[mamadrood]

IMP must be a Interface Message Processor [1], an Arpanet equivalent to our routers. And TIP must be Terminal Interface Processor [2], not really sure of their usage but basically they would allow remote sessions on the network, my guess is that they were some early forms of modern modems.

[1] https://en.wikipedia.org/wiki/Interface_Message_Processor

[2] https://en.wikipedia.org/wiki/Tip

[EvanAnderson]

I went down this rabbit hole this morning myself. There's a nice document at Bitsavers (http://www.bitsavers.org/pdf/bbn/imp/BBN1822_Jan1976.pdf) that has details about the two different IMP models, and the TIP and Pluribus IMP (an interesting multiprocessor IMP that I'd never heard about prior to today).

The TIP was the "Terminal IMP" (per the linked document) that provided connections to 64 terminals directly to the network through the IMP (with no intervening host).