Enter the complex network (8)
I believe the answer is:
ethernet
'network' is the definition.
(I know that Ethernet is a type of LAN)
'enter the complex' is the wordplay.
'complex' indicates anagramming the letters.
'enter'+'the'='enterthe'
'enterthe' with letters rearranged gives 'ETHERNET'.
(Other definitions for ethernet that I've seen before include "Local area computer network" , "Network of a number of computers" , "comms system" , "System connecting several computers" , "Communication system" .)