---
title: backend.socket.tcpi_data_segs_out
summary: null
url: >-
  https://www.fastly.com/documentation/reference/vcl/variables/backend-connection/backend-socket-tcpi-data-segs-out
---

**Type:** INTEGER  
**Access:** read-only

**Available in:** fetch

Includes retransmission segments carrying data.

Unlike `backend.socket.tcpi_segs_out`, `backend.socket.tcpi_data_segs_out` excludes segments carrying no data (e.g., pure ACK).