A network baseline is a reference point for normal network behavior. It captures typical performance metrics and usage patterns, such as latency, throughput, packet loss, and device resource utilization, as well as normal traffic flows and patterns over a representative period. When troubleshooting, comparing current measurements to the baseline helps you spot anomalies quickly, pinpoint where problems are likely occurring, and decide what corrective action is needed. It also helps distinguish temporary spikes from real issues and guides decisions about fixes or further investigation. This isn’t a security policy, which governs access and protections. It isn’t simply a list of devices and configurations, which is asset management. And it isn’t about service-level objectives, which set targets rather than describe normal behavior.

In network management, a managed device is one that can be monitored and controlled by a network management system, typically through an SNMP agent that runs inside the device. The statement describing a network node that contains an SNMP agent and sits on a managed network directly signals this capability: the SNMP agent is what the management system uses to query status, gather data, and apply configurations or alarms. That explicit presence of an SNMP agent on a device confirms it as part of the managed environment. The other options describe common network or peripheral devices but don’t specify management capabilities. A router is a network device that may be manageable, but without mentioning an SNMP agent or management system, it doesn’t clearly define a managed device. A printer could also be managed in some setups, yet the description doesn’t guarantee SNMP-based management. A USB storage device used for backups is not inherently a network-managed device and typically operates as local or direct-attached storage rather than a managed network node.

Key distinction is how the keys are used to protect data. Symmetric cryptography relies on one shared secret key to both encrypt and decrypt information. Everyone who needs access must have that same key, which makes the process fast for large amounts of data but requires secure key exchange and protection of the key itself. Asymmetric cryptography uses a pair of keys: a public key that can be shared openly for encryption or verification, and a private key that stays secret for decryption or signing. This setup not only enables encryption without distributing a secret key but also enables digital signatures, where a message signed with the private key can be verified with the corresponding public key. So the statement that symmetric uses a single shared key for encryption and decryption, while asymmetric uses a key pair for encryption/decryption and digital signatures, is the correct description. The other options mix up how the keys are used and the capabilities of each type.

VLANs divide broadcast domains, and 802.1Q tagging is the method that lets a single physical link carry traffic for multiple VLANs. It does this by inserting a 4-byte tag into Ethernet frames that identifies the VLAN ID the frame belongs to. This tag sits after the source MAC address and before the EtherType, and it carries the VLAN ID along with optional priority bits used for QoS. Because the tag distinguishes VLANs, switches can forward frames from different VLANs over the same trunk link without mixing them. Frames for a VLAN on a trunk are tagged so the receiving switch knows which VLAN to place the frame into. Frames belonging to the native VLAN on a trunk can be sent untagged, depending on the configuration, which is why you sometimes hear that native VLAN frames are untagged. This mechanism is distinct from ARP, which is a protocol for mapping IP addresses to MAC addresses, and it does not involve duplicating frames or disabling trunks. The statement that best describes 802.1Q tagging is that VLANs create separate broadcast domains; 802.1Q inserts a 4-byte tag into Ethernet frames to identify VLAN IDs; trunks carry multiple VLANs; native VLAN frames are untagged.