Region : Indonesia

Model : TL-WR841HP

Hardware Version : V1

Firmware Version : 3.15.2 Build 150519 Rel.64477n

ISP : Smartfren EvDo Rev B

Hi everyone,

I am trying to describe my problem as detail as possible, so you may find this post is very long.


Purchase
I purchased WR841HP(HG) from one of the online shop in my country on 8 April 2015. This is the revised version which has 2 x 8 dBi antena (instead of 5 dBi). After the product arrived on 11 April 2015, I do standard testing. Turns out, LAN port 2 is not working at all. Already tried with different devices, from PC, laptop, router, switch and all lead to the conclusion that port number 2 is not working.


I contacted the shop support and sent it back on 15 April 2015. They tested it and said that nothing wrong, send it back to me. After arrived for second time on 24 April 2015, found out it is the same router. But Yeah now port 2 is working (wonder what happen at the first time or what they have fix at there). Nothing problem at all until two days later, I started to figured out some kind of weird thing when I am fiddling around with Orvibo S20.


WR841HP configuration
To get an overview of my current network configuration before jumping to the problem, here it is. All configuration is from scracth. Not stated here means I leave it default.


==============================
Disable WPS


WAN Static IP
IP : 192.168.0.11 (goes to MR3020 LAN port)
SM : 255.255.255.0
DG : 192.168.0.10 (MR3020 LAN IP)
D1 : 192.168.0.10
D2 : 0.0.0.0


LAN Static IP
IP : 192.168.1.11
SM : 255.255.255.0


Wireless Settings
SSID : XXXXX XXXX
Region : Indonesia
Transmit Power : 100%
Channel : 11 (no other channel from neighbour)
Mode : 11bgn mixed
Channel width : Auto


Wireless Security
WPA/WPA2 PSK
Version : Automatic
Encryption : Automatic
Wireless Password : (Combination of Uppercase, lowercase, symbol; total 36 chars)


DHCP Enable
Start IP : 192.168.1.111
End IP : 192.168.1.130
Address lease time : 1440 min
DG : 192.168.1.11
DD :
PD : 192.168.1.11
SD : 8.8.8.8


Address Reservation
1 AC-CF-23-XX-XX-XX 192.168.1.5 (Orvibo S20)


Basic Security
SPI Firewall : Disable
Parental control, Access Control, Bandwidth control all are off
IP & MAC binding and Wireless Mac Filtering also disabled
==============================


Detail of devices
Devices used to found this problem :
1. MR3020 router with CE81B modem, as internet source, LAN IP 192.168.0.10, wifi is enable with different SSID, channel 1
2. WR841HP router (this router), WAN IP static : 192.168.0.10, LAN IP : 192.168.1.11 (see configuration above)
3. PC windows 7 64 bit, Connected via LAN to LAN Port 1 WR841HP, Static IP192.168.1.19
4. Laptop Windows 7 32 bit, Connected via LAN to LAN Port 2 WR841HP, DHCP reserved IP 192.168.1.23. Alternatively connected via Wifi to WR841HP, DHCP IP 192.168.1.112
5. Orvibo S20, wifi smart socket, connected via Wifi to WR841HP, DHCP reserved IP 192.168.1.5
6. Andromax V, Android JB 4.2, connected via Wifi to WR841HP, Static IP 192.168.1.22
7. Andromax C2, Android JB 4.3, connected via Wifi to WR841HP, Static IP 192.168.1.26


MR3020 is the source of ISP through the CE81B Modem, located at subnet 192.168.0.x. All other devices located at subnet 192.168.1.x. All subnet mask are 255.255.255.0. Every wifi devices are located very close to router (within 2-3 meters / 10 feet), with full bar signal. All wifi are 802.11 b/g/n, except Andromax C2 only b/g




==============================


Ping Delay
After returned back from RMA, on the next sunday, I tried to play with raw UDP command via Packet Sender from PC (192.168.1.19) to orvibo (192.168.1.5), I found out there are a lot of the packets get dropped. Seems like it never reach orvibo (while everything is connected). When I try to ping, it just give
Reply from 192.168.1.19: Destination host unreachable.





All 4 packets are lost. Then I got to repeat again, checking if the Orvibo is really connected or not. The ping failed again. 3rd ping, 1 or 2 from 4 ping has reply, with a huge time (above 1000 ms). After that the ping is working for several minutes. Then if I test to ping again after about 3-5 minutes later, it fails again the same way, before finally has reply. Sometimes it gives Request timed out, which means the time for the ping is more than 2 seconds (default windows timeout). Sometimes it takes 2 times ping command (about 5 - 8 packets), sometimes 1st try works (but at the 4th packet). So it seems the first ping will always delay about 5-20 seconds.


I don't if the Orvibo S20 has the bad wireless chipset or it is the router problem. So I do more test again using my phones and laptop. And it fail in the same way, for every wireless client. Means andromax v, andromax c2 and laptop which connect wirelessly will always found this problem. Every device connected via wifi, face same the problem when pinging each other or my PC (connected via LAN). The same for my PC pinging wifi devices. Everytime there is wifi device involved, this delay will show up.


But pinging the router IP (Gateway), gives no error, it success every time. The same if I use WR841HP tool at System Tools > Diagnostic, Ping to every wifi devices always success at first try, with sometimes huge time or Request Time Out (since the timeout default only 800 ms). Ping to LAN device (PC) always give time 1 ms (Of course). So it seems like some kind of wireless "AP Isolation", but only temporary (about 5-20 seconds).


More test via LAN
To make sure this is not client devices problem, I have done some sub checking. For PC and laptop both have comodo firewall installed, and have been turned off during test. Windows firewall also turned off.
Both android screen is on during test, and no task killer installed. All devices are tested from time to time, power cycled (reboot) before another test. All test are done at one time and keep tested to prove the problem consistency, regardless devices' state (when fresh boot or after long uptime). And it must not be the firewall/task killer problem, because at last it still can ping, only delayed for 5-20 seconds.


To add more proof, I disconnect the laptop from wifi and plug in the LAN Cable to the port 2 at WR841HP. It get DHCP IP at 192.168.1.112. Then I tried to ping my PC, it success with time 1 ms (of course). Ping from my PC to laptop also success immediately. (before when using wifi, it got the same delay). Then I tried to ping to the wifi devices from the laptop which is now connected via LAN, same problem occur. (because the target is wifi devices). So, it is not the device (laptop), since connected via LAN cable works perfectly. But only connected via wifi give problem.


Wireshark the ping
Desperate of trying, I tried to setup wireshark at my PC LAN interface, to see what is going on at the ping process. I tried to minimize most of other network activity to reduce the potential interference to the whole network (and also to have cleaner view in wireshark). For a typical ping to success, it starts by the pinger send an ARP broadcast requesting for the mac address of the target IP (assume the mac address is not in the ARP cache anymore). The target IP should reply the ARP immediately and gives its own mac address to pinger. Then pinger send the ICMP request (ping) to target IP. And if the target IP has cache the mac at first, it will reply the ping directly to the pinger. If not, there will another ARP broadcast to find the pinger mac address.


When the capture start, I switch to cmd and start to ping Orvibo S20 (or other wifi devices). I can see my PC send a lot of ARP broadcast (10-20) trying to find out the mac address of the S20. But no reply at all, thus Destination host unreachable. Second ping, when it start to show up the ping success (with huge time), I can see the ARP reply from the S20. And the strange thing is the ARP reply comes as much as the ARP broadcast at the first ping (10-20), sometimes the ARP broadcast is more, about 30-50 before ARP reply comes for about 10-20. Which mean the S20 is actually replying, but the ARP broadcast/reply got stuck at the WR841HP router. It seems the router is the one who delay the ARP packet, which cause the whole huge timeout for the first connection. Since mac address will be cached after ARP broadcast/reply, so any subsequent ping will be faster, until the mac address is wiped out from the ARP cache (typically after 3-5 minutes).




I test it using another wifi devices, all give the same result, ARP reply delayed. When I test ping from PC to laptop when both are using LAN cable, the ARP reply always show up immediately, just directly after the broadcast. So there is definitely something wrong with the wifi interface of the WR841HP router. I will just called this problem as ARP delay.


MR3020 is normal
FYI, before I purchased this WR841HP router, I have been using MR3020 as the wifi router for almost 2 years, and AFAIK no such problem arise. I tested again, all wifi devices to this MR3020, give no such error. It will always success at first ping. Yes, there is a slight delay at first ping (200-2000 ms), but not until 5-20 seconds.


Solution Tried
What I have tried to do to fix this ARP delay :
1. Enable the WPS
2. Change the subnet to 192.168.0.x
3. Change the SSID and password
4. Lower the Transmit power to 15% (normal), change channel, mode, channel width.
5. Change region to other country, united states and other countries
6. Change the beacon interval, RTS threshold, DTM interval, disable WMM, disable Short GI
7. Most devices has been set to static IP or reserved DHCP IP
8. All firewall in basic security/advance security turned off
9. Tried to set every mac address of the wifi devices to IP & MAC binding, to ensure the router remember their mac. But still delay.
10. Downgrade and upgrade firmware from anything available, all give same result. I have tried all the firmware available
wr841hpv1_en_3_15_1_up_boot(130425).bin
[*]wr841hpv1_en_3_15_2_up_boot(131119).bin (default from purchase)
[*]wr841hpv1_en_3_15_2_up_boot(141208)_beta.bin (suggested in this forum)
[*]wr841hpv1_en_3_15_2_up_boot(150519).bin (firmware V1.20, currently on this)
11. Tried to reset to factory defaults with no configuration at all(everything is default) and test the ping, still get delay
12. Removed the antenna, move to other electric socket.
I have tried a lot of thing, but still to no avail. So frustated that I almost want to slay the cat at the neighbourhood (okay, it is exaggerated :))


Annoyance
Why this ARP delay is very annoying? Of course, that means every new connection will be delayed, search will be timeout and it seems the connection is broken. These are the list of the uncomfortable things that I experienced because of this ARP delay.
1. First, of course, cannot ping properly or scan network to check all connected devices. Every scan will not show up every devices, it needs to be scan almost 5-10 times to show every devices.
2. Android esFTP delay. When I tried to access my files at andromax V, the windows cannot show up the FTP folder immediately just like MR3020 before. It takes several refreshes, and restart the esFTP to get it working. Very annoying since it takes about 10-20 seconds just to start copying files.
3. Airdroid connection also suffer delay, similiar to esFTP above.
4. Orvibo S20 very often cannot be controlled, since the command failed to be sent to the S20. Tasker support for using UDP sender / Packet Sender also become useless, since most of the first wave packet were dropped caused by these delays.
5. My Tplink SC3230N remote view will always slightly get delayed. Sometimes I need to manually reseat the electric plug to get the camera reconnected to the WR841HP.
6. Remote control to my android TV box also get delayed when it is idle. When we are watching movie and need to pause it, the remote still need 5 seconds to reconnect to the tv box.
7. Trying to remote VNC/desktop to my PC will give connection error at the first try. Always need to retry several time.
8. Hosting testing server always need a lot of restart. Since when the server go idle without connected client, it will suffer from ARP delay and cannot be connected again after several minutes.
9. Syncing files/folders will always failed with errors. Need to be repeated
10. Sending file via Es File Explorer requires several times of seaching before it find other devices.
11. Tasker combined with unified remote to control PC will get dropped command sometimes, cause by idle connection
12. HP Wifi printer will be seems offline to windows occasionally
I can keep on going on with this list, but I am sure it is very clear already that this bug is killing me.


Reporting
I first discover this problem about the first week after it returns from the RMA (LAN port 2 problem). It is about the end of April 2015. I have posted at Tplink Indonesia official kaskus lounge, but no solution given, only escalated to technician. Original post is at here http://www.kaskus.co.id/post/55403a4412e25760428b456c#post55403a4412e25760428b456c and summarized up post is at the Product review place http://www.kaskus.co.id/post/556096989e7404115c8b456c#post556096989e7404115c8b456c


I found the v1.20 firmware at around end of May, but too scared to test it. Yesterday I found this forum and test the beta firmware and finally to this v1.20 firmware. All still give the same ARP delay. I wonder if it only happens at my unit, or all WR841HP suffer from the same ARP delay. If it is only my unit, then I will send it to RMA again. But if all have the same problem, then tplink should be working on new firmware to solve this terrible bug.


Reproduce the problem
For those who wish to try it out to find if other WR841HP also face the same problem, you might try these to reproduce the ARP delay problem :
1. Turn on the WR841HP
2. Connect two device wirelessly, or at least one of them, the other through LAN port
3. Ping from either way, and check if there is ping delay as stated
4. If no ping delay, wait for about 5 minutes (for the ARP cache to be cleared), and try ping again.


Final
I am sorry for a very long post, because I don't have much time to make it shorter. :)
I have stated every thing about this problem, from Purchase time, Router Configuration, Devices configuration, network topology, the Ping Delay, LAN test, Wiresharking, MR3020 normal, every solution tried, why it is annoying, reporting and step to reproduce the problem. What I need know is the solution that works. If it happens that the defect is only on my unit, then this long post should convinced that I have tried hard to fix the problem but to no avail. This post should be enough to get me a new replacement unit, after I sent this to the RMA.


Thank you for reading until here, and I hope to find a working solution for this problem


Regards,
Desmanto