Implementation of WLRU algorithm to improve scalability in software defined network

Packet forwarding in a Software Defined Network (SDN) architecture was conducted by a matching process between packet information with flow entry. Network traffic with multiple IP or MAC addresses will increase the number of flow entry insertion and may result in the flow table on the switch running out of space for new flow entry. Flow table overflow that occurred will decrease network scalability in packet forwarding. This study implemented the Weighted Least Recently Used (WLRU) algorithm in the flow table's entry management process to prevent flow table overflow conditions and reduce the number of repeated insertions for an entry. The implementation was conducted using a single linked list data structure and Snort as a packet monitoring. The entry management implementations using the WLRU algorithm successfully overcame the flow table overflow conditions and improved network scalability by being able to forward up to 402 packets, which means 4 times more than before, that only 97 packets. In trade-off overcame the flow table overflow condition, the WLRU algorithm affected the RTT delay value with a minimum value of 19.54 milliseconds, a maximum value of 1607.40 milliseconds, and an average value 195.72 milliseconds.