IBM eX5 Implementation Guide

330 IBM eX5 Implementation Guide

Figure 7-29 Onboard Ethernet port used when IMM Network Interface is Shared

Although this design eliminates a physical switch port and patch cable configuration, both the

media access control (MAC) address for the second Ethernet port and the MAC address for

the IMM will address through this network port. Therefore, at least two separate IP addresses

are assigned to the same physical port. Sharing the port also prevents you from configuring

the two onboard Ethernet ports in a network team using 802.3ad load balancing.

Using 802.3ad load balancing results in dropped packets for the IMM MAC address. Smart

load balancing and failover are still available network teaming options. However, keeping the

public traffic from the management traffic become more difficult. To maintain this separation,

you must use network teaming software to establish a VLAN to be used by the server to send

public tagged traffic to the network switch. You must configure the switch port as a trunk port

to support both the public-tagged VLAN traffic, plus the untagged traffic for the management.

You must define the management VLAN as the native VLAN on the switch port, so that its

untagged traffic from the switch will be accepted by the IMM MAC and dropped by the second

Ethernet port’s MAC. Although this configuration is more complex, it is a common practice in

virtualized servers running on a common set of host computers.

Although the IMM uses a dedicated RISC processor, there are limitations to the amount of

network traffic to which the IMM can be exposed before complex functions, such as booting

from a remote DVD or USB storage, become unreliable because of timing issues. Although

the OS has all of the necessary drivers in place to deal with these timing issues, the UEFI is

not as tolerant.

Therefore, for maintaining secured access, keep the IMM on a separate management

network.

7.7.3 IMM communications troubleshooting

The User’s Guide for Integrated Management Module - IBM BladeCenter and System x is an

excellent guide to help you with every aspect of configuring and using the IMM. It is available

at this website:

http://ibm.com/support/entry/portal/docdisplay?lndocid=MIGR-5079770

Most communication errors are due to network switch configuration options, such as blocked

ports or VLAN mismatches. A first step in determining this type of problem is to connect

directly to the IMM port with a mobile computer and Ethernet patch cable to see if you can

ping and then start a web session. The management port is a 10/100 Ethernet port, so if your

mobile computer does not have a 10/100/1000 Ethernet port on it, you need to replace the

patch cable with a 10/100 crossover cable. Only 1Gb Ethernet ports have the ability to