Data communications services networks x

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Can any expert help me out in explaining about the X.25 Networks?

Best Answer by jmarcatch
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Answered By 0 points N/A #90290

Data communications services networks x



Here are the basics of the X.25 network:
  • The X.25 network contains the standard protocols for packet switching across networks.

Basic aspects of the X.25 network:

  • Packet switching.
  • Information from many different users is combined into packets.
  • Packets are sent to the Packet Data Network (PDN).
  • Packet are routed through the network cloud to the destination.
  • The user has a virtual connection instead of a dedicated connection as in circuit switching protocols.
  • The circuit is shared by many different users.
  • Packets switching results in cost savings compared to circuit switching.
  • The X.25 was one of several protocols designed for secure transmission of voice traffic using analog lines.


The protocol specifies:

  • How terminals talk to packet forming devices.
  • How packet assemblers talk to packet switches.
  • How packet switching nodes talk to one another.
  • The X.25 network handles the assembly of packets, delivery, and the disassembly of packets.
  • The Packet Assembler/Dissembler (PAD) in X.25 networks.
  • Assembles asynchronous transmissions into a single, synchronous X.25 packet (up to 128 data bytes in length).
  • The PAD is like a 56 Kbps statistical multiplexer which will send packets to an X.25 switch.
  • The switch separates and routes packets to destination with a specified algorithm.
  • Analog lines often see lots of errors.
  • X.25 networks use a series of error checks to overcome the errors often experienced using analog lines.
X.25 Networks are best used in various environments, such as:
  • Where asynchronous communications is desired.
  • Where the line quality poor, the X.25 networks can overcome poor line quality.
  • Where data traffic is small and in bursts.
  • Where a decrease in transmission expenses is desired.
Answered By 590495 points N/A #90292

Data communications services networks x



X.25 is one of the oldest and still available packet-switched services that were made available in public in most countries during the 1970s and 1980s to lower down the cost of accessing different online services. Examples of X.25 networks that were made publicly available are Tymnet, Compuserve, Datanet 1, PSS, Euronet, Telenet, and Datapac. It is an ITU-T standard protocol suite that is used as packet switch in a Wide Area Network communication [WAN] or simply an X.25 WAN.

It is composed of nodes of packet-switching exchange or PSE that acts as the networking hardware, and plain old telephone service connections, ISDN connections, and or rented lines that acts as the physical links. It is a group of protocols used by telecommunications companies and also used in financial transaction systems like ATMs or Automated Teller Machines that was popular in the 1980s. After the great advancement in technology, the X.25 is being replaced to a great degree by less complicated protocols such as Internet Protocol or IP.

Here is how to describe an X.25 Network:

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