Another known take on the router-based schemes comes from Hazeyama et al. In their approach, they wish to integrate the SPIE approach as outlined by Snoeren, with their approach of recording the layer 2 link-id along with the network ID (VLAN or true ID), the MAC address of the layer 2 switch that received the packet and the link id it came in on. This information is then put into two look-up tables – both containing the switch (layer 2 router) MAC id for look-up. They rely on the MAC:port tuple as a method of tracing a packet back (even if the MAC address has been spoofed).