CCNA Wireless Chapter 12, 13 and 14 Exam Answers
Mobility is not synonymous with hot spot connectivity , rather it means a client can move between APs while keeping its IP address
The two types of client mobility are…
1) L2 mobility – client roams AP’s in same subnet
2) L3 mobility – client roams to AP in different subnet
What is a mobility group?
A group of WLC’s which share information with eachother
What is the maximum amount of WLC’s allowed in a mobility group?
What are the four requirements when creating mobility groups?
1) IP connectivity between WLC’s
2) Same workgroup name
3) Same virtual interface IP (ex. 188.8.131.52 in labs)
4) The MAC and IP of every other device in the group
What is a mobility domain?
The scope of communication between WLC’s in a WLAN
Mobility groups can be used to isolate roaming between different VLAN’s
Can clients roam between mobility domains?
What 4 things are required when a client is roaming between controllers?
1) Same mobility domain
2) Same revision of code
3) All AP’s need to have same SSID’s available
4) Again, virtual interface IP has to be the same
What is a simple way to describe intra-controller roaming?
New AP, same WLC
In intra-controller roaming, when is the client entry made in the database?
After the first AP association
What exactly is PKC?
Proactive key caching, it creates faster roaming times for 802.11i clients
What is a simple way to describe inter-controller roaming?
A client roams between two different WLC’s
What is the basic 4 step process of a client performing inter-controller roaming?
1) The client roams from WLC1 to WLC2
2) WLC2 makes a mobility announcement in order to find the WLC that has the client’s MAC (which is WLC1)
3) WLC1 responds to this announcement, handshakes and ack’s
4) This process moves the client DB entry to WLC2
How is L3 roaming accomplished?
Through a process called EoIP (ethernet over IP).
It is a tunnel created between controllers.
Original controller called “anchor”, the new controller is called the “foreign”
What are the two types of L3 roaming?
The 3 primary components of WLC configuration are:
1) WLAN – the SSID and its corresponding parameters
2) Interface – virt. conn. to IP stack
3) Port – phys. connection to wired LAN
Two types of interface on a WLC are:
Out of the two types of interfaces on a WLC, which one is created by the WLC and which one is created by an administrator?
Describe the management interface:
For in-band management
Used to communicate with other NW devs.
Also used by LAP in discovery phase
Describe the AP manager interface:
This is how the WLC communicates with LAP’s
Describe the virtual interface:
Used by WLC to terminate VPN’s from LAP’s, for DHCP relay connections, mobility management etc
What is special about the virtual interface?
It should not have a routable IP
Describe the service port:
For out-of-band management
What is special about the service port?
No trunking support
Describe the role of dynamic interfaces:
They link SSID’s to VLAN’s
What is the maximum amount of dynamic interfaces allowed on a WLC?
What 4 roles can an AP fulfill?
3) WG bridge
3 things required for converting an autonomous AP to an LWAPP LAP are:
1) Upgrade tool
2) IPSU tool
3) LAP IOS image
What version does the LAP IOS image have to be?
12.3 (7) JA or above
What does the text file contain which is used to upgrade the IOS for LAP purposes?
1) IP of AP
2) Username/PW for telnet auth
3) Enable mode PW
What IP is used for TFTP servers pushing out autonomous AP IOS images?
It must be on the 10.0.0.0 /24 NW