[an error occurred while processing this directive][an error occurred while processing this directive]

M320 Routers FPCs and CoS

On Juniper Networks M320 Multiservice Edge Routers, CoS is supported with two types of FPCs: the Enhanced II FPC and the Enhanced III FPC. The Enhanced III FPC provides different CoS functionality than the standard and Enhanced III FPCs. You can mix the FPC types in a single M320 router, but CoS processing for packets traveling between the Enhanced II and Enhanced III FPCs differ from the processing of packets traveling between FPCs of the same type. In cases of mixed FPC types, only the least common denominator of CoS functions is supported.

In particular, the drop priority classification behavior is different for packets traveling between Enhanced II and Enhanced III FPCs in an M320 router chassis. In the Enhanced III FPC, the packet is always classified into one of four packet drop priorities whether the tri-color statement is configured or not. However, depending on the presence or absence of the tri-color statement, the four colors might have a different meaning to the Enhanced II FPC. For more information about the tri-color statement, see Enabling Tricolor Marking.

When packets flow from an Enhanced II FPC to an Enhanced III FPC, the drop priority classification behavior is shown in Table 1.

Table 1: Drop Priority Classification for Packet Sent from Enhanced III to Enhanced II FPC on M320 Routers

Enhanced III FPC Drop Priority

Enhanced II FPC Drop Priority (Without Tricolor Marking Enabled)

Enhanced II FPC Drop Priority (with Tricolor Marking Enabled)

low

low

low

medium-low

low

medium-low

medium-high

high

medium-high

high

high

high

When packets flow from an Enhanced II FPC without tricolor marking enabled to an Enhanced III FPC, the drop priority classification behavior is shown in Table 2.

Table 2: Drop Priority Classification for Packet Sent from Enhanced II FPC Without Tricolor Marking to Enhanced III FPC on M320 Routers

Enhanced II FPC (Without Tricolor Marking Enabled)

Enhanced III FPC

low

low

high

medium-high

When packets flow from an Enhanced II FPC with tricolor marking enabled to an Enhanced III FPC, the drop priority classification behavior is shown in Table 3.

Table 3: Drop Priority Classification for Packet Sent from Enhanced II FPC with Tricolor Marking to Enhanced III FPC on M320 Routers

Enhanced II FPC (With Tricolor Marking Enabled)

Enhanced III FPC

low

low

medium-low

medium-low

medium-high

medium-high

high

high


Published: 2010-04-14

[an error occurred while processing this directive]