Networking(2021) Flashcards
The Internet:
Description
and
Benefits
- Global system of interconnected networks that use the standard Internet Protocol Suite( TCP/IP)
- No Centralized Governance
- Quite Resilient
- Reliance on the Endpoints in communication to handle most of the processing
- Ensures Data Integrity, Reliability and Authentication
- High degree of Redundancy
ICANN
Overview
Internet Corporation for
Assigned Names and Numbers
Organization that oversees the two Principle Name Spaces:
- Internet Protocol Address Space
- Domain Name System
Two Principle
Name Spaces
of the Internet
- Internet Protocol Address Space
- Domain Name System
IETF
Overview
Internet Engineering Task Force
- Deals with
- technical underpinnings
- standardization of core protocols
- IPv4 and IPv6
- International participants, anyone may contribute technical expertise
Internet Topology/Routing:
Backbone
Backbone
- Main data routes between large, strategically interconnected networks and core routers
- Hosted by commercial, government, academic and other high-capacity network centers
- Typically Fiber Optic Trunk Line
- ISPs interchange traffic over the backbone by privately negotiated interconnection agreements
- Backbone Providers sell services to ISPs, through Transit Agreements
ISP
- Overview
- Three Types
Internet Service Providers
Provide Access to the Internet in a local area
Three Types
- Access ISPs
- Hosting ISPs
- Transit ISPs
Access ISPs
Function
Directly connect customers to the internet.
Uses copper wires, wireless, or fiber-optic connections, etc
Hosting ISPs
Function
Lease Server Space for
Smaller Businesses
Routinely Provide:
- FTP
- Web-Hosting Services
- Clouds
- etc…
Transit ISPs
Function
Provide large Tuples
for connecting
Hosting ISPs to Access ISPs
4 Largest
Internet Backbone Providers
AT&T
MCI
Sprint
Century Link
Ethics in Networking:
Major Issues
- Net Neutrality
- Spam Email, Anti-Spam
- Stealth Blocking
- Web Control by Governments
- Censorship
- Pornography
- Quality of Information
- User Generated Content
- Reviews, posts, etc
- Cyberbullying
Factors of Cost
- Overhead
- Transaction Cost
- Risks
- Damage
(I’m not sure this belongs in this deck)
Tragedy of the Commons
A Dilemma arising from the situation in which:
Multiple individuals, acting independently, solely and rationally, consulting their own self interest,
will ultimately deplete a shared resource,
even when it is clear that it is not in anyone’s long term interest for this to happen.
Example: Spammers using resources(both physical and human) without bearing the entire cost of those resources.
Overview
Messages embedded in files transferred between computers
- Addressed via DNS IP Address
- Routed over the internet
- Possibly fragmented into packets
Email:
Format
some_id@domain_name
- Generic top-level domain (.edu, .gov, .com, .net)
-
DNS( Domain Name Server) translates host names to IP Address
- Analogous to a Phone Book
- A Hostname is a Domain Name with one or more associated IP Addresses
Spam:
Definition
The use of electronic messaging systems
to send
unsolicited bulk messages
indiscriminately
Spam:
Origin of Term
1970 Monty Python “Spam” Sketch
Nearly every menu item was spam,
vikings chanting “spam spam spam”,
thus “spamming” the dialogue
How do Spammers
get
Email Addresses?
Two Major Ways:
- Opt-in Lists
- Dictionary Attacks (Try everything)
How Spammers
Seek Anonymity
- Change email and IP Addresses to disguise the sending machine
- Hijack another system as a spam launch pad
Why spammers spam
- It is cheap
- About 100x cheaper than physical junk mail
- Wider audience
- Profit guaranteed:
- profitable even if only 1 in 100,000 buys product
Costs of Spam
-
Overhead
- bandwidth
- developing or acquiring spam tool
- taking over or acquiring host, etc
-
Transaction Cost
- Incremental cost of contacting each recipient once a method of spamming is constructed, multiplied by #recipients
-
Risks
- Chance and severity of legal and/or public reactions
-
Damage:
- Impact on the community/communication channels
Anti-Spam
Methods
- CAPTCHA
- Challenge-Response test
- Real Time Blackhole Lists
- Grey-listing
- Text Recognition
- Leads to more picture based spam
- Statistical Modeling & Heuristics
- Neural Networks, AI, etc
- Cryptography
Anti-Spam Method:
Greylisting
Greylisting
General method based on
behavior of sending server,
rather than the content of the messages
Net Neutrality:
Overview
Disagreement about the ability of
Broadband Providers to use their “Last Mile” of infrastructure
to block internet applications and content.
- Neutrality Proponents claim telecom companies seek to impose a Tiered Service Model in order to control the pipeline and remove competition
Net Neutrality:
Last Mile definition
Last Mile:
Final leg of delivering connectivity from a communications provider to a customer
Net Neutrality:
Important Events
- [2010] FCC issues Open Internet(NN) order
- Verizon and MetroPCS challenge the order
- Case Pending at US Court of Appeals for the DC Circuit for 2 years
- [Jan 14, 2014] DC Circuit Court declares FCC has no authority to enforce NN rules
- [2015] FCC reclassifies broadband access as a telecommunications service, so NN applies.
Net Neutrality:
Open Internet order
- Issued by FCC in 2010
- More commonly known as
- Net Neutrality Rules
- Essentially prohibits ISPs from blocking lawful web content
- Challenged in US Court of Appeals for DC Circuit
- Challenged by Verizon and MetroPCS
