Prestel
In 1983, the Prestel messaging service known as “Prestel Mailbox” was launched, initially hosted on the computer known as "Enterprise", and later available from all IRC computers by means of a centralised messaging computer known as "Pandora". This facility extended the original day one concept of “Response Frames” whereby an end user could send a message back to the IP who owned the page via special pages, for example to order goods or services. The user’s name, address, telephone number, and date could be added automatically to the message when the IP set up the response frame by means of codes which triggered extraction of key data from the users account held on the IRC computer. Initially response frames were ingathered by an IP from each IRC individually, but later the facility to collect messages from all IRCs at the UDC from where they could be ingathered centrally was implemented, and with the introduction of Mailbox, they could be retrieved from any IRC.
Multicast address
IPv4 multicast addresses are defined by the most-significant bit pattern of "1110". This originates from the classful network design of the early Internet when this group of addresses was designated as "Class D". The CIDR notation for this group is . The group includes the addresses from to . Address assignments from within this range are specified in RFC 5771, an Internet Engineering Task Force (IETF) "Best Current Practice" document (BCP 51).