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JunosE 11.2.x Link Layer Configuration Guide
Ethernet Oversubscription for Dynamic Interfaces
516
When the maximum number of active ATM 1483 subinterfaces has been reached, the
router prevents all additional subscribers from connecting to the line module until at
least one currently active subscriber logs out, which causes the router to tear down the
dynamic interface column for that subscriber. When a dynamic interface column is torn
down, the router enables the first currently inactive subscriber that receives traffic to
connect to the router and become active as a replacement for the subscriber that logged
out.
Example
Consider an ATM line module that supports a maximum of 16,000 configured
subinterfaces and a maximum of 8000 active subinterfaces. If all 16,000 static ATM 1483
subinterfaces attempt to connect to the router, only the first 8000 subinterfaces to
receive traffic are able to log in, generate dynamic interface columns, and become active.
When a subscriber connected through one of these active subinterfaces logs out, the
router enables the first of the remaining 8000 inactive subinterfaces that receives traffic
to connect as a replacement for the subscriber that logged out.
Bulk-Configured VC Ranges
An active bulk-configured VC range is associated with a dynamic ATM 1483 subinterface
that supports a dynamic upper-layer encapsulation type. For ATM line modules that
support VC oversubscription, the maximum number of active bulk-configured VCs per
line module is less than the maximum number of individual VCs created from the total
number of bulk-configured VC ranges that the line module supports.
For details about how oversubscription works for bulk-configured VC ranges, see "ATM
Oversubscription for Bulk-Configured VC Ranges" on page 621 in "Configuring Dynamic
Interfaces Using Bulk Configuration" on page 619.
Combination of Static ATM 1483 Subinterfaces and Bulk-Configured VC Ranges
ATM line modules are sometimes configured with a combination of static ATM 1483
subinterfaces and bulk-configured VC ranges. In these configurations, both the static
ATM 1483 subinterfaces and bulk-configured VC ranges can support active subinterfaces.
The combined total of active static ATM 1483 subinterfaces, and active dynamic ATM 1483
subinterfaces created from bulk-configured VC ranges, cannot exceed the maximum
number of active subinterfaces supported by the line module.
For details about how oversubscription works for ATM modules configured with both
static ATM 1483 subinterfaces and bulk-configured VC ranges, see "ATM Oversubscription
for Bulk-Configured VC Ranges" on page 621 in "Configuring Dynamic Interfaces Using
Bulk Configuration" on page 619.
When you configure S-VLAN subinterfaces over Ethernet interfaces to support dynamic
PPPoE subinterfaces, you can take advantage of VLAN and S-VLAN oversubscription.
For more information on S-VLAN oversubscription, see "S-VLAN Oversubscription" on
page 185 .
Copyright © 2010, Juniper Networks, Inc.
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