Used in packet switched computer networks & Telecommunication Networks.
Define upper limits on bandwidth & burstiness on data transmission
Analogy of fixed capacity bucket into which tokens are added at a fixed rate
Used in application to provide download bandwidth limits in software applications like torrent & download managers.
To control the download speed on 3G network by our cellular provider.
Throttling mechanism – E.g. to limit the amount of web requests sent to a server. If there are too many submissions for a request, then the extra requests are queued until the resource becomes available.
method is executed no more than M times in a sliding window of N seconds.
It is about regulating average rate of data flow. May be termed as Traffic shaping
Method of congestion control by providing shape to data flow before entering packet into network
The packet does not conform if there are insufficient tokens in the bucket, and the contents of the bucket are not changed. Non-conformant packets can be treated in various ways:
They may be dropped.
They may be enqueued for subsequent transmission when sufficient tokens have accumulated in the bucket.
They may be transmitted, but marked as being non-conformant, possibly to be dropped subsequently if the network is overloaded.
Sender & carrier negotiate a traffic pattern
Token Bucket
Leaky Bucket
Leaky Bucket
Control rate in a network
Implemented as a single server queue with constant service time
If bucket full, packets are discarded
Input rate may vary but output rate remains constants
Saves busty traffic into fixed rate traffic by averaging the data rate.
Algorithm –
Initialize counter to ‘n’ at every tick of clock
If n is greater than size of packet in front of queue, send the packet into the network & decrement the counter by size of the packet. Repeat until n is less than size of packet
Reset the counter & go to step 1
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