.sub.n <
γ
. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A system for adapting access to a packet switching network comprising:
- a) a dynamic bandwidth adaptation mechanism which continuously monitors the mean bit rate of a signal source and the loss probability of a connection in the network;
b) means for filtering the mean bit rate and loss probablilty values to remove noise; c) means for testing whether the values fall within a pre-defined acceptable adaptation region in a mean bit rate, loss probability plane; d) means for triggering bandwidth adaptation procedures when values fall outside of the region; and e) means for acquiring a new connection bandwidth, and determining new parameters for the adaptation mechanism when the values fall outside of the region.
- a) a dynamic bandwidth adaptation mechanism which continuously monitors the mean bit rate of a signal source and the loss probability of a connection in the network;
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8. A packet communication network comprising:
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a) a plurality of nodes; b) means for interconnecting source nodes and destination nodes for establishing a connection having an allocated bandwidth for the transmission of digital packets of information from a source node to a destination node in the network; c) a dynamic access control mechanism; d) a leaky bucket control circuit for controlling a flow of signals from a source node into the network; e) first means for measuring a mean bit rate of the signals to the leaky bucket and providing a first input to the dynamic access control mechanism; f) means for measuring first and second loss probabilities for packets launched by the leaky bucket control circuit into the network and providing a second input to the dynamic access control mechanism; g) means for establishing limits on the values of simultaneous pairs of measurements from said first means and said second loss probability; h) means responsive to a pair of mean bit rate and second loss probability measurements falling outside of said limits for modifying the bandwidth allocated to the connection; and i) supervising means coupled to the dynamic access control mechanism for calculating a fairness variable used in controlling requests for bandwidth allocation modifications among a plurality of connections.
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9. In a packet communication network including a plurality of interconnected source nodes and destination nodes for establishing a connection having an allocated bandwidth for the transmission of digital packets of information from a source node to a destination node in the network, a method for dynamically modifying bandwidth allocated to the connection to the network comprising the steps of:
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a) controlling a flow of signals from a source node into the network through a leaky bucket control circuit; b) measuring a mean bit rate of the signals to the leaky bucket and providing a first input to a dynamic access control mechanism; c) measuring first and second loss probabilities for packets launched by the leaky bucket control circuit into the network and providing a second input to the dynamic access control mechanism; d) establishing limits on the values of simultaneous pairs of measurements from the mean bit rate and said second loss probability; e) modifying the bandwidth allocated to the connection using the dynamic access control mechanism according to a pair of mean bit rate and second loss probability measurements falling outside of said limits; and f) supervising the modification of bandwidth allocations among a plurality of connections.
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Specification