Intel® Ethernet 600 Series

Linux Performance Tuning Guide
Ethernet Products Group (EPG)

ID Date Version Classification
861164 08/28/2026 Public

Changing Link Speed

By default, Intel® Ethernet Controller E610 devices do not advertise 2.5 Gbps or 5 Gbps. To have your device advertise these speeds, use the following command: ethtool -s <ethX> advertise N

where N is a combination of the following bitmask values in hexadecimal format:

Link Speed Advertisement Bitmask Values

Link Speed Hex Value Binary Bit Position Description
100 Mbps Full 0x008 Bit 3 100BASE-T Full Duplex
1 Gbps Full 0x20 Bit 5 1000BASE-T Full Duplex
2.5 Gbps Full 0x800000000000 Bit 47 2500BASE-T Full Duplex
5 Gbps Full 0x1000000000000 Bit 48 5000BASE-T Full Duplex
10 Gbps Full 0x1000 Bit 12 10000BASE-T Full Duplex

For example, to turn on 100 Mbps, 1 Gbps, and 2.5 Gbps: ethtool -s <ethX> advertise 0x800000000028

For example, to turn on all modes: ethtool -s <ethX> advertise 0x1800000001028

For example, to check the current advertised capabilities of an interface: ethtool <ethX>

After changing advertised link modes, confirm the negotiated speed and advertised capabilities by running ethtool ethX. Verify that the reported Speed, auto-negotiation, Advertised link modes, and Link partner advertised link modes match the intended configuration.

For more details, refer to the ethtool man page. Note:On Linux systems that use interfaces(5), this can be specified as a pre-up command in /etc/network/interfaces so that the interface is always brought up with NBASE-T support.

For example: iface <ethX> inet dhcp pre-up ethtool -s <ethX> advertise 0x1800000001028 || true Note:Not all network interfaces support all advertised speeds. To check what your driver supports, run ethtool -i <ethX>. Root privileges may be required for these commands. Some hardware may also ignore manual speed settings if auto-negotiation is off or unsupported.