---
title: client.socket.tcpi_delta_retrans
summary: null
url: >-
  https://www.fastly.com/documentation/reference/vcl/variables/client-connection/client-socket-tcpi-delta-retrans
---

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

**Available in:** recv, deliver, log, error

The number of transmitted packets in the current connection that
contained data being retransmitted measured between when this request
started and now. For HTTP/1, this is the number of retransmissions
associated with this HTTP request. For multiplexed versions of HTTP
(e.g., HTTP/2) the number cannot be accurately ascribed to any
particular HTTP request. This metric primarily covers the response
message data and therefore is most meaningful after that has been sent
(e.g., in `vcl_log`). Bytes the HTTP stack has sent by
the time this metric is read may not have been sent successfully to
the client yet due to other system buffers and therefore more
retransmissions are still possible after VCL is no longer executing.