Which statement about BRIs network structure is true?

• A. BRIs require fiber optic connections for all channels.
• B. BRIs provide two B channels at 64 kbps each and one D channel at 16 kbps, and B channels can be aggregated to 128 kbps.
• C. BRIs do not support data transmission.
• D. BRIs use four fixed 256 kbps channels.

Answer: (B)

BRI is ISDN’s Basic Rate Interface, built around two 64 kbps B channels for user data and a single 16 kbps D channel for signaling and control. The two B channels can be bonded to create up to 128 kbps of end-user data when you need more throughput. The D channel handles call setup, maintenance, and signaling, and isn’t intended as a primary data path. BRIs don’t require fiber; they typically run over copper twisted-pair. They do support data via the B channels, and they do not use four fixed 256 kbps channels.