Transport Layer Flashcards

1
Q

Define sliding window - 3 big points

A

Receiver or destination will not wait for all the bytes for its window size to be received before replying. Receiver will send bytes after every two segments it receives. Benefit: allows the sender to continuously transmit segments. (If the buffer space of the receiver decreases, it will reduce its window size to inform the source to reduce the number of bytes it sends)

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2
Q

TCP Header Field: Control bits - describe size of the field, and label the major flags.

A

6 bits. URG, ACK, PSH, RST, SYN AND FIN

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3
Q

Describe the 3-way handshake

A

Point: The initializing client requests a client-to-server communication session with the server. 2: Server responds with an ACK, and a request a server-to-client communication session. 3: The initiating client ACK the server-to-client communication session.

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4
Q

Describe ACK (2 important functions)

A

ACK flag used in connection establishment and session termination

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5
Q

Describe SYN

A

Synchronize sequence numbers used in connection establishment

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6
Q

Describe FIN

A

No more data from sender and used in session termination.

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7
Q

Sequence and ACK numbers - how are they different over the course of handshake.

A

Sequence and ACK numbers. Client sends a SYN to server (SYN is a seq number 102). Server ACK with + 1 of the seq number (102). Server sends its own sequence number (300). Process is repeated for last step.

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7
Q

How many bytes for the UDP Header

A

8 bytes (64 bits)

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8
Q

UDP Header - list the five fields

A

Source and Destination Port, Sequence Number, Length and Checksum

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9
Q

What is a socket pair?

A

Combination of source IP, source port, or the destination IP and destination port is known as a socket. Sockets enable multiple processes, running on a client, to distinguish themselves from each other. Essentially, a client can throw different source port numbers to do multiple sessions, like requesting something from the file server or web server (https). Both are using the same destination IP server. The transport layer keeps track of the port numbers (source), so they can be forwarded to the correct application.

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10
Q

UDP - describe the differences

A

stateless protocol, connectionless, better delivery protocol.

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11
Q

Highlights of TCP

A

Stateful protocol, provides reliability, flow control, connection oriented protocol. Tracks segments, re-transmits any un-ack data, sends data at an efficient rate. (Tracks the state of the session)

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12
Q

Fields of a TCP Header

A

Source, Destination Port, sequence number, ack number, header length, reserved, control bits, window size, checksum and urgent.

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12
Q

TCP Header

A

20 bytes (160 bytes)

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13
Q
A
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14
Q
A
15
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16
Q
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17
Q
A