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Enabling Tricolor Marking and Limitations of Three-Color Policers

This topic describes how to enable TCM on Juniper Networks devices, as well as limitations you need to be aware of when you are using TCM.

Table 1 lists the default state for TCM on Juniper Networks devices:

Table 1: Devices Versus TCM

TCM Enabled by Default

TCM Disabled by Default

M120 routers

M320 routers with Enhanced II FPCs

MX Series routers

T Series routers with Enhanced II FPCs

T4000 routers

T640 routers with Enhanced Scaling FPC4s

EX Series switches

T1600 routers with Enhanced Scaling FPC4s


If you do not enable TCM on platforms that require it, you cannot configure medium-low or medium-high packet loss priority (PLP) for classifiers, rewrite rules, drop profiles, or firewall filters.


On MX Series and M120 routers, you can apply three-color policers to aggregated interfaces.


On T Series routers, three-color policers and hierarchical policers are supported on aggregated interfaces if all child links are hosted on Enhanced Scaling FPCs.

TCM has some limitations that must be kept in mind during configuration and operation.

  • When you enable TCM on a 10-port Gigabit Ethernet PIC or a 10-Gigabit Ethernet PIC, for queues 6 and 7 only, the output of the show interfaces queue interface-name command does not display the number of queued bytes and packets, or the number of bytes and packets dropped due to RED. If you do not configure tricolor marking on the interface, these statistics are available for all queues.

  • When you enable TCM, Transmission Control Protocol (TCP)-based configurations for drop profiles are rejected. In other words, you cannot include the protocol statement at the [edit class-of-service schedulers scheduler-name drop-profile-map] hierarchy level. The result is that drop profiles are applied to packets with the specified PLP and any protocol type.

  • On Gigabit Ethernet IQ PICs, for IEEE 802.1 rewrite rules, only two loss priorities are supported. Exiting packets with medium-high loss priority are treated as high, and packets with medium-low loss priority are treated as low. In other words rewrite rules corresponding to high and low apply instead of those corresponding to medium-high and medium-low. For IQ PICs, you can only configure one IEEE 802.1 rewrite rule on a physical port. All logical ports (units) on that physical port should apply the same IEEE 802.1 rewrite rule.

  • When some PICs with Frame Relay encapsulation mark a packet with high loss priority, the packet is treated as having medium-high loss priority on M320 Multiservice Edge Routers and T Series Core Routers with Enhanced II FPCs and T640 Core Routers with Enhanced Scaling FPC4.

  • In a single firewall filter term, you cannot configure both the loss-priority action modifier and the three-color-policer action modifier. These statements are mutually exclusive.

To enable TCM:

  • Enable two-rate tricolor marking.