CS99I
Meeting 1 Notes
Updated by Gio Wiederhold,
20 Jan 2001.
Topics Covered briefly
Course Goals
Discussion; understanding what's going on; not telling what the future will bring.
Student participation: reading, arguing, writing. Freshies only
Technology Origin:
Resource sharing for ARPA (the Defense Department/s Advanced Research Projects
Agency) Contractors.
Objectives:
- Remote use of computers: TELNET protocol
- File transfer for remote execution: FTP protocol
- Robustness: redundant linking
- Limited loss on failure, load balancing: packeting of messages
Reading: CS99 chapter about the Internet.
Technologies
Multiple levels of providers:
- Local servers for LANs
- Local Internet service providers
- Regional Internet services (BART, Los Nettos, (what was yours in your home town?)
- Backbone linkages -- wide, trancontinental links (leased from the phone companies, as MCI etc.)
Cable transmission versus Plain-old-telephone-service (POTS)
Bandwidth usage for messages, images, TV
Transmission Control Protocol: TCP, specifies
Packets with headers: from, to, number
Nodes with forwarding information tables
Later: four level adresses: 171.64.64.64. (what is yours?)
Three level addresses: cs.stanford.edu, translated by domain name servers (DSN)
Later a simplified protocol for email: SMTP
Internet protocol (IP), provided for interconnection of local subnetworks networks
(LAN>, connected by Internetwork routers.
LANs often use the Ethernet protocol local wire networks with
Carrier Sense Multiple Access (CSMA) and
Collision detection (CD) and
exponential backoff
developed origunally for satelite networks (Aloha net in Hawaii).
The ethernet protocol is a broadcast protocol, versus a point-topoint protocol.
Thet protocols differ in terms of
- Security
- Cost reimbursement. Alternatives are:
- Receiver pays: Voluntary subscription. Example: Public TV - PBS.
- Receiver pays: Required subscription, controlled access. Example: Stanford SITN.
- Receiver pays: Government levies taxes or fees. Example: British, Dutch TV.
- Sender pays: Corporate or organizational support. Example: churches.
- Sender pays: Government supports sender. Example: Voice of America.
- Sender pays: Commercial tax on sales. Example:.
- Sender pays: Advertising. Example:.
- Manufacturer of receiving equipment is taxed: Example: attempted with VCRs, as in (
France).
- Manufacturer of receiving supplies: Example: DAT tapes.
- others?
And combinations of these methods.
Their effectiveness differs in media, settings [ref World-wide Wireless magazine ~1910]
(social, ubiquity, ...).
Who should get paid: the broadcast service, the contents supplier, ... ?
[Napster]. More discussion needed.
Limiting Broadcast Access
Protecting minors versus First-amendment rights.
See COPA (Child Online Protection Act ) Commission material.
Distributed, autonomous development
Requests for comments (RFCs) to proposals, collected at SRI International.
Implemented and adopted by the community, after discussion, when effective.
Alternate means of developing standards
Implement, show, convince others of usefullness and leverage
Committee of wise men, government mandates
Commercial value of getting one's standard accepted
Surfeit of standards, confusion, cost, dirty tricks.
Binary Number representation
Counting with only two symbols {0, 1} .
(need a reference to reading?).
more in next set of notes
Notes
See class chapter about the Internet and
the glossary.