Changing Link Speed

Intel® Ethernet 600 Series

Linux Performance Tuning Guide

ID	Date	Version	Classification
861164	07/29/2025		Public

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

where "N" is a combination of the following Bitmask Values (Hex):

Link Speed	Hex Value	Binary Bit Position	Description
100 Mbps Full	0x008	Bit 3	100BASE-T Full Duplex
1Gbps Full	0x20	Bit 5	1000BASE-T Full Duplex
2.5 Gbps Full	0x80000000000	Bit 43	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 0x80000000028

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>

For more details, refer to the ethtool man page. Note:On Linux systems with INTEFFACES(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 <eth> advertise 0x1800000001028 || true Note:All Network interfaces may not support all advertised speeds. To check what your driver supports, run ethtool -i <ethX>. User might need to use root privileges for these commands. Also, some hardware may ignore manual speed settings if auto-negotiation is off or unsupported.