TCP settings for 1 Gbps Internet Access

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Level 1

4 points

TCP settings for 1 Gbps Internet Access

I have an iMAC running 10.14.6 and I'm connected to the Internet via a fiber full duplex 1 Gbps connection with my iMAC using its GigE connection. What's interesting is I'm seeing ~900 Mbps up and ~300 Mbps down. What I'm wondering is whether its worth while to tune TCP settings and if this the case what are the recommended values?

Kirk

P.S. Here is a what I'm seeing with ifconfig:

en0: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> mtu 1500 index 5

eflags=410009c0<ACCEPT_RTADV,TXSTART,RXPOLL,ARPLL,ECN_ENABLE,FASTLN_ON>

options=10b<RXCSUM,TXCSUM,VLAN_HWTAGGING,AV>

ether ac:87:a3:24:75:ef

inet6 fe80::1407:4e13:3ee1:e6f1%en0 prefixlen 64 secured scopeid 0x5

inet 192.168.0.3 netmask 0xffffff00 broadcast 192.168.0.255

nd6 options=201<PERFORMNUD,DAD>

media: autoselect (1000baseT <full-duplex>)

status: active

type: Ethernet

link quality: 100 (good)

state availability: 0 (true)

scheduler: FQ_CODEL

link rate: 1.00 Gbps

qosmarking enabled: yes mode: none

low power mode: disabled

Posted on Aug 27, 2019 4:13 PM

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Answer 1

Aug 27, 2019 4:21 PM in response to KirkSpessard

You will never achieve the full 1 GBps bandwidth above the link level due to packet collisions, retransmits, TCP checksums, errors, etc. I would not waste the time attempting to tweak your existing network settings based on the first sentence. I didn't and do not regret it.

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Answer 2

dtaht

Level 1

4 points

Aug 28, 2019 6:04 PM in response to KirkSpessard

It depends a bit on what tools you are using to do the measurement. What did you use?

Around here we use "flent.org" to measure stuff,

if you install that and run the rrul test we can get a good picture of why your download is so poor. Was it just one flow? Try 4....

If you have another speedtest tool you were using (browsers simply can't do a gbit - iperf? netperf?), try a few flows of that.

also (as root)

netstat -sp tcp

netstat -I en0 -qq

once before, during, and after the test might yield some useful stats.

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TCP settings for 1 Gbps Internet Access

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