"extensive network" is a correct and usable phrase in written English. You can use this phrase when referring to a broad, intricate arrangement of people, businesses, or organizations connected with each other. For example, "The fashion industry has an extensive network of designers, models, and photographers.".
The state has an extensive network of highways.
Most countries have an extensive network of pipelines.
Politicians are therefore looking covetously at Mr Obama's extensive network.
The order appeared to apply to Hamas's extensive network of schools and health clinics.
I guess I have a very extensive network as it turns out.
She leaves behind an extensive network of family and friends spanning generations and geography.
Israeli forces have discovered a much more extensive network of tunnels than expected.
When I feel like I can't trust my brain 100%, Ludwig really comes in handy. It makes me translate and proofread faster and my output more reliable.
Claudia Letizia
Head Translator and Proofreader @ organictranslations.eu