Chapter 1 - Internetworking Flashcards
Define: Broadcast Domain
A set of all devices on a network which are allowed to hear all broadcasts on that specific segment
What causes traffic congestion (major factors)
Too many hosts Broadcast Storms Too much multicast Low bandwidth Adding hubs for connectivity ARP broadcasts
What are four ways a router functions in a network
Packet switching
Packet filtering
Internetwork communication
Path selection
What are the names of the layers in the OSI model
Application Presentation Session Transport Network Data Link Physical
What are the typical things you will find in the application layer
File, print, message, databases, and application servers.
What happens in the Presentation layer
Presents the data to the application layer. Data encryption, compression and translation happen
What happens in the Session layer
Keeps data separate from each other and handles dialog control
What purpose does the transport layer fulfill
Provides reliable (TCP) or unreliable (UDP) and performs error correction. Maintains the end to end connections
What purpose does the network layer fulfill
Provides logical addressing and routes traffic
What does the data link layer do
Combines packets into bytes and bytes into frames. Also provides access to media using MAC addressing and performs error detection.
What is the physical layer and what does it do
Items you can physically touch. They move bits between devices, specify voltages, wire speed, and pinouts.
What is a collision domain
A term used to describe a network scenario in which one segment is forced to pay attention no matter what
Why do we use VLANS
to logically break up broadcast domains in a layer 2 switched network
What is a WLAN controller
Used to manage medium to large number of access points
Define Reference model
A conceptual blueprint of how communications should take place. Divides processes into layers
What do the top three layers of the OSI model define
How applications communicate between hosts
What do the bottom four layers of the OSI model define
how data is transferred through physical media and how to rebuild data from transmitting hosts.
Outline the Application Layer of the OSI Model
The application layer acts as a interface between the application and the next layer down by providing ways for the application to send info down through the protocol stack. Communication is identified and confirms for partner availability and verifies the resources needed to permit the type of communication to take place
Outline the Presentation Layer
Presents data to the application layer and is responsible for data translation and code formatting. The presentation layer formats the data in a generic way so that the receiving computer can read it. Generic data is formatted to its original state when receiving.
Outlne the Session Layer
Set up, manage, and tear down sessiosn between presentation layer entities and will keep user data separate.
Has three modes
1. Simplex - one way communication
2. Half-Duplex - Two way, but only one at a time
3. Full-Duplex - Two way communication simultaneously.
Outline the transport Layer
Segments and reassembles data into a single data stream. Provides end to end data transport services and establishes a logical connection between the sender and the destination
** TCP & UDP reside here **
- Hides details of network dependent info
Provides mechanisms for multiplexing upper-layer applications
What is flow control and what layer is this a feature of
To ensure data integrity at the transport layer by allowing applications to request reliable data transport. This prevents overflow.
Segments are delivered are acknowledged, and if acknowledge not received it is resent.
This is a part of the transport layer
What is the purpose of Windowing and what layer is this a feature of
The quantity of data segments the transmitting machine can send without an acknowledgment. Measured in bytes, this is used to control the amount of outstanding acknowledgements
Define Positive Achknowledgement
The receiver is required to communicate back to the sender with an ACK. Should the receiver not respond before a predetermined time out period the data will be retransmitted
What happens in the Network Layer
Device addressing, location tracking, and determining the most efficient route are all functions that happen here. Routers operate at this layer.x
What are three components of the Routing Table
Network Addresses: different routing tables are kept for different schemas
Interfaces: The exit interface a packet will take when destined for a specific network
What does the Data Link Layer encompass
Provides the physical transmission of data transfer and provides error notification, network topology, and flow control
Ensures data is delivered to proper device using hardware addressing
Two Sublayers
1) Media Access Control: in charge of physical addressing, line disicpline, logical topologies, error notification, ordered delivery of frames, and optional flow control
2) Logical Link Control: Indentifies network protocols and encapsulates them
What functions do switches and bridges perform
Track what port a frame was received on and adds it to the filter table. If the switch does not recognize it sends it to all connected deivces and adds it to the table if a device replies.
What does the physical layer encompass
Sends and recieves bits that can be represented in different ways.
- State transitions - voltages high to low
- varying audio tones
Specifies the electrical, mechanical, procedural and functional requirements for activating maintain and deactivating a physical link between end systems.
What are 6 topologies to remember
Mesh Star Logical Physical Ring Bus
What is a mesh topology
Every network device is connected to each other
What is a Star topology
Central device connects computers and network devices together
What is a Ring topology
cable starts & ends at same point.
What is a logical topology
defines a logical path on which the signal will travel
