Term
| What does the sequence number of a TCP connection represent? |
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Definition
| The number corresponding to the first byte of data sent in that segment |
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Term
| Why is the initial sequence number chosen randomly? |
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Definition
| To protect against two incarnations of the same connection reusing the same sequence number too soon |
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Term
| Why does TCP include an end-to-end checksum when there are other (practically always) hop-by-hop error detection mechanisms in place? |
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Definition
| There are no garauntee that each hop will perform perfectly, and they may introduce errors while transferring data from their input to output buffers or reorder messages |
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Term
| What are flags used during the 3-way handshake in TCP? |
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Definition
| (SYN, sequence number=x), (SYN+ACK, sequence num=y), (ACK, acknowledgment=y+1) |
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Term
| Why can the last ACK of the 3-way handshake get lost without disrupting the opening of the connection? |
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Definition
| the client side is already in the ESTABLISHED state, so the local application process can start sending data to the other end |
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Term
| Why is that TCP when in the TIME_WAIT state cannot move to the CLOSED state until it has waited for two times the maximum amount of time an IP datagram might live in the Internet (i.e., 120 seconds)? |
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Definition
| The Reciever assuses that the Final ACK was not delivered to the Sender, so as to protect against the sender from retransmitting the final seg and accedentally terminating the connection of a later incarnation |
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Term
| What is the goal of the AdvertisedWindow? |
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Definition
| flow control, preventing the sender from overwhelming the rec by managing the rate of transmission |
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Term
| What does the size of a window represent in a sliding window algorithm? |
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Definition
| A limited value of unacknowledged bytes at anygiven time |
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Term
| What is the difference between the EffectiveWindow and the AdvertisedWindow? |
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Definition
| The Effective window is computed by the sender to determine the amount of bytes it can send, the Advertised window is the space in the receiving buffer that is avaliable for incoming bytes computed by the reciever |
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Term
| How does a sending TCP figure out when the AdvertisedWindow changes from zero to a positive value? |
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Definition
| The sending side sends a 1 byte data segment which will trigger a Advertised window response |
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Term
| What is the output of the following Python code:count = 0 while count < 5: print count count += 1 # This is the same as count = count + 1 |
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Definition
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