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    Changing VC Subranges

    Changing VC subranges within a bulk-configured VC range includes the following tasks:

    Adding New VC Subranges to an Existing VC Range

    You can add a new VC subrange to an existing VC range only when the new subrange does not overlap with any existing subrange. Any overlap causes the addition to fail.

    You can add multiple subranges to an existing VC range simultaneously. However, the entire operation fails if even one of the new subranges overlaps with an existing subrange.

    The following example specifies the original VC subranges.

    host1(config-if)#atm bulk-config test vc-range 1 1 101 150 vc-range 2 2 201 250 vc-range 5 5 501 550 vc-range 3 3 301 350

    To add subranges to this bulk-configured VC range, you can choose either of the following methods. Each method adds a new subrange (4, 4, 401, 450) to the existing VC range, test.

    • Specify one new subrange at a time.
      host1(config-if)#atm bulk-config test vc-range 4 4 401 450
    • Specify the new subrange and all the existing subranges. If you use this method, all the existing subranges and their order must match exactly, or the operation fails.
      host1(config-if)#atm bulk-config test vc-range 1 1 101 150 vc-range 2 2 201 250 vc-range 5 5 501 550 vc-range 3 3 301 350 vc-range 4 4 401 450

      The following operation fails because the order of subranges does not match the existing order.

      host1(config-if)#atm bulk-config test vc-range 2 2 201 250 vc-range 1 1 101 150 vc-range 5 5 501 550 vc-range 3 3 301 350 vc-range 4 4 401 450 vc-range 6 6 601 650

    You can create a placeholder VC range by specifying a VC range name without specifying any subrange parameters. This VC range has no circuit reservation, but you can assign a profile to it, and add subranges later as desired. The following commands illustrate this approach.

    host1(config-if)#atm bulk-config test host1(config-if)#profile atm1483 bulk-config-name test atmProfile host1(config-if)#atm bulk-config test vc-range 4 4 401 450 vc-range 6 6 601 650

    Removing VC Subranges from an Existing VC Range

    You can remove VC subranges from an existing VC range if no dynamic ATM 1483 subinterfaces currently exists for any circuit within those subranges. The removal operation fails if any such dynamic ATM 1483 subinterface exists. You must first remove the dynamic ATM 1483 subinterfaces before you can remove the subranges. Removal of a subrange automatically results in the removal of all overriding profile assignments on that subrange.

    You can remove only a single specific VC subrange at a time. The following example specifies the original VC subranges.

    host1(config-if)#atm bulk-config test vc-range 1 1 101 150 vc-range 2 2 201 250 vc-range 5 5 501 550 vc-range 3 3 301 350

    To remove one subrange (1, 1, 101, 150) and leave the remaining subranges, and the named VC range, test, intact:

    • Issue the no atm bulk-config command in Interface Configuration mode.
    host1(config-if)#no atm bulk-config test vc-range 1 1 101 150

    To remove more than one VC subrange, you must issue multiple removal commands, one for each subrange. You cannot remove only part of a subrange. A removal command cannot encompass more than one subrange, even if the subranges are adjacent. However, if you do not specify any subranges, you can remove all subranges in the VC, and the named VC range, at the same time.

    • Issue the no atm bulk-config command in Interface Configuration mode.
    host1(config-if)#no atm bulk-config test

    Modifying a VC Subrange by Shortening or Expanding the Subrange Values

    You can shorten or expand a subrange by modifying the subrange values of a VC range. You can expand a subrange if none of the circuits added overlap with any other subrange. You can shorten a subrange if none of the circuits dropped have existing dynamic ATM 1483 subinterfaces.

    You can modify a subrange so that it completely includes at least one other subrange from within the same VC range effectively merges the subranges. Each subrange that is merged with another frees up a subrange for subsequent configuration. The subranges that are merged do not need to be adjacent to each other.

    The router retains any overriding profiles assigned to a subrange if the assignment falls within the modified subrange. If the assignment falls outside of the newly modified subrange, the router drops the overriding profile assignment. If two subranges are merged, the router retains overriding profiles that were assigned to the separate subranges and applies the overriding profiles to the newly merged subrange.

    You can modify only a single specific subrange at a time. To modify a VC subrange:

    • Issue the atm bulk-config command in Interface Configuration mode.
    host1(config-if)#atm bulk-config test vc-range 1 1 101 150 vc-range 2 2 201 250 vc-range 5 5 501 550 vc-range 3 3 301 350

    To modify the second subrange from (2, 2, 201, 250) to
    (2, 3, 210, 230):

    • Issue the atm bulk-config modify command in Interface Configuration mode.
    host1(config-if)#atm bulk-config test modify vc-range 2 3 210 230

    The router retains any overriding profiles assigned to a subrange after you modify the subrange if the override assignment still falls within the modified subrange. If the assignment falls outside of the newly modified subrange, the router drops the overriding profile assignment.

    You cannot modify a subrange at the same time you are adding or removing a subrange. If the new modified values for a subrange partially overlap with another subrange, the operation fails and the router displays an error message.

    Merging Multiple VC Subranges Belonging to an Existing VC Range

    You can merge multiple subranges of any particular VC range to form a single unified subrange, conserving subrange resources. Merging takes place only when you modify a subrange so that it completely includes at least one other subrange of the same VC range. The merged subranges do not need to be adjacent to each other.

    If the encompassing subrange has any circuits that are outside the subranges to be merged, those circuits are added. The encompassing subrange must cover a subrange completely to incorporate it in the merged subrange. The merge operation fails if the encompassing subrange completely overlaps some subranges but only partially overlaps with another subrange. The encompassing subrange does not have to encompass all subranges of the VC range.

    Each subrange that is merged with another frees up a subrange. E Series routers currently support a maximum of 300 bulk-configured VC ranges per chassis. Therefore, if a VC range consists of 5 subranges, 295 subranges are still available for subsequent configuration. If you merge 2 of those subranges, resulting in a new total of 4 subranges in the VC range, then 296 subranges are available for configuration.

    The router retains any overriding profile assignments on the subranges made before the merger, and applies them to the new merged subrange. You can separate merged subranges either by removing the merged subrange and then adding new separate subranges or by modifying the merged subrange to remove some portion of the subrange and then adding a new subrange.

    The following example specifies the original VC subranges.

    host1(config-if)#atm bulk-config test vc-range 1 1 101 150 vc-range 2 2 201 250 vc-range 5 5 501 550 vc-range 3 3 301 350

    To merge two subranges, (1, 1, 101, 150) and
    (2, 2, 201, 250), and effectively replace them with the new subrange (1, 2, 101, 250):

    • Issue the atm bulk-config modify command in Interface Configuration mode.
    host1(config-if)#atm bulk-config test modify vc-range 1 2 101 250

    To separate the merged subranges, you can modify the unified subrange and add subranges as needed, provided that no dynamic ATM 1483 subinterfaces currently exist for any circuit within those subranges.

    If you merge subranges by using SNMP, the new merged subrange takes the lowest instance value of the incorporated subranges. For example, if a VC range has three subranges with instance values of 2, 4, and 5 and the subranges with instance values of 2 and 5 are merged, the new merged subrange has an instance value of 2.

    Changing the Administrative State of VC Subranges

    VC subranges have an administrative state that enables you to remove dynamic ATM 1483 subinterfaces on various subranges that belong to a single VC range. This functionality is important because subrange removal requires that no dynamic ATM 1483 subinterfaces exist for any circuit on that subrange. The removal operation fails if any such interfaces exist.

    By default, the administrative state of a VC subrange is up. When you change the administrative state to down by using the atm bulk-config shutdown command, the router deletes all dynamic ATM 1483 subinterfaces on the affected subranges. You can use the show atm subinterface command or the show atm vc command to monitor the progress of the removal of all dynamic ATM 1483 subinterfaces for the specified subrange.

    No additional dynamic ATM 1483 subinterfaces can be created for the subrange until you restore the administrative state to up by using the no atm bulk-config shutdown command.

    The following example specifies the original VC subranges.

    host1(config-if)#atm bulk-config test vc-range 1 1 101 150 vc-range 2 2 201 250 vc-range 5 5 501 550 vc-range 3 3 301 350

    You cannot specify a partial subrange; the specified subrange must exactly match a subrange that has already been configured. The router removes all dynamic interface columns built on any of the circuits in this subrange. No additional dynamic ATM 1483 subinterfaces can be created until you change the administrative state to up.

    To change the administrative state of VC subranges:

    1. Change the administrative state of the second subrange (2, 2, 201, 250) to down:
      host1(config-if)#atm bulk-config test shutdown vc-range 2 2 201 250
    2. Change the administrative state of the same VC subrange to up:
      host1(config-if)#no atm bulk-config test shutdown vc-range 2 2 201 250
    3. Shut down all four subranges belonging to the named VC range, test, regardless of their current state:
      host1(config-if)#atm bulk-config test shutdown

    The time required for the router to complete an administrative state change depends on the number of VC subranges configured.

    Published: 2014-08-14