Operating instructions

62 Cisco Systems Intelligent Gigabit Ethernet Switch Module
5. Ensure proper IP subnet selection.
Make sure that the IP subnet that is used by the IGESM is
different from the subnet that is
defined on the Management Module for its own IP addresses. As with step 3, it is
important to isolate the IGESM management path to the Management Module because
we are now going to manage the IGESM via its own uplinks. Different IP subnets between
the Management Module and the IGESM will complete this isolation.
Adhering to these five rules enables successful management of and access to IGESMs via
the IGESM’s own uplinks (g0/17 - 20).
Figure 5-42 shows an important attribute of utilizing the IGESM uplinks for IGESM
management. In this case, although the VLAN that is assigned to the IGESM management
VLAN is being carried over the uplinks, it can have an impact on BladeCenter operations
because it is carried over to the Management Module through ports g0/15 or 16. This internal
link, and the fact that the Management Module attempts to proxy for devices in the
BladeCenter, is key to why only scenarios 3 and 4 are considered viable options when using
the IGESM uplinks to manage the IGESM.
Figure 5-42 Discussion of management via IGESM uplinks and internal link to Management Module
5.3.6 Considerations: More than a single IGESM in a given BladeCenter
When installing multiple IGESMs into a BladeCenter chassis, the most common (and
recommended) approach is to place all IGESMs on the same management VLAN, in the
same IP subnet, regardless of whether you will manage the IGESMs via the Management
Module uplink or the IGESM’s uplink. Following this simple approach helps ensure that the
recommended scenarios in this document operate as desired.
A user may want to place the IGESMs into different management VLANs, such as if different
groups will be managing certain IGESMs and they require VLAN isolation between each
IGESM in a BladeCenter. This might seem straightforward to perform, but in reality it can lead
to unexpected error messages being generated on the IGESMs.
The issue with placing IGESMs in a single chassis into different management VLANs is that,
because the Management Module connects each IGESM
1
and each IGESM always makes
Management
Module
IGESM
Bay 1 - 4
Flow Name Flow Line VLAN Description
IGESM traffic Y Shows VLAN Y also flowing to MM
BladeCenter
MGMT
Interface
VLAN Y
VLAN Y
ETH 0
ETH 1
To blade servers
Sw Bay - external
management
over all ports
enabled