Posted: Fri Sep 07, 2012 13:14 Post subject: Asus RTN16 WDS - Clients unable to reach eachother sometimes
About me: Been using ddwrt for many years on many different routers. Flashed hundreds of times, never an issue. Love the product. Familiar with the wiki, etc.
My Goal:
* I need to cover a large amount of area with 802.11n.
* I want one SSID to make it fairly seamless, and allow clients to do their thing without needing to switch between SSIDs.
* All clients need to be able to talk to eachother
My Solution:
* Two RTN16's running v24-sp2 std-usb-nas build 19519
* WDS enabled on both to keep things simple
Here's the router setup:
Primary:
* Connected to the WAN
* WAN type DHCP
* DHCP host
* LAN IP x.x.x.1 / SUB 255.255.255.0
* WDS is set to LAN & has BSSID MAC of the Secondary
* Router type: GATEWAY
Secondary:
* WAN disabled
* LAN IP x.x.x.2 / SUB 255.255.255.0
* DHCP / DNSMASQ / SPI FIREWALL / ttraffD all disabled
* Gateway x.x.x.1 / Local DNS x.x.x.1 (both point to Primary)
* WDS is set to LAN & has BSSID MAC of the Primary
* Router type: ROUTER (dynamic routing interface is disabled)
For both:
* Wireless settings are the same across the board, same security (WPA2/AES), same protocol (NG, 20mhz, ch6), same SSID
* WDS link node signal is 100%, flawless connection
Description of situation:
Clients connect without issue, and have access to the internet perfectly. They can reach either router. For all intents and purposes, this is how it should work.
The PROBLEM is, clients at times, cannot talk to each other. This is a big issue. It's some form of routing issue, perhaps I misunderstand the limits of WDS, or perhaps I have missed something altogether.
Here's what I have noticed, and I can repeat this time and time again:
* When the clients are all connected to the same physical router, they cannot talk to each other no matter what.
* If a client is connected to one router, and another client is connected to the other router, THEN they can talk to each other. Clients can only talk to eachother if they are on different physical routers.
For example:
Box1 is connected to Primary
Box2 is connected to Secondary
Box1 & Box2 can talk to eachother all day long. If both boxes connect to the same router, say Secondary (or Primary), then they can no longer talk to each other.
The only exception to this is if a device is wired to that particular router, then the wired device can always be reached, and it can always reach other routers.
Example
Box1 wireless to Secondary
Box2 wireless to Secondary
Box3 wired to Secondary
Box1 & Box2 can't reach each-other, but they can reach Box3, and Box3 can reach either of them.
What I have tried:
* I've enabled STP and disabled it.. made no difference.
* I've enabled dynamic routing and set it to LAN & WLAN and it also made no difference. It's all the same subnet, I don't see why it would need to route anyhow.
* I set the wireless to a simple protocol, G only, and it made no difference
I have setup many wireless bridges and other forms of networks with ddwrt in the past. If I am here posting on the forum, then I am absolutely stumped.
Can anyone help me as to where I went wrong?
Summary so far
* 5 Different DDWRT builds all have the same issue - sometimes connectivity occurs, but it's rare and unstable
* Tomato v1.28.9054 works without a hitch
Last edited by vesperwillow on Tue Sep 11, 2012 13:37; edited 3 times in total
If the connection is working and computers can't see each other, my guess is that this is a build issue. Try a different build. There is a whole thread on the builds for rt-n16.
I use wds using linksys hardware and computers could always see each other. _________________ SIG:
I'm trying to teach you to fish, not give you a fish. If you just want a fish, wait for a fisherman who hands them out. I'm more of a fishing instructor.
LOM: "If you show that you have not bothered to read the forum announcements or to follow the advices in them then the level of help available for you will drop substantially, also known as Murrkf's law.."
I will definitely bump down a build or two in a short while, and see if that helps.
I updated my original post with some more info. I tested it again, this time by adding a device to one of the routers using a cable. Looks like the issue only occurs when clients are connected wirelessly.
If something is wired to the routers, the wired device has no issues whatsoever.
Makes me curious if broadcast/packets aren't being properly bridged?
Stick to broadcom forum recommended builds... _________________ SIG:
I'm trying to teach you to fish, not give you a fish. If you just want a fish, wait for a fisherman who hands them out. I'm more of a fishing instructor.
LOM: "If you show that you have not bothered to read the forum announcements or to follow the advices in them then the level of help available for you will drop substantially, also known as Murrkf's law.."
I hit save between each step, then issued a reboot. Both routers immediately connect via WDS, link quality is superb. Clients can talk to each other ONLY if they're not on the same physical router, or as long as what they're talking to is using one of the LAN ports on either of the routers.
Sounds like something isn't bridging/routing between the WDS/WLAN interfaces on the routers themselves.
Also, if any of the senior coders/admins or whatnot want to look at the setup, I don't mind setting up a login so you can reach each router and see if the setup looks right or whatnot.
14896 is a bad build, (see broadcom forum announcements) but I doubt that is your problem. If all clients to each router are able to connect to the internet, WDS is working.
As a test, try setting up one router as a repeater bridge and see if clients are able to see each other.
It could also be a security/operating system problem. What OS are you using on the clients? Win7? _________________ SIG:
I'm trying to teach you to fish, not give you a fish. If you just want a fish, wait for a fisherman who hands them out. I'm more of a fishing instructor.
LOM: "If you show that you have not bothered to read the forum announcements or to follow the advices in them then the level of help available for you will drop substantially, also known as Murrkf's law.."
1. Ah, thought I had a good one. I'll go back and try the build before that, as per the announcement. Misread the forum post.
2. If I toss one into RB mode, and add a virtual SSID, here's how it works:
* Clients on the virtual SSID can talk to each other, and reach WAN
* Clients on the normal SSID can talk to each other, and reach WAN
* You can reach both routers no matter how you're connected
* Either router can reach any client regardless of how they're connected
-However-
* Clients on the virtual SSID can't reach clients on the normal SSID, and vice-versa. AP isolation is not enabled.
Also, ping times are crazy. anywhere from 50-1000ms. Wasn't like this in any other mode I've tried.
3. Multiple clients. Android phones, linux box, 3 windows XP machines (sp2/sp3), one fresh XP bland build, Windows 7 box, all of them with firewalls disabled.
Did some more testing. 14929 didn't do much better, but I did notice some odd behavior that I'm going to try and repeat with the other builds.
With 14929, it acted pretty much the same as others. On accident, I left one of the ping windows open for quite awhile (ping x.x.x.x -t) and after about 10 minutes it started getting a response.
I tested again by disconnecting and then reconnecting clients to the same router, again trying to ping. It didn't take as long to get responses this time, except for new clients which took a short while to respond.
Definitely seems like an odd routing issue.
Let the WDS connection sit overnight. Took a look at it today, the WDS connection seemed to drop out by itself, even though the routers are in the same room. Rebooted one and the link came back up again just fine.
Another oddity I noticed, I can get clients to talk to each other on the same router (after a short period of time), but that only works on one router. If I connect the clients to the other router, they won't under any circumstance talk to each other.
Repeater Bridge option also wasn't any better. I hate to think I'll be relegated to two different SSIDs to overcome some strange oddity.
Will try these tests with the other builds.
Would there be any value in posting the syslogs? It would be great if some other folks with NT16's could setup a WDS link and see if this is an Asus or DD issue.
I went back to 19519 lastnight, and clients were able to ping/route to each-other after anywhere from 5-100 attempts. After a period of time if there was no communication between clients, they would go through the 'delay' to reach each-other again until they could.
Unlike build 14929, the WDS connection did not die when left overnight, however in the morning the clients could not route to each-other no matter how long they sat there.
Clearly does look like a routing issue since at some point clients can talk. I'm going to try openwrt and some other firmware to see if the issue exists there as well, if so then it's likely hardware, but if not then it's got to be in ddwrt.
I want to add that, through all of this, the clients can access the internet flawlessly, and each router. The issue is, there's no reliable network connectivity between the clients on the WLAN.
When it fails, go to each router WDS tab and hit the "apply" button. See if that fixes it. _________________ SIG:
I'm trying to teach you to fish, not give you a fish. If you just want a fish, wait for a fisherman who hands them out. I'm more of a fishing instructor.
LOM: "If you show that you have not bothered to read the forum announcements or to follow the advices in them then the level of help available for you will drop substantially, also known as Murrkf's law.."
I tried that a couple of times already, and only once did it ever show pings work, but only for about a second. I did note that sometimes between/during reboots, clients could talk briefly, but when one of the routers came up they'd lose that ability.
Right now here's what's happening:
* Each router has a client. They can't reach each other.
* While logged into the host router, it can reach both routers and both clients.
* While in the secondary router, it can reach both routers, it can reach the client on the host router, but it can't reach the client which is connected to itself
Seems like every now and then, after a reboot or reconnect, the ability and exact path to reach a client randomly changes. A few moments ago prior to a reboot, both clients could reach each other across the routers, but no longer.
Talked to another guy who had a similar issue between two linksys 54g routers, he couldn't get WDS to work right with ddwrt sometimes, could never get the clients to talk to each other, but when he went to tomato, it worked flawlessly. I haven't tried it yet, but I have downloaded the firmware. Just tinkering around with ddwrt some more at the moment.
Definitely seems to be something up with internal routing. Every now and again the syslogs will show 'packet received with source address as own address', have never seen that error on any other routers before.
The setup is the same as it has been, although a few minutes ago I set the slave router to Dynamic Routing (Both) to see if that would help.. of course it didn't.
Installed tomato 1.28b on both the routers, set them up into WDS mode and ran the tests. They all passed 100%, connectivity was solid between routers, all clients, WAN/LAN.
Ping times were also notably lower than DDWRT, in the single-ms range, versus the 50-100 range dd was giving me.
So.. any way to see why ddwrt doesn't work, but tomato works without a hitch?
