page_title: TRAME
section_title: TRAME 2
hierarchical_section_title: TRAME / Evolution / TRAME 2
caption_attribution_description: English: Drawing the TRAME packet switching network by 1994
context_page_description: TRAME was the name of the second computer network in the world similar to Internet to be used in an electric utility. Like Internet, the base technology was packet switching and it was developed by the electric utility ENHER in Barcelona and deployed by this same Utility first in Catalonia and Aragón, Spain, and later in other places. Its development started in year 1974 and the first routers, called nodes by that time, were deployed by year 1978. The network has been in operation until year 2016, obviously with successive technological software and hardware updates.
context_section_description: In year 1990, TRAME 2 was completely deployed and TRAME 1 substituted. The processor of the new hardware was Intel 80286 and the hardware structure and the external aspect of routers was very similar to that of TRAME 1. The software was written in C language and the mentioned emulator continue to be used.
  The improvements over TRAME 1 were the introduction of the standardized X.25 access protocol to enable the connection of corporate IT terminals to the network, the ability to cope with the 64kbit/s of the new digital lines, an increased switching capacity and the introduction of an end-to-end protocol to avoid loss of packets and disordering as required by X.25.
  An important improvement was the possibility to use dual homing to increase terminal availability; They could be connected to the network by two access ponints. For the purpose, the terminals had two addresses, a primary one and a secondary one.
  Regarding addressing, in 1991 two bits were added to the addressing to indicate the network.  The address space was thus increased to 16 bits and up to 4 networks could be freely meshed as in a single one. This addressing scheme was maintained in the following TRAME versions.
caption: Figure IV: Topology of the TRAME network in year 1994
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