Hello all,

I'm trying to use OpenWrt on a TP-Link TL-WDR3600 version 1.4, but it's hardly usable.
I get packet losses resulting in very poor performance (transfers get stuck for a couple of seconds).
Stock firmware is working perfectly in every respect.

In my setup, TP-Link is an AP. One of LAN cables goes to a DOCSIS router
Technicolor TC7200, another one to a PC.

Interestingly, this issue applies only to Internet traffic,
LAN traffic (going through WDR3600 and TC7200) is not affected.

OpenWrt version: from AA to latest trunk.

Has anyone any suggestion (apart from exchanging the DOCSIS device for different model)?
Thanks in advance.

You mentioned LAN traffic isn't affected. According to TC7200 specs, it has built in WIFI. Odds are if WIFI is enabled on both OpenWRT and the TC7200, there may be WIFI interference.

It's not wifi. The problems begin right after flashing OpenWrt, with default config (wifi disabled).

I have the TP-Link TL-WDR3600 as well running on OpenWRT Attitude (AA). BB (Breaking Barrier) revision I found to be buggy on this device. If you are running BB, you may consider flashing AA instead.

I also had issues when I first installed AA on the TP-Link TL-WDR3600 with the firewall. Once I uninstalled the firewall, and then reinstalled firewall again, and it re-wrtote a new firewall config, rebooted, everything worked flawless with WAN traffic.

Firewall has nothing to do here. I'm having this issue even when WDR3600 is merely switching.

To illustrate this issue I did a little test.
HTTP download of a 16 MiB file from internet to a PC. Wired connection.

With stock firmware:

With OpenWrt latest trunk:

Cabling was exactly the same (all cables connected to LAN ports).
Network config the same.

Since LAN to LAN traffic is unaffected, the switch must be working OK.

Did you already tried to disable jumbo frames in PC LAN interface ? Atheros SOC doesn't support jumbo frames.

Jumbo frames are disabled all the time.

As I mentioned, all cables go to the LAN ports. WAN port is free. VLAN config is default.

So this IS the switch.

It appears that the traffic between devices in my apartment is unaffected.

The traffic traversing the NAT in cable modem/router is clearly affected.

Any QoS or shaping software installed in the router ?

Qo-scripts package relies on info about the internet link from the config file, where upload and download speeds are declared.

(Last edited by zhadoom on 5 Jan 2014, 12:36)

I have no QoS related software on WDR3600.

The cable modem/router doesn't use QoS, too.

After some research, I found the culprit.

Disabling IEEE 802.3az LPI solves the issue for the moment.

Currently, EEE_CTRL is not initialized at all (by default LPI is enabled for all ports).

Ideally, it would be configurable from userspace.

Hey Jonm.

Could you elaborate a bit what you did? Is this a config option for /etc/config/network? I tried to investigate about config options for the "config switch" and "config switch_vlan", but the official documentation only covers very view settings.

Regards,
Stephan.

Hi Stephan,

Unfortunately, it's not configurable yet.

I added this to target/linux/generic/files/drivers/net/phy/ar8216.h:

#define AR8327_REG_EEE_CTRL        0x100

and this to target/linux/generic/files/drivers/net/phy/ar8216.c:

        priv->write(priv, AR8327_REG_EEE_CTRL, 1<<12 | 1<<10 | 1<<8 | 1<<6 | 1<<4);

inside ar8327_hw_config_pdata().

Best wishes,
Jonm

Or better disable it selectively for one port, e.g.:

        t = priv->read(priv, AR8327_REG_EEE_CTRL);
        t |= 1<<4;
        priv->write(priv, AR8327_REG_EEE_CTRL, t);

Hey Jonm.

Thank you for your response.
I don't have any issues with that, so I most likely will not try this in the near future. But good to know that there is such a thing, and good to know that this is available through source code manipulation currently.

I don't know if adjusting the LPI selectively is really better. This results in having switch ports that appear completely equal in both, GUI and hadware behave differently. Who hasn't ever adjusted his wires because of furniture moving and didn't take notes which wire has to go where. When all switch ports are equal or if differences can be seen on the GUI tool, that's not a problem. But I usually don't store source code for several years.
Don't get me wrong, I do see why having this adjusted selctively sould be possible. But I dislike having such a configuration with no proper configuration interface (config files are good as well, of course).

Regards,
Stephan.

Energy Efficient Ethernet means cooler switch IC and lower energy bills, so I prefer to have it enabled wherever possible.

And maybe this issue is solvable by fine tuning AR8327N parameters instead of disabling the feature. However, as the issue manifests so rarely, I doubt any OpenWrt developer will ever do anything with it.

could you please provide the test script / commands that create those graphs ?

I might have seen Issues with EEE too or these might be bugs of client LAN chip (both Intel with EEE : 82574LM and 82579V)
atm I deactivated EEE on the Intel side

jumbo frames on AR8327N were just enabled in december 2013 (changeset 39076) - EEE might take a short time ^^
If nobody reports to the mailing list/bug tracker the issue will not be widely known

I am willing to test with AR8327N (WDR3600, Archer C7) and AR8337N (sitecom wlr-8100) and some client HW with/without EEE to track down the bug

These particular graphs were created by hand with qtiplot. Data were collected from ifconfig output every 250 ms. And transfer was performed with wget. But normally I observe the net behaviour with KDE Network Monitor Widget that sits on my desktop.

For me, these problems exist exclusively between WDR3600 and my cable modem.

It might be reported already: #14597

I have a similar setup:

* WDR4300 v1.6 running BB trunk
* Default settings
* LAN port 1 connected a switch
* LAN as a DHCP client
* WAN port not connected

Internet access from the WDR4300 was woeful. Applied the changes posted by jonm and the problem was  resolved.

I would love to see the patch applied to trunk.

Hi,i me too have problem with tp-link wdr3600 v1.4,running AA r33312.I can constandly  see dropped packets in network interface.I have also problem with the wifi,it is stop working all the time and i have to restart the wireless in order to work.
So is there any solution in my problem?I want to have fix it so i have a stable system and then install packages...
Do i have to make a new image?What changes sould i do?
Thank you very much.

It's the bug of AR8327 in openwrt.

So what should i do?Not about the switch issue about the wifi.The wifi is unstable.

Hello all,
i have the similiar issue.

can please anyone provide a patch file for me?

thank you.

mod77

Just for Info:
As workaround i put an old 100Mbit Switch between the WDR3600 and Technicolor 7200.
Solved the Problem for me as an temporary solution.

But i`m still interested for an Openwrt Patch.

Here I place a working patch and an image for 3600 (BB, r39770).