TCP / IP and Subnet Masking Flashcards
Tcp / ip version 4
current version of TCP / IP
TCP / IP Protocol
Is actually a protocol suite (i.e. a collection of protocols)
The main two protocols are made up of TCP and IP protocols
IP
Internet Protocol
What does IP do?
IP is the protocol w / in TCP/IP that is in controls routing of info to different comps, devices, servers.
Deals with IP addresses, subnet masks, default
Figures out where other comps are so they can begin communication.
It is a “routable protocol”
Connects computers based on the computers IP addresses
Protocol Suite
A collection of protocols
TCP
Transmission Control Protocol
Routable Protocol
makes it so you can divide comps into subnetworks with a boundary that is a router.
Go through a router to connect to other subnetworks.
Allow you to divide huge NWs into small NWs and can connect these smaller NWs with routers
NOn routable protocol
with non routable, all computers are connected
OSI Model
Basic steps of NW communication procedure.
What does TCP do?
Manages the communication process
Windowing
Process by which the client comp sends info to server comp.
The process that happens when comps are
Why was the internet created?
For the military. For WW3 scenarios. If nuclear armageddon has happened and you have diverse military installations trying to communicate with each other. This is the scenario tcp ip was created under.
Realization that communication might be flaky, if you send all info at once it might be garbled. Created “windowing” to test quality of transmission lines and sends “packets” (bits and bytes) of info. Acknowledgement is send back to sending computer to let it know packets where received. Sender will increase amount of packets sent after acknowledgment.
What does a receiving computer send to the sending computer when it receives packets?
It sends a confirmation message of data received
What does the sending computer do when it receives a confirmation of data received from its target computer?
It sends more packets than the last transmission
What does the sending computer do when there is an error in data sent?
Goes back to sending one packet at a time
What OSI layer is TCP?
Layer 4 - Transmission Layer
What OSI layer is IP?
Layer 3 - Networking Layer
IP Adresses
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Subnet Mask
Way to segment a NW logically so comps and devices can’t talk to other comps and devices on same NW. If you have a lot of comps and devices on your NW you don’t necessarily want them all talking to eachother
Default Gateway
the Router (can be other devices too) for the subnetwork the device that connects your subnetwork to all the other networks out there
DNS Server
Map domain names to IP addresses
What does your comp do when you enter a domain name?
It talks to the DNS and asks what the domain name means. DNS tells your comp what
Your comp will first search the local NW for the website. If it doesn’t find it it goes to the default gateway to get connected out to the website on the internet.
DHCP
Dynamic Host Control Protocol
What does your computer need to know
Comp needs to know its ip , default gateway, subnet mask , and what DNS to talk to
Static IP
Manually way to give NW info to your computer
Can take a long time if you have a lot of computers to enter info for. Problem : same info entered for two comps will cause havoc
Dynamic IP addresses
You can give your comp dynamic ip addresses:
Where DHCP comes in.
When comp connects to NW it will call out the DHCP server.
Dhcp server will then give it an IP address, tell it the subnet mask, default gateway, and DNS server.
Dhcp keeps track of addresses given out so that all addresses are unique
What does dhcp allow for?
The automatic distribution of IP addresses
It keeps track of IP adresses issued so that no two computers receive the same IP address
What happens in DHCP process?
- your comp asks for an IP address
- you have already told dhcp the scope of ip addresses it can give out. You tell it the subnet mask, the default gateway, and the DNS servers this is all preconfigured by you
- DHCP server will then give all info to comp with a “lease time”
Configured into DHCP by server admin. - Half way through lease your comp will try to renew lease on IP
- DHCP server says yes or no
- if comp can’t contact dhcp at 50% mark, it tries again at next 50% mark and continues until it gets in touch.
Contact time has a 50% “half life”.
NAT
Network Address Translation
People at first thought each comp would have to have its own ip that was unique to the world. not just your office but unique to the world. nat fixed this issue
How NAT works
each router needs own ip address. once inside router / inside internal nw , you can reuse addresses.
server on internet is concerned with the routers external ip address
Router has nat built into it. router routs info to the client comp in its network w / o nat every comp would need a unique ip address.
NATs purpose
Makes it so each computer doesnt need an absolute unique IP address
Subnet Masking
sdf
Define a Protocol
a protocol is a set of rules and procedures used for communication.
a protocol sets the rules and procedures for computers on a nw to talk to communicate
Stack definition
a “stack” of many small protocols to make up one big protocol
Analogy for NW Protocols
USPS “protocol”
Fedex “protocol”
rules and procedure to send packages and mail. Both have same basic components to their protocols (they have the same standards of communication: packaging, addressing, payment, getting package onto the network