Exam 1 Flashcards
Wide Area Network(WAN)
Spans a relatively large geographical area. Typically, a WAN consists of two or more local-area networks (LANs). Largest WAN is the internet.
Local Area Network(LAN)
Spans a relatively small area. Most LANs are confined to a single building or group of buildings, however, one LAN can be connected to other LANs over any distance. A system of LANs connected in this way is called a wide-area network (WAN).
Access Network
Network which directly connects subscribers to their immediate service provider.
Cellular Data Network
Wireless network distributed over land areas called cells, each served by at least one fixed-location transceiver, known as a cell site or base station.
Storage Network(SAN & NAS)
Storage networks provide a centralized repository for digital data that can be accessed by many users, and they use high-speed connections to provide fast performance. It’s most common to find storage networks in enterprise settings, although some vendors do sell networked storage products for consumers and small businesses.
Personal Area Network(PAN)
A computer network organized around an individual person. Personal area networks typically involve a mobile computer, a cell phone and/or a handheld computing device such as a PDA. You can use these networks to transfer files including email and calendar appointments, digital photos and music.
Protocol
An agreement on how a communication is to proceed
What three things comprise a packet? (2 main ones)
Header, Payload (Data), Trailer
What is a point to point network?
- Between two participants
- simplex, duplex, full duplex
- no need for addressing
What is a broadcast and select network?
- multiple nodes attached to a shared medium
- everyone hears every transmissions (broadcast)
- addresses needed to select transmission intended for a node
What is the main motivation for layered models?
- Networks require many different types of expertise.
- Need to mix and match
What is the difference between WLAN and PAN?
- WLAN covers greater distance
- PAN can be wired
- PANs tend to be lower power (both transmitted and consumed)
- PANs tend to have more application specific profiles (stereo over bluetooth)
- PANs usually easier to configure
Unicast
Point to point, most prevalent in internet today
Multicast
One-to-many
Broadcast
One-to-all
Anycast
One to closest node (DNS is an example)
What is the main motivation for a Layered Network Model?
- Networks require many different types of expertise
- Need to mix-and-match
What are the three characteristics of a Layered Network Model?
o Black box functionality
o Simple well defined interfaces (service of a layer)
o Vertically stacked
Layer 1
Physical
• Sending individual bits through channels (concerned with sizes of connectors, voltages, frequencies…)
Layer 2
Link
• Moving data from one end of a channel to the other end of the channel
• Error detection, error control
• Framing (how do I decide what the beginning and end is?)
Layer 3
Network
- Delivering messages end-to-end
- Routing, shortest path decisions
Layer 4
Transport
- What happens during the conversation? What happens if things go wrong? How do we fix it?
- Error control
- Flow control
Layer 5
Session
- Most transportation of data requires communication between two unicast parties.
- Session layer deals with conversation itself (how do we start, how do we finish, how do we maintain)
Layer 6
Presentation
- Least significant layer, deals with different data representations.
- Different platforms, different systems represent data (bits, characters) in different ways
- Ex: Big endian vs. little endian
- “Translation layer” between platforms
- When internet became non-US centric, ‘hacks’ for fixing presentation issues were built into the Application layer
