Vocab Flashcards
A network topology and associated communication protocols that allow an organizations computers to send/receive data.
Computer network
Represents the wires or wireless links that connect computers together for the purpose of data communication
Network topology
Name the network topologys
Star Bud Ring Mesh Tree P2P
What is the equation used to create a full connected network?
(N * (N-1))/ 2
Represents the rules that permit two computers to transmit digital data
Communication protocol
What are the communication protocols used?
Ethernet, IPv4, IPv6, TCP, UDP, HTTP
Represents the an undesirable situation where an increase in data within a computer network causes a decrease in the throughput across the computer network
Network congestion
Represents the number of packets successfully delivered by all computers attached to a computer network
Throughput
Represents the an undesirable situation where an increase in data within the computer network causes a decrease in throughput across the computer network
Network congestion
What are the causes of network congestion?
- Too many frame retransmissions due to collisions and / or corruption
- Too many hosts placed in a collision domain
- Too many hosts placed in a broadcast domain
- Broadcast storms
- Too much multicast traffic
- Low bandwidth network links
- Using HUBs with the network
Represents the set of all computing devices attached to a network segment that are allowed to “hear” all the packet broadcasts sent out on that specific network segment
Broadcast domain
What can computers that reside in the same broadcast domain do?
Can communicate with each other via a data link layer broadcast frame
Any network segment that is used by two or more computers to transmit data
Collision domain
With respect to collision domains , when a device is using the network segment , another device must:
wait to transmit
With respect to collision domains , when a device is using the network segment , another device must wait to transmit
Network contention
A network of networks
Internetwork
An internetwork is created when two or more unique networks are:
- connected together by a common router
- configured to use a logical addressing scheme with a protocol, such as IPv4 or IPv6
Cisco network devices are comprised of:
Routers, switches, bridges, and/or hubs
Layer 3 device or network layer device - “Speak” a network layer protocol
*IPv4, etc.
Pass packets between networks
Cisco router
A network segment represent _________ and ________
1 broadcast domain
1 collision domain
Layer 2 device or Data Link Layer device -“Speak ” a data link layer protocol *Ethernet, etc.
A single interface represents one (1) unique collision domain
A frame sent by one device is delivered to the device attached and that has the destination MAC address
Cisco switch
Layer 2 device or Data Link Layer device - General “speak” two layer 2 protocols
Function is similar to switches
Historically , two interfaces
- One interface speaks one DLL protocol
- The other speaks another DLL protocol
- E.g X.25 - Ethernet bridge
Cisco bridge
Layer 1 device or Physical Layer device
A frame sent by one device is copied and sent to all other attached devices
are essentially Repeaters
interfaces reside within the same collision domain
is essentially a bus network topology
Cisco hub
What are the goals of internetworking
To create efficient internetworks that allow users to communicate and share services and resources
Minimize network contention
Rules & misc. thoughts
- Avoid using bridges and hub
- Use routers to create more broadcast domains
- Use switches to create more collision domains
A router with 4 active interfaces will create how many broadcast domains?
4 broadcast domains
A switch with 25 active interfaces will create how many collision domains?
25 collision domains
simply a model of “how” communication should take place between two or more computing devices
Reference model
Reference models often define several service layers. What are some facts about the layers?
- Each service layer provides unique functions
- Layering provide abstraction !!!
- We can replace one layer with a new layer as long as the new layer provides the same unique functions
There are two comm reference models. What are they?
- Transmission Control Protocol/Internet Protocol (TCP/IP)
2. Open System Interconnect (OSI)
The _____ model is not a layered architecture because no implementation of the model exists
OSI
What are the seven layers of the OSI reference model?
Application (top) Presentation Session Transport Network Data-link Physical (bottom)
This Layer is responsible for pushing / pulling bits to / from adjacent node
Physical
Physical layer the PDU is a:
Bit
Data link is responsible for:
- Uniquely identifying each piece of network hardware via a Medium Access Control (MAC) address (A.K.A Hardware Address )
- Controlling when a station places bits on the transmission media
- Detecting Frame errors
Data link layer the PDU is a:
Frame
Network layer the PDU is a:
Packet
Network layer is responsible for:
-Uniquely identifying each network attached device via a network address (IP address )
– Determining where a Packet should go next (i.e. Routing )
Transport layer the PDU is a:
Segment if TCP is used
Datagram if UDP is used
Transport layer is responsible for:
- Providing connection-oriented end-to-end communication from the user’s perspective.
- Providing connectionless communication from the user’s perspective
Session layer the PDU is a:
Message
Session layer is responsible for:
- Establishing, maintaining, and releasing a connection between two hosts.
- Two types of communication sessions
- Connection Oriented communication *Connectionless communication
communication is similar to a telephone call
- You “set-up” a communication path between two computers before the transmission of data occurs
- Each Transport Layer segment traverses the same communication path from source to destination
- The communication path is “ broken ” when one of the computers is finished communicating
Connection-oriented communication
Communication is to sending mail via the postal system.
- Each Transport Layer segment can traverse a separate path from source to destination .
- A segment may not arrive in the order in which it was sent.
Connectionless
Presentation layer the PDU is a:
Message
Presentation layer is responsible for:
- Defining how the data is presented to the user or application so that it is recognizable using the specific hardware
- Data encryption
The presentation layer received the message from this layer. It can/may be modified and sent to the session layer. What layer sent it?
Application layer
TCP/IP reference model layers
Application
Transport
Internet
Host-to-network
The process/application layer provides:
Similar service of application, presentation, and session layers from OSI model
Host-to-host layer is essentially the OSI ________ layer
Transport
Hybrid reference model used for the semester with 5 layers:
Application Transport Network Data link Physical
