Virtual Path Interfaces

The ATM1600 has been extended with the capability to define Virtual Path Interfaces (VPIFs), which are ATM virtual path connections on an ATM1600 ATM interface that appear as additional IP interfaces to the router. The virtual path interfaces may be used as trunk connections between ATM1600s crossing an ATM cloud on provisioned permanent virtual circuits.

Basic Operation of Virtual Path Interfaces

A VPIF is configured via the ATM1600 console and given an interface number outside of the 16 possible interface numbers corresponding to slots in the ATM1600 chassis. The switch informs the switch controller of these interfaces using GSMP messages. These interfaces are configured with IP addresses, as are all other IP-switched ATM interfaces, and are then available as paths for carrying IP traffic between the IP Switches.

IP interfaces 1 through 16, which correspond to the physical interfaces on the ATM1600, carry traffic on VPI zero. A physical ATM interface with a virtual path interface configured using some other VPI will be unlikely to have the IP interface configured corresponding to the physical port. This is because traffic on VPI zero will most likely not be understood by the wide area network.

The ATM1600 supports the configuration of up to 16 virtual path interfaces numbered 17 through 32.

Using Virtual Path Interfaces

As mentioned, creation and deletion of virtual path interfaces is done at the ATM1600 console. Configuration information is stored in non-volatile memory on the ATM1600.

Three console commands are used to configure and manage virtual path interfaces. These are the define vpif, show vpif and delete vpif commands.

The form of the define command is:

The following example shows virtual path interface number 17 being defined as virtual path number 5 on the ATM interface in ATM1600 slot 4:

After defining one or more multiport interfaces, the switch and controller must restart their communication in order to exchange the new list of available interfaces.

This is done by restarting the ATM1600 using the reboot command:

The show vpif command is used as shown below to display all configured virtual path interfaces:

Virtual path interfaces are removed using the delete vpif command. The example below shows virtual path interface number 17 being removed:



Copyright © 1997 Ipsilon Networks, Inc.
Updated May 21, 1997
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