Dell C1048P Port Extender Networking Configuration Guide for the C9000 Series - Page 496

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. You must enable the fan-out mode in order for this mechanism to work. 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. NOTE: Although it is possible to configure the remaining three 10 Gigabit ports, the Link UP event does not occur for these ports leaving the lanes unusable. Dell Networking OS perceives these ports to be in a Link Down state. You must not try to use these remaining three 10 Gigabit ports for actual data transfer or for any other related configurations. NOTE: Trident2 chip sets do not work at 1G speeds with auto-negotiation enabled. As a result, when you peer any device using SFP, the link does not come up if auto-negotiation is enabled. Therefore, you must disable auto-negotiation on platforms that currently use Trident2 chip sets (9000 series). This limitation applies only when you convert QSFP to SFP using the QSA. This constraint does not apply for QSFP to SFP+ conversions using the QSA. Important Points to Remember • Before using the QSA to convert a 40 Gigabit Ethernet port to a 10 Gigabit SFP or SFP+ port, you must enable 40 G to 4*10 fan-out mode on the device. • When you insert a QSA into a 40 Gigabit port, you can use only the first 10 Gigabit port in the fan-out mode to plug-in SFP or SFP+ cables. The remaining three 10 Gigabit ports are perceived to be in Link Down state and are unusable. • You cannot use QSFP optical cables in a QSA setup. • When you remove the QSA module alone from a 40 Gigabit port, without connecting any SFP or SFP + cables; Dell Networking OS does not generate any event. However, when you remove a QSA module that has SFP or SFP+ optical cables plugged in, Dell Networking OS generates a SFP or SFP+ Removed event. • You can use the QSA on any of the ports. However, the existing maximum fan-out restrictions apply to the ports. 496 Interfaces