---
title: "W5500 vs. W5100 / W5200"
url: "https://maker.wiznet.io/forum/10711"
markdown_url: "https://maker.wiznet.io/forum/10711/md"
type: "Forum topic"
category: "Ethernet Chips"
author: "emvilla"
created: "2014-12-03T09:01:45+09:00"
last_activity: "2017-05-04T08:34:30+09:00"
language: "en"
views: 23040
replies: 3
source: "WIZnet Makers forum (https://maker.wiznet.io/forum/)"
---

# W5500 vs. W5100 / W5200

## Question

Asked by emvilla on 2014-12-03 in Ethernet Chips.

Hello,

I noted a different behaviour between W5500 and W5100 responding to [SYN] packet when all sockets are busy and no more connections can be accepted.
While W5100 answer with a [RST] packet, W5500 send a [RST,ACK] packet, I presume to speed up the ethernet traffic.
This difference impacts on browsers behaviour:

- with W5100 there is a retransmission of the [SYN] packet and the request is acknowledged as soon a socket becomes available

- with W5500 the request is aborted

Is there a way to set W5500 in order to send only the [RST] packet without the ACK as W5100 does?
I haven’t a W5200 to test. Does anybody knows how W5200 behaves?

Thanks
Best regards
E.M.Villa

## Replies

### Reply 1 by hjjeon0608, 2014-12-08

Hi,

W5100 is implemented to send RST packet.
W5200/W5500 are implemented to send RST/ACK packet.

It is designed as hardware not software, so it cannot be changed unfortunately.

### Reply 2 by emvilla, 2014-12-08

Hi hjjeon,

thanks for your answer.
Since we are tuning our project in these days and we want to use Wiznet, I think we will probably use W5100.
Could you tell me please if W5100 is a valid choice for new projects?
Or it will be discontinued soon?

Thank you very much.
Regards
E.M.Villa

### Reply 3 by hjjeon0608, 2014-12-08

Hi,

W5100 is in Arduino official ethernet shield and we don’t have plan to discontinue.
But W5500 is more cheap, better performance and have 8 sockets.

So, W5500 is more suitable for web server. But if RST packet is critical issue, maybe W5100 is good choice.

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Source: https://maker.wiznet.io/forum/10711