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23 Cards in this Set
- Front
- Back
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What is the TCP IP 3 Way handshake?
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Builds sessions of communication between devices.
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What kind of connection is TCP?
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Reliable connection.
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What kind of connection is UDP?
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Best effort connection, unreliable. No ack/syn.
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What is UDP designed for?
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UDP is designed for real time communicaiton. IE voip, online games, ext.
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How does TCP keep its packets in order?
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TCP uses sequence numbers.
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What are sequence numbers used for?
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So receiving device can put packets back in correct order.
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How does TCP start a session?
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Session starts with 3 way hand shake.
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What is a syn packet?
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Synchronization packet.
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What is a ack packet?
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Acknowledgment packet.
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How is the handshake performed?
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Source device send syn packet.Destination packet responds with syn/ack packet. (Syn to finish the synchronization and ack to acknowledge the orig syn packet was received.) Source device replies w/ ack that the distinations syn/ack packet has been received.
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What happens after handshake?
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Data begins to move back and forth between devices.
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How often does a packet get a sequence number?
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Every packet gets one.
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Are response packets also sequenced?
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Yes.
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What does Ack 11 mean?:
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It means I received 10 successfully and I'm ready for 11.
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How does computer know when to resend data if it thinks the receiving device never got its packet?
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Each packet is imbued with a timer that says if I haven't received an ack by this time, I will resend.
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The handshake process sounds so slow, how do they remedy?
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Through TCP Windowing.
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How does TCP Windowing work?
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First packet is sent, if it is received, 2 packets are sent if it is received, 4 packets are sent ext. This will increase limitlessly until there is a problem.
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What is there is a problem with the Window?
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It will start stepping each window down. From 4 to 2, then from 2 to 1. Until it feels the window is reliable.
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Does it ever increase the window after it has been decreased?
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Eventually it will attempt to increase the window size again.
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What is the process of increasing the window size called?
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It is called sliding window.
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What does comp do if it doesn't receive the next ack in the sequence. (IE sent sync 10 got ACK 9)?
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Comp assumes failure, resends previous packet and slides window down.
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What does the sequence number actually represent?
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How many bytes the sender is sending at once.
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What is a good example of sequence numbers?
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100Bytes sent. Acks 101. 200 Sent.
Acks 201. 400 Sent. Acks 201. Failure. Slides window down. Sends 201. |
