Explanation
USE CASE: a) Controls the dynamic addition and removal of ports to groups Technology: 3) LACP USE CASE: b) Tags Ethernet frames with an additional VLAN header Technology: 1) 802.1Q USE CASE: c) Used to authenticate EAP-Capable client on a switch port Technology: 2) 802.1X USE CASE: d) Used to identify a voice VLAN to an IP phone Technology: 4) LLDP The following table summarizes the switching technologies and their use cases:
Technology
Use case
1) 802.1Q
802.1Q is a standard that defines how to create and manage virtual LANs (VLANs) on a network. VLANs allow network administrators to logically segment a network into different broadcast domains, improving security, performance, and manageability. 802.1Q tags Ethernet frames with an additional VLAN header that contains a VLAN identifier (VID), which indicates which VLAN the frame belongs to1.
2) 802.1X
802.1X is a standard that defines how to provide port-based network access control (PNAC) on a network.
PNAC allows network administrators to authenticate and authorize devices before granting them access to network resources. 802.1X uses the Extensible Authentication Protocol (EAP) to exchange authentication messages between a supplicant (a device that wants to access the network), an authenticator (a device that controls access to the network, such as a switch), and an authentication server (a device that verifies the credentials of the supplicant, such as a RADIUS server)
3) LACP
LACP stands for Link Aggregation Control Protocol, which is part of the IEEE 802.3ad standard that defines how to bundle multiple physical links into a single logical link, also known as a link aggregation group (LAG) or an EtherChannel. LAGs provide increased bandwidth, load balancing, and redundancy for network connections. LACP controls the dynamic addition and removal of ports to groups, ensuring that only ports with compatible configurations can form a LAG3.
4) LLDP
LLDP stands for Link Layer Discovery Protocol, which is part of the IEEE 802.1AB standard that defines how to discover and advertise information about neighboring devices on a network. LLDP operates at Layer 2 of the OSI model and uses TLVs (type-length-value) to exchange information such as device name, port number, VLAN ID, capabilities, and power requirements. LLDP can be used to identify a voice VLAN to an IP phone by sending a TLV that contains the voice VLAN ID and priority.
References: 1 https://en.wikipedia.org/wiki/IEEE_802.1Q 2 https://en.wikipedia.org/wiki/IEEE_802.1X 3
https://en.wikipedia.org/wiki/Link_aggregation
https://en.wikipedia.org/wiki/Link_Layer_Discovery_Protocol

Layer 2 MAC authentication is a method of authenticating devices based on their MAC addresses without requiring any client-side configuration or credentials. The switch sends the MAC address of the device to an authentication server such as ClearPass or RADIUS, which checks if the MAC address is authorized to access the network. If yes, the switch grants access to the device based on the assigned role and policies. If no, the switch denies access or redirects the device to a captive portal for further authentication.
References: https://www.arubanetworks.com/techdocs/ArubaOS_86_Web_Help/Content/arubaos- solutions/1-ov

dBm is a unit of power that measures the ratio of a given power level to 1 mW. The formula to convert dBm to mW is: P(mW) = 1mW * 10^(P(dBm)/10). Therefore, -20 dBm corresponds to 0.01 mW, as follows: P(mW) = 1mW * 10^(-20/10) = 0.01 mW Reference: https://www.rapidtables.com/convert/power/dBm_to_mW.html The dBm is a logarithmic unit of power relative to 1 milliwatt (mW). -20 dBm means that the signal strength is 20 decibels lower than 1 mW. In terms of mW, this is 0.01 mW. Each 10 dB decrease represents a tenfold decrease in power. Therefore, -20 dBm is 10-210-2 or 0.01 mW.

To troubleshoot an Aruba CX 6200 switch that is failing to boot correctly, accessing the switch via the RJ-45 console port on any of its member switches provides direct access to the switch's console for troubleshooting. This method allows a network technician to interact with the boot process, view boot messages, and access boot options, including the selection of different OS images or ServiceOS for recovery purposes.