Real-time communication is possible thanks to networks of expensive mass relay comm buoys that can daisy-chain a transmission via lasers.
Comm buoys are maintained in patterns built outward from each mass relay. The buoys are little more than a cluster of primitive, miniature mass relays. Each individual buoy is connected to a partner on another buoy in the network, forming a corridor of low-mass space. Tightbeam communications lasers are piped through these "tubes" of FTL space, allowing virtually instantaneous communication to anywhere on the network. The networks connect across regions by communications lasers through the mass relays.
With this system, the only delay is the light lag between the source or destination and the closest buoy. So long as all parties remain within half a light-second (150,000 km) of buoys, seamless real time communications are possible. Since buoys are maintained in all traveled areas, most enjoy unlimited instant communications. Ships only suffer communications lag when operating off established deep space routes, around uninhabited outer system gas giants, and other unsettled areas.
During wartime, comm buoy networks are the first target of an attack. Once the network is severed, it can take anywhere from weeks to years to get a message out of a contested system. In systems where a buoy network has not yet been built or has been destroyed, rapid communication means ferrying information through high-speed courier ships and unmanned data drones.