Concentrate mixed-rate Ethernet aggregation in a fixed Cisco NCS 5500 routing chassis. NCS-55A1-24Q6H-SS= combines 24 interfaces supporting 1 Gbps or 10 Gbps operation, 24 interfaces supporting 10 Gbps or 25 Gbps operation, and six 100 Gbps interfaces. This port mix provides separate capacity tiers for lower-rate aggregation, 25 Gbps-facing connections, and high-capacity uplinks. MACsec is included for deployments that require link-layer traffic encryption. Use the 1/10 Gbps and 10/25 Gbps interface groups to connect equipment operating at their respective Ethernet rates, while reserving the six 100 Gbps interfaces for higher-capacity links. The fixed chassis format places all stated interface capacity in one platform rather than requiring separate interface modules to establish the published port configuration. That makes the interface allocation clear when mapping network connections by speed tier. The distinguishing characteristic of this NCS55A1 configuration is its three-tier interface arrangement: 24 ports at 1/10 Gbps, 24 ports at 10/25 Gbps, and six ports at 100 Gbps. MACsec further differentiates the configuration for networks that need encrypted Ethernet links. Select this chassis when the required design calls for these exact interface quantities and rates, rather than a uniform-speed fixed routing platform.