ccna Flashcards
What is a switch?
A switch is a device that connects multiple computers on a network via ethernet cables.
What does the switch use for memory?
CAM content addressable memory
What does the switch store in its CAM?
MAC addresses
Do MAC addresses ever change?
No.
What are the messages going through the switch called?
Frames
What is a hub?
A hub is an outdated device that we used before the switch. It is not secure and just repeats electrical signals to all devices in a network.
What addresses does a switch use to populate the CAM addresses?
Source MAC addresses.
What addresses will a switch use to make forwarding decisions?
Destination MAC addresses
What is a router?
router is a device used to connect networks.
What is a network?
A group of IP addresses.
What happens when you send a ping to an IP address?
The switch sends the ping to every device on the network. The device with the correct IP address responds with their MAC address. Now your computer knows the MAC address and can send data to them directly.
What layers do routers handle?
Layer 3, IP addresses
What does a router send to find a MAC address?
ARP message
What is an ARP message?
Address Resolution Protocol. When you try to ping an IP address on your network system your system had to turn the IP address into a MAC address. It is sent to a special MAC address that causes all machines on a network to receive it.
What is a DNS sever?
A Domain name server puts a friendly name like netflix.com to an Ip address.
What year was the first network created?
1969
What was the first network called?
ARPANET
What was the first company to figure out how to make a network?
IBM
What is TCP/TP and OSI?
A set of rules and standards on how a network works.
What do we use today? ICP/IP or OSI?
ICP/IP
What are the ICP/IP layers?
1 Physical
2 Data Link
3 Network
4 Transport
5 Application
What are the OSI layers?
1 Physical
2 Data Link
3 Network
4 Transport
5 Session
6 Presentation
7 Application
What is the difference between the ICP/IP and OSI models?
The ICP/IP model combines layers 5, 6, and 7 of the OSI models.
What operates primarily at layer 2 of the OSI model?
Switch
What is layer 1?
Physical stuff(ethernet cables)
What is layer 2?
Data Link, MAC addresses
What deals with MAC addresses?
switches
What is layer 3?
Network, IP addresses
What deals with IP addresses?
Routers
What is layer 4?
Transport layer. ensures error-free data delievry between devices.
What are the two main options on the transport layer?
TCP and UDP
What is the difference between TCP and UDP?
TCP is reliable and UDP is fast
What is layer 7?
Application layer. In ICP/IP layers 5, 6, and 7 are sombined.
What is a segment?
Data encapsulated in an L4 header.
What is a packet?
Data and L4 header encapsulated in an L3 header.
What is a frame?
Data, L4 header, L3 header, encapsulated in an L2 trailer and L2 header.
What does the presentation layer handle on the OSI model?
Data format and encryption
What does the session layer handle on the OSI model?
keeping a link if communication open
What makes TCP reliable?
3-way handshake
What is a 3-way handshake?
Application sends a syn message to a device
the device sends a syn ack message back
the application sends a ack message back
What does TCP stand for?
Transmission control protocol
Why is UDP fast?
It sends data continuously without waiting for verification
What is UDP used for?
UDP is used for real time streaming like youtube videos or playing video games online
What is an ephemeral port?
A tmeporary port assigned by the web browser to make sure that server information gets sent to the correct place
What does FTP stand for?
File transfer Protocol
What is the FTP port number?
21
What does the FTP protocol do?
handles file transfer between the client and server on the internet
What is the HTTP port number?
80
What does the HTTP protocol do?
allows the fetching of resources, such as HTML documents. It is the foundation of any data exchange on the web and it is a client server protocol which means requests are made by the recipient. Usually the Web browser.
What does SMTP stand for?
Simple mail transfer protocol
What port number is SMTP?
25
Is the FTP protocol a TCP or a UDP protocol?
TCP
Is the HTTP protocol a TCP or a UCP protocol?
TCP
Is the SMTP protocol a TCP or a UDP protocol?
TCP
IS the DHCP protocol a TCP or a UDP protocol?
TCP
Is the TFTP protocol a TCP or a UDP protocol?
UDP
Is the TFTP protocol a TCP or a UDP protocol?
UDP
Is the DNS protocol a TCP or a UDP protocol?
Both
What does the SMTP protocol do?
It is used to send and receive email. Primarily sends messages to a server for forwarding.
What does DHCP stand for?
dynamic host configuration protocol
What is the DHCP port number?
67,68
What does the DHCP protocol do?
It is a network protocol used on Ip networks. It automatically assigns an IP address and other information to each host on a network so they can communicate efficiently with other endpoints.
What does SNMP stand for?
Simple network management protocol
What is the SNMP port number?
161
What does the SNMP protocol do?
It allows devices to communicate even if the devices are on different hardware and run different software.
What does TFTP stand for?
trivial file transfer protocol
What is the tftp port number?
69
What does the TFTP protocol do?
simple protocol for exchanging files between two TCP/IP machines
