A field guide to the city
The map
Every network has a story. In Byte City, it starts with a seven-floor house.
From top to bottom
Seven floors, one house.
7
Layer 7
Application
The storefront
The storefront, the mail room, the Yellow Pages: where a person's request begins.
6
Layer 6
Presentation
The packing room
The packing room: label it, seal it, shrink-wrap it.
5
Layer 5
Session
The delivery window
The delivery window: open, maintain, close.
4
Layer 4
Transport
The numbered doors
The truck (TCP) and the bullhorn (UDP), and the numbered doors (ports).
3
Layer 3
Network
The road atlas
The mail bag with the address tag, the road atlas, the gate at the end of the street.
2
Layer 2
Data Link
The switch-depot
The crate with two brass plaques, sorted at the switch-depot.
1
Layer 1
Physical
The road
The road: copper, glass tube, or radio.
The language of the city
Byte City glossary
The picture on the left. The networking term on the right.
HouseA host
Lawn signIP address
Brass plaqueMAC address
Garage doorPort
TruckTCP
BullhornUDP
Yellow PagesDNS
Leasing officeDHCP
GateDefault gateway
Switch-depotSwitch
IntersectionRouter