Avocent 590-222-501M manual Blocking and non-blocking configurations

22AMX Switch Series Installer/User Guide

single list in the OSCAR interface, as if all the target devices were connected to one switch. You can also cascade non-Avocent KVM switches, but to access the attached target devices you must first select the non-Avocent switch from the OSCAR interface target list, and then connect to the target device using the methods provided by the non-Avocent KVM switch. To use seamless cascading, you will need to configure the cascaded target device as Multiple Device Mode (MDM).

Blocking and non-blocking configurations

Before setting up a cascaded AMX switching system, evaluate how many users and how many target devices are needed in your system. You can then choose how to best configure your system: as a blocking or a non-blocking configuration, or a combination.

Whether the configuration is blocking or non-blocking is determined by how user paths are connected in the switching system. In a cascaded system, UTP cable is connected from the server ports on the primary switch to the user ports on the secondary switches. To add a tertiary level of switches, UTP cable is connected from the server ports on secondary switches to the user ports on the tertiary switches (see Figure 2.12 on page 24 for an example). Each length of UTP cable acts as a path to connect users to target devices.

Blocking and non-blocking configurations are defined as follows:

•Non-blocking configuration – the number of user paths between each level of switches is equal to or greater than the number of users the primary switch supports. The maximum number of user paths are available and thus any user (with the appropriate access rights) can access any target device in the switching system at any time.

•Blocking configuration – the number of user paths between each level of switches is less than the number of users the top level switch supports. A limited number of user paths are available in this configuration, which at times might prevent or block a user from accessing a target device. However, you may be able to attach more target devices to the switching system when using a blocking configuration.

Figure 2.11 illustrates one possible blocking configuration in an AMX switching system. In this example, a four-user AMX switch is cascaded off of an eight-user AMX switch. The target devices attached to the primary switch will never be blocked and can be accessed at any time. The secondary switch has only four user paths attached to it, creating a blocking configuration. When connections are made to four of the target devices on the secondary switch, there are no more user paths available for that switch. The other users in the system can share access to the connected target devices, but they cannot connect to any other target device on that switch. Once a user closes a connection to a target device, that user path is open and can be used to connect to any target device in the switching system.