The operation field can take the values 1 for request, 2 for reply, 8 for inverse request, 9 for inverse reply and 10 for NACK. The inverse request and inverse reply messages can bind the physical address to an IP address in a PVC situation. The request and reply message can be used to bind a physical address to an IP address in an SVC situation. The inverse request and inverse reply can also be used to build the server’s
mapping table.