The legal effect of subletting is that the original tenant is still bound by the lease he or she has with the landlord, and is therefore still responsible for paying rent. However, the new tenant (or subtenant) is also included within the definition of tenant under the Residential Tenancies Act and therefore also has a legal duty to pay rent when due.
The original tenant could choose to pay rent directly to the landlord, and collect the rent from the subtenant. This option allows the original tenant to be sure that rent is paid to the landlord. Another option is to see if the landlord would agree to accept the rent directly from the subtenant. However, if the subtenant did not pay the rent for any reason, the original tenant would still be responsible for paying the rent.