Overview

The 100GE and 40GE optical interfaces can be used as a single interface or split into multiple independent interfaces. The 40GE interface can be split into four 10 Gigabit Ethernet sub-interfaces. The 100GE can be split into four 25 Gigabit Ethernet sub-interfaces or split into four 10 Gigabit Ethernet sub-interfaces. With the port breakout function, one port can connect to various types of interfaces on the peer devices.

After a single interface is split into four sub-interfaces, the original interface will not exist. The 10GE optical sub-interface or the 25GE optical sub-interface supports the same configurations and features as other non-breakout optical interface except that the interface is named in a different way. For details about interface name in different port modes, see Interface Name in Different Port Modes.

After the interface is split, you need to use a breakout cable to connect to the device at the other end. For example, as shown in the following figure, a 40GE interface must use a breakout cable to connect to the device at the other end after being split into 4 x 10GE sub-interfaces. If the connected peer interface is also a split 40GE interface, the interfaces on both ends can be plugged into the same type of 40GE optical module QSFP+ and connected by one optical fiber instead of using a breakout cable.

Figure 1. The breakout cable

According to the port mode configuration set interface qe-interface-mode <SFP | QSFP | FLEX> command, the switch works in one of the three port modes: QSFP, SFP and FLEX.

• QSFP: In this mode, all the ports are not split.

• SFP: In this mode, all 40GE and 100GE ports are split. The 40GE interfaces are split into 4 x 10GE sub-interfaces, and the 100GE interfaces are split into 4 x 25GE sub-interfaces.

• FLEX: Flexible mode. In this mode, user can split part of the 40GE or 100GE interfaces as required. After switching to this mode, you can use set interface gigabit-ethernet <port-name> breakout <10g-4x |25g-4x|donot> command to split the 40GE and 100GE ports as required. The 40GE interfaces can be split into 4 x 10GE sub-interfaces, and the 100GE interfaces can be split into 4 x 25GE or 4 x 10GE sub-interfaces.

The breakout sub-interfaces can also be merged into one interface through the port merge operation by using set interface gigabit-ethernet <port> breakout donot command.

Interface Name in Different Port Modes

The interface names may be different in different port modes, for example:

On S4148 Series Switch

On Switches Other than S4148 Series Switch