Dell PowerSwitch S4820T Configuration Guide for the S4820T System 9.100.0 - Page 380

Splitting QSFP Ports to SFP+ Ports The platform supports splitting a single 40G QSFP port into four 10G SFP+ ports using one of the supported breakout cables (for a list of supported cables, refer to the Installation Guide or the Release Notes). NOTE: When you split a 40G port (such as fo 1/4) into four 10G ports, the 40G interface configuration is still available in the startup configuration when you save the running configuration by using the write memory command. When a reload of the system occurs, the 40G interface configuration is not applicable because the 40G ports are split into four 10G ports after the reload operation. While the reload is in progress, you might see error messages when the configuration file is being loaded. You can ignore these error messages. Similarly, such error messages are displayed during a reload after you configure the four individual 10G ports to be stacked as a single 40G port. To split a single 40G port into four 10G ports, use the following command. • Split a single 40G port into four 10G ports. CONFIGURATION mode stack-unit stack-unit-number port number portmode quad • number: enter the port number of the 40G port to be split. NOTE: To revert the port mode to 40G, use the no stack-unit stack-unit-number port port-number portmode quad command. Important Points to Remember • Splitting a 40G port into four 10G ports is supported on standalone and stacked units. • You cannot use split ports as stack-link to stack a system. To verify port splitting, use the show system stack-unit stack-unit-number fanout {count | configure} command. To verify port splitting, use the show system stack-unit stack-unit-number fanout {count | configure} command • The quad port must be in a default configuration before you can split it into 4x10G ports. The 40G port is lost in the configuration when the port is split; be sure that the port is also removed from other L2/L3 feature configurations. • The system must be reloaded after issuing the CLI for the change to take effect. Converting a QSFP or QSFP+ Port to an SFP or SFP+ Port You can convert a QSFP or QSFP+ port to an SFP or SFP+ port using the Quad to Small Form Factor Pluggable Adapter (QSA). QSA provides smooth connectivity between devices that use Quad Lane Ports (such as the 40 Gigabit Ethernet adapters) and 10 Gigabit hardware that uses SFP+ based cabling. Using this adapter, you can effectively use a QSFP or QSFP+ module to connect to a lower-end switch or server that uses an SFP or SFP+ based module. When connected to a QSFP or QSFP+ port on a 40 Gigabit adapter, QSA acts as an interface for the SFP or SFP+ cables. This interface enables you to directly plug in an SFP or SFP+ cable originating at a 10 Gigabit Ethernet port on a switch or server. You can use QSFP optical cables (without a QSA) to split a 40 Gigabit port on a switch or a server into four 10 Gigabit ports. To split the ports, enable the fan-out mode. Similarly, you can enable the fan-out mode to configure the QSFP port on a device to act as an SFP or SFP+ port. As the QSA enables a QSFP or QSFP+ port to be used as an SFP or SFP+ port, Dell Networking OS does not immediately detect the QSA after you insert it into a QSFP port cage. After you insert an SFP or SFP+ cable into a QSA connected to a 40 Gigabit port, Dell Networking OS assumes that all the four fanned-out 10 Gigabit ports have plugged-in SFP or SFP+ optical cables. However, the link UP event happens only for the first 10 Gigabit port and you can use only that port for data transfer. As a result, only the first fanned-out port is identified as the active 10 Gigabit port with a speed of 10G or 1G depending on whether you insert an SFP+ or SFP cable respectively. 380 Interfaces