Chapter 1:
● What is the internet? “Nuts and bolts”
“network of networks”
○ The Internet is a network of networks,
consisting of billions of devices like
mobile networks, home networks, and
datacenter networks.
Key components:
● Packet switches (routers, switches) that forward data.
● Communication links (fiber, copper, radio, satellite) that
define the transmission rate (bandwidth).
● Hosts = end systems (devices running network apps).
● Network is a collection of devices managed by an
organization
Internet standards
● RFC: Request for Comments
● IETF: Internet Engineering Task Force
The Internet: a “service” view
Infrastructure: provides: services to applications: ( Web, streaming video, social media)
provides programming interface to distributed applications:
● “hooks” allowing sending/receiving apps to “connect” to, use Internet Transport service
● provides service options, analogous to postal service
● What is a protocol? The format, order of messages sent and received among network organization,
and actions taken on msg transmission, receipt
○ Protocols govern communication between computers.Control sending, receiving of
messages
○ Examples include HTTP (web), TCP/IP, WiFi, and Ethernet.
Network edge: hosts, access network, physical media
hosts: clients and servers( servers are often in data center)
Access network, physical media: wired , wireless communication links
Network core: interconnected routers, network of networks
, How to connect end systems to edge routers?
residential access, nets institutional access networks (school, company) mobile access networks (WiFi,
4G/5G)
frequency division multiplexing (FDM): different
channels transmitted in different frequency bands
Access networks: cable‐based access
HFC: hybrid fiber coax
asymmetric: up to 40 Mbps – 1.2
Gbs downstream transmission rate,
30‐100 Mbps upstream transmission
rate
network of cable, fiber attaches
homes to ISP router
• homes share access network to
cable headend
Access networks: digital subscriber line (DSL)
use existing telephone line to central office DSLAM
● data over DSL phone line goes to Internet
● voice over DSL phone line goes to telephone net
○ 24‐52 Mbps dedicated downstream transmission rate(from the Internet to the user)
○ 3.5‐16 Mbps dedicated upstream transmission rate(from the user to the Internet)
Wireless access network;base station aka “access point”
● What is the internet? “Nuts and bolts”
“network of networks”
○ The Internet is a network of networks,
consisting of billions of devices like
mobile networks, home networks, and
datacenter networks.
Key components:
● Packet switches (routers, switches) that forward data.
● Communication links (fiber, copper, radio, satellite) that
define the transmission rate (bandwidth).
● Hosts = end systems (devices running network apps).
● Network is a collection of devices managed by an
organization
Internet standards
● RFC: Request for Comments
● IETF: Internet Engineering Task Force
The Internet: a “service” view
Infrastructure: provides: services to applications: ( Web, streaming video, social media)
provides programming interface to distributed applications:
● “hooks” allowing sending/receiving apps to “connect” to, use Internet Transport service
● provides service options, analogous to postal service
● What is a protocol? The format, order of messages sent and received among network organization,
and actions taken on msg transmission, receipt
○ Protocols govern communication between computers.Control sending, receiving of
messages
○ Examples include HTTP (web), TCP/IP, WiFi, and Ethernet.
Network edge: hosts, access network, physical media
hosts: clients and servers( servers are often in data center)
Access network, physical media: wired , wireless communication links
Network core: interconnected routers, network of networks
, How to connect end systems to edge routers?
residential access, nets institutional access networks (school, company) mobile access networks (WiFi,
4G/5G)
frequency division multiplexing (FDM): different
channels transmitted in different frequency bands
Access networks: cable‐based access
HFC: hybrid fiber coax
asymmetric: up to 40 Mbps – 1.2
Gbs downstream transmission rate,
30‐100 Mbps upstream transmission
rate
network of cable, fiber attaches
homes to ISP router
• homes share access network to
cable headend
Access networks: digital subscriber line (DSL)
use existing telephone line to central office DSLAM
● data over DSL phone line goes to Internet
● voice over DSL phone line goes to telephone net
○ 24‐52 Mbps dedicated downstream transmission rate(from the Internet to the user)
○ 3.5‐16 Mbps dedicated upstream transmission rate(from the user to the Internet)
Wireless access network;base station aka “access point”
