Course content
The seven chapters follow a packet down the protocol stack, from the application layer to the link layer, and then out to the data centre and the wireless edge.
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Chapter 1
Computer Networks and the Internet
What is the Internet made of, and where does the time go?
Hosts, links, packet switching, the four delays, and layering.
Learning outcomes
- Describe what the Internet is made of, and what it does for the programs running on it.
- Identify hosts, access networks, and the physical media that connect them.
- Explain packet switching, store-and-forward, and how a queue forms.
- Explain why the Internet is a hierarchy of separately owned, interconnected networks.
- Compute the four delays, traffic intensity, and end-to-end throughput.
- Explain layering and encapsulation as the way a huge system stays manageable.
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Chapter 2
The Application Layer
How does your program talk to a program on another machine?
The Web, naming, mail, sockets, and getting content to millions of people.
Learning outcomes
- Explain how a network application is built from processes, sockets, and a transport service.
- Read a real HTTP request and response, and say what every line of it does.
- Trace a name through the Domain Name System hierarchy to an address.
- Compare the push protocol that sends mail with the pull protocols that fetch it.
- Compute response times, link utilization, and how long a file takes to reach many people.
- Write a client and a server over both transport protocols, and serve a web page from your own code.
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Chapter 3
The Transport Layer
How do bytes arrive intact over a network that loses them?
Multiplexing, reliable transfer, connection setup, and congestion control.
Learning outcomes
- Explain what a transport protocol adds to a network that only carries packets between hosts.
- Trace an arriving segment to the one socket it belongs to, under both transport protocols.
- Read a datagram header, and compute the checksum that says whether it arrived intact.
- Build a reliable protocol over a channel that corrupts and loses, and compute what each version costs.
- Dissect a connection: how it opens, how it recovers a lost segment, and how it is kept from flooding the receiver.
- Judge whether a congestion-control algorithm shares a bottleneck fairly, and what happens to one that does not.
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Chapter 4
The Network Layer and Routing
How does a packet find a machine it has never met?
Addresses, forwarding, routing algorithms, and what is inside a router.
Learning outcomes
- Distinguish the job of deciding where traffic should go from the job of moving it there.
- Trace a datagram through a router, from the arriving bit to the outgoing link.
- Compute a subnet plan for a given address block, and read any address as a network and a host.
- Derive the paths a network settles on, by both families of routing algorithm.
- Explain why routing between networks is decided by policy rather than by distance.
- Program a forwarding table as match-plus-action rules, and say what moves when the control plane is centralized.
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Chapter 5
Link Layer Services and Protocols
How do machines sharing one wire take turns without colliding?
Error detection, multiple access, Ethernet, switches, and building a local network.
Learning outcomes
- Explain what a link-layer protocol must do that no layer above it can do for itself.
- Compute the check bits that let a receiver tell a corrupted frame from an intact one.
- Compare the three families of protocol that let many machines share one channel.
- Trace a frame across two subnets, naming which addresses change at each hop and which do not.
- Distinguish a switch from a router by what each one reads, learns, and forwards.
- Design a local network with separated broadcast domains, and defend the boundaries you drew.
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Chapter 6
Cloud Networking Principles
What changes when the network lives inside one building?
Data center topologies, sharing infrastructure, and the links between data centers.
Learning outcomes
- Explain what changes about a network when one operator owns every link, host and switch in it.
- Compute the oversubscription and bisection bandwidth of a data center topology, and say what it can carry.
- Justify the transport and link mechanisms a data center uses in place of the ones the Internet uses.
- Isolate one tenant's traffic on a fabric shared by thousands, and say what enforces the boundary.
- Plan the connection between two data centers a continent apart, and say what the distance costs.
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Chapter 7
Wireless Communications and Mobility
What breaks when the wire is gone and the host moves?
Wireless links, Wi-Fi network design, and staying reachable while moving.
Learning outcomes
- Compute what a link's signal-to-noise ratio does to its error rate and to the bit rate it can sustain.
- Trace a station from powering on to sending its first frame, and say what it did at each step.
- Design a wireless network for a floor of a building, and defend the channel plan you chose.
- Describe the elements of a cellular network and the state each one holds about a device.
- Explain how a packet reaches a host that has moved, and what breaks if nothing is done about it.