Multi-speed Ports

If a port supports multiple speeds, the software configures the speed automatically based on the optic type it detects in the port; you do not need to configure the port speed. For multi-speed copper ports, Auto-Negotiation detects the speed.

Note

Some VIMs must operate with all ports at the same speed, or with a group of ports at the same speed, while others can operate with ports at different speeds. For more information, see Fabric Engine Release Notes. The sys vim-speed command is supported only on VIMs that must operate with all ports at the same speed. An error message displays if you run the command on an unsupported VIM.

In addition to the documented maximum port speed, and in cases where the hardware supports it:

SFP ports are for 1 Gbps but can also support 100 Mbps.
SFP+ ports are for 10 Gbps but can also support 1 Gbps or 100 Mbps.
SFP28 ports are for 25 Gbps but can also support 10 Gbps or 1 Gbps.
QSFP+ ports are for 40 Gbps but can also support 4x10 Gbps if channelization is supported and enabled.
QSFP28 ports are for 100 Gbps but also can support 40 Gbps, or 4x25 Gbps or 4x10 Gbps if channelization is supported and enabled.

Note

A 100 Gbps DAC in a 100 Gbps port can negotiate down to 40 Gbps depending on the hardware and peer connection.

SFP28, SFP+ and SFP ports have the same physical size.

QSFP28 and QSFP+ ports have the same physical size.

To know if a port supports multiple speeds or channelization, see the applicable hardware documentation.

25/10G Dual Speed Optics Behavior

The following lists the default behavior for 25/10G dual speed optics when inserted in a port:

Table 1. Default behavior for 25/10G dual speed optics
Port type	Default speed	Auto-negotiation	FEC
SPF28	25G	Disabled	Enabled
SFP+	10G	Disabled	Disabled
QSFP28 with QSA	25G	Disabled	Enabled
QSFP+ with QSA	10G	Disabled	Disabled

10/1G Dual Speed Optics Behavior

The following lists the default behavior for 10/1G dual optics when inserted in a port:

Table 2. Default behavior for 10/1G dual optics
Port type	Default speed	Auto-negotiation	FEC
SPF28	10G	Enabled	Disabled
SFP+	10G	Enabled	Disabled
SFP	1G	Enabled	Disabled
QSFP28 with QSA	10G	Enabled	Disabled
QSFP+ with QSA	10G	Enabled	Disabled