My Asus RT-AC68U setting to fight buffer bloat ECN

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bsmithline
DD-WRT Novice


Joined: 28 Aug 2009
Posts: 6

PostPosted: Sun May 17, 2015 19:16    Post subject: My Asus RT-AC68U setting to fight buffer bloat ECN Reply with quote

This is how I setup my Asus RT-AC68U to fight buffer bloat

Used: DD-WRT v24-sp2 (03/05/15) std (SVN revision 26446)

Available: ftp://ftp.dd-wrt.com/betas/2015/03-05-2015-r26446/asus-rt-ac68u/asus_rt-ac68u-firmware.trx

One I found at dd-wrt.com v24 PreSP2 [Beta] Build:23940 had problem with port forwards that would cause the RT-AC68U to crash/restart....

Workstation set to use ECN from the guide found at http://en.wikipedia.org/wiki/Explicit_Congestion_Notification.

Before any changes where made on Fontier FIOS 25 MB connection received an "F" on the DSLREPORTS speed test. With Qos set to enable Port:WAN Packet Schedule:HTB Queueing Discipline the best I could do was "C" on the test even with workstations ECN set to on.


http://www.bufferbloat.net/projects/bloat/wiki/Linux_Tips

Enable ECN, SACK, and DSACK

These sysctl settings can be stored in the main /etc/sysctl.conf file, or in a file in the /etc/sysctl.d directory [NOT WITH .DD-WRT v24-sp2 (03/05/15) std (SVN revision 26446) FIRMWARE]

net.ipv4.tcp_ecn=1
net.ipv4.tcp_sack=1
net.ipv4.tcp_dsack=1

Note that there is still some broken ECN CPE (e.g. home router) equipment out there; if you have problems in some environments, please let us know.


TELNET to RT-AC68U login: root then the password you used when you setup dd-wrt on RT-AC68U

Only change need to DD-WRT v24-sp2 (03/05/15) std (SVN revision 26446)

echo 1 >/proc/sys/net/ipv4/tcp_enc

To check values make sure all are 1 [ note

cat /proc/sys/net/ipv4/tcp_enc
cat /proc/sys/net/ipv4/tcp_sack
cat /proc/sys/net/ipv4/tcp_dsack

If not use echo 1 >/proc/sys/net/ipv4/tcp_XXXX for the one you need to change.

Changed value in dd-wrt NAT / QoS tab

Packet Scheduler to HFSC

Test run at http://www.dslreports.com/speedtest HTML 5 now show either an A or A+.
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MDA400
DD-WRT User


Joined: 10 Jan 2015
Posts: 103

PostPosted: Mon May 18, 2015 4:32    Post subject: Reply with quote
Actually there is a wiki for the correct QoS settings:
http://www.dd-wrt.com/wiki/index.php/Quality_of_Service

HTB scheduler, FQ_Codel queue discipline, and 80-90% bandwidth limit is the recommended. ECN is fine to have enabled, but alone it doesn't do enough for an entire network's bufferbloat and isn't available in every device (playing a game and downloading a file at the same time/walking and chewing gum).

The dslreports test isnt the best indicator for buffer bloat. You must ping a website like google from command line then fully saturate your connection and observe how big the variation in latency is (jitter).
bsmithline
DD-WRT Novice


Joined: 28 Aug 2009
Posts: 6

PostPosted: Sun Jun 07, 2015 22:56    Post subject: CHANGED FIRMWARE and setup on my setup Asus RT-AC68U to figh Reply with quote
Reason for change was no buffer bloat issues on upload, however more testing was showing issues with the download with the DD-WRT firmware. Reason for the change to Asuswrt-Merlin is it an alternative, custom version of firmware made for the Asus product line.

Used: Asuswrt-Merlin Stable (all): 378.53 Date: 26-Apr-2015

Available: http://asuswrt.lostrealm.ca/download

AGAIN NOTE: I found at dd-wrt.com v24 PreSP2 [Beta] Build:23940 had problem with port forwards that would cause the RT-AC68U to crash/restart....

Workstations set to use ECN from the guide found at http://en.wikipedia.org/wiki/Explicit_Congestion_Notification.

Before any changes were made on Frontier FIOS 25 MB connection received "B’s" on the DSLREPORTS speed test with Windows 7 IE with ENC on in the workstation settings.
When Enable Smart QoS was turned “ON” [Adaptive QoS on the sidebar/QoS tab] and upload and download set to 25 MB multiple tests reported solid “A’s” which makes me feel much better about my decision to pay extra for the Asus RT-AC68U that supports open source software to replace my 5 year old router that has firmware that is no longer being updated.

TELNET to RT-AC68U to view the defaults used by Asuswrt-Merlin Stable (all): 378.53 Date: 26-Apr-2015
# cat /proc/sys/net/ipv4/tcp_ecn
2
# cat /proc/sys/net/ipv4/tcp_sack
1
# cat /proc/sys/net/ipv4/tcp_dsack
1

As multiple tests reported solid “A’s” on the DSLREPORTS speed tests I did not make any changes.
Tests run at http://www.dslreports.com/speedtest HTML 5 again now show solid A’s

Hopes this helps someone new to this process setup an Asus router that will indeed help fight buffer bloat and the loss of packets.

When I first started to work on the Internet at a little mom, and pop ISP when it first opened up in the 1990’s there was and still is a site called Internet Traffic Report [ http://www.internettrafficreport.com ]. Back then it was showing anywhere from 4% to 6% packet loss in North America. As the years rolled on some days it was at or above 10%. If you looked at Asia it was even worse.

Now in 2015 I notice that it is at 0% packet loss worldwide. Looks like the big boys found a way to fight any connection speed, and buffer issues that where the cause of what was an ever increasing packet loss issue. My wish is that it would now make it all the way down to the end of the last mile. The issues with packet loss due to buffer bloat that are now at the end of the home and business connections I feel helps lead to the congestion issues we see during the high use periods at night.
Haul
DD-WRT Novice


Joined: 30 Jan 2015
Posts: 20

PostPosted: Wed Jun 10, 2015 5:47    Post subject: Reply with quote
None of those settings will affect download/upload speeds for flows passing THROUGH the router. They will only affect transfers going to or from the router itself (e.g., you log into the router and run a wget on it). They can have an impact when set on the hosts behind your router though. Any changes in speed that you saw when changing these /proc tunables on the router itself are purely coincidental.
Fonfoo
DD-WRT Novice


Joined: 14 Sep 2015
Posts: 4

PostPosted: Mon Sep 14, 2015 9:58    Post subject: Reply with quote
Hi guys!

I'm new to this forum and hope that posting myquestion here is the right way to do this. If not, I apologize.

Can any of you tell me if HotSpotSystem is one of the services you find in "service -> hotspotsystem"?

Thanks!
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