reliable

adj

1. Suitable or fit to be relied on; worthy of dependence, reliance or trust; dependable, trustworthy

   “a reliable witness to the truth of the miracles”

   “the best means, and the most reliable pledge, of a higher object”

   “According to General Livingston's humorous account, his own village of Elizabethtown was not much more reliable, being peopled in those agitated times by unknown, unrecommended strangers, guilty-looking Tories, and very knavish Whigs.”

2. Such that either a sent packet will reach its destination, even if it requires retransmission, or the sender will be told that it didn't.

noun

1. Something or someone reliable or dependable

   “the old reliables”