An IRU is a long-term agreement giving the holder an effectively exclusive right to use particular fiber strands or capacity for a fixed period, commonly fifteen to twenty-five years. It sits between leasing and owning: you do not own the cable, but your right to use those strands is not revocable at the provider's convenience.
A lease is a recurring service relationship that can be renegotiated or terminated on the terms in the contract. An IRU is a long-horizon grant, usually paid substantially up front, which is treated very differently for accounting purposes and gives the holder far stronger security over the asset for the term.
Maintenance of the physical plant — locates, repairs after cuts, and route upkeep — generally remains with the owner and is covered by an ongoing operations and maintenance charge alongside the up-front payment. The maintenance terms deserve as much attention as the grant itself, because they govern what happens on the day a backhoe finds the cable.
Whether the strands are specified and exclusive, what the repair commitment and response time are, whether the right is assignable if your organization restructures, what happens at term end, and how relocations forced by roadworks are handled and paid for.
IRUs are the standard structure for dark fiber because the value of dark fiber is long-horizon control, and a short lease undermines the reason to buy it. They are common between carriers and increasingly used by utilities, universities, and public agencies building networks they intend to operate for decades.
IRU is one of the specifications these comparisons turn on.
Describe the requirement and an engineer will tell you which service actually fits — without a rate card or a sales script in the way.
Service availability depends on location, network proximity, capacity, and engineering review. Share an address and we will confirm what can be delivered there.