Quiz Let Flashcards
osi model Application
Provides access to the network for applications and certain end-user functions. Displays incoming information and prepares outgoing information for network access.
osi model presentation layer
Converts data from the application layer into a format that can be sent over the network. Converts data from the session layer into a format that the application layer can understand. Encrypts and decrypts data. Provides compression and decompression functionality.
osi model session layer
Synchronizes the data exchange between applications on separate devices. Handles error detection and notification to the peer layer on the other device.
osi model transport layer
Establishes, maintains, and breaks connections between two devices. Determines the ordering and priorities of data. Performs error checking and verification and handles retransmissions if necessary.
osi model network layer
Provides mechanisms for the routing of data between devices across single or
multiple network segments. Handles the discovery of destination systems and
addressing.
osi model data link layer
Has two distinct sublayers: LLC and MAC. Performs error detection and handling for the transmitted signals. Defines the method by which the medium is accessed. Defines hardware addressing through the MAC sublayer.
osi model physical layer
Defines the network’s physical structure. Defines voltage/signal rates and the physical connection methods. Defines the physical topology.
TCP/IP Model Compared to OSI Model
Application layer: Application, Presentation and Session layer of the osi model
Transport layer:Transport layer
Internet layer: Network layer
Network interface layer: Data link layer
Physical layer
Loopback address
IPv4 127.0.0.1
IPv6 0:0:0:0:0:0:0:1 (::1)
Networkwide addresses
IPv4 public address
Global unicast IPv6 address ranges
Private network addresses
IPv4
- 0.0.0
- 16.0.0
- 168.0.0
IPv6
Site-local address ranges (FEC0::)
Autoconfigured addresses
IPv4
Automatic private IP addressing (169.254.0.0)
IPv6
Link-local addresses of FE80:: prefix
FTP
20 data transfres and 21 for listen to commands
SSH
22 TCP
Telnet
23 TCP
SMTP
25 TCP
DNS
53 TCP
POP3
110 TCP
NNTP
119 TCP
NTP
123 TCP
IMAP4
143 TCP
HTTPS
443 TCP
DNS
udp port 53
TFTP
UDP port 69
BOOTPS/DHCP
UDP port 67 for sending data to the server, and UDP port 68 for data to the client.
SNMP 161
UDP Port 161
MAC address
A MAC address is a 6-byte hexadecimal
address that enables a device to be uniquely identified on the network. A MAC address combines numbers and the letters A to F. An example of a MAC address is 00:D0:59:09:07:51.
CLASS A Address
A Class A TCP/IP address uses only
the first octet to represent the network
portion,
Class A addresses span from 1 to 126, with
a default subnet mask of 255.0.0.0.
and a Class C address uses three octets.
CLASS B Address
A Class B address uses two octets.
Class B addresses span from 128 to 191,
with a default subnet mask of 255.255.0.0.
CLASS C Address
Class C address uses three octets.
Class C addresses span from 192 to 223, with a default subnet mask of 255.255.255.0.
local loop back
local loop backThe 127 network ID is reserved for the IPv4
local loopback.
Steps 1 in Troubleshooting Methodology
Identify the problem: . Gather information. . Identify symptoms. . Question users. . Determine if anything has changed.
Steps 2 in Troubleshooting Methodology
Establish a theory of probable cause:. Question the obvious.
Steps 3 in Troubleshooting Methodology
Test the theory to determine cause:
After theory is confirmed, determine next steps to resolve problem.
If theory is not confirmed, re-establish new theory or escalate.
Steps 4 in Troubleshooting Methodology
- Establish a plan of action to resolve the problem and identify potential effects.
Steps 5 in Troubleshooting Methodology
Implement the solution or escalate as necessary.
Steps 6 in Troubleshooting Methodology
Verify full system functionality and if applicable
implement preventative measures.
Steps 7 in Troubleshooting Methodology
Document findings, actions, and outcomes
Virtualization
Virtualization makes it possible to take a
single physical device and make it appear
as if it is a number of stand-alone entities.
virtual switch
A virtual switch works the same as a physical
switch but enables multiple switches to exist on the same host, saving the implementation of additional hardware.
Network as a Service (NaaS)
Network as a Service (NaaS) is a cloud
computing model offered by many telecom
providers provided on demand in a pay as-
you-go model. OpenStack is the open source NaaS project.
NAT
NAT translates private network addresses
into public network addresses.
Link State routing protocols
A router that uses a link-state protocol
differs from a router that uses a distance vector
protocol because it builds a map of the entire network and then holds that map in memory. Link-state protocols include Open Shortest Path First (OSPF) and Intermediate System-to-Intermediate System (IS-IS).
What do Hop mean in routers
Hops are the means by which distance vector
routing protocols determine the shortest way to reach a given destination. Each router constitutes one hop, so if a router is four hops away from another router, there are three routers, or hops, between itself and the destination.
RIP
Routing Information Protocol (RIP) is a distance-vector routing protocol used for TCP/IP.
Example of distance vector routing protocols
Distance-vector protocols in use today include Routing Information Protocol (RIP and RIPv2), Enhanced Interior Gateway Routing Protocol (EIGRP), and Border Gateway Protocol (BGP).
Switch improvement over a HUB
Switches introduce micro segmentation,
by which each connected system effectively
operates on its own dedicated network connection.
PoE
Power over Ethernet (PoE) is a technology
that enables electrical power to be transmitted over twisted-pair Ethernet cable. The power is transferred, along with data, to provide power to remote devices. These devices may include
remote switches, wireless access points,
VoIP equipment, and more.
Default gateways
Default gateways are the means by which a device can access hosts on other networks for which it does not have a specifically configured route.
Internet Protocol
IP is a network protocol responsible for providing addressing and routing information
TCP/IP
The TCP/IP suite is used by all major operating systems and is a routable protocol.
DHCP/BOOTP
DHCP/BOOTP is a network service that automatically assigns IP addressing information.
In a network that does not use DHCP, you need to watch for duplicate IP addresses that prevent a user from logging on to the network.
Subnetting
Subnetting is a process in which parts of the host ID portion of an IP address are used to create more network IDs.
APIPA
APIPA is a system used on Windows to automatically self-assign an IP address in the 169.254.x.x range in the absence of a DHCP server.