Networking Fundamentals Flashcards
Interconnection of Network made possible by…
Open Systems Interconnection (OSI)
OSI Model
7 layers
- Application
- Presentation
- Session
- Transport
- Network
- Data link
- Physical
OSI: TCP/IP Model
- Application:
- Application
- Presentation
- Session - Host-to-Host
- Transport - Internet
- Network - Network Access
- Data link
- Physical
Network Protocol is a …
Standard set of rules that determines how systems will communicate across networks.
Open Network Architecture is…
One that no vendor owns, that is not proprietary, and that can easily integrate various technologies and vendor implementation of those technologies.
OSI:Encapsulation
Each protocol at a specific OSI layer on one computer communicates with a corresponding protocol operating at the same OSI layer on another computer.
OSI: Protocol Data Unit (PDU)
A protocol at each layer adds its own information to the message, creating a PDU.
OSI: Protocol at each layer has 3 responsibilities..
- Communication to above layer
- Communication to lower layer
- Communication to same layer in the other network
OSI: Attacks, network can be used as
- used as a channel for attack
- the target of an attack
OSI: Examples of Application Layer Protocol
- SMTP: Simple Mail Transfer Protocol
- HTTP:Hypertext Transfer Protocol
- LDP:Line Printer Daemon
OSI: Presentation layer is
- Concerned not with the meaning but with the syntax and format of the data
- Compresses data / Encrypt
OSI: Session Layer
Responsible for establishing a connection between two applications, maintaining it during the transfer of data, and controlling the release of this connection.
OSI:Session Layer works in 3 phases:
(Dialog Management)
- Connection establishment
- Data Transfer
- Connection release
OSI: Examples of Session Protocol layer
- L2TP: layer 2 tunnelling protocol
- PPTP: Point-to-Point Tunnelling Protocol (PPTP)
- RPC: Remote Procedure Call
OSI: Session layer Protocol can enable communication between two applications to happen in 3 different modes: (technical term)
- Simplex
- Half-Duplex
- Full-Duplex
OSI: Session Layer Vs. Transport Layer
- Session Layer: Application-to-Application
- Transport Layer: Computer-to-Computer
OSI: Which Layer Protocol is least used protocols in a network environment;
Session Layer Protocols
OSI: Transport Layer
When two computers are going to communicate through a connection-oriented protocol, they first agree on how much information each computer will send at a time , how many o verify the integrity of the data once received, and how to determine whether a packet was lost along the way. The 2 computers agree on these parameters through a handshaking process at the transport layer
OSI:Network Layer, layer 3
The main responsibilities of the network layer are to insert information into the packet’s header so it can be properly addressed and routed, and then to actually route the packet to its proper destination.
OSI: Data Link Layer, Layer 2
The network layer has already figured out how to route the packet through the various network devices to its final destination, but we still need to get the data over to the next, directly connected device. This happens at the data link layer.
OSI: Data Link Layer, Layer 2 has two functional sub layers:
- Logical Link Control (LLC): which interface with network layer above
- Media Access Layer (MAC): designed to interface with the physical layer below.
OSI: Data Link Layer, Layer 2 - Framing
When the data link layer applies the last header and trailer to the data message, this is referred to as framing m. This unit of data is now called a frame
ISO: Physical Layer, layer 1
Converts bits into electromagnetic signals for transmission.
PROTOCOL: Layer 7 - Application
- File Transfer Protocol (FTP)
- Network Time Protocol (NTP)
- Simple Mail Transfer Protocol (SMTP)
- Internet Message Access Protocol (IMAP)
- Hyper Transfer Protocol (HTTP)
PROTOCOL: Layer 6 - Presentation
-American Standard Code for Information Interchange (ASCII)
- Tagged Image File Format (TIFF)
- Motion Picture Experts Group (MPEG)
- Musical Instrument Digital Interface (MIDI)
PROTOCOL: Layer 5 - Session
- Layer 2 Tunnelling Protocol (L2TP)
- Network Basic Input Output System (NetBIOS)
- Password Authentication Protocol (PAP)
- Point-to-Point Tunnelling Protocol (PPTP)
- Remote Procedure Call (RPC)
PROTOCOL: Layer 4 - Transport
- Transmission Control Protocol (TCP)
- User Datagram Protocol (UDP)
- Stream Control Transmission Protocol (SCTP)
- QUIC (not an acronym)
PROTOCOL: Layer 3 - Network
- Internet Protocol (IP)
- Internet Control Message Protocol (ICMP)
- Internet Group Management Protocol (IGMP)
- Routing Information Protocol (RIP)
- Open Shortest Path First (OSPF)
PROTOCOL: Layer 2 - Data Link
- Address Resolution Protocol (ARP)
- Reverse Address Resolution Protocol (RARP)
- Serial Line Internet Protocol (SLIP)
- Wireless Ethernet (IEEE 802.11)
PROTOCOL: Layer 1 - Physical
- RS/EIA/TIA-422, RS/EIA/TIA-423, RS/EIA/TIA-449, RS/EIA/TIA-485
- 10Base-T, 10Base2, 10Base5, 100Base- TX, 10Base-FX, 10Base-T, 1000Base-T, 1000Base-SX
- Integrated Services Digital Network (ISDN)
- Digital Subscriber Line (DSL)
- Synchronous Optical Networking (SONET)
Bus Topology are of two main types:
- Linear bus topology
- Tree bus topology
Bus Topology is prevalent in
Vehicular networks, of which are Controller Area Network (CAN) bus is by far the most popular standard
Example of full mesh topology
A Typical Internet of Things (IoT) home automation network work using ZigBee.
Medium Access Control (MAC) mechanisms deal with…
(Resides data link Layer 2)
How computer systems communicate over these media and are built into the network interfaces
3 most common approaches to MAC
- Carrier Sense Multiple Access
- Token Ring
- Polling
MAC: Carrier Sense Multiple Access (CSMA)
(Collisions)
Which provides a standard way to access the shared medium, communicate, and recover from any errors that may occur.
MAC: Carrier Sense Multiple Access (CSMA) - 2 Variants
- Collision Detection (CD)
- Collision Avoidance (CA)
MAC:CSMA: Collision Detection (CD)
Protocol, they monitor the transmission activity, or carrier activity, on the wire so they can determine when would be the best time to transmit data.
MAC:CSMA: Collision Avoidance(CA)
In which all stations with data to transmit first check the medium to see if it’s quiet, If it is, they send their data. If it isn’t, they start a random time before they check again
MAC:CSMA: Token Passing
(No collisions)
Some MAC technologies also use tokens, which are 24-bit control frames used to control which computers communicate at what intervals.
MAC:CSMA:
Collision and Broadcast Domains.
A Collision Domain is…
- a group of devices that are contending, or competing, for the same shared communication medium.
- Example: All devices that are connected to a particular wireless access point (WAP) belong to the same collision domain.
- Collision domains are sets of computing nodes that may produce collisions when they transmit data.
- These are normally nodes connected by hubs, repeaters, or wireless access points.
Increase in Network Latency means…
Data Transmission Delays
CSMA:MAC
Broadcast Domain
Are sets of computing nodes that all receive a layer 2 broadcast frame. These are normally all nodes that are interconnected, with no routers in between them.
CSMA:MAC: Polling
- Polling is a medium access control mechanism that relies on a primary station that periodically polls all others in its collision domain.
- Each polled device responds by stating whether or not it has anything to send. How urgent it is.
- Polling is much more common in WAN
Layer 2 Protocols
Examples
- Ethernet
- Token Ring
- FDDI
LAYER 2: PROTOCOL:
Ethernet
- Ethernet is a set of technologies that enables several devices to communicate on the same network.
- Ethernet usually uses a bus or star topology
LAYER 2: PROTOCOL:
Ethernet is defined by the following characteristics:
- Contention-based technology ( all resources use the same shared communication medium)
- Uses broadcast and collision domains
- Uses the CSMA access method
- Supports full-duplex communication
- Can use coaxial, twisted-pair, or fibre-optic cabling types, but most commonly uses UTP cables
- is defined by IEEE 802.3 family of standards
LAYER 2: PROTOCOL: Token Ring Technology
- Was originally developed by IBM and then defined by the IEEE 802.5.
- It uses Token passing technology with a star-configured topology
- The ring part of the name pertains to how the signal travel, which is in a logical ring.
- Each computer is connected to a central hub, called a Multi station Access Unit (MAU)