---
title: "TCP send process - retry send?"
url: "https://maker.wiznet.io/forum/10315"
markdown_url: "https://maker.wiznet.io/forum/10315/md"
type: "Forum topic"
category: "Ethernet Chips"
author: "mboehmer"
created: "2014-06-17T14:45:38+09:00"
last_activity: "2017-05-04T08:33:11+09:00"
language: "en"
views: 884
replies: 0
source: "WIZnet Makers forum (https://maker.wiznet.io/forum/)"
---

# TCP send process - retry send?

## Question

Asked by mboehmer on 2014-06-17 in Ethernet Chips.

Hi,

as stated inside the “W5500 TCP Function” application note, it is recommended to check if the requested number of bytes has really been transmitted by W5500. Which makes me curious: In case I have a large data block to send by W5500, I would assume that i fill the TX buffer (best in multiples of MTU), start send process, wait for IR_SENDOK, and then continue with next send data block until all data has been sent.

When do I need to check for correct amount of data sent? If IR_SENDOK has been set, can I assume then that all data has been sent correctly which was ordered to sent by Sn_TX_WR register?

Please clarify.

Michael

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Source: https://maker.wiznet.io/forum/10315