more, the congestion control scheme should be fair. Most congestion schemes aim at achieving max-min fairness. An allocation of transmission rates to sources is said to be max-min fair if:

No link in the network is congested

The rate allocated to a source

cannot be increased without decreasing the rate allocated to another source

, whose allocation is smaller than the rate allocated to the source

In other words, this principle postulates that increasing the transmission rate of one end-system necessarily decreases the transmission rate allocated to another end-system with an equal or smaller allocation.

To visualize the different rate allocations, it’s useful to consider the graph shown below. Consider hosts A and B that share a bottleneck link.