Term
| In 802.11 what is the amount of time called that all stations must wait before transmitting? |
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Definition
| DCF interframe Space, or DIFS. |
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Term
| What is an SSID, and if two device have different SSIDs, can they communicate? |
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Definition
| Service Set Identifier, and No. SSIDs must match to communicate. |
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Term
| What is the technical term for an Ad-Hoc network? |
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Definition
| Independent Basic Service Set (IBSS) |
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Term
| What three things can an AP require of a wireless client before it will be allowed to communicate? |
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Definition
| matching SSID, compatible wireless data rate, and Authentication credentials. |
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Term
| What is the difference between an IBSS, a BSS, and an ESS? |
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Definition
-IBSS is ad-hoc.
-BSS is only one AP.
-ESS connects more than one AP. |
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Term
| In simple terms, a Wireless AP is in charge of mapping a VLAN to a(n) ____? |
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Definition
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Term
| If an AP wants to service multiple SSIDs, what must it connect to the physical switched network with? |
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Definition
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Term
What is a cell and what is roaming?
Define the difference between layer 2 and layer 3 roaming. |
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Definition
-A cell is an AP's coverage area.
-roaming is moving from one AP to another.
-L2 roaming maintains the same IP for the client.
-L3 roaming means the client must change IPs when it changes APs. |
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Term
| Can traffic from two clients attached to the same AP pass directly through the air to the destination? |
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Definition
| No, it must travel through the AP. only Ad-Hoc (IBSS) can go from source directly to destination without the AP. |
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Term
| What wireless mode is an AP that is standalone or autonomous in? |
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Definition
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Term
| What does the 'Cisco Unified Wireless Network' suggest doing? |
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Definition
| Using LAPs and WLCs to centralize certain wireless functions on a network. |
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Term
| The division of labor used by the Cisco Unified Wireless Network in regard to LAPs and WLCs is known as what type of architecture? |
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Definition
| a Split-MAC architecture. |
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Term
| What two types of tunnels are used by LAPs and WLCs to communucate? |
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Definition
-LWAPPs (Lightweight Access Point Protocol) (Cisco Proprietary)
-CAPWAP (Control and Provisioning Wireless Access Point protocol) (standards-based) |
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Term
| What are the two types of traffic that are transmitted over LWAPP/CAPWAP and which one is encrypted? |
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Definition
| Control messages (encrypted!), and normal data. |
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Term
| LAPs and WLCs come with what type of certificate in order to authenticate with one another? |
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Definition
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Term
| What is an optional serve platform that can be used as a single GUI front-end to all the WLCs in a network? |
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Definition
| the Wireless Control System. |
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Term
| What are the 5 steps that a LAP must do to bootstrap and become active? |
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Definition
1. Get a DHCP IP address.
2. Learn the IP of any available WLC.
3. Send a join request, and receive a reply.
4. Download newer software (if necessary).
5. Build a secure LWAPP/CAPWAP tunnel. |
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Term
| What are the two ways that a LAP can discover the IP address of the WLC? |
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Definition
| Through DHCP option 43, or if in the same broadcast domain they can talk directly to one another via broadcast. |
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Term
| How many WLC can a single LAP know about. |
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Definition
| 3. Primary, secondary, tertiary. |
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Term
| What happens when a LAP loses its connection with the WLC? |
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Definition
| it will reboot and attempt to locate another WLC. |
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Term
| In regard to Wireless technology, what is an HREAP and what does it do? |
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Definition
| Hybrid Remote Edge Access Point. In the event the LAP loses its connection to the WLC, it allows the users to maintain their connections without forcing the LAP to reboot in order to reconnect to a different WLC. (makes it act like an autonomous AP.) |
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Term
| What is an intra-controller roam, and what happens to allow this to occur? |
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Definition
-When a client's wireless association stays within the same controller.
-The controller simply updates its tables to use the LWAPP/CAPWAP tunnel to the new LAP. |
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Term
| Explain Inter-controller roaming on the same IP subnet. |
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Definition
| The WLCs in question will simply exchange a mobility message, where information about the client is sent from one WLC to another. |
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Term
| Explain Inter-controller roaming on different IP subnets. |
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Definition
| When a client roams into a new controller, that controller creates an Ether-IP tunnel from itself to the WLC when the clients IP natively resides. Incoming traffic then flows to the original WLC and then through the tunnel to the new WLC. |
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Term
| What is an Anchor point and Foreign agent in inter-controller roaming? |
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Definition
-Anchor point, the WLC that a client originally joined the wireless network at.
-Foreign agent, any WLC serving the client from a different subnet. |
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Term
| What is a mobility group in wireless roaming? How many WLCs with one support? |
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Definition
| Mobility groups are collections of WLC that allow inter-controller roaming between members of the same group. You can have 24 WLCs. |
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Term
| What has to happen for a client to roam between two WLCs that are NOT in the same mobility group? |
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Definition
| They must get a new IP and their session information will be dropped. |
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Term
| When setting up the switchport, does a wireless LAP need to have a trunk port or an access port? |
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Definition
| Access port! Everything else is handled trough the LWAPP/CAPWAP tunnel! |
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Term
| What network layer should a WLC be located at? |
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Definition
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Term
| Can WLCs support Etherchannel autonegotiation? |
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Definition
| No they cannot! You must enable unconditional Etherchannel on the Switch in order to establish the Etherchannel. |
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