This article provides an explanation of the scale-subscriber license behavior.

Once the subscriber count reaches 90 percent of the configured licenses, the license mode goes into a temporary demo state for 30 days, during which the system is NOT limited by the license count and can terminate any number of subscribers. After 30 days, the licensing returns to an "invalid" state and terminates subscribers that exceed the installed license count.

By Junos BRAS licensing design, once the subscriber count on the system reaches 90 percent of the configured licenses, the licensing mode goes into a temporary demo state for 30 days. During this temporary demo state, the system is NOT limited by the license count and can terminate any number of subscribers, up to the maximum system scalability level.

This behavior was designed to allow Juniper customers to have a 30-day limitless period once the license limit is reached or is close to being reached. During this temporary demo period, additional licenses can be installed or subscribers can be reprovisioned to match the license count MX BRAS.

After 30 days, the system licensing returns to an "invalid" state and can terminate only subscribers up to licenses installed.

Alternatively, the customer can change this behavior by enforcing the MX router to strictly allow only subscribers up to licenses installed.

Below is the configuration to enforce strict behavior. With this configuration, scale-subscriber never shows an expiry and the MX router will not terminate subscribers once the license limit is exhausted.

set system services subscriber-management enforce-strict-scale-limit-license

For example, an MX Series router is configured with 16k scale-subscriber licenses:

lab@MX480-RE0> show system license
License usage:
Licenses Licenses Licenses Expiry
Feature name used installed needed
subscriber-accounting 1 1 0 permanent
subscriber-authentication 0 1 0 permanent
subscriber-address-assignment 1 1 0 permanent
subscriber-vlan 0 1 0 permanent
subscriber-ip 0 1 0 permanent
scale-subscriber 0 16000 0 permanent
scale-l2tp 0 1000 0 permanent
scale-mobile-ip 0 1000 0 permanent

Once the system sees 14.4k subscribers, it starts showing that the license will expire in 29 days:

lab@MX480-RE0> show system license
License usage: 
Licenses Licenses Licenses Expiry
Feature name used installed needed 
subscriber-accounting 1 1 0 permanent
subscriber-authentication 0 1 0 permanent
subscriber-address-assignment 1 1 0 permanent
subscriber-vlan 0 1 0 permanent
subscriber-ip 0 1 0 permanent
scale-subscriber 14400 16000 0 29 days scale-l2tp 0 1000 0 permanent
scale-mobile-ip 0 1000 0 permanent

After 30 days, the expiry flag on the license returns to an "invalid" state.
To restore the "permanent" state, the customer must delete and add the BRAS and Scaling license again:

lab@D4-MX480-RE0> show system license 
License usage: 
Licenses Licenses Licenses Expiry
Feature name used installed needed 
subscriber-accounting 1 1 0 permanent
subscriber-authentication 0 1 0 permanent
subscriber-address-assignment 1 1 0 permanent
subscriber-vlan 0 1 0 permanent
subscriber-ip 0 1 0 permanent
scale-subscriber 14400 16000 0 invalid
scale-l2tp 0 1000 0 permanent
scale-mobile-ip 0 1000 0 permanent

lab@D4-MX480-RE0> request system license delete E400185416 
Delete license E400185416 ?
 [yes,no] (no) yes 


lab@D4-MX480-RE0> request system license delete E400461716    
Delete license E400461716 ?
 [yes,no] (no) yes 


lab@D4-MX480-RE0> request system license add terminal         
[Type ^D at a new line to end input,
 enter blank line between each license key]
E400185416 <key>

E400185416: successfully added
add license complete (no errors)

lab@D4-MX480-RE0> request system license add terminal    
[Type ^D at a new line to end input,
 enter blank line between each license key]
E400461716 <key>
E400461716: successfully added
add license complete (no errors)

lab@D4-MX480-RE0> 

lab@MX480-RE0> show system license
License usage:
Licenses Licenses Licenses Expiry
Feature name used installed needed
subscriber-accounting 1 1 0 permanent
subscriber-authentication 0 1 0 permanent
subscriber-address-assignment 1 1 0 permanent
subscriber-vlan 0 1 0 permanent
subscriber-ip 0 1 0 permanent
scale-subscriber 0 16000 0 permanent
scale-l2tp 0 1000 0 permanent
scale-mobile-ip 0 1000 0 permanent