Aggregate Ethernet access connections and higher-speed uplinks in a single fixed Cisco NCS 520 platform. The N520-20G4Z-A= configuration provides 20 Gigabit Ethernet interfaces plus 4 10 Gigabit Ethernet interfaces, giving network teams a defined interface mix for access aggregation, service handoff, and transport-edge roles. Its 24 Ethernet interfaces combine dense Gigabit connectivity with separate 10 Gigabit capacity for aggregation paths. The 20 Gigabit Ethernet interfaces fit deployments with many lower-speed Ethernet endpoints or downstream network elements. Four 10 Gigabit Ethernet interfaces provide higher-bandwidth connections where traffic must be concentrated toward an upstream network, aggregation layer, or transport-facing connection. This port allocation helps preserve 10 Gigabit capacity for uplink and aggregation functions rather than consuming it for individual Gigabit attachments. Commercial-temperature operation distinguishes this configuration for indoor network environments that do not require an extended-temperature platform. The unit occupies 1 rack unit, supporting dense installation where rack space is limited. Select this NCS 520 variant when the required physical interface count is specifically 20 Gigabit Ethernet connections and 4 10 Gigabit Ethernet connections, with a commercial-temperature operating classification.