Configuring IPv6 TCP Properties 671Configuring the AgingTime for PMTUAfter the MTU of the path from the source host to the destination host isdynamically determined (refer to “IPv6 PMTU Discovery” on page 663), the sourcehost sends subsequent packets to the destination host on basis of this MTU. Afterthe aging time expires, the dynamically determined PMTU is removed and thesource host re-determines an MTU to send packets through the PMTU mechanism.The aging time is invalid for static PMTU.Follow these steps to configure the aging time for PMTU:Configuring IPv6 TCPPropertiesThe TCP properties you can configure include:■ synwait timer: When a SYN packet is sent, the synwait timer is triggered. If noresponse packet is received before the synwait timer expires, the TCPconnection establishment fails.■ finwait timer: When the TCP connection status is FIN_WAIT_2, the finwaittimer is triggered. If no packet is received before the finwait timer expires, theTCP connection is terminated. If a FIN packet is received, the TCP connectionstatus becomes TIME_WAIT. If other packets are received, the finwait timer isreset from the last received packet and the connection is terminated after thefinwait timer expires.■ Size of the IPv6 TCP sending/receiving buffer.Follow these steps to configure TCP properties:Configuring IPv6FIB-Based ForwardingWith the caching function of IPv6 FIB enabled, the device searches the FIB cachewhen forwarding packets, thus reducing the time in searching IP packets andimproving the forwarding efficiency.In the load sharing mode of IPv6 FIB, the device can decide how to select an equalcost multi-path (ECMP) route to forward packets. Currently, two load sharingmodes are supported:To do... Use the command... RemarksEnter system view system-view -Configure aging time forPMTUipv6 pathmtu age age-time Optional10 minutes by default.To do... Use the command... RemarksEnter system view system-view -Set the finwait timer of TCPpacketstcp ipv6 timer fin-timeoutwait-timeOptional675 seconds by defaultSet the synwait timer of TCPpacketstcp ipv6 timer syn-timeoutwait-timeOptional75 seconds by defaultSet the size of the TCPsending/receiving buffertcp ipv6 window size Optional8 KB by default
