Slow internet speeds after ISP upgrade

Discussion in 'Tomato Firmware' started by pyrodex, Jan 23, 2019.

  1. pyrodex

    pyrodex Networkin' Nut Member

    ASUS RT-N66U running Tomato v 1.28 by shibby

    their modem > router > gb switch > desktop

    all CAT5e cables

    Old service was ~120/10. Upgraded tonight (same routing as above) and first test from was ~140/20. This matches my new service of ~400/20, but only the upload, obviously.

    Ran a CAT5e from modem directly to desktop and saw ~450/20.

    Rebooted everything and connected again with my router in place. Same slow result for download as above.

    Found some things here and elsewhere, so I opened an SSH session with Putty and ran
    modprobe bcm_nat

    I saw BCM fast NAT: INIT in the output. No change in speed.

    The adapter is set to auto negotiation for speed and duplex.

    Sure would love to see the faster download speed! Thanks in advance.
  2. txnative

    txnative Addicted to LI Member

    Did you run the test on the pc from the modem also? I'm not sure the AC66U can handle the 400 down, the next time you do telnet or ssh to the router run the cmd top and see if your cpu maxes out while test is downloading one test with BCM_NAT one without..
  3. pyrodex

    pyrodex Networkin' Nut Member

    I did a speedtest from the modem directly, yes.

    cpu usage hit about .35 during a speedtest. I'm not sure how to disable BCM_NAT.
  4. maurer

    maurer Network Guru Member

    ddimitrov likes this.
  5. txnative

    txnative Addicted to LI Member

    It seems that the n66u could at least go a bit further with or without using BCM_NAT after google search and found a user receiving his ISP upgraded bandwidth, pyrodex is using an older shibby build, but we don't know his setup for his network, however the link is here for some reference
  6. maurer

    maurer Network Guru Member

  7. ddimitrov

    ddimitrov Network Newbie Member

    Some of the results posted there by Shibby were not quite correct. In fact, he had not tested RT-N18U but had tested RT-AC68U. He admitted later that he had thought both routers had had the same CPU (so he had assumed RT-N18U had same performace), while RT-AC68U's CPU was dual-core and RT-N18U's CPU - single core.

    I tested today my new router - Linksys EA6700 (which has the same CPU as RT-AC56U/RT-AC68U - Broadcom ARM BCM4708A0 @ 800MHz, dual-core) and can confirm similar results as above (using Freshtomato 2019.1.015-beta):

    Linksys EA6700 without CTF ~ 300Mbps / 200Mbps Down/Up
    Linksys EA6700 with CTF ~ 750Mbps / 350Mbps Down/Up

    My previous router, Linksys E3200, whose Broadcom MIPS CPU @ 500MHz is more similar to that of RT-AC66U, had the following results:

    Linksys E3200 without BCM_NAT ~ 145Mpbs / 120Mbps Down/Up
    Linksys E3200 with BCM_NAT ~ 235Mpbs / 180Mbps Down/Up
    Last edited: Jan 24, 2019
  8. pyrodex

    pyrodex Networkin' Nut Member

    I appreciate the replies and ideas.

    Once I return from vacation in Norway, I think I'll install Merlin Mainly to keep my bandwidth logs on the current router intact through the end of the month.

    If no success, then I'll have to upgrade to something like an EdgeRouter and convert my RT-N66U to an access point. At least then I can move it closer to where it should be. I think the Linksys AP near the kitchen currently does most of the work.
  9. Monk E. Boy

    Monk E. Boy Network Guru Member

    In my experience with QoS on an N66 you can generally do 100Mb (50Mb/50Mb = 100Mb) but not much more. You're pushing 160Mb. Maybe if you stripped away more features, like disabling WiFi, you could push more packets between interfaces. Routing packets between interfaces (barring Ethernet/WiFi, which isn't a route, it's a bridge) is CPU driven. Enabling hardware acceleration (BCM_NAT, etc.) tends to short circuit your ability to control access via iptables.

    N66 works great in AP mode, you can saturate the interfaces all day long and it won't bat an eye so long as in bridge mode.

    The ER-X is a pretty nifty router, although I'm not sure if it can handle 420Mb. My ER-X at work is handling around a 250Mb connection with SmartQoS enabled for outbound traffic, and the CPU almost never getting above 10%. However I do have both hardware offload settings enabled. So I got that going for me, which is nice.
    Last edited: Jan 26, 2019
  10. pyrodex

    pyrodex Networkin' Nut Member

    So I'm back from vacation and installed Merlin. Great success; full speeds on the LAN.

    Having a bit of trouble with WiFi though. Still doing some research and testing. Thanks for the suggestions.

    416Mbps/23Mbps at 16ms. All for the low low price of $69.99/month.
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