X3950 X6 Imm2 Communication - IBM x3850 X6 Planning And Implementation Manual

To maintain separation between public and management traffic, network teaming software
must be used to establish a VLAN to be used by the server to send public-tagged traffic to the
network switch. The switch port must be configured as a trunk port to support both the
public-tagged VLAN traffic, plus the untagged traffic for the management. The management
VLAN must be defined as the native VLAN on the switch port, so that its untagged traffic from
the switch will be accepted by the IMM2 MAC and dropped by the second Ethernet port's
MAC.
While the IMM2 uses a dedicated 32-bit RISC processor, there are limitations as to the
amount of network traffic that the IMM2 can be exposed to before complex functions, such as
booting from a remote DVD, or USB storage will become unreliable because of timing issues.
While the operating system has all of the necessary drivers in place to deal with these timing
issues, the UEFI is not as tolerant. For this reason (maintaining secured access), the IMM2
should be kept on a separate management network.

5.1.5 x3950 X6 IMM2 communication

The x3950 X6 has two IMM2 management processors. The two IMMs in the x3950 X6 will
communicate between each other internally through the mid-plane. Because the IMMs are
internally linked, discovery, communication, sharing information related to partitioning, critical
events, and management can be achieved with only one connection to the primary IMM2. The
primary IMM2 is located on the top half of the x3950 X6 as seen in Figure 5-5.
Figure 5-5 The primary IMM2 port at the back of an x3950 X6
136
IBM System x3850 X6 and x3950 X6 Planning and Implementation Guide