This paper considers exclusively linear time-invariant distributed

-ports specified by a convolution operator:

. It defines

stability in the time-domain and characterizes it for a broad class of such

-ports. It characterizes absolutely stable

-ports. Finally, it defines absolute

-stability--i.e., stability of given

-port under any loading by passive

-ports,

-ports,

,-ports, where

. The necessary and sufficient conditions for absolute

-stability are obtained using Doyle\´s

functional. The paper is self-contained.