INSY 3303 Exam 2 Review

PDU (protocol data unit)

(sometimes called a packet) a single unit of data that contains information that is needed to transmit the message through the network.

What are the sources of errors?

- Line Noise - White Noise - Impulse Noise - Cross talk - Echoes - Attenuation - Intermodulation Noise

Routing Protocols

-Border Gateway Protocol (BGP) -Internet Control Message Protocol (ICMP) -Routing Information Protocol (RIP) -Intermediate System to Internet State (IS-IS) -Open Shortest Path First (OSPF) -Enhanced Interior Gateway Routing Protocol (EIGRP) -Interior Gateway Routing Protocol (IGRP)

What are the different error-detection methods?

-Parity checking -Checksum -Cyclic Redundancy Check (CRC)

What are some error prevention techniques?

-Shielding (protecting wires with an insulated coating) -Moving cables away form sources of noise -Using amplifiers and repeaters to avoid attenuation.

What are the three steps that are performed in Building-Block Network Design Process?

1. Needs Analysis 2. Technology Design 3. Cost Assessment

ARP (Address Resolution Protocol)

A core protocol in the TCP/IP suite that belongs in the Network layer of the OSI model. ARP obtains the MAC (physical) address of a host, or node, and then creates a local database that maps the MAC address to the host's IP (logical) address.

Backbone Network (BN)

A large network to which many networks within an organization are connected. It usually is a network that interconnects all networks on a single site.

What is Cyclic Redundancy Check (CRC)?

A mathematical algorithm that is executed on a data string by both the sender and the receiver of the data string. If the calculated values match, the receiver can conclude that the data string was not corrupted during transmission.

DHCP (Dynamic Host Configuration Protocol)

A network service that provides automatic assignment of IP addresses and other TCP /IP configuration information.

name server

A series of computers throughout the internet that provides DNS services. These servers contain address databases and stores thousands of internet addresses and their corresponding IP addresses.

HDLC (High-level Data Link Control)

An ISO developed synchronous data link layer protocol used in WANs with longer addresses and control fields.

What is parity checking?

An additional bit is added to each byte in the message that can detect if the hardware loses a bit during the internal movement of a byte.

IOS

Cisco Internetwork Operating System Software is an operating system used in about 90% of routers.

What makes EIGRP unique?

Computers or routers store their own routing tables as well as the routing tables for all of their neighbors so they have a more accurate understanding of the network.

What functions do the IP segment perform?

IP is the network layer protocol and performs addressing and routing. IP software is used at each of the intervening computers through which the message passes; it is IP that routes the message to the final destination.

What are the disadvantages to using BGP?

It is large, complex, and often hard to administer.

Enterprise Edge

Made up of the last three components of the network architecture. It is the parts of the network that are at the edge of an enterprise campus and connect that campus to the rest of the world.

Error Control

Network errors, such as those that occur during transmission, are controlled by the network hardware and software.

WAN (Wide Area Network)

Networks that typically run long distances, connecting different offices in different cities or countries.

What functions does the TCP segment perform?

TCP is the transport layer protocol that links the application layer to the network layer. It performs segmenting: breaking the data into smaller PDUs called segments, numbering them, ensuring each segment is reliably delivered, and putting them in the proper order at the destination.

Segment

The Protocol Data Unit (PDU) at the transport layer.

LLC (Logical Link Control)

The first sublayer of the data link layer and is responsible for communicating with the network layer software and for taking the network layer Protocol Data Unit (PDU) and surrounding it with a data link layer PDU.

Data Center

The fourth network architecture component and it contains the organization's servers.

TLD (top-level domain)

The highest-level category used to distinguish domain names-for example, .org, .com, and .net. A TLD is also known as the domain suffix.

Access Layer

The layer that provides network access. Ex. Local Area Network (LAN)

TCP connections

The negotiation by the transport layer at the sender with the transport layer at the receiver to determine what size packets should be set up that is done via establishing a session between the sender and receiver.

Distribution Layer

The second network architecture also called the building backbone network. This layer distributes network traffic to and from LANs.

MAC (Media Access Control)

The second sublayer of the data link layer that controls the hardware.

UDP (User Datagram Protocol)

The second type of transport layer protocol that is used when the sender needs to send a single small packets to the receiver.

Core Layer

The third network architecture component and is also known as the campus backbone. This layer connects all the buildings on one campus.

Transmission Efficiency

The total number of information bits divided by the total bits in transmission.

Subnet Mask

This is given to every computer in a TCP/IP network to determine which computers are on the same subnet and which computers are outside of its subnet.

eCommerce Edge

This is the final network architecture component. It is a special LAN with a group of severs that enables electronic data exchange between the organization and the external entities with which it does business with.

RTP (Real-time Transport Protocol)

This is used to send packets across a connection. It contains information about the sending application, a packet sequence number, and a time stamp so that the data in the RTP packet can be synchronized with other RTP packets by the application layer software, if needed.

QoS (Quality of Service)

This type of routing is a special type of connection-oriented messaging in which different connections are assigned different priorities.

Overhead bits

Used for purposes such as error checking and marking the start and end of characters and packets.

NAK

a Negative Acknowledgement message that is sent when a packet contains an error

Frame

a block of data being transmitted

Bottleneck

a circuit that is filled almost to its capacity and is the critical point that determines whether users get good or bad response times.

Repeater

a device that receives an incoming signal, translates it into a digital message and retransmits the message.

RFP (Request for Proposal)

a document that specifies what equipment, software, and services are desired and ask vendors to provide their best prices.

BGP (Border Gateway Protocol)

a dynamic distance vector exterior routing protocol used on the Internet to exchange routing information between autonomous systems—that is, large sections of the Internet.

RIP (Routing Information Protocol)

a dynamic distance vector interior routing protocol that is commonly used in smaller networks, such as those operated by one organization.

EIGRP (Enhanced Interior Gateway Routing Protocol)

a dynamic hybrid interior routing protocol developed by Cisco that records information about a route's transmission capacity, delay, reliability, and load.

RSVP (Resource Reservation Protocol)

a general purpose QoS protocol that permits application layer software to request connections that have certain minimum data transfer capabilities.

Simulation

a mathematical technique in which the network comes to life and behaves as it would under real conditions that is used to model the behavior of the communication network

TRIB (Transmission Rate of Information Bits)

a measure of the effective number of information bits that is transmitted over a communication circuit per unit of time.

DNS (Domain Name Service)

a server name resolution system that translates an internet address (application layer address) into an IP address (network layer address).

What is the goal of the Building-Block Network Design Process?

a simpler design process and a more easily managed network built with a smaller range of components.

Multicasting

addresses from 224-239 that belong to Class D sending messages to a group of computers rather than to one computer or every computer on a network.

ICMP (Internet Control Message Protocol)

an error-reporting protocol that enables computers to report routing errors to message senders.

Turnpike effect

an expression that means that traffic increases much faster than originally forecast.

Information bits

bits used to convey the user's meaning.

What is technology design?

examining the available technologies and assessing which options will meet the users' needs.

Asychronous Transmission

often referred to as start-stop transmission because the transmitting computer can transmit a character whenever it is convenient, and the receiving computer will accept that character.

Common Carrier

private companies such as AT&T, Bell Canada, Sprint, and BellSouth that provide communication services to the public.

TCP/IP (Transmission Control Protocol/Internet Protocol)

protocol that was developed for the U.S. Department of Defense's Advanced Research Project Agency network (ARPANET) in 1974. the transport/network layer protocol used on the Internet. It is the world's most popular protocol set, used by almost all BNs and WANs.

Error Detection

sending extra data with each message. These error-detection data are added to each message by the data link layer of the sender on the basis of some mathematical calculations performed on the message

Subnet

subnetworks that subdivide the network into logical pieces to make the overall network more efficient.

Circuit Loading

the amount of data transmitted on a circuit

Roll-call polling

the controller works consecutively through a list of clients, first polling client 1, then client 2, and so on, until all are polled.

LAN (Local Area Network)

the first network architecture component also called the access layer because it provides access to the network.

ACK (acknowledgement message)

the part of the ARQ algorithm that lets the sender know that the package has been correctly received without errors.

Polling

the process of sending a signal to a client computer that gives it permission to transmit

Address Resolution

the process of translating the application layer address (or server name) of the destination into a network layer address, and in turn translate that into a data link layer address

What is a needs analysis?

the process of understanding the fundamental current and future network needs of the various users, departments, and applications.

Throughput

the total number of information bits received per second, after taking into account the overhead bits and the need to retransmit frames containing errors.

Segmenting

to take one outgoing message from the application layer and break it into a set of smaller segments for transmission through the network. It also means to take the incoming set of smaller segments from the network layer and reassemble them into one message for the application layer.

Server Name Resolution

translation of application layer addresses into network layer addresses and is done using the Domain Name Service (DNS) (Ex. Website URL to IP address)

What is a checksum?

when a byte is added to the end of the message and is calculated by adding the decimal value of each character in the message, dividing the sum by 255, and using the remainder as the checksum.

ARQ (Automatic Repeat reQuest)

when a receiver that detects an error simply asks the sender to retransmit the message until it is received without error.

Synchronous Transmission

when all the letters or data in one group of data are transmitted at one time as a block of data called a frame. is often used on both point to point and multipoint circuits.

Baselining

when designers must review the list of applications that will use the network and identify the location of each, and the information is added to the emerging network documentation.

Building-Block Network Design Process

when networks that use a few standard components throughout the network are cheaper in the long run than networks that use a variety of different components on different parts of the network.

Hub Polling (token passing)

when one device starts the poll and passes it to the next computer on the multipoint circuit, which sends its message and passes the poll to the next.

What is a cost assessment?

when the relative costs of the technologies are considered.