Network Theory Flashcards
a self-contained network that spans a relatively small area, such as a single building, floor, or room, although some can be significantly larger.
Local Area Network (LAN)
a network that spans a large area, often across multiple geographical locations. Typically connect multiple LANs and other networks using long-range transmission media.
Wide Area Network (WAN)
Covers and area equivalent to a city or a municipality.
Metropolitan Area Network (MAN)
covers an area equivalent to an academic campus or business park. Typically owned or used exclusively by an entity.
Campus Area Network (CAN)
connects two to three personal devices such as a smart phone connected to a laptop with cables, usually for a single person’s use.
Personal Area Network (PAN)
is a variation of a PAN that connects wireless devices in close proximity but not through a Wireless Access Point or Access Point (examples include Bluetooth and Infrared)
Wireless Personal Area Network (WPAN)
a self contained network of two or more devices connected by using a wireless connection. spans a small area, such as a small building, floor, or room.
Wireless Local Area Network (WLAN)
is the single largest global WAN, linking virtually every country in the world. Publicly owned and operated.
Internet
is a private network that uses Internet Protocols and Services to share a company’s information with its employees.
Intranet
is a network that includes elements of both LANs and WANs
Enterprise Network
layers work in one direction on one host and in the opposite direction on the remote host. Each layer processes the portion of the request corresponding to the procedures at that specific layer, then hands off the request to the next layer, each layer processing the request components within the layer’s protocols, processes, and structure. The model provides a theoretical representation of what happens to information being sent from one device to another on a network.
Open Systems Interconnection (OSI) model-
What are the 7 layers of the OSI model
Application, Presentation, Session, Transport, Network, Data Link, Physical
Enables applications on a network node (device) to request network services.
Application Layer (Layer 7)
Translates Application layer data into an intermediate form that both client and server can process.
Presentation Layer (Layer 6
Establishes and controls data communication between applications operating on two different devices, regulating when each device can send data and how much it can send. The two parties have to agree on how to communicate.
Session Layer (Layer 5)
Performs the actual establishment, maintenance, and tear down of the connection. Optionally divides long communications into smaller segments, including error recognition and correction, and data receipt acknowledgement.
Transport Layer (Layer 4)
Adds logical addressing (network addresses) and chooses the best route.
Network Layer (Layer 3
Structures the data into a format appropriate for the transmission medium. Adds physical addresses such as media access control (MAC) addresses or frame relay data link connection identifier (DLCI) numbers. Usually includes simple error checking.
Data Link Layer (Layer 2)
Transmits bits (binary digits) from one device to another and regulates the transmission stream over a medium (wire, fiber optics, or radio waves)
Physical Layer (Layer 1)
Protocols and Network Devices associated with the Application Layer (Layer 7)
HTTP, FTP, SMTP, IMAP - Application proxy
Protocols and Network Devices associated with the Presentation Layer (Layer 6)
Encryption, compression, character sets, multimedia formats, MIME types, codecs, etc. - Application proxy
Protocols and Network Devices associated with the Session Layer (Layer 5)
TCP and UDP PORT numbers - Firewalls
Protocols and Network Devices associated with the Transport Layer (Layer 4)
TCP and UDP PROTOCOLS - Firewalls
Protocols and Network Devices associated with the Network Layer (Layer 3)
IP, ICMP, and IGMP protocols - Layer 3 Switches, Routers and Firewalls
Protocols and Network Devices associated with the Data Link Layer (Layer 2)
Ethernet, token ring, frame relay, PPP, HDLC, wireless access protocol, ATM, X.25, etc. - Switches/Bridges and Access Points
Protocols and Network Devices associated with the Physical Layer (Layer 1)
Cabling, connectors, antennas, transceivers, baseband, broadband, signaling types, voltages, waveforms, modulation, frequencies, and clock rates. NICs, hubs, repeaters etc. - Hubs, repeaters, patch panels, cables, and network cards.
the process of adding delivery information and the actual data transmitted on each layer.
Encapsulation
At the receiving end, the process of removing the added information is done as data passes to the next higher layer
de-encapsulation
The term given for frames, packets, segments, and datagrams are sometimes used interchangeably when referring to data being transmitted over a network.
PDUs
PDU type at Layers 7 thru 5
Message
PDU type at Layer 4
Segment or Datagram
PDU type at Layer 3
Packet
PDU type at Layer 2
Frame
PDU type at Layer 1
Bit or Bit Stream
a method for data transfer from a source address to a destination address
Unicast
data is sent from a source node to all other nodes on a network
Broadcast
data is sent from a server to specific nodes that are predefined as members of a multicast group.
Multicast
a transmission method in which data is sent from a server to the nearest node within a group. That node then initiates a second transmission and transmits the data to the next nearest node with the group. The process is repeated until all nodes within the group have received the data.
Anycast
a measure of the number of bits that are transmitted per unit of time. Usually measured in bits per second.
Bit Rate
measures the number of symbols that are transmitted per unit of time. A symbol consists of a fixed number of bits depending on what the symbol is defined as.
Baud Rate
competitive media access, the nodes themselves negotiate for media access time.
Contention-Based
a central device or system controls when and for how long each node can transmit.
Controlled or Deterministic
is a contention-based media access method designed for use in Ethernet LANs, where nodes contend for use of the physical medium. Mostly used in non-switched Ethernet LANs.
Carrier Sense Multiple Access/Collision Detection (CSMA/CD)
Steps in CSMA/CD data transmission
- Data to Transmit
- Check Network
- Transmit
- Collision
- Wait - The two nodes that collided wait for a random back off period (in milliseconds).
- Re transmit
is a contention-based media access method that is primarily used in IEEE 802.11-based wireless LANs. nodes can transmit whenever they have data to send. However, they take steps before they transmit data to ensure that the media is not in use. Typically used in Wireless Networks.
Carrier Sense Multiple Access/Collision Avoidance (CSMA/CA
Steps in CSMA/CA data transmission
- Data to Transmit
- Check Network
- RTS Signal Sent
- Wait
- Transmit
- Monitor for other RTS Signals
the channel is divided into discrete time slots with each node having an assigned time slot. used in baseband connections. Rely on use of a Multiplexer (MUX).
Time-Division Multiplexing (TDM)
Data from multiple nodes is sent over multiple frequencies, or channels, using a network medium. used in broadband connections. Rely on use of a Multiplexer (MUX).
Frequency-Division Multiplexing (FDM)
this multiplexing mode of communication is the one-way transmission of information. Radio and Television broadcasts are examples. Only receive, no sending.
Simplex
this multiplexing mode of communication permits two-way communications, but in only one direction at a time.
Full Duplex
digital signals to be sent as DC pulses over a single, unmultiplexed signal channel
Baseband
