Unlike a baseboard management controller, the IMM does not require IPMI device drivers or USB daemons for in-band IMM communication. Instead, a LAN over USB interface enables in-band communications to the IMM; the IMM hardware on the system board presents an internal Ethernet interface from the IMM to the operating system. LAN over USB is also called the USB in-band interface in the IMM web interface.
In a scalable blade complex, each IMM is shown as a LAN over USB device in the operating system. For each blade server in the scalable blade complex to be a unique and known IP address, both blade servers have different default IP addresses. The default IP address for the primary blade server is 169.254.95.118, and the Keyboard Controller Style (KCS) address is 0x6CA8.
For packets to be routed correctly from the host to the IMMs, each of the LAN over USB interfaces must appear on a separate subnet to the host. The IMM implements a DHCP server that services only the LAN over USB interface. It assigns the subnet mask on the LAN over USB interfaces for the host to 255.255.255.0.
| Blade server | Logical node ID | IMM IP address | Host address | Host subnet | Host subnet mask | Keyboard Controller Style (KCS) address |
|---|---|---|---|---|---|---|
| Primary | 0 | 169.265.95.118 | 169.254.95.120 | 169.254.95.0/24 | 255.255.255.0 | 0x8CA6 |
| Secondary | 1 | 169.265.96.118 | 169.254.96.120 | 169.254.96.0/24 | 255.255.255.0 | 0x8CA8 |
LAN over USB devices are not aware of LAN over USB devices in other partitions. If you configure the two blade servers as two independent partitions in a scalable blade complex, each blade server is considered to the primary blade server of the hardware partition that contains that blade server. The logical ID of the primary in each partition is 0 and the default IP address of each primary blade server is 169.254.95.118.