Reading notes for October 13 class

• Internet in its essence is a collection of interconnected networks
• Internet Society oversees the formation of the policies and protocols that define how we use and interact with the internet
• ISP-Internet Service Provider
o ISPs then connect to larger networks that become a part of the internet
• POP- Point of presence, or a place for local users to access the company’s network, often through a local phone # or dedicated line.
o Then high-level networks connect to each other through Network Access Points (NAPs)
• Dozens of large internet providers interconnect at NAPs in various cities and trillions of bytes of data flow between the individual networks at these points.
o Therefore, internet is a collection of huge corporate networks that agree to all intercommunicate with each other at the NAPs.
• Routers determine where to send information from one computer to another
o More specifically, routers are special computers that send your messages along pathways
 Needs to make sure info. goes where it is meant to and not where it is not meant to go
• Internet backbones are fiber optic trunk lines and a trunk line has multiple fiber optic cables that increase the backbone’s capacity.
o Fiber optic cables are classified OC-aka optical carrier
• The four numbers in an IP address are called octets
o These octets are used to make classes of IP addresses that can be assigned to a particular business, etc.
o These octets are split into two sections: Net and Host
 Net-always contains the first octet that ids the network
 Host (or node)- identifies the actual computer on the network
• Domain Name System maps text names to IP addresses automatically
o Ex. .com, .edu
• URL- Universe Resource Locator: http://[etc]
• DNS servers handle billions of requests every day and they are essential to the internet’s smooth functioning
• All of the machines on the internet are either servers or clients
o Those that provide services to other machines are called servers
o And those that request and receive these services are called clients
 Servers have a static IP address that doesn’t change very often
 Any server machine makes it services available using numbered ports
• The client machine then accesses the service using a specific protocol.
• Every web server complies to the hypertext transfer protocol (HTTP)