P5020 QorIQ Communications Processor Product Brief, Rev. 1
Features
Freescale Semiconductor18
When all SERDES are otherwise allocated, it is possible to enable two of dTSECs by means of RGMII or
RMII physical interfaces.
3.9.4.1.2 FMan Parse Function
The primary function of the packet parse logic is to identify the incoming frame for the purpose of
determining the desired treatment to apply. This parse function can parse many standard protocols,
including options and tunnels, and supports a generic configurable capability to allow proprietary or future
protocols to be parsed.
There are several types of parser headers, shown in the following table.
The underlying notion is that different frames may require different treatment, and only through detailed
parsing of the frame can proper treatment be determined.
Parse results can (optionally) be passed to software.
3.9.4.1.3 FMan Distribution and Policing
After parsing is complete, there are two options for treatment (see Table 6).
Key benefits of the FMan policing function are as follows:
Table 5. Parser Header Types
Header Type Definition
Self-describing Announced by proprietary values of Ethertype, protocol identifier, next header, and other standard fields.
They are self-describing in that the frame contains information that describes the presence of the
proprietary header.
Non-self-describing Does not contain any information that indicates the presence of the header.
For example, a frame that always contains a proprietary header before the Ethernet header would be
non-self-describing. Both self-describing and non-self-describing headers are supported by means of
parsing rules in the FMan.
Proprietary Can be defined as being self-describing or non-self-describing
Table 6. Post-Parsing Treatment Options
Treatment Function Benefits
Hash • Hashes selected fields in the frame as part of a spreading mechanism
• The result is a specific frame queue identifier.
• To support added control, this FQID can be indexed by values found in the frame,
such as TOS or p-bits, or any other desired field(s).
Useful when spreading
traffic while obeying QoS
constraints is required
Classification
look-up
• Looks up certain fields in the frame to determine subsequent action to take,
including policing
• The FMan contains internal memory that holds small tables for this purpose.
• The user configures the sets of lookups to perform, and the parse results dictate
which one of those sets to use.
• Lookups can be chained together such that a successful look-up can provide key
information for a subsequent look-up. After all the look-ups are complete, the final
classification result provides either a hash key to use for spreading, or a FQ ID
directly.
• Useful when hash
distribution is insufficient
and a more detailed
examination of the frame
is required
• Can determine whether
policing is required and
the policing context to use
