X.25 or X.400

[Sangeeta Dubey]

WHAT IS X.25 OR X.400

[Rakesh K. Sharma]

X.25 is an ITU-T standard protocol suite for packet switched wide area network (WAN) communication. An X.25 WAN consists of packet-switching exchange (PSE) nodes as the networking hardware, and leased lines, Plain old telephone service connections or ISDN connections as physical links. X.25 is a family of protocols that was popular during the 1980s with telecommunications companies and in financial transaction systems such as automated teller machines. X.25 was originally defined by the International Telegraph and Telephone Consultative Committee (CCITT, now ITU-T) in a series of drafts[1] and finalized in a publication known as The Orange Book in 1976.[2]

While X.25 has been, to a large extent, replaced by less complex protocols, especially the Internet protocol (IP), the service is still used and available in niche and legacy applications.

[Sangeeta Dubey]

Thank you for the information.

Any one know .what is x.400

[Anupama Chetia]

X.400 is a suite of ITU-T Recommendations that define standards covering electronic mail service provided by Data Communication Networks for Message Handling Systems (MHS).

[Reena Sachdev]

www.patton.com/technotes/x25_basics.pdf

[Reena Sachdev]

X.400 is the messaging (notably e-mail) standard specified by the ITU-TS (International Telecommunications Union - Telecommunication Standard Sector). It's an alternative to the more prevalent e-mail protocol, Simple Mail Transfer Protocol (SMTP). X.400 is common in Europe and Canada. It's actually a set of standards, each in the 400-number range.