How can I set up a roaming wlan with AP only (Please help!!)
Is there a way that I can set up my office roaming Wlan network with 3 Aironet 1250 APs without a Wlan controller or WDS . If I set up my 3 AP with 3 different channels and with the same SSID, would my mobile station switch to a different AP if I am in and out of range? Please help and let me know what I need to pay attention to on the configuration. Thanks!
Re: How can I set up a roaming wlan with AP only (Please help!!)
Roaming decision is usually client triggered (there are some scienarios where the AP, using CCX extensions will assist the client in the roaming decision).
When a client threshold falls below a certain level (this level is per vendor) in either the signal strenght (RSSI) or SNR (Signal to Noise Ratio), or multiple packet losses, the client would search for a SSID with the same configuration (SSID, Security settings, ...) to roam to. it will send a de-authentication, de-association and re-associate to the new SSID (if it is in range). If both APs have the same configuration (SSIDs are mapped to the same vlan) and a decent overlap between them, you should have a successful L2 roam (the client remains connected with the same IP, little or no packet loss occur).
WDS (and then WLC) achieve something called Fast secure roaming (of course some other features) by caching the session keys and distributing them to the APs when the client roams to them.
When a client associates with and APs via WPA/WPA2, a 4 way handshake occurs to establish the session keys (the keys that are going to be used to encrypt the traffic). A very important key is something called PMK (Pairwise Master Key) which is used to derive another set of keys. The 4 way handshake process takes sometimes as long as 1 sec to complete and if you are using WPA/WPA2 enterprise (with 802.1x dynamic key negotiation) can take even more as the requests have to be forwarded to the Radius server (which could be in a remote site).
When a client roams from AP to another AP (based on the criteria that I have mentioned earlier), it has to re-establish the connection and re-negotiate the keys. This add delay in the roaming and can cause degraded call quality if the roaming client is a wireless IP Phone. What WDS and WLC does is the cache the PMK and when a client roam from one AP to another (registered with the same WDS or WLC), it sends the PMK to that AP saving it the 4way negotiation.
Other reasons you would want to have a WLC in your wireless network
- Centralize configuration for all your AP (this inclues security settings, SSIDs, QoS, ...)
Transferring Crash file from standby:
Login to the Active WLC in HA.
(Cisco Controller) >transfer upload datatype crash
(Cisco Controller) >transfer upload filename <Desired filename>
(Cisco Controller) >transfer up...
This is the start of a display filter cross reference between Wireshark and OmniPeek.
The 1st installment is a table of advanced filters. More filters will be added as time allows.
It is a living doc, so check back for changes every so often
Please feel ...
I have created a Powershell script to automatically add a Wireless Guest User on Cisco WLCs. (tested on 2500 Series)
The script should be completely self explanatory.
Powershell SNMP Module (Install-Module -Name SNMP)
SNMP Write Access to...