Problem when switching Wifi APs

[bigboboz]

I installed a second wifi AP upstairs due to poor wifi speeds upstairs but I have noticed that when I switch APs, I am unable to connect to other devices on the network (such as my NAS!) for 5 to 10 minutes.

So after I head upstairs and reconnect, I can't connect for a period, can't even ping the IP address. If I access my NAS via it's external IP address, there are no issues.

Is this normal behaviour when running two APs? I have tried googling for the problem but either I'm the only one having this problem or more likely I don't know what to search for!

Any advice?
Thanks in advance
Rob

 

[stevech]

No.
Do your Access Points behave as access points or do you have cascaded routers (hope not).

Sounds like your client device gets confused, assuming your AP is setup correctly (not a 2nd router).

 

[KGB7]

Need more info on your second AP. Is it a pure/dedicated AP or just a router and you calling it AP? Or is it a router setup in AP mode?

Need more info.

 

[bigboboz]

Don't have the model number of the AP at the moment but it's not a router, it's a Netcomm that came bundled with two APs to bridge over wifi but the UI has the option to run in different modes. It's set up with a static IP with my modem/router operating as the DHCP server. The Netcomm is connected via LAN to the router.

Happy to look up the model number if this is important but from your responses, it sounds like this behaviour is not normal.

I have a spare DGDN3700 lying around, is it possible to use this as an AP?

Thanks,
Rob

 

[bigboboz]

Ok it's a NetComm NP121 CB in AP mode. The router is a Netgear D6300 but I had the same problem with the DGDN3700.

 

[thiggins]

First, make sure that there is only one DHCP server active and that it is set to hand out the proper gateway and DNS information.

When connected to the router, try pinging the router IP and upstairs AP IP.

Are the two APs set to the same or different SSID?

How long is the time that you can't connect?

You can repurpose any router as an AP. See http://www.smallnetbuilder.com/wire...onvert-a-wireless-router-into-an-access-point

 

[bigboboz]

First, make sure that there is only one DHCP server active and that it is set to hand out the proper gateway and DNS information.

Definitely only have the one DHCP server running, have checked the Netcomm is off and even tried using my NAS as the DHCP server, switching it off on the Netgear

When you say, set to hand out the proper gateway and DNS info, the router is set to get DNS automatically from ISP, is there anything further to do for this?

When connected to the router, try pinging the router IP and upstairs AP IP.

Are the two APs set to the same or different SSID?

How long is the time that you can't connect?

You can repurpose any router as an AP. See http://www.smallnetbuilder.com/wire...onvert-a-wireless-router-into-an-access-point

After switching APs it's about 5 min before I can connect again, this includes just trying to ping the IP addresses.

The APs at the moment aren't the same SSID but have been in the past and the behaviour was no different, in fact it was wo rse because I wasn't aware if I changed between APs.

Tonight as I play around switching between APs, it seems that the connection to the NAS only drops when switching from my Netcomm AP to my Netgear router. In this instance, I can't ping the NAS or the Netcomm for roughly 5 min. I'm sure in the past, it didn't matter, switching knocked me out for the 5min...

I'll check out your link re repurposing, but probably won't have time to try it out until the weekend. The Netcomm is only 100mbit, so the old Netgear will still be a step up in performance.

Thanks,
Rob

 

[thiggins]

Check that the problem wireless client has the same IP address info including gateway and DNS before and after the switch.

I meant try pinging the problem connections BEFORE you make the switchover.

Are you SURE that the Netcomm is in AP mode and connected via Ethernet?

 

[bigboboz]

Sorry, yes I have checked that I ping before I change. I double checked the Netcomm just now and it clearly states AP mode. The other options are Repeater Mode and Client Bridge Mode. It is definitely working via ethernet as it doesn't have the wifi details for the new Netgear so it is only possible that devices connected to the Netcomm can see the internet and other devices.

The gateway on the Netcomm is the router IP but it doesn't state the DNS address anywhere...is there another way to check it's DNS?

I did notice under LAN the Netcomm has '802.1d Spanning Tree' Disabled. What would this be?

 

[azazel1024]

Spanning tree is a method for an ethernet switch to determine if a "loop" is created in the topology.

Without special methods such as spanning tree, link aggregation, etc, if you accidently connect two ports from an ethernet switch to another switch, a loop will develop as it tries to pass traffic too/from both ports. It'll lock up the switch to all traffic after a few seconds.

802.1d is one of the older and more basic methods of preventing that. Its algorithmic logic within the switch for it to determine when there is one or more loop created, weight the switching path through the network and disable the slower port(s). At least until such time as the enabled port becomes disabled/disconnected, in which case it'll re-enable the port that spanning tree disabled.

Its a relatively slow and not terribly efficient method to prevent looping. Rapid Spanning Tree and others have semi-superseeded it.

Anyway, that shouldn't be causing any issues unless you have your access point connected to another switch/router through more than 1 port, or else you have it connected in to your network topology in some other way at more than one point allowing a loop.

 

[roldogg]

What security type are you using on the Netcom and what security type are you using on your primary router? Also, do you have the wireless channel for the Netcom AP set to Auto or have you picked a static channel?

 

[bigboboz]

Both WPA2(AES)

Netgear(router) is auto and the Netcomm is fixed at channel 11. The previous Netgear that also had the problem was fixed on channel 1.

 

[bigboboz]

Switched the Netgear to channel 1 and the issue is still there

 

[roldogg]

If the AP is not physically hooked up and hardwired into your primary router, then it's running as a repeater. If it's running as a repeater, then open security and WEP are the only security settings that will work, not WPA2.

 

[bigboboz]

The AP is hard wired into the primary router

 

[roldogg]

This Netgear NP121 came with 2 devices, one they call an Access Point and the other they call a Client Bridge, but you said you already have a primary router, correct? This Netgear NP121 kit is for someone who only has a modem. It's configured to connect one device to your modem and the other device positioned elsewhere extending your signal.

 

[bigboboz]

That's correct, there were 2 devices but the way they can be used is flexible. The instructions go into the various options.

I have it in AP Mode and it is hard wired connected to the router and currently has a separate SSID currently but in the past it has been the same and the problem was there either way but with separate SSID's I can at least control if I'm switching.

 

[roldogg]

The two are setup to work together. If the IP address of your current router is 192.168.1.1, then you need to change the IP address on these routers because they use an IP of 192.168.20.2 & 192.168.20.50. Let me know what your IP address is on your primary router, and I'll tell you how to set it up. Do you want the AP to be a separate network than your primary router or do you want everything on the network to work together?

 

[bigboboz]

My router's IP address is 192.168.1.254 with DHCP range 192.168.1.1 to 25

The Netcomm NP121 IP is fixed on 192.168.1.121 and gateway set to the router's IP above

Most definitely want everything on the network to work together and the problem is they're not quite at the moment. If I flick between the APs it's about 5min before devices can see each other. Unless I use my WAN IP which has the right ports forwarded.

 

[azazel1024]

Try setting the actual router to x.x.x.1

That is the general convention for gateway routers.

It might have no impact at all...but it also might.

It sounds like net discovery is messed up right now.

The few options I see are that a device is interfering with network discovery. ARP caches are getting messed up on devices somehow when switching between the router and the access point. MAC tables are skewed between the two devices.

Is this an issue of actual network discovery, where you just can't see devices? Or is this is an out right issue of inability to access other devices for 5 minutes or so? If the former, that sounds like a windows master browser issue. Try disabling netbios on all devices you can and making sure that LLDP is enabled on all devices you can. You can also try it the other way, by making sure netbios is enabled and LLDP is disabled.

Both former and later, make sure that the router and AP have ICMP set to allowed/enabled and ensure that they do NOT have ICMP snooping enabled. You can also go the opposite direction and ensure that they are disabled/ICMP snooping disabled.

This sounds like it is an issue where possibly the master browser is not updating in a timely manner (what networking devices do you have other than the AP/router? A server? NAS? Media streamer (especially if it can or does have media attached)? Does the router have attached storage? If the router doesn't have attached storage, is any kind of storage server disabled?

Other thoughts, is UPnP disabled on the router and AP? If not, KILL IT DEAD WITH FIRE. UPnP can be of some help with some things, but it is full of vulnerabilities like WOW, and it can also occasionally break things.

I may come up with some other suggestions at some point.