Ideambox
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TOOL IDB-SWE-014
BLE GATT MTU

Desktop only

Engineering tools are available only on desktop screens.

BLE GATT MTU & throughput

Effective GATT throughput from MTU, PHY (1M / 2M / Coded), connection interval, and packets per event. Real numbers — not the marketing 2 Mbps.

Connection event timeline interval — ms
conn evt interval idle remainder PDU breakdown P 1 B ACC ADDR 4 B LL 2 B PDU 247 B L2CAP+ATT+app CRC 3 B THROUGHPUT vs PHY rate — kbps full-MTU latency: — ms
Engineering notes

Overheads (per LL packet)

  • 1 byte LL header + 4 byte L2CAP + ATT opcode/handle + ~3 byte MIC if encrypted.
  • Preamble (1B on 1M, 2B on 2M, 10B on Coded) + Access Addr 4B + CRC 3B + InterFrame 150µs.

Reality

  • iOS clamps minimum interval to 15 ms.
  • Coded PHY adds redundancy bits → reduces effective rate.
  • Encryption adds 4 bytes MIC per PDU.

Result

Live