This article explains why the following errors may occur on MX Series 3D Universal Edge Routers:

• too many classifiers of type xxx,33
• too many classifiers of type xxx,49
• too many rewrites of type xxx, 33

On MX routers with JUNOS 15.1 or higher, the following errors may appear when executing commit or commit check:

user@MX1# commit check
error: cos_config: too many classifiers of type IEEE 802.1ad, 33
error: configuration check-out failed
 
user@MX2# commit check
error: cos_config: too many classifiers of type IEEE 802.1ad, 49
error: configuration check-out failed
 
user@MX1# commit check 
error: cos_config: too many rewrites of type IEEE 802.1ad, 33 
error: configuration check-out failed

In this case, the classifiers/rewrites-rules number under [class-of-service] hierarchy is over the limitation. However, in other cases, the errors may appear even when the classifiers or rewrites-rules are more than 32.

The commit check at this point performs only while Enhanced Subscriber-Management is enabled on the MX router, known as [system services subscriber-management enable] statement exists.

Since the enhanced subscriber management is introduced in Junos 15.1R3, a user will not encounter this error on Junos releases earlier than 15.1R3.  Release 15.1R3 or later without subscriber-management enabled, class-of-service classifiers and rewrite-rules have no such limitations as well.

The following releases are improved to increase classifiers per type limitation from 32 to 48:

• 16.1R5
• 16.1R6
• 16.2R3
• 17.1R3
• 17.2R2
• 17.3R1-S1
• 17.3R2
• 17.4R1

Users who expect to use classifiers more than 32 should upgrade Junos to a release as above.

The real limitation of classifiers, rewrites-rules without subscriber-management is hardware related.  Refer to the specific hardware scaling document.