IP in IP is an unusual mechanism: not only does it use two network layers, it uses the same protocol on both.

From whatever reason, the fact remains that his letters are by no means uncheery reading; his books and study, most of all his friendships (with one fellow-captive especially), seem to have kept him contented and even happy.

Gernsback's second response to his readership was to establish a letter column, called 'Discussions', which became a regular feature from the January 1927 issue.

In 860 the Rus’ streamed southwards and laid siege to Constantinople itself.