A network technician racked up two 9240 mobility gateways in a single cluster that will be terminating 1700 APs in a medium-sized branch office Next…

To achieve maximum wired bandwidth utilization from the two physical SFP28 links per gateway, the administrator must aggregate them into a single logical link. This is accomplished by creating a port channel, also known as a Link Aggregation Group (LAG). A port channel combines the capacity of the member physical interfaces, allowing traffic to be load-balanced across them. This configuration effectively creates a single 50Gbps logical interface (2 x 25Gbps) for each gateway, providing both increased throughput and link redundancy, which directly addresses the goal of maximizing bandwidth utilization.

B. Make all ports trunk interfaces and permit data VLANs: This is a necessary step for passing tagged traffic but does not aggregate the bandwidth of the physical links. This configuration would be applied to the logical port-channel interface after it is created.
C. Disable the spanning tree and allocate unique VLANs to each port: Disabling the spanning tree is dangerous and can cause network loops. Allocating unique VLANs to each port would segregate traffic, preventing bandwidth aggregation, which is the opposite of the stated goal.
D. Manually set 25Gbps speeds on all ports: Port speeds are typically auto-negotiated. While verifying the speed is a good practice, manually setting it does not combine the bandwidth of the two separate links into a single, higher-capacity logical path.

1. ArubaOS 8.10.0.0 User Guide: In the "Configuring Network Interfaces" chapter, the section "Configuring Port Channels" states, "A port channel is an aggregation of network interfaces that creates a single logical link from multiple physical links. This logical link provides aggregated bandwidth and link redundancy." This directly supports creating a port channel to maximize bandwidth. (Reference: Page 398)

2. Aruba Mobility Gateway 9200 Series Data Sheet: This document specifies the port capabilities of the 9240 gateway, noting it has "4x 10G/25G SFP28 ports." This confirms the hardware context for aggregating 25Gbps links. (Reference: Page 2, "Interfaces and Indicators" section)

3. Aruba Campus Switching and Mobility Validated Solution Guide: These guides consistently recommend using Link Aggregation (LAG) or port channels for connecting high-throughput devices like Mobility Gateways to the core switching infrastructure to ensure high availability and aggregate bandwidth. (Reference: General best practices sections in various VSGs, e.g., Aruba Campus for Midsize Networks VSG, Chapter 4 "Network Design").