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How Long Will It Take

Lesson 6 of 32 in Coddy's The OSI Model course.

Two different things make a link feel fast. Bandwidth is how many bits fit per second; latency is how long one bit takes to arrive. A satellite link can have huge bandwidth and terrible latency at the same time.

For bulk transfers, bandwidth dominates, and the math is one line: convert the file to bits, divide by the link speed. A 100 MB file is 800 megabits; over a 100 Mbps link that is 800 / 100 = 8 seconds, at best.

Real transfers run slower because of the overhead the upper layers add, which you will meet layer by layer in this course.

Challenge

Beginner

Compute the best-case time, in whole seconds, to move a 100 MB file over a 100 Mbps link, and print just the number.

Expected output:

Try it yourself

Terminal

All lessons in The OSI Model

1Why Layers

The Layering Idea Seven Layers Numbers and Names Recap - The Stack

4The Network Layer

IP and TTL Ping and ICMP Routing Tables Recap - Layer Three

7Encapsulation

Wrapping Data Headers Everywhere Reading a Capture Recap - Follow the Wrap

2The Physical Layer

Bits on a WireHow Long Will It TakeDuplex and Collisions

5Transport: TCP and UDP

Ports The TCP Handshake TCP vs UDP Sockets in Action Recap - Layer Four

8The Journey of a Packet

A Click Happens Crossing the Networks Arriving and Climbing Recap - End to End

3Data Link and MACs

Frames and MACs Reading a MAC ARP Recap - Layer Two

6The Upper Layers

Session and Presentation The Application Layer Watching the Layers Recap - Top of the Stack

Practice on your own: Terminal playground