The OOB management network is a separate network for management traffic only. It is used by administrators to configure, manage, and monitor devices such as switches and servers. Payload traffic initiated by the network end-users does not traverse the OOB management network. Switches used for management are generally 1 GbE. The benefit of using OOB is that you can still access a switch even if part of the network between you and the switch goes down. The following figure shows how the Dell PowerSwitch S3048-ON switch can be used for this purpose:
The OOB management network example for multiple racks figure shows an OOB management network for multiple racks. Each S3048-ON may be used to manage up to 48 devices on the network, typically enough for a single rack of equipment. The switch may then be connected to other adjacent management switches, or upstream to a management core. In Figure 5, the red lines indicate cables connecting all OOB traffic. Note that each device (servers, switches, storage) has a single cable connection attached to the management network. Although a stack of switches is seen as one single switch by other devices on the network, and only one cable connection is required for the entire stack, a second cable is used as a backup in case the stack master fails.
The OOB management network for a single rack figure below demonstrates how OOB management might look in a single rack. There is one cable from the management switch to each device on the network to be managed. Cables running to Dell switches are connected to the OOB management ports of the switches. Cables running to Dell PowerEdge servers are connected to the iDRAC ports of the servers.