Upgrade Considerations

The following considerations apply to using ATM VC classes when you upgrade to the current JUNOSe software release from a lower-numbered JUNOSe software release:

• It is possible to use VC classes for PVCs created in a lower-numbered release with the atm pvc command. In such cases, the router uses the following rules to determine the PVC attribute values:
  • Nondefault values explicitly specified for PVC attributes with the atm pvc command take precedence over the attribute values specified in the associated VC class. As a result, the router takes the values for these attributes from the atm pvc command settings.
  • Default values implicitly specified for PVC attributes with the atm pvc command have a lower precedence than the attribute values specified in the associated VC class. As a result, the router takes the values for these attributes from the assigned VC class.
• The output of the show configuration command uses either the pvc command format or the atm pvc command format to display ATM PVCs. The display format of configuration information for ATM PVCs created with the atm pvc command depends on the JUNOSe software release from which you are upgrading, as follows:
  • When you upgrade to the current JUNOSe software release from a JUNOSe release numbered lower than Release 7.3.x, the output of the show configuration command uses the pvc command format (pvc vcd vpi/vci) to display configuration information for all ATM PVCs. This occurs even if those PVCs were created in a JUNOSe release numbered lower than Release 7.3.x with the atm pvc command. For example, assume that you created a PVC in JUNOSe Release 7.2.x by issuing the command atm pvc 2 0 33 aal5snap 0 0 0. The show configuration command in the current JUNOSe software release displays the identifier for this PVC as follows:

    pvc 2 0/33

  • When you upgrade to the current JUNOSe software release from JUNOSe Release 7.3.x or a higher-numbered release, the output of the show configuration command uses the atm pvc command format to display configuration information for ATM PVCs created with the atm pvc command. For example, assume that you created a PVC in JUNOSe Release 7.3.x or Release 8.0.x by issuing the command atm pvc 2 0 33 aal5snap 0 0 0. The show configuration command in the current JUNOSe software release displays the identifier for this PVC as follows:

    atm pvc 2 0 33 aal5snap 0 0 0

    For PVCs previously created in the lower-numbered release by using the pvc command, the show configuration command displays configuration information using the pvc command format, as described previously.

For information about how to use the show configuration command, see chapter Managing the System in JUNOSe System Basics Configuration Guide.

To make the most efficient use of the VC class feature when you upgrade to the current JUNOSe software release, we recommend that you follow these steps:

1. Delete any PVCs created with the atm pvc command and recreate them by using the pvc command. For information about creating a data PVC by using the pvc command, see Creating Data PVCs.
2. Configure the VC class as described in Configuring VC Classes.
3. Assign the VC class in one of the following ways:
   • Assign the VC class to the individual PVC when you create or modify the PVC.
   • Assign the VC class to the associated ATM major interface or ATM 1483 subinterface before you create the PVC.

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