The HMC-to-CPC communication is now possible through only an Ethernet switch that is  connected to the J03 or J04 port on the SEs. Other IBM Z systems and HMCs also can be  connected to the switch. To provide redundancy, install two Ethernet switches. Only the switch (and not the HMC directly) can be connected to the SEs. The connectivity between HMCs and the SEs is shown in Figure 11-8. Figure 11-8 HMC and SE connectivity Various methods are available for setting up the network. It is your responsibility to plan and  design the HMC and SE connectivity. Select the method that is based on your connectivity  and security requirements. Security:  The configuration of network components, such as routers or firewall rules, is  beyond the scope of this book. Whenever the networks are interconnected, security  exposures can exist. For more information about HMC security, see  Integrating the  Hardware Management Console‘s Broadband Remote Support Facility into your  Enterprise , SC28-6951.  For more information about the HMC settings that are related to access and security, see  the HMC and SE console help function or IBM Knowledge Center. 368  IBM 14 Model ZR1 Technical Guide