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How a transmission works
Web browsing, email, and web services involve TCP/IP-controlled packet
transmission characterized by reliable, adaptive, and fast router-enabled
client-server exchanges. The following remarkable features are part of a host of
intricate interactions governed by multiple protocols:
- Packetizing. All data to be transmitted is broken down into packets of
variable length (normally a few hundred bytes, in any case less than 64 kB) determined by the maximum transmission capacity of the weakest
link in the packet's pathway. Each packet carries a 160-bit (20 bytes) header identifying packet size, sequence, sender, destination, data
quality (checksum), and additional specs.
- Addressing. A hierarchical structure of the IP address
specifies first the network and then the host within it. Additional levels of hierarchy are inserted in the presence of subnets.
- Switching. Normally, a router forwards a packet to the next router according to a
routing table stored in every router. If a connection is
unavailable or too slow, the packet is being sent via a different route. The router learns new routes and automatically builds
a dynamic routing table.
- Reassembling. At the destination, a router checks quality and sequence of arriving packets, puts the packets into
correct sequence, and reassembles the transmitted message. If a packet is corrupt or missing, its retransmission is requested.
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