A compatible computer and network-attached storage (NAS) device can use a direct Ethernet link or a standalone 2.5GbE switch for local transfers without replacing the router. Both devices and the equipment carrying the transfer must support the faster connection; a 2.5GbE link does not guarantee a corresponding increase in file-copy speeds.
The distinction is between local network traffic and internet access. Transfers between devices communicating directly on the same local network do not need to travel over the internet. A faster internet plan or a router’s multi-gigabit wide area network (WAN) port therefore does not, by itself, accelerate that local connection.
Direct Ethernet connects a computer and NAS
A direct connection places an Ethernet cable between the computer and NAS, with no router or switch in that path. With compatible 2.5GbE interfaces at both ends, this provides a dedicated local link.
QNAP’s networking documentation describes direct 2.5GbE connections between NAS and PC. Its separate troubleshooting procedure uses a static IP address on the computer and leaves the gateway field empty. The devices still need appropriate address settings to communicate.
The dedicated link connects the two devices. Internet connectivity and access from other computers require additional network paths; the direct cable does not automatically provide either.
A PCIe network card or USB Ethernet adapter can add 2.5GbE to a compatible computer. Cable Matters says its USB-C adapter requires compatible hardware, network equipment and cables to reach its stated maximum of 2.5Gbps, and that additional drivers may be necessary.
A standalone switch connects several devices
A switch-based arrangement connects the NAS and computers to 2.5GbE ports on the same switch. In a straightforward home NAS setup, another Ethernet cable can connect the switch to a LAN port on the existing router.
When the computer and NAS communicate within the same subnet and switched network, their local file-transfer traffic can pass between them on the switch without crossing the router uplink. A gigabit uplink to the router therefore does not impose a gigabit limit on that particular transfer.
Devices reached through other links remain subject to those links’ capacity. A computer connected through a gigabit port does not gain a 2.5GbE connection simply because the NAS and switch support the faster rate.
Link capacity differs from file-transfer speed
2.5GbE has a nominal rate of 2.5Gbps, compared with 1Gbps for gigabit Ethernet. That is 2.5 times the nominal bandwidth, rather than a promise that files will copy 2.5 times faster.
TP-Link says actual throughput from its 2.5GbE PCIe adapter is not guaranteed and varies with computer performance, cable class and environmental factors. Microsoft’s SMB troubleshooting guidance also identifies storage performance and CPU workload as factors that can limit file transfers.
Existing cabling does not necessarily need replacement. Cable Matters lists Cat5e and Cat6 cables as supported by its 2.5GbE adapter. That specification does not establish compatibility or performance for every existing installation.
