Figure 1 shows a NAT in front of both z/OS® hosts. A configuration with a NAT in front of only one of the z/OS hosts is supported as well. If there is a NAT device in front of the responder, the NAT's address mapping must be static. If there is a NAT device in front of the initiator, the NAT's address mapping can be static or dynamic. A dynamic mapping can use either one-to-one address translation or many-to-one address port translation (NAPT).
Either UDP-encapsulated transport mode or UDP-encapsulated tunnel mode can be negotiated in a z/OS host-to-z/OS host configuration.