Change RWIN Value macOS Monterey 12.3 Stable Build

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Level 1

22 points

Change RWIN Value macOS Monterey 12.3 Stable Build

How do I change the RWIN value in macOS Monterey. I have created a sysctl.conf file and the RWIN value does not change. Here is below what my configuration is located in /etc/systctl.conf.

kern.ipc.somaxconn=2048

net.inet.tcp.rfc1323=1

net.inet.tcp.win_scale_factor=4

net.inet.tcp.sendspace=1042560

net.inet.tcp.recvspace=1042560

net.inet.tcp.mssdflt=1448

net.inet.tcp.v6mssdflt=1412

net.inet.tcp.msl=15000

net.inet.tcp.always_keepalive=0

net.inet.tcp.delayed_ack=3

net.inet.tcp.slowstart_flightsize=20

net.inet.tcp.local_slowstart_flightsize=9

net.inet.tcp.blackhole=2

net.inet.udp.blackhole=1

net.inet.icmp.icmplim=50

However Speedguide.net TCP Analyzer shows these results. The TCP Window is the value that needs to be optimized for a fast fiber connection.

« SpeedGuide.net TCP Analyzer Results »

Tested on: 2022.03.17 15:00

IP address: 172.226.x.xx

Client OS/browser: Mac OS (Safari 15.4)

TCP options string: 020405b40402080ab0995de10000000001030307

MSS: 1460

MTU: 1500

TCP Window: 64256 (not multiple of MSS)

RWIN Scaling: 7 bits (2^7=128)

Unscaled RWIN : 502

Recommended RWINs: 64240, 128480, 256960, 513920, 1027840

BDP limit (200ms): 2570 kbps (257 Kilobytes/s)

BDP limit (500ms): 1028 kbps (103 Kilobytes/s)

MTU Discovery: ON

TTL: 49

Timestamps: ON

SACKs: ON

IP ToS: 00000000 (0)

MacBook Pro 14″, macOS 12.3

Posted on Mar 17, 2022 12:13 PM

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Answer 1

MAPE15 Author

Level 1

22 points

Mar 17, 2022 1:34 PM in response to etresoft

I have used the site for years for optimizing my Windows OS TCP/IP stack. However, the macOS side is different and does not seem to take the values I input and use them. Is there a way to check these settings in terminal or commands to change them? Are there any 3rd party tools to perform these changes for Macs?

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Answer 2

etresoft

Level 9

57,736 points

Mar 17, 2022 2:52 PM in response to MAPE15

MAPE15 wrote:

I have used the site for years

That's what I mean. That site looks really old. I ran the analyzer with my Linux machine that has 10 Gig on a fibre connection and it says my BDP is limited to a value a fraction of what it actually does. When I tried to look for other information about these values, even on Linux, I found nothing newer than 10 years old. I think all of that has been overcome by events and modern technology. And then the Mac is radically different than Linux. Don't be fooled by that BSD compatibility stuff - it has been heavily hacked to look like BSD, but it is nowhere close.

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Answer 3

etresoft

Level 9

57,736 points

Mar 17, 2022 4:44 PM in response to MAPE15

MAPE15 wrote:

So what can we do to improve the network performance/tuning of macOS Monterey?

First you have to establish some metrics to definitely state that it needs improving. That was easier 10-15 years ago. But today you have to be extra careful with high-speed components, RF networking, and internet congestion. If there is a problem, it is really difficult to definitively blame something as low-level as an operating system TCP configuration. There are too many other things that are more likely to be the cause.

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Answer 4

MAPE15 Author

Level 1

22 points

Mar 17, 2022 4:47 PM in response to etresoft

Correct. I was trying to use something like Netspot or Wifiner to analyze my environment and determine if there is internet congestion or RF interference but they are too expensive. Any ideas on what else to try to improve performance for Fiber Optic Connections 1Gbps+?

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Answer 5

etresoft

Level 9

57,736 points

Mar 17, 2022 5:56 PM in response to MAPE15

MAPE15 wrote:

Any ideas on what else to try to improve performance for Fiber Optic Connections 1Gbps+?

Are you getting poor performance? What do other people with the same service report?

Your network is only going to be as fast as the slowest link. I don't know what your network looks like, but if it is anything like normal consumer fibre connections, there are lots of hops between here and there. It is very unlikely to have all of those links hit 1 GBs. Even when you look at the commercial equipment on the other side, they exceed 1 GBs, but their bandwidth is shared between hundreds or thousands of people doing speed tests on their 1 GBs connections.

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Answer 6

MAPE15 Author

Level 1

22 points

Mar 17, 2022 6:12 PM in response to etresoft

I have been trying out different Wi-Fi 6 routers and YMMV. I found an older Wi-Fi 6 that came out in 2018 and it performed over 50% faster than the newest 2021/2022 models. Trying to determine whether it is just the routers I am using or something else (Google Fiber ONT- (no modem straight fiber connection out of wall to router), laptops, game console, phones, etc).

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