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Routing & Switching · Intermediate

Load Balancing Hash

The algorithm that selects which member link of an EtherChannel or ECMP group carries a flow, based on header fields.

Definition

Hash inputs can include source/destination MAC, IP and Layer 4 ports. Choosing inputs with enough entropy avoids polarization where most traffic uses one link. Because hashing is per flow, a single flow never exceeds one member's bandwidth.

Example

port-channel load-balance src-dst-ip

Exam tip

A single large flow cannot use more than one link; uneven utilization often means a poor hash choice.

Related terms