CCNA Lan Chapter #7

The network administrator uses the "Network Name (SSID)" setting to configure the unique identifier that client devices use to distinguish this wireless network from others. The SSID (Service Set Identifier) is a case-sensitive alphanumeric string that is assigned to the wireless network. Client devices use the SSID to identify and connect to a specific wireless network. By configuring the SSID, the network administrator can ensure that client devices can correctly identify and connect to the intended wireless network.

Wireless networks broadcast data over a medium that allows easy access, which makes security important. Since wireless signals can be intercepted by anyone within range, it is crucial to ensure that the data being transmitted is protected from unauthorized access. Without proper security measures, sensitive information can be easily intercepted and compromised, leading to potential data breaches and privacy violations. Therefore, implementing strong security protocols in wireless networks is essential to safeguard the integrity and confidentiality of the transmitted data.

Wireless access points should be implemented with each access point using a different channel in order to keep signals from interfering with each other. When multiple access points use the same channel, their signals can overlap and cause interference, resulting in reduced network performance and connectivity issues. By using different channels, access points can operate on separate frequencies, minimizing signal interference and improving overall network stability and performance.

When a rogue access point is added to a WLAN, unauthorized users can gain access to internal servers, causing a security hole. This means that individuals who are not authorized to use the network can infiltrate the system and potentially compromise sensitive information or disrupt network operations. This poses a significant risk to the security and integrity of the WLAN.

Authentication serves the purpose of determining that the correct host is utilizing the network. This means that it verifies the identity of the host before granting access to the WLAN. By doing so, it ensures that only authorized users can connect to the network and prevents unauthorized access or misuse of the network resources.

The network design process that identifies where to place access points is called a site survey. This involves conducting a thorough analysis of the physical location to determine the optimal placement of access points for maximum coverage and performance. A site survey takes into consideration factors such as building layout, obstacles, signal interference, and user requirements to ensure a well-designed and efficient wireless network.

A wireless access point uses the CSMA/CA (Carrier Sense Multiple Access with Collision Avoidance) access method to allow for multiple user connectivity and distributed access. CSMA/CA is a protocol used in wireless networks to avoid collisions between data packets by employing a "listen before talk" approach. It ensures that a device checks for the presence of other devices transmitting on the same channel before transmitting its own data, thus minimizing the chances of collisions and optimizing network efficiency.

A wireless access point uses beacons to allow WLAN clients to learn which networks are available in a given area. Beacons are broadcasted by the access point at regular intervals and contain information about the network, such as the network name (SSID) and supported capabilities. When a WLAN client receives a beacon, it can use the information to determine if it wants to connect to that network. Beacons are an essential part of the WLAN discovery process and help clients identify and connect to available networks.

The poor performance within a small area of the room suggests that there may be RF channel overlap. To address this issue, the technician should first verify the channels in use on each wireless access point and then change them to non-overlapping channels. This will help improve performance by reducing interference between the access points.

MAC address filtering is a wireless security feature that allows a network administrator to configure an access point with wireless NIC unique identifiers. By enabling MAC address filtering, only the wireless NICs with these specific identifiers will be allowed to connect to the wireless network. This provides an additional layer of security by preventing unauthorized devices from accessing the network, even if they have the correct authentication credentials or knowledge of the SSID.

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A wireless client will transmit a probe request to discover the available WLAN networks. This is a message sent by the client device to search for nearby access points. The probe request contains information about the client and its capabilities, and it is broadcasted to all nearby access points. The access points then respond with a probe response, providing details about their network and allowing the client to choose the most suitable network to connect to.

CSMA/CA (Carrier Sense Multiple Access with Collision Avoidance) is a protocol used in wireless networks to avoid media contention. Media contention occurs when multiple devices try to access the wireless medium simultaneously, leading to collisions and degraded network performance. CSMA/CA solves this problem by implementing a mechanism where devices listen for ongoing transmissions before transmitting, reducing the likelihood of collisions. Therefore, the correct answer is media contention.

Many wireless routers incorporate a gateway for connecting to other network infrastructures, allowing them to connect to other networks and access the internet. They also have a built-in Ethernet switch, which allows wired devices to connect to the router and communicate with each other. Additionally, wireless routers have a wireless access point, which enables devices to connect to the network wirelessly and access the internet.

A wireless access point is responsible for converting data from the 802.11 wireless protocol to the 802.3 Ethernet protocol. This conversion allows devices connected to the wireless access point to communicate with devices on a wired network. By encapsulating the data into the appropriate frame format, the wireless access point enables seamless transmission of data between wireless and wired networks.

The adoption of 802.11g over 802.11a has been favored due to two main conditions. Firstly, 802.11a suffers from a shorter range compared to 802.11g, making it less practical for larger areas or outdoor environments. Secondly, 802.11g is backward compatible with 802.11b, allowing for seamless integration with older devices and networks. On the other hand, 802.11a is not backward compatible, limiting its compatibility and interoperability with existing infrastructure.

802.11n is the correct answer because it provides the most compatibility with older wireless standards while offering greater performance. It is backward compatible with previous standards (802.11a, 802.11b, and 802.11g) and can operate on both the 2.4GHz and 5GHz frequency bands. It also supports multiple-input multiple-output (MIMO) technology, which improves data transfer rates and overall network performance.

By forcing all devices on a WLAN to authenticate and monitoring for any unknown devices, it ensures that only authorized devices can access the network. This procedure prevents man-in-the-middle attacks where an attacker intercepts communication between two parties, posing as one of them. By authenticating all devices and monitoring for unknown devices, any unauthorized device attempting to perform a man-in-the-middle attack will be detected and blocked, ensuring the security of the network.

A rogue access point represents a security risk for the local network because it is an unauthorized access point that can be used by attackers to gain access to the network and intercept sensitive information. With SSID broadcast disabled, an attacker must sniff the SSID before being able to connect, which adds an extra layer of security as it makes it more difficult for attackers to identify and connect to the network.

MAC address filtering prevents the contents of wireless frames from being viewable. Disabling an access point from broadcasting the SSID prevents the access point from being discovered. Default SSIDs on specific manufacturer APs are generally known and may permit hostile wireless connections. Manually adding a network and setting the known SSID on a wireless client makes the network visible even if the SSID is not being broadcast.

The first accurate statement is that open authentication uses no client or AP verification. This means that any client can connect to the network without providing any credentials or being verified by the access point.

The second accurate statement is that 802.11i incorporates a RADIUS server for enterprise authentication. RADIUS (Remote Authentication Dial-In User Service) is a protocol that provides centralized authentication, authorization, and accounting for network access. In the case of 802.11i, a RADIUS server is used for authentication in enterprise environments.