markdowns
Computer Networks
A quick guide through computer networks
The internet (network of networks)
Interconnected ISPs
- hosts => end systems
Packet switches => forward packets
- routers, switches
Comunication Links
- fiber, copper, radio, satellite
- transmition rate: bandwith
Networks
- collection of devices, routers, links: managed by an organization
Protocols Define the format, order of messages sent and received among network entities, and actions taken on msg transmission, receipt.
- control sending, receiving of messages
- HTTP, streaming, video, skype, TCP, IP, Wifi, 4G, Ethernet
A closer look at internet structure
Network edge
- hosts: clients and servers
- servers often in data centers
Computer Networks
A quick guide through computer networks
The internet (network of networks)
Interconnected ISPs
- hosts => end systems
Packet switches => forward packets
- routers, switches
Comunication Links
- fiber, copper, radio, satellite
- transmition rate: bandwith
Networks
- collection of devices, routers, links: managed by an organization
Protocols Define the format, order of messages sent and received among network entities, and actions taken on msg transmission, receipt.
- control sending, receiving of messages
- HTTP, streaming, video, skype, TCP, IP, Wifi, 4G, Ethernet
A closer look at internet structure
Network edge
- hosts: clients and servers
- servers often in data centers
Access networks, physical media
- Wired, wireless comunication links
Cable based access
Frequency division multiplexing (FDM): different channels transmitted in different frequency bands
- HFC : hybrid fiber coax
- asymmetric: up to 40 Mbps - 1.2 Gbs downstream and 30 - 100 Mbps upstream
- Network of cable, fiber attaches homes to ISP router
Digital subscriber line (DSL)
- Use existing telephone line to central office DSLAM
- 24 - 52 Mbps dedicated downstream
- 3.5 - 16 Mbps dedicated upstream
Home Networks
Wireless access networks
- Shared wireless access network connects end system to router via base station aka access point
Network core
- Interconnected routers
- Network of networks