1-4For an S7900E series Ethernet switch in an IRF, its 100-Mbps, GE and 10GE ports are numbered in theformat of interface type A/B/C/D; for an S7900E series Ethernet switch not in any IRF, its 100-Mbps,GE and 10GE ports are numbered in the format of interface type B/C/D.z A: Number of the switch in an IRF;z B: Slot number of the card in the switch;z C: Sub-slot number on a card;z D: Number of a port on a card.If the switch uses LSQ1SRP2XB or LSQ1SRP12GB SRPUs, it simulates two virtual LPU slots with theslot numbers following the largest slot number. The virtual LPUs correspond to the SRPUs, and theEthernet ports on the virtual LPUs correspond to the Ethernet ports on the SRPUs and the numberingrules for the ports are the same as those described earlier. If you want to configure the Ethernet ports onthe SRPUs, you need to configure on the virtual LPUsFor more information about SFP and XFP ports involved in this chapter, see 3Com S7900E FamilyGetting Started Guide.Configuring Flow Control on PortWhen flow control is enabled on both sides, if traffic congestion occurs at the ingress port, it will send aPause frame notifying the egress port to temporarily suspend the sending of packets. The egress port isexpected to stop sending any new packet when it receives the Pause frame. In this way, flow controlhelps to avoid dropping of packets. Note that this will be possible only after flow control is enabled onboth the ingress and egress ports.Follow these steps to enable flow control on a port:To do… Use the command… RemarksEnter system view system-view —Enter Ethernet port or OLT portviewinterface interface-typeinterface-number —Enable flow control flow-controlRequiredBy default, receive flow controlis disabled on a port.Configuring the Suppression Time of Physical-Link-State Change on an EthernetPortAn Ethernet port operates in one of the two physical link states: up or down. During thephysical-link-state change suppression time, the physical-link-state changes of ports will not bepropagated to the system. Only after the suppression time has elapsed will the system be notified of thephysical-link-state changes by the physical layer. This functionality reduces the extra overheadoccurred due to frequent physical-link-state changes within a short period of time.Follow these steps to configure the suppression time of physical-link-down-state changes on a port:
