Comptia Network Chapter 1 Combined Flashcards
OSI Model
The seven layers describing network functions
Physical Layer
The lowest, or first, layer of the OSI model. Protocols in this layer generate and detect signals so as to transmit and receive data over a network medium.
Data Link Layer
The second layer in the OSI model. Its primary function is to divide the data it receives from the Network layer into frames that can then be transmitted by the Physical layer. Also MAC ADDRESSES
Network Layer
The third layer in the OSI model. Protocols in this layer translate network addresses into their physical counterparts and decide how to route data from the sender to the receiver. IP ADDRESSES
Transport Layer
The fourth layer of the OSI model. In this layer protocols ensure that data are transferred from point A to point B reliably and without errors. this layer services include flow control, acknowledgment, error correction, segmentation, reassembly, and sequencing. TCP/UDP
Session Layer
The fifth layer in the OSI model. This layer establishes and maintains communication between two nodes on the network. It can be considered the "traffic cop" for network communications.
Presentation Layer
The sixth layer of the OSI model. Formatting and Encryption/Decryption are done here.
Application Layer
The seventh layer of the OSI model. Application layer protocols enable software programs to negotiate formatting, procedural, security, synchronization, and other requirements with the network.
TCP/IP
The dominant set of protocols for the transfer of data over the Internet.
UDP
User Datagram Protocol. Used instead of TCP when guaranteed delivery of each packet is not necessary. UDP uses a best-effort delivery mechanism. Best for streaming
SMTP
Simple Mail Transfer Protocol
HTTP
Hypertext Transfer Protocol
FTP
File Transfer Protocol
TCP/IP Layers
Network Access (layer 1,2), Internet (layer 3), Transport(layer 4), Application(layer 5,6,7)
Subnet Mask
In IPv4 addressing, a 32-bit number that, when combined with a device's IP address, indicates what kind of subnet the device belongs to.
IP Address Class A and Subnet Mask
1.0.0.0 - 126.0.0.0 SM= 255.0.0.0
IP Address Class B and Subnet Mask
128.0.0.0 - 191.255.0.0 SM=255.255.0.0
IP Address Class C and Subnet Mask
192.0.0.0 - 223.255.255.0 SM= 255.255.255.0
IP Address Class DAnd Subnet Mask
Multicasting Layer. 224.0.0.0- 239.0.0.0
local host
This is a host on the same local network as the sending host. The hosts share the same network address. 127.0.0.1
APIPA
Automatic Private Internet Protocol AddressingAssigns a class B IP address from 169.254.0.0 to 169.254.255.255 to the client when a DHCP server is either permanently or temporarily unavailable.
Private IP Address Class A range
10.0.0.0- 10.255.255.255 SM: 255.0.0.0 (/8)
Private IP Address Class B range
172.16.0.0 - 172.31.255.255 SM: 255.240.0.0 (/12)
Private IP Address Class C range
192.168.0.0 - 192.168.255.255 SM: 255.255.0.0 (/16)
CIDR (Classless Inter Domain Routing)
A subnetting method that selects a subnet mask that meets an individual network's networking and node requirements and then treats the mask like a 32-bit binary word.
TFTP Port Number
UDP 69
SFTP Port Number
TCP 22
SMTP Port Number
TCP 25
POP3 Port Number
TCP 110
IMAP Port Number
TCP 143
HTTP Port Number
TCP & UDP 80
HTTPS Port Number
TCP 443
Telnet Port Number
TCP & UDP 23
SSH Port Number
TCP 22
RDP Port Number
TCP 3389
DNS Port Number
TCP/UDP 53
DHCP Port Number
UDP 67 (server), 68 (client)
SNMP Port Number
UDP 161
NTP Port Number
Network Time Protocol. UDP 123
TLS
Transport Layer Security. Used to encrypt traffic on the wire. TLS is the replacement for SSL and like SSL, it uses certificates issued by CAs. PEAP-TLS uses TLS to encrypt the authentication process and PEAP-TLS requires a CA to issue certificates.
SIP Port Number
5066
RTP
Real-time Transport Protocol. A standard used for delivering audio and video over an IP network.
Routers
Devices that move data across different networks
Routing Tables
Tables on a router that determine where the router will send packets on the network.
MTU (maximum transmission unit)
The largest IP packet size in bytes allowable by routers in a path without fragmentation and excluding the frame size.
Link State Routing
A routing method that floods routinginformation to all routers within a network to build and maintain a more complex network route database.
Distance Vector Routing
Each router passes a copy of its routing table to its adjacent neighbors. The neighbor adds the route to its own table, incrementing the metric to reflect the extra distance to the end network. The distance is given as a hop count; the vector component specifies the address ofthe next hop.
IGP (Interior Gateway Protocol)
A routing protocol, such as RIP, that can only route data within an autonomous (internal) network.
EGP (Exterior Gateway Protocol)
A routing protocol that can span multiple, autonomous networks. BGP and EIGRP are examples of Exterior Gateway Protocols.
Routing Information Protocol (RIP)
A dynamic protocol that uses distance-vector routing algorithms to decipher which route to send data packets.
Routing Information Protocol version 2 (RIPv2)
A newer version of RIP that supports a more complex IP addressing scheme and uses multicast packets rather than broadcasts to transmit routing table updates.
OSPF (Open Shortest Path First)
A link-state routing protocol used on IP networks.
IGRP (Interior Gateway Routing Protocol)
A distance-vector routing protocol developed by Cisco as an improvement over RIP and RIP v2.
EIGRP (Enhanced Interior Gateway Routing Protocol)
An improvement over IGRP that includes features that support VLSM and classful and classless subnet masks.
Router Convergence
All routers have same Topology and routing information
Spanning Tree Protocol (STP)
Defined by the IEEE 802.1D standard, it allows a network to have redundant Layer 2 connections, while logical preventing a loop, which could lead to symptoms such as broadcast storms and MAC address table corruption.
Broadcast Domain
A logical area in a computer network where any node connected to the computer network can directly transmit to any other node in the domain without a central routing device.
Collision Domain
The portion of an Ethernet network in which collisions could occur if two nodes transmit data at the same time.
Virtual Local Area Network (VLAN)
a logical network that can separate physical devices without regard to the physical location of the device
Port Mirroring/Spanning
Copies the traffic from one, a group, or all ports to a single port and disallows bidirectional traffic on that port. Used to view traffic on other ports in a switched environment.
Transmission Control Protocol (TCP)
provides reliable, ordered, and error-checked delivery of a stream of packets on the internet. TCP is tightly linked with IP and usually seen as TCP/IP in writing.
Address Resolution Protocol (ARP)
Part of the TCP/IP protocol for determining the MAC address based on the IP address.
DNS (Domain Name System)
The Internet's system for converting alphabetic names into numeric IP addresses.
Troubleshooting Theory
Steps a technician uses to solve a problem. CompTIA A+ defines six steps: identify the problem; establish a theory of probable cause; test the theory to determine cause; establish a plan of action to resolve the problem and implement a solution; verify full system functionality and if applicable implement preventive measures; and document findings, actions, and outcomes.
Virtual Switch
A software-based switch that providesfunctionality similar to physical switches, and is used for connecting virtual systems to form a network.
Virtual PBX (Private Branch Exchange)
phone system that handles such features as call routing, voicemail, faxing, etc. that is hosted by an outside vender
onsite
hosting virtual devices on hardware physically located in a corporate data center.
offsite
hosting virtual devices on hardware physically located in a service provider's data center.
NaaS (Network as a Service)
A method by which service providers lease resources on the network such as communication services and infrastructure.
Where does a hub send data?
To all systems connected to the hub.
What uniqely indentifies every NIC
Media access control address.
Which MAC address begins a frame?
Recieving system
A frame ends with a special bit called the frame check sequence(FCS). What does the FCS do?
Verifies that the data arrived directly
Which of the following is an example of a MAC address?
00-44-55-A3-04-0C
Which layer of the TCP/IP model controls the segmentation and reassembly of the data?
Transport layer
C1 Name the seven application layers from top to bottom
Application,Presentation,Session,Transport,Network,Data Link,Physical
C1 acronym
Please do not throw saugauge pizza away
Clearly defined set of rules
Protocols
OSI seven layer model encourages...
modular design of networking, meaning that each layer has as little to do with the operation of other layers as possible.
UTP: definition and explanation
Unshielded twisted pair: cable used in networking industry.
An example of a Central Box
router
Components of the Physical Layer
Cables, router, fiber optics, radio waves
NIC definition
Network Interface card: Interface between the PC and the network.
NIC is part of what layer?
Data Layer
What is unique for every NIC?
has 48 bit mac address
MAC stands for
media control address
EUI defininition and explanation
Extended Unique Indentifier
frame: define and explain
a container for a chunk of data moving across a network. It encapsulates information and data for easier transmission
NIC does what with frames?
reads them
Five layers of a generic frame
Recipients MAC addressSenders MAC addressTypeData FCS
Sections of a Frame
header: MAC address and typepayload: What's in the frametrailer: FCS Frame check sequence
three ways to check a MAC address: linux, mac, and Windows
Linux: ip aWindows: cmd, ipconfig/allMac: ifconfig
another word for hub: and its definition
switch: is networking hardware that connects devices on a computer network by using packet switching to receive and forward data to the destination device
FCS are how long?
4 bytes
Define a unicast frame
any frame addressed specifically to another device's MAC address
What is the only layer that has sublayers?
Data link layer
CRC define and explain
cyclic redundancy checkbinary math that recieving NIC uses to verify data arrived is intact
any device dealing with a mac address is part of what layer?
data link layer
LLC define explain
Logical Link Control The aspect of the NIC that talks to the systems OS
what are the two jobs of the Data layers?
LLC and MAC
network protocol
software used to move past the physical MAC addresses to the logical
Describe the Network Layer
containers called packets get created and addressed so they can go from one network to another.
Describe IP address
known as a logical address to distinguish it from the physical MAC addresss
router definition
connects each of the subnets.use the IP address, not the MAC
What is the container called in a IP _________. What are the three layers
PacketDesination IP, Source IP, Data
Four layers of IP packet
Frame HeaderPacket headerdatafcs
Describe Segmentation and what layer is it
Transport LayerSegmentation and reassembly software. When a serving computer receives a request for some data, it must be able to chop the requested data into chunks that will fit into a packet (and eventually into the NIC's frame), organize the packets for the benefit of the receiving system, and hand them to the NIC for sending.
Describe the Session Layer
Connecting applications to applications.Session tracking and naming
Describe the Presentation Layer
Data Conversion. Example Encryption/Decryption
Application Layer
API's, Itrefers to the code built into all operating systems that enables network-awareapplications.
encapsulation
the process of preparing data to go into a network.
What are the four layers of the TCP/IP model
Link/Network Interface: Physical+DataInternet: NetworkTransport Transport/SessionApplication