Operation Manual – Port Correlation ConfigurationH3C S5500-EI Series Ethernet Switches Chapter 1 Port Correlation Configuration1-4To do... Use the command... RemarksEnable flow control flow-control RequiredTurned off by default1.1.4 Configuring the Suppression Time of Physical-Link-State Change onan Ethernet PortAn Ethernet port operates in one of the two physical link states: up or down. During thesuppression time, physical-link-state changes will not be propagated 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 extraoverhead occurred due to frequent physical-link-state changes within a short period oftime.Follow these steps to configure the suppression time of physical-link-state changes onan Ethernet port:To do... Use the command... RemarksEnter system view system-view —Enter Ethernet port view interface interface-typeinterface-number —Configure the up/downsuppression time ofphysical-link-statechangeslink-delay delay-timeRequiredThe default suppressiontime is 0 seconds,indicating that thephysical layer reports thechange of the port state tothe system right after theport state changes.1.1.5 Enabling Loopback Test on an Ethernet PortYou can enable loopback testing to check whether the Ethernet port functions properly.Note that no data packets can be forwarded during the testing. Loopback testing fallsinto the following two categories:z Internal loopback test, which is performed within switching chips to test thefunctions related to the Ethernet ports.z External loopback test, which is used to test the hardware functions of an Ethernetport. To perform external loopback testing on an Ethernet port, you need to installa loopback plug on the Ethernet port. In this case, packets sent from the port arereceived by the same port.
