fractional T1

Definition of fractional T1 in The Network Encyclopedia.

What is Fractional T1?

A type of Internet connection. A fractional T1 line is a T1 line, leased by a T-carrier service provider to a customer, that carries only a fraction of the regular T1 bandwidth of 1.544 Mbps.

Regular T1 lines consist of 24 DS0 channels multiplexed together, while fractional T1 lines consists of fewer than 24 channels. Fractional T1 lines typically consist of a combination of nailed-up channels and switched channels.

The technology of fractional T-carrier services is the same as that of regular T-carrier services; the extra channels are simply unused. Customers might want to lease fractional T1 services when they don’t require the entire bandwidth (or cost) of a regular T1 line.