technology

Internet Technology

Store and Forward Networking (BITNET)

The idea of hopping between computers. Queues were formed. If a computer was down, the messages would remain on the disk until the next computer was back up.

Research Networks (1960s-1980s)

Packet Networks were used.

How to share one link so a long message doesn't block the flow?
How to deal with outages more dynamically.

The goal was Half a second to send a message across US.

The 20 year period was about Efficient Message Transmission like perfecting Packet Switching.

Packet Switching

Q: How do we move data simultaneously?

A: Break it into packets $\to$ label each packet for sequence $\to$ add a to and from address. $\therefore$ the receiver has everything they need to reconstruct the message even if the packets don't arrive in sequence.

This lead to a shared network infrastructure where the computers no longer had to have lots of disk space or compute power. They only needed to forward packets. A Router

$\therefore$ They only focus on packets. Not reliability.

Layered Network Protocol

This approach was taken to break the problem of designing a network into smaller subproblems.

The Layers
Application Layer (Web, email, File Transfer) application_layer
Transport Layer (TCP) transport_layer. Reliable Connections
Internetwork Layer(IP) ip. Simple, Scalable, Unreliable
Link Layer link_layer (Ethernet, WiFi). Physical Connections

We currently follow the TCP/IP model. Also existed was a 7 layer OSI (Open System Interconnection) model.

Domain Name System (DNS)

It converts user-friendly names like www.umich.edu to network-friendly names like 141.211.32.166. It can be thought of as being in between the IP layer and the Transport layer.

IP Addresses reflect on technical "geography". Read left $\to$ right
Domain names reflect on organizational structure. Read right $\to$ left.

So a Domain Name like www.sets.iub.edu.bd is read like: In Bangladesh $\to$ an educational institution $\to$ IUB $\to$ SETS school of IUB $\to$ www, a particular server at the school.

Ownership of the Domain names are also right to left. Only the domain owners of .edu can decide who can use the name. Once they allow an organization to use it, like .umich.edu, committee within U Michigan can decide who can use their name. Once a school like School of Information requests for it, then they can use .si.umich.edu.

Children

Backlinks

Web Hosting