Operation Manual – IP Addressing and PerformanceH3C S7500E Series Ethernet Switches Chapter 2 IP Performance Configuration2-42.3 Configuring TCP Attributes2.3.1 Configuring TCP Optional ParametersTCP optional parameters that can be configured include:z synwait timer: When sending a SYN packet, TCP starts the synwait timer. If noresponse packets are received within the synwait timer timeout, the TCPconnection is not successfully created.z finwait timer: When the TCP connection is in FIN_WAIT_2 state, finwait timer willbe started. If no FIN packets are received within the timer timeout, the TCPconnection will be terminated. If FIN packets are received, the TCP connectionstate changes to TIME_WAIT. If non-FIN packets are received, the systemrestarts the timer from receiving the last non-FIN packet. The connection is brokenafter the timer expires.z Size of TCP receive/send bufferFollow these steps to configure TCP optional parameters:To do… Use the command… RemarksEnter system view system-view —Configure TCP synwaittimer’s timeout valuetcp timer syn-timeouttime-valueOptionalBy default, the timeoutvalue is 75 seconds.Configure TCP finwaittimer’s timeout valuetcp timer fin-timeouttime-valueOptionalBy default, the timeoutvalue is 675 seconds.Configure the size of TCPreceive/send buffer tcp window window-sizeOptionalBy default, the buffer is 8kilobytes.Caution:The actual length of the finwait timer is determined by the following formula:Actual length of the finwait timer = (Configured length of the finwait timer – 75) +configured length of the synwait timer2.4 Configuring ICMP to Send Error PacketsSending error packets is a major function of ICMP protocol. In case of networkabnormalities, ICMP packets are usually sent by the network or transport layerprotocols to notify corresponding devices so as to facilitate control and management.
