On Multiple SSID

Jeff Meden blade
Fri Oct 24 15:51:25 PDT 2003


Although I haven't worked with the Cisco APs that claim this feature, 
according to those who have, it does act and appear like a completely 
different access point, allowing 'virtual' segregation of the clients, 
with different IP ranges, access filters, etc. but all residing on the 
same channel and hence sharing the same bandwidth. 

Jeff

SR Dasgupta wrote:

>Thanks for the tip. You are very right. The timing is quite important. 
>I wannna know if with cisco do you see multiple SSIDs at the same time as a list on the wireless laptop? 
>or you get to see first ssid for some fixed time and then the second SSID for a fixed time and so on.
>As I understand, with one radio interface we can see only one SSID at any given point of time on the 
>wireless laptop and not the entire list which we view with ,say, four access points with four different SSIDs.
>Plz correct me if I am wrong here.
>
>-----Original Message-----
>From:	Jeff Meden [SMTP:blade at ncweb.com]
>Sent:	Thursday, October 23, 2003 9:47 PM
>To:	srdasgupta at contechsoftware.com
>Subject:	Re: On Multiple SSID
>
>Getting a multiple SSID config to work with hostap requires great care 
>in the timing of the changes.  If you are 'scanning' with the client you 
>will have to have enough time between SSID changes to enter the 
>information, and associate with the AP.  If the client is expecting a 
>certain SSID, then you only need to leave enough time for the client to 
>detect the AP, and associate with it.  Yes, cisco does do multiple SSIDs 
>with one radio, they have much different frame control than any other 
>driver to date, afaik, and they use it very well.  Hope this helps!
>
>Jeff Meden
>
>SR Dasgupta wrote:
>
>  
>
>>Guys, I tried this stuff today in a small C code. I kept assigning new SSID using iwconfig
>>every 1 micro-second, but couldnot see multiple SSIDs on the wireless laptop. On every 
>>rescan all I could see is a different SSID which is not something great. Let me know if I am
>>wrong here and any of you have observed otherwise.
>>I guess if anyone wants their AP to support multiple SSIDs, then the AP would need as 
>>many number of wireless interfaces. Even I would want to know if cisco does it with 1 interface.
>>
>> 
>>
>>    
>>
>>>-----Original Message-----
>>>From:	CASASSOVICI Alexander [SMTP:casassov at wave-storm.com]
>>>Sent:	Friday, September 12, 2003 9:49 PM
>>>To:	hostap at shmoo.com
>>>Subject:	RE : RE : Multiple SSID
>>>
>>>Do u happen to have any link or doc about how cisco is exactly doing
>>>ther multiple ssid stuff?
>>>
>>>Thanx
>>>
>>>--
>>>CASASSOVICI Alexander  -- Ingenieur ENST
>>>Societe WaveStorm
>>>mobile : +33 (0)6 61 17 05 66
>>>tel : +33 (0)1 45 81 42 13
>>>mel : casassov at wave-storm.com
>>>
>>>
>>>   
>>>
>>>      
>>>
>>>>-----Message d'origine-----
>>>>De : Justin Reigle [mailto:jreigle at alamedanet.net]
>>>>Envoye : vendredi 12 septembre 2003 17:08
>>>>A : CASASSOVICI Alexander
>>>>Objet : Re: RE : Multiple SSID
>>>>
>>>>CASASSOVICI Alexander wrote:
>>>>     
>>>>
>>>>        
>>>>
>>>>>Great!!!
>>>>>
>>>>>Can u map each ssid to a vlan and have various security policies
>>>>>       
>>>>>
>>>>>          
>>>>>
>>on
>> 
>>
>>    
>>
>>>each
>>>   
>>>
>>>      
>>>
>>>>>SSID ? (eg one ssid non-crypted and one with eap/tls & 802.1x)
>>>>>
>>>>>--
>>>>>CASASSOVICI Alexander  -- Ingenieur ENST
>>>>>Societe WaveStorm
>>>>>mobile : +33 (0)6 61 17 05 66
>>>>>tel : +33 (0)1 45 81 42 13
>>>>>mel : casassov at wave-storm.com
>>>>>
>>>>>
>>>>>
>>>>>       
>>>>>
>>>>>          
>>>>>
>>>>I recommend that you look a little more closely at exactly how Cisco
>>>>implements this feature. Once you understand what is actually going
>>>>     
>>>>
>>>>        
>>>>
>>on
>> 
>>
>>    
>>
>>>>with Cisco's "Multiple SSID" support, then you'd realize that this
>>>>     
>>>>
>>>>        
>>>>
>>is
>> 
>>
>>    
>>
>>>>not possible with Prism2 firmware. The problem lies in how Prism2
>>>>handles Probe-Request/Response.
>>>>
>>>>Changing your SSID to create the illusion of multiple APs in the
>>>>     
>>>>
>>>>        
>>>>
>>area
>> 
>>
>>    
>>
>>>is
>>>   
>>>
>>>      
>>>
>>>>pretty useless IMO...
>>>>
>>>>- Justin Reigle
>>>>     
>>>>
>>>>        
>>>>
>>><< File: Alexander Casassovici (casassov at wave-storm.com).vcf >>  <<
>>>   
>>>
>>>      
>>>
>>File:
>> 
>>
>>    
>>
>>>ATT00001.txt >>
>>>   
>>>
>>>      
>>>
>><< File: Alexander Casassovici (casassov at wave-storm.com).vcf >> 
>>
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>> 
>>
>>    
>>
>
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>  
>






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