Cisco switch modules with SVI may experience dropped packets - IBM Servers

Resolving The Problem

Source

RETAIN tip: H196718

Symptom

If the management Virtual Local Area Network (VLAN) interface, also called the Switched Virtual Interface (SVI), is created on a VLAN that passes data traffic, packets may be dropped.

The dropped packets can be observed with the following command:

Affected configurations

The system is configured with one or more of the following IBM Options:

• Cisco Catalyst Switch Module 3012 for IBM BladeCenter, Option 43W4395, any component
• Cisco Gb Ethernet Switch Module for BladeCenter, Option 32R1892, any model
• Cisco Systems Fiber Intelligent Gigabit Ethernet Switch Module for BladeCenter, Option 32R1888, any model

This tip is not hardware specific.

This tip is not software specific.

Workaround

Do not create a SVI on a VLAN that is also used for data traffic. The SVI VLAN should be for device management only.

Additional information

When the user creates a management VLAN interface, also known as a SVI, that is the same as a user data VLAN; all broadcast and multicast packets for that VLAN are sent to the Switch Central Processing Unit (CPU). It is possible to overrun the CPU with these packets. This condition is common to all switching platforms, including blade ethernet switch applications.