Understanding the network connections

The HMC is connected to a Service LAN which is used to manage the CPCs. The HMC is also connected to the customer or Open Environment for remote access.

This worksheet is not a network design tool. It assumes the customer has an idea on how the HMC and SE connections should be made. The intent of this worksheet is to ask enough questions to get the information you need to fill the installation panels for the HMC and SE network.

3931 introduces the PTP/NTP direct connection. Additional planning is required compared to previous systems. Ethernet connection(s) (recommended Cat5e and higher) are required between the External Time source (ETS) and ETS1/ETS2 ports on IBM z16 oscillator card(s). In addition, (up to) 2 TCP/IP addresses(es) that are routable to the ETS must be configured for ETS1/ETS2 ports.
  • A single drawer system configuration:
    • ETS1 is connected to port J03 of OSC0 (H101) in CPC0 (A10)
    • ETS2 is connected to port J03 of OSC1 (H102) in CPC0 (A10)
  • In a two drawer or larger system configuration:
    • ETS1 is connected to port J03 of OSC0 (H101) in CPC0 (A10)
    • ETS2 is connected to port J03 of OSC0 (H101) in CPC1 (A15)
8561 introduces the Hardware Management Appliance (HMA) feature:
  • The HMA feature allows the HMC and SE to run on the same physical hardware.
  • The HMC and SE continue to have their own dedicated network connections.
  • The network interfaces on the HMC component of the HMA appear as em1 and em2 rather than eth0 and eth1.
  • The routing of the physical cabling for the HMC component of the HMA network must now be run to the CPC location rather than the previous Standalone HMC location.
  • All other network configuration information on HMA consoles remain the same as standalone consoles.
  • The CPC must always be defined to both host HMCs.
  • Both HMCs of the Hardware Management Appliance must have at least one network interface that share a common subnet for discovery purposes (for example, HMC1: 192.168.10.42/255.255.255.0, HMC2: 192.168.10.43/255.255.255.0).