Cisco Cisco IOS Software Release 12.0(23)S

The effects of different bumping configuration approaches are as follows:

Implicit bumping: If you configure implicit bumping, bumped traffic is sent to the VC configured to 
handle the next lower precedence level. When the original VC that bumped the traffic comes back 
up, traffic it is configured to carry is restored to it. When no other positive forms of the bump 
command are configured, the bump implicit command takes effect.

Explicit bumping: If you configure a VC with the bump explicit command, you can specify the 
precedence level to which traffic on a VC will be bumped when that VC goes down, and the traffic 
will be directed to a VC mapped with that precedence level. If the VC that picks up and carries the 
traffic goes down, the traffic is subject to the bumping rules for that VC. You can specify only one 
precedence level for bumping.

Bumped traffic: The VC accepts bumped traffic. You can configure bumped traffic explicitly using 
either the bump traffic or the no bump traffic command, or let the default take effect by specifying 
neither. 

No bumped traffic: To configure a discrete VC to reject bumped traffic when the traffic is directed 
to the VC, use the no bump traffic command. 

When no alternative VC can be found to handle bumped traffic, the bundle is declared down. To avoid 
this occurrence, configure explicitly the bundle member VC that has the lowest precedence level.

To use this command in vc-class configuration mode, you must enter the vc-class atm global 
configuration command before you enter this command.

To use this command to configure an individual bundle member in bundle-vc configuration mode, first 
enter the bundle command to enact bundle configuration mode for the bundle to which you want to add 
or modify the VC member to be configured. Then, use the pvc-bundle command to specify the VC to 
be created or modified and enter bundle-vc configuration mode. 

This command has no effect if the VC class that contains the command is attached to a standalone VC, 
that is, if the VC is not a bundle member. In this case, the attributes are ignored by the VC. 

VCs in a VC bundle are subject to the following configuration inheritance guidelines (listed in order of 
next highest precedence):

VC configuration in bundle-vc mode

Bundle configuration in bundle mode (with effect of assigned vc-class configuration)

Subinterface configuration in subinterface mode

The following example configures the class called premium-class to define parameters applicable to a 
VC in a bundle. Unless overridden with a bundle-vc bump configuration, the VC that uses this class will 
not allow other traffic to be bumped onto it.

vc-class atm premium-class

no bump traffic

bump explicitly 7