version 16, including all changes.
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LawrenceDoliveiro |
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TCP is an [Acronym] of TransmissionControlProtocol. It is part of the [TCP/IP] protocol stack. |
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PerryLorier |
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LawrenceDoliveiro |
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TCP is connection-oriented: before two parties can communicate, they must ''open'' a common connection; after they have finished communicating, they ''close'' the connection. The initiation of the connection is ''asymmetric'': one end needs to ''listen'' for connection attempts, while the other end initiates a connection during this time. However, once the connection is opened, it is ''symmetric'' and ''full-duplex''--both ends are equally capable of transmitting arbitrary information at arbitrary times. |
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TCP is an ordered stream--data sent from one end will arrive at the other end in the same order. Communication is ''reliable''--all transmissions are automatically acknowledged, with timeouts and retries if any lower-level packets are lost, including automatic sequencing to detect duplicates (as can happen when a lower-level packet wasn't "lost", but simply took too long to arrive). Compare [XCP] and [DCCP]. |
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PerryLorier |
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Someone who's done 312 recently want to write a big long discussion about Nagle, Slow start, backoff, congestion control, window sizes etc? |
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JohnMcPherson |
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We have separate pages discussing TcpStates, and the TcpWindow. |
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!!TCP Header: |
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PerryLorier |
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|00|01|02|03|04|05|06|07|08|09|10|11|12|13|14|15|16|17|18|19|20|21|22|23|24|25|26|27|28|29|30|31 |
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||||||||||||||||||||||||||||||||^[IPv4]/[IPv6] Header |
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||||||||||||||||Source Port |||||||||||||||| Destination Port |
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|||||||||||||||||||||||||||||||| Sequence Number |
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|||||||||||||||||||||||||||||||| Acknowledgement |
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||||Data Offset||||Reserved|[CWR]|[ECE]|[URG]|[ACK]|[PSH]|[RST]|[SYN]|[FIN]||||||||||||||||Window |
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||||||||||||||||Checksum||||||||||||||||Urgent Pointer |
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||||||||||||||||||||||||||||||||Optional Options / Padding |
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||||||||||||||||||||||||||||||||v Data |
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!!TCP Options: |
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! End of option list |
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|00|01|02|03|04|05|06|07 |
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|||||||| 0 |
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! No Op (Padding) |
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|||||||| 1 |
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! Maximum Segement Size |
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|||||||| 2 |||||||| length (4) |||||||||||||||| MSS |
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|||||||||||||||| MSS (Continued) |||||||||||||||| |
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! Window Scale Option |
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|||||||| 3 |||||||| length (3) |||||||| Shift Count |||||||| |
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! [SACK] |
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|||||||| 4 |||||||| length (2) |
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! [SACK] Information |
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|||||||| 5 |||||||| length |||||||||||||||| Left edge of first block |
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|||||||||||||||| Left edge of first block (continued) |||||||||||||||| Right edge of first block |
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|||||||||||||||| Right edge of first block (continued) |||||||||||||||| ..... |
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|||||||||||||||| ....... |||||||||||||||| Left edge of last block |
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|||||||||||||||| left edge of last block (continued) |||||||||||||||| Right edge of last block |
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|||||||||||||||| Right edge of last block (continued) |
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! TCP Timestamps |
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|||||||| 8 |||||||| length (10) |||||||||||||||| TS Value |
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|||||||||||||||| TS Value (Continued) |||||||||||||||| TS Echo Reply |
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|||||||||||||||| TS Echo Reply (Continued) |||||||||||||||| |
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---- |
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See also: |
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* [A very nice cheat sheet | http://www.sans.org/newlook/resources/tcpip.pdf] for [TCP/IP] |
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* [assigned tcp options|http://www.iana.org/assignments/tcp-parameters] |
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PerryLorier |
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* [Linux Congestion Control | http://www.cs.helsinki.fi/u/sarolaht/papers/linuxtcp.pdf ] |
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IanMcDonald |
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* TcpTuning |
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PerryLorier |
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---- |
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CategoryProtocols, CategoryNetworking |
