19. Understanding Wireless Roaming and Location Services Flashcards
What can a client do to connect with an AP?
Send Association requests or reassociation requests
What happens with frames if a client roams to another AP?
The old AP will send them over the wired network to the new AP
What is intracontroller roaming?
When a client roams APs that are placed within the same WLC
What does a WLC need to do with intracontroller roamin?
Update his client association table so it knows which CAPWAP tunnel to use
What can be changed during a client reassociation?
- DHCP
- Client authentication
What are the 3 techniques to minimize time at a key exchange?
- CCKM
- Key caching
- 802.11r
What is CCKM?
One WLC maintains a database of clients and keys omn behalf of its APs and provides them to other controllers
What is a requirement for CCKM?
CCX support from clients
What is Key caching?
Clients maintain a list of keys used with prior APs and present them during roaming.
What is 802.11r?
Addresses fast roaming or fast BSS transition. A client can cache a portion of the authentication server key and present them to future APs during roaming.
What is intercontroller roaming?
When a client roams between APs that both have a different WLC
What is L2 interroaming?
When a client roams between APs and stays on the same subnet (VLAN)
How is L2 interroaming called?
Local to local
What is L3 interraoming?
When a client roams between AP that are in different VLANs
How is L3 interroaming called?
Local to foreign
What happens during L3 interraoming?
An extra tunnel is created between the original WLC (anchor) and new WLC (foreign controller)
Who decides the anchor role at L3 interraoming?
Done automatically. The first association of AP and WLC is the anchor. This can be changed manually
What is a mobility group?
Groups where WLCs can be placed in to provide faster roaming
What does a mobility group support?
- L2/L3 roaming
- CCKM
- Cached credentials
- 802.11r
Can clients roam between mobility groups?
Yes, but nothing is shared/cached
What is inter-subnet roaming?
Multiple-controller deployments support client roaming across access points managed by controllers in the same mobility group on different subnets.
