Throughput

Throughput is rate (bits/time unit) at which bits transferred between sender/receiver

• Instantaneous: rate at given point in time
• Average: rate over longer period of time

Bottleneck link: link on end-to-end path that constrains end-to-end throughput

Scenario

Suppose there are 10 connections all sharing a backbone bottleneck link

• $R_C$ is the client’s bandwidth, $R_S$ is the server’s, $R$ is the backbone link’s
• Then the per-connection throughput is $\min (R_C,R_S,R/10)$
• In practice, the bottleneck is often $R_C$ or $R_S$ rather than $R$

Throughput vs Bandwidth

Bandwidth vs Throughput

• Bandwidth is the capacity at a particular point
• Throughput is the reality, the rate at which data is actually transmitted

When data is being transmitted between two links, the throughput is whatever the smaller bandwidth is (the bandwidth of the bottleneck link)

TODO check if this understanding of throughput is right

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