j. Revenue Recognition The Company recognizes revenues derived from leasing fiber optic telecommunications infrastructure and the provision of telecommunications and colocation services when the service has been provided and there is persuasive evidence of an arrangement, the fee is fixed or determinable, customer acceptance has been obtained with relevant contract terms, and collection of the receivable is reasonably assured. Taxes collected from customers and remitted to a governmental authority are reported on a net basis and are excluded from revenue. Most revenue is billed in advance on a fixed-rate basis and the remainder is billed in arrears on a transactional basis determined by customer usage. The Company often bills customers for upfront charges, which are non-refundable. These charges relate to activation fees, installation charges or prepayments for future services and are influenced by various business factors including how the Company and customer agree to structure the payment terms. These upfront charges are deferred and recognized over the underlying contractual term. The Company also defers costs associated with customer activation and installation to the extent of upfront amounts received from customers, which are recognized as expense over the same period for which the associated revenue is recognized. The Company typically records revenues from leases of dark fiber, including indefeasible rights-of-use (IRU) agreements, over the term that the customer is given exclusive access to the assets. Dark fiber IRU agreements generally require the customer to make a down payment upon the execution of the agreement with monthly IRU fees paid over the contract term; however, in some cases, the Company receives up to the entire lease payment at the inception of the lease and recognizes the revenue ratably over the lease term. Revenue related to professional services to provide network management and technical support is recognized as services are provided. In determining the appropriate amount of reven