Stacking with M-LAG (Multichassis Link Aggregation Group) is the most suitable. It provides device-level redundancy, active-active forwarding, and millisecond-level convergence by allowing a downstream device to form a single link aggregation group with two upstream stacked switches. This offers superior performance and simpler management compared to VRRP (which has a master/backup model) or relying solely on STP for redundancy.

Configuring a wired test client (or a controlled wireless client) to perform 802.1X authentication while running a packet capture (e.g., with Wireshark) on the client or at a strategic network point is the most direct method. This allows you to see the entire EAP exchange between the client, the authenticator (AP/switch), and the RADIUS server, revealing timeouts, rejected attributes, or protocol errors that logs might only summarize.

The primary advantage is improved security and network stability. Smaller subnets (each a broadcast domain) confine broadcast traffic, reducing unnecessary network overhead and limiting the scope of potential broadcast storms. More importantly, they allow for granular security policies (ACLs) at the subnet/VLAN boundaries, enabling control over east-west traffic and containing the impact of certain security incidents.

Classification and Marking is the process of identifying traffic based on headers (e.g., IP, port, protocol) and then setting a trustable priority marker (like DSCP for IP or 802.1p for Ethernet) on the packet as close to the source as possible (the trust boundary). This marking is what downstream network devices use to apply consistent Per-Hop Behaviors (PHBs) like queuing and dropping. The other options describe policing, reservation (IntServ), and queuing/scheduling, which are subsequent steps.

The most straightforward method is to configure a stateful firewall policy (often using a zone-based model). A policy denying all inbound traffic initiated from the untrust zone (internet) to the trust zone (internal network) is standard. While NAT (Option C) provides a degree of obscurity, it is not a security feature by design. A stateful firewall explicitly controls sessions based on connection state, providing stronger and more manageable security for this scenario.

A layer 2 loop causes broadcast, multicast, and unknown unicast frames to circulate indefinitely, multiplying rapidly (broadcast storm). The Spanning Tree Protocol (STP) process on the switch must work excessively to try to recalculate the topology and block ports, leading to high CPU usage. The other issues might cause high traffic or memory usage but would not typically cause the STP process itself to spike in CPU consumption.

Configuring an EtherChannel (Link Aggregation Group using LACP) with the two links bundles them into a single logical interface. This provides both link redundancy (if one physical link fails, traffic flows over the other) and load balancing (traffic is distributed across both active links). VRRP is for gateway redundancy, not for a single point-to-point management link. Separate IP subnets would require manual failover by the NMS.

In the 802.1X framework, the Authenticator is the network access device (Switch, Wireless Controller/AP) that sits between the Supplicant (client) and the Authentication Server (RADIUS). Its role is to enforce the physical (or wireless) port access, acting as a controlled gate. It relays authentication messages between the Supplicant and Server, and then opens or blocks the port based on the Server’s decision.

For slow throughput issues, checking bandwidth utilization and packet loss is critical. Sustained high utilization indicates congestion, which leads to queuing delays and packet drops (loss). Packet loss triggers TCP retransmissions, drastically reducing effective throughput. While latency and jitter are important for real-time traffic, high bandwidth utilization and loss are the primary indicators of a congestion-related throughput problem for bulk data transfers like file copies.

Stacking with M-LAG (Multichassis Link Aggregation Group) is the most suitable. It provides device-level redundancy, active-active forwarding, and millisecond-level convergence by allowing a downstream device to form a single link aggregation group with two upstream stacked switches. This offers superior performance and simpler management compared to VRRP (which has a master/backup model) or relying solely on STP for redundancy.0