What is port-channel hashing used for in a switch or NIC team?

• A. Distributing flows across member links based on fields like source/destination IP and port.
• B. Calculating VLAN tagging for traffic segmentation.
• C. Determining the best path in a spanning tree.
• D. Encrypting traffic on a port-channel.

Answer: (A)

Port-channel hashing decides which physical link in a bonded group carries a given flow. It does this by computing a hash from packet header fields—typically source and destination IP addresses, source and destination ports, and the protocol—and then mapping that hash to one of the member links. This approach spreads different flows across the available links to increase overall bandwidth while keeping all packets belonging to the same flow on the same link to preserve in-order delivery. While some implementations may include additional fields like VLAN, the main purpose is consistent, flow-based distribution across the team.

This is why the best choice describes distributing flows across member links based on header fields. The other options don’t describe per-flow load distribution: VLAN tagging isn’t driven by hashing, spanning-tree relies on topology decisions, and encryption is a separate security function.