I have a question for any wireless expert who can help.
At home I have two wireless access points - one upstairs and one downstairs - to give a good signal anywhere in the house.
What I would like is to have a seamless wireless access from any laptop whether mine or a visitor with the appropriate encryption password.
Now my thinking is that using the *same* ssid and encryption protocol and password for both APs should do the trick nicely - so that is how I have things set up (with different channel for each AP's output) and indeed if I power up a laptop running F14 upstairs it connects nicely with a lovely strong signal - but if I then go downstairs and boot the same machine then it tries to connect to the upstairs AP despite the nearest signal about 10 feet away being a great deal stronger! So the system tries to connect to the last AP it connected to even if a local signal is stronger - this is illogical behaviour and it is not clear if NetworkManager or wpa_supplicant is the culprit - or if I am not supposed to expect things to work that way!
I had a visitor who had a laptop here this weekend - and the same problem arose - I decided to try to set up two connections in NetworkManager both with the same ssid and encryption/password but tag them with the MAC address of each AP - the box steadfastly refused to reconnect to the nearest (and strongest) AP after having been connected to the weak one first, and I had to remove the definition for the weak signal altogether in NM's list of connections, and only leave the connection tagged with the MAC address of the nearest strong signal before restarting the NetworkManager service before I could persuade NM to connect to the near and strong AP!
I don't know if the design of NetworkManager ever considered this scenario and whether any developer ever put in place code to hook up to a valid strong signal even if a previously valid signal (which is currently weaker) still exists - but it seems to me that the decision logic in NetworkManager is both perverse and flawed?
Anyone help with some knowledge here?
Thanks
On 01/30/2011 11:49 AM, mike cloaked wrote:
I don't know if the design of NetworkManager ever considered this scenario and whether any developer ever put in place code to hook up to a valid strong signal even if a previously valid signal (which is currently weaker) still exists - but it seems to me that the decision logic in NetworkManager is both perverse and flawed?
I'm guessing that it's never occurred to the devs that somebody might set things up like that. You might want to put this on Bugzilla as a feature request because I doubt that most people would consider it to be a bug.
On 01/30/2011 03:10 PM, Joe Zeff wrote:
On 01/30/2011 11:49 AM, mike cloaked wrote:
I don't know if the design of NetworkManager ever considered this scenario and whether any developer ever put in place code to hook up to a valid strong signal even if a previously valid signal (which is currently weaker) still exists - but it seems to me that the decision logic in NetworkManager is both perverse and flawed?
I'm guessing that it's never occurred to the devs that somebody might set things up like that. You might want to put this on Bugzilla as a feature request because I doubt that most people would consider it to be a bug.
If behavior is as described then its a bug - that's precisely how ALL access points are set up for any case where there is more than a single AP on same SSID .. i.e. every commercial, office, hotel, campus, airport etc wifi is done exactly that way ... many personal setups use multiple AP's as well on same SSID - its the correct way to do it.
gene
mike cloaked mike.cloaked@gmail.com writes:
At home I have two wireless access points - one upstairs and one downstairs - to give a good signal anywhere in the house.
What I would like is to have a seamless wireless access from any laptop whether mine or a visitor with the appropriate encryption password.
Even if you get NetworkManager to play ball, it isn't going to be seemless unless you bridge the wireless AP's and hand out IP addresses from some other server on your net. Once the IP address changes as you move from one AP to another, all your connectins will die.
-wolfgang
On 01/30/2011 03:16 PM, Genes MailLists wrote: bug.
If behavior is as described then its a bug - that's precisely how ALL access points are set up for any case where there is more than a single AP on same SSID .. i.e. every commercial, office, hotel, campus, airport etc wifi is done exactly that way ... many personal setups use multiple AP's as well on same SSID - its the correct way to do it.
gene
Anyone not familiar with wifi roaming may want to google it ... cisco used to have a guide on this very topic ... it pre-dated 802.11n but the setup is (essentially) the same .. (N changes channel frequencies which brings more issues to noodle upon) ..
g/
On 01/30/2011 03:20 PM, Wolfgang S. Rupprecht wrote:
mike cloaked mike.cloaked@gmail.com writes:
At home I have two wireless access points - one upstairs and one downstairs - to give a good signal anywhere in the house.
What I would like is to have a seamless wireless access from any laptop whether mine or a visitor with the appropriate encryption password.
Even if you get NetworkManager to play ball, it isn't going to be seemless unless you bridge the wireless AP's and hand out IP addresses from some other server on your net. Once the IP address changes as you move from one AP to another, all your connectins will die.
-wolfgang
The standard roaming setup uses 1 dhcp server .. your ip wont change when you roam.
On 01/30/2011 03:21 PM, Genes MailLists wrote:
On 01/30/2011 03:20 PM, Wolfgang S. Rupprecht wrote:
The point of roaming with multiple AP's is to be able to seamlessly move around without the connections dying ... as far as user is concerned its a single network - just like when you roam with a cell phone - you don't care when the connection is handed off to a new cell tower - you don't care here either - you just start talking to a new AP.
So if indeed something is preventing roaming from working as it was intended & designed to work - then something is awry somewhere - not saying its not an AP setup problem - just saying what the OP described he is expecting to happen, is the norm.
Genes MailLists lists@sapience.com writes:
The point of roaming with multiple AP's is to be able to seamlessly move around without the connections dying ... as far as user is concerned its a single network - just like when you roam with a cell phone - you don't care when the connection is handed off to a new cell tower - you don't care here either - you just start talking to a new AP.
So if indeed something is preventing roaming from working as it was intended & designed to work - then something is awry somewhere - not saying its not an AP setup problem - just saying what the OP described he is expecting to happen, is the norm.
The OP is clearly up against a NM issue in the selection criteria for the roaming case. Even if he solves that he won't be home free.
Roaming isn't as simple as setting up two wireless routers with the same SSID. One needs to strip down one or both of the routers and turn them into a bridge so that all firwalling and NAT-ing is done consistantly no matter which wireless box one accesses. Then there is the issue of running spanning tree or something to prevent all AP's from retransimtting all packets they hear. Without that each AP pollutes the airwaves a bit by re-transmitting each packet it recieves. With overlapping AP coverage that is going to cause quite a bit of interference.
My advice to the OP would be to get a better AP with a more powerful radio. Typical consumer junk is 15mW. Without looking too hard one can get a good 100mW - 300mW init for not much more. (Google: Ubiquiti)
-wolfgang
On 01/30/2011 03:42 PM, Wolfgang S. Rupprecht wrote:
Genes MailLists lists@sapience.com writes:
My advice to the OP would be to get a better AP with a more powerful radio. Typical consumer junk is 15mW. Without looking too hard one can get a good 100mW - 300mW init for not much more. (Google: Ubiquiti)
-wolfgang
With respect - please if you really dont know or understand something, do not post speculation without caveating it speculative opinion - some reading this may be misled.
Your post is speculative and not correct.
Sorry ...
On 01/31/2011 05:15 AM, Genes MailLists wrote:
On 01/30/2011 03:42 PM, Wolfgang S. Rupprecht wrote:
My advice to the OP would be to get a better AP with a more powerful radio. Typical consumer junk is 15mW. Without looking too hard one can get a good 100mW - 300mW init for not much more. (Google: Ubiquiti)
-wolfgang
With respect - please if you really dont know or understand something, do not post speculation without caveating it speculative opinion - some reading this may be misled.
Your post is speculative and not correct.
I am not sure what aspect of the previous post you find speculation or in need of a caveat, but....
My Dad lives in 2 story home + basement and is a MS only user (don't attempt to argue this point). For historical (hysterical?) reasons the Internet connection is on the 2nd floor. He had a wireless AP and connectivity on the ground floor was fine....reception in the basement was weak and subject to frequent disconnects.
We replaced his wireless AP with product (after trying and returning other products) from Ubiquiti and he is now a happy camper. He even has connectivity his detached garage.
OK, maybe the caveat would be YMMV but in my Dad's case it would have resulted in sound advice.
On Sunday 30 January 2011 20:10:15 Joe Zeff wrote:
On 01/30/2011 11:49 AM, mike cloaked wrote:
I don't know if the design of NetworkManager ever considered this scenario and whether any developer ever put in place code to hook up to a valid strong signal even if a previously valid signal (which is currently weaker) still exists - but it seems to me that the decision logic in NetworkManager is both perverse and flawed?
I'm guessing that it's never occurred to the devs that somebody might set things up like that. You might want to put this on Bugzilla as a feature request because I doubt that most people would consider it to be a bug.
Please post the bug number here. I have exactly the same need, and the same problem, so I'll want to subscribe to the bug report.
Anne
On Monday 31 January 2011 01:18:35 Ed Greshko wrote:
On 01/31/2011 05:15 AM, Genes MailLists wrote:
On 01/30/2011 03:42 PM, Wolfgang S. Rupprecht wrote:
My advice to the OP would be to get a better AP with a more powerful radio. Typical consumer junk is 15mW. Without looking too hard one can get a good 100mW - 300mW init for not much more. (Google: Ubiquiti)
-wolfgang
With respect - please if you really dont know or understand something,
do not post speculation without caveating it speculative opinion - some reading this may be misled.
Your post is speculative and not correct.
I am not sure what aspect of the previous post you find speculation or in need of a caveat, but....
My Dad lives in 2 story home + basement and is a MS only user (don't attempt to argue this point). For historical (hysterical?) reasons the Internet connection is on the 2nd floor. He had a wireless AP and connectivity on the ground floor was fine....reception in the basement was weak and subject to frequent disconnects.
We replaced his wireless AP with product (after trying and returning other products) from Ubiquiti and he is now a happy camper. He even has connectivity his detached garage.
OK, maybe the caveat would be YMMV but in my Dad's case it would have resulted in sound advice.
Ed, can I ask for practical details? Currently my router gives wifi coverage on the ground floor and first floor (and is little used, but desirable). By the time the signal reaches my office in a stone building in the garden it is very weak. I tried adding a second router with the wan omitted and hit the problem described in this thread. I have removed that and now have a switch box without wifi in the office, but now my Internet tablet can't connect so I need wifi here again.
Does the AP you recommend simply attach to the switch box? Are there good instructions somewhere that deal with any special settings? Any practical advice you can add?
Thanks
Anne
On 01/31/2011 06:39 PM, Anne Wilson wrote:
Ed, can I ask for practical details? Currently my router gives wifi coverage on the ground floor and first floor (and is little used, but desirable). By the time the signal reaches my office in a stone building in the garden it is very weak. I tried adding a second router with the wan omitted and hit the problem described in this thread. I have removed that and now have a switch box without wifi in the office, but now my Internet tablet can't connect so I need wifi here again.
Does the AP you recommend simply attach to the switch box? Are there good instructions somewhere that deal with any special settings? Any practical advice you can add?
I didn't want to directly come out and name the product in question. Didn't want to appear as if I were advertising for them.... :-)
But, since you asked. My Dad ending up getting this http://www.ubnt.com/powerapn
The datasheet and guides are on their site. I think he paid just over $100/US for the unit.
He is quite happy with it. And since, I thought, we were talking about a unit for single household use I thought I'd mention his experience.
There really isn't that much more I can add. I didn't do the setup for him myself since he lives about 6K miles away.
Wolfgang S. Rupprecht wrote:
My advice to the OP would be to get a better AP with a more powerful radio. Typical consumer junk is 15mW. Without looking too hard one can get a good 100mW - 300mW init for not much more. (Google: Ubiquiti)
Ubiquiti 300mbit hardware is running off of 100mbit ethernet. Not much better than "consumer junk."
On 31/01/11 09:50, Michael Cronenworth wrote:
Wolfgang S. Rupprecht wrote:
My advice to the OP would be to get a better AP with a more powerful radio. Typical consumer junk is 15mW. Without looking too hard one can get a good 100mW - 300mW init for not much more. (Google: Ubiquiti)
Ubiquiti 300mbit hardware is running off of 100mbit ethernet. Not much better than "consumer junk."
I bought an EnGenius ECB9500, a better choice I think.
http://www.senao.com/English/Default.aspx?TYPE=vipplayercard.htm&PT=prod...
On 01/31/2011 10:50 PM, Michael Cronenworth wrote:
Wolfgang S. Rupprecht wrote:
My advice to the OP would be to get a better AP with a more powerful radio. Typical consumer junk is 15mW. Without looking too hard one can get a good 100mW - 300mW init for not much more. (Google: Ubiquiti)
Ubiquiti 300mbit hardware is running off of 100mbit ethernet. Not much better than "consumer junk."
An interesting, yet potentially irrelevant point. In my Dad's case, he has 4 systems but does very little intensive transfers between systems. His main need is Internet access....with the DSL being the bottleneck and no where near 100m. So, for him, it matters not.
It all boils down to requirements.
On Sun, Jan 30, 2011 at 07:49:35PM +0000, mike cloaked wrote:
I have a question for any wireless expert who can help.
At home I have two wireless access points - one upstairs and one downstairs - to give a good signal anywhere in the house.
What I would like is to have a seamless wireless access from any laptop whether mine or a visitor with the appropriate encryption password.
Now my thinking is that using the *same* ssid and encryption protocol and password for both APs should do the trick nicely - so that is how I have things set up (with different channel for each AP's output) and indeed if I power up a laptop running F14 upstairs it connects nicely with a lovely strong signal - but if I then go downstairs and boot the same machine then it tries to connect to the upstairs AP despite the nearest signal about 10 feet away being a great deal stronger! So the system tries to connect to the last AP it connected to even if a local signal is stronger - this is illogical behaviour and it is not clear if NetworkManager or wpa_supplicant is the culprit - or if I am not supposed to expect things to work that way!
Roaming and initial AP selection are really different topics. Neither is as simple as some of the responders have asserted.
For roaming "seamlessly", simply using the same ssid and encryption info won't matter much if the AP's aren't bridged. Most consumer APs out of the box use a routed NAT configuration. This means that when you switch between APs you will get a different IP address and connection disruptions will result. To avoid that, you need to make sure the APs are bridging between wireless and ethernet, and further you must ensure that both APs plug into the same bridged segment on the ethernet side. Somewhere on that network there needs to be a single (or several coordinated) DHCP servers so that the same IP address is equally valid on the wireless sides of either AP. In the best cases the APs will runn IAPP or something similar to smooth the wireless handoffs between the two APs, but in practice that is not entirely essential.
As for the inital AP selection...you assert that it is illogical to select an AP you know over a stronger AP you may not know. I'm not sure I agree. So long as the known AP remains serviceable, there is no particular reason to switch to another AP simply because he registers a stronger signal. In a perfect world you could easily determine which AP is "better" simply by the signal strength of a beacon, but in reality a number of factors can effect real world "better"-ness.
I would only consider the AP selection issue a bug if NM insists on using an unreachable AP even when the other is reachable. In either case, if you want to roam between the APs you should ensure that they are both bridging the wireless connections to the same ethernet subnet.[1]
John
[1] There are other potential configurations for roaming, including mobile IP and the like. If you (i.e. anyone reading) feels like trying to explain them in an email then feel free. :-)
On Mon, Jan 31, 2011 at 4:15 PM, John W. Linville linville@redhat.com wrote:
For roaming "seamlessly", simply using the same ssid and encryption info won't matter much if the AP's aren't bridged. Most consumer APs out of the box use a routed NAT configuration. This means that when you switch between APs you will get a different IP address and connection disruptions will result. To avoid that, you need to make sure the APs are bridging between wireless and ethernet, and further you must ensure that both APs plug into the same bridged segment on the ethernet side. Somewhere on that network there needs to be a single (or several coordinated) DHCP servers so that the same IP address is equally valid on the wireless sides of either AP. In the best cases the APs will runn IAPP or something similar to smooth the wireless handoffs between the two APs, but in practice that is not entirely essential.
In my case the APs are connected to a single LAN on the wired side and the dhcp server is run on a Fedora machine such that the ip address is tied to the MAC of the wireless NIC on any one machine - hence the ip that I am given and maintain within the house is the same whichever AP a wireless laptop connects to.
As for the inital AP selection...you assert that it is illogical to select an AP you know over a stronger AP you may not know. I'm not
Not quite - in my case both APs have been registered on the laptop and it is certainly possible to define two separate "connections" in NM both with the same ssid and encryption plus password (in my case WPA-Personal with AES encryption) - but with different bssid where each corresponds to the hardware address of the AP in question. So even if both are defined to a specific laptop in the list of "known" connections to NM the laptop always appears to attempt to connect to the one it was last connected to - and where that signal is weak, with the near AP being both already known to the machine and strong the connection icon seems to spin and is very iffy about whether it might connect or not - but the logic would say it should now the near strong and already known connection would be the one it should attempt to connect to - surely? So the near strong signal is certainly not one that is unknown to the laptop's NM list in this case.
I would be less concerned about the roaming but certainly in this case the initial connection should go to the near and strong signal as it is already defined in the system - but it appears this is not the case!
sure I agree. So long as the known AP remains serviceable, there is no particular reason to switch to another AP simply because he registers a stronger signal. In a perfect world you could easily determine which AP is "better" simply by the signal strength of a beacon, but in reality a number of factors can effect real world "better"-ness.
I would only consider the AP selection issue a bug if NM insists on using an unreachable AP even when the other is reachable. In either
This is exactly the case - and the main source of irritation - and I believe others have verified this behaviour on their own systems.
case, if you want to roam between the APs you should ensure that they are both bridging the wireless connections to the same ethernet subnet.[1]
Which is indeed the case at home - I can't vouch for whether this is the case on the system at work but I could find out!
John
[1] There are other potential configurations for roaming, including mobile IP and the like. If you (i.e. anyone reading) feels like trying to explain them in an email then feel free. :-) -- John W. Linville The truth will set you free, but first it will
Would be great to see these issues tackled....
-
Anne Wilson -
Bob Goodwin -
Ed Greshko -
Genes MailLists -
Joe Zeff -
John W. Linville -
Michael Cronenworth -
mike cloaked -
Wolfgang S. Rupprecht