Schema Field Reference

This page summarizes the fields defined by the JSON Schemas under fboss/lib/asic_config_v3/schemas/. The schemas are the authoritative reference. They define the complete structure of each configuration file, and every field includes a description.

The configuration files contain two kinds of keys.

• Framework fields are the fields listed on this page. They are declared in the schemas and interpreted directly by the generator. Introducing a new framework field requires adding it to the corresponding schema.
• Setting maps are sections such as platform_sai_overrides, device_config_overrides, or the ASIC-level global_defaults and sai_overrides, whose keys are vendor SDK and SAI setting names, port speeds, or output table entries. The schemas deliberately accept any key inside a setting map, because the set of valid vendor settings cannot be enumerated, so adding a setting there requires no schema change.

Platform Configuration

Platform configuration, defined by platform_config.schema.json. This schema validates every platforms/<platform>/asic_config.json file.

Top-level fields

Field	Required	Description
platform_name	yes	Platform identifier. Must match the directory name under platforms/.
vendor	yes	ASIC vendor identifier. Must match a directory name under vendors/.
asic	yes	ASIC chip identifier. Must match the basename of a JSON file under vendors/<vendor>/<family>/asics/.
num_ports_per_core	no	Number of front-panel ports per ASIC core. Combined with the ASIC's lanes-per-core value to derive the number of lanes per port.
num_lanes_per_port	no	Explicit override of the derived lanes-per-port value, for platforms that wire only a subset of the lanes.
defaults	no	Shared settings inherited by every variant. A variant's own settings take precedence over the corresponding defaults.
variants	yes	Named configuration variants. Each variant produces a separate output file.

Variant fields

Each entry under variants, as well as the defaults block, may declare the following fields.

Field	Description
asic_config_params	Parameters controlling generator behavior: config_type (output format), config_gen_type (generation profile, for example DEFAULT), exact_match (enables exact-match forwarding table entries), and mmu_lossless (enables MMU lossless mode for PFC and RDMA workloads).
port_config	Front-panel port settings: default_speed (in Mbps), speed_to_fec (mapping from speed to FEC mode), enable (the value emitted for PC_PORT.ENABLE), and pc_port_overrides (extra PC_PORT key/value lines emitted verbatim, for example LINK_TRAINING).
cpu_port	CPU port settings: speed (in Mbps) and num_lanes.
mgmt_port	Management port settings: enabled (whether the port is emitted at all), enable (the PC_PORT.ENABLE value), in_port_block (include the port in the PORT MTU range), and speed_variants (per-speed settings keyed by speed).
mgmt_port_overrides	Platform overrides of the ASIC-level management port defaults: logical_id, physical_id, speed, num_lanes, and fec.
port_mapping_overrides	Adjustments to the logical-to-physical port mapping formula: core_range (which cores participate, for example "0-15,48-63"), num_lp_ports_on_even_core, num_logical_ports_per_datapath, lp_start_step_offset, lp_offset_simple, and special_core_offset_apply_all.
platform_sai_overrides	Platform-level SAI settings. These take precedence within the layered global sources and override the ASIC-level SAI overrides.
device_config_overrides	Key/value pairs written to the DEVICE_CONFIG output table, for example clock frequencies.
features	Boolean toggles for optional configuration sections: generate_dlb_config, generate_dlb_ecmp_config, generate_low_clock_freq_settings, and generate_autoload_board_settings. Absent flags default to disabled.
conditional_settings	Platform-level conditional settings, evaluated after the ASIC-level ones so that platform values take precedence.
preamble_file	Path, relative to the asic_config_v3 directory, of a preamble file prepended to the generated YAML. Honored only when the ASIC declares preamble_support: true.
platform_mapping_name	Overrides the platform_mapping_v2 directory consulted for lane-map and polarity data. Defaults to platform_name. Useful when several variants share one asic_config.json but consume sibling platform mapping directories.
ctr_eflex_config	Variant-level override of the ASIC's ctr_eflex_config (enhanced flex counter) pass-through block. When present, it replaces the ASIC-level value in its entirety.

In addition to the fields above, the generator honors a variant-level override of any data block routed by the ASIC's pass_through_settings. Declaring flex_counter_settings, port_config_defaults, fp_config_defaults, or tm_thd_config_defaults in a variant replaces the corresponding ASIC-level block, in the same way as ctr_eflex_config. The schema currently declares only ctr_eflex_config among these.

The platform schema accepts unknown keys at the top and variant levels, so a key that is not listed here does not fail validation; the generator ignores it without an error or warning. When a setting appears to have no effect, verify the field name against this reference.

ASIC Configuration

Broadcom XGS ASIC configuration, defined by broadcom_xgs_asic_config.schema.json. This schema validates the per-ASIC files under vendors/broadcom/xgs/asics/.

Field	Description
vendor, asic	Chip identity, for example broadcom and tomahawk5.
port_architecture	Core, lane, and datapath layout consumed by the port mapping logic: num_cores, num_lanes_per_core, num_logical_ports_per_datapath, num_physical_ports_per_datapath, and num_lp_ports_on_even_core_default.
mmu_size	MMU buffer size in bytes. Also used as the MAX_FRAME_SIZE and port MTU values.
table_names	Ordered list of output YAML table names. Controls which tables appear in the output and their order.
mgmt_port_defaults	Default management port settings: logical_id, physical_id, speed, num_lanes, and fec. Platforms may override these per variant.
preamble_support	Whether the ASIC supports a preamble section prepended to the output YAML. When false, any preamble_file declared by a platform is ignored.
global_defaults	ASIC-specific SDK settings copied into the global output table.
sai_overrides	ASIC-specific SAI settings layered on top of the vendor SAI common values.
flex_counter_settings, ctr_eflex_config, port_config_defaults, fp_config_defaults, tm_thd_config_defaults	Named data blocks routed into output tables by pass_through_settings.
dlb_defaults, dlb_ecmp_config_defaults	Dynamic Load Balancing settings, applied through conditional settings gated by the corresponding feature toggles.
pass_through_settings	Declarative routing list. Each entry names a source data block in this file and the target_table it is copied into.
conditional_settings	ASIC-wide conditional settings, described below.

Conditional setting entries

Each entry in a conditional_settings array supports the following fields. The entry structure is defined in the Broadcom XGS ASIC schema. Platform-level entries follow the same structure, but the platform schema does not currently validate their internal structure, so field names and the condition format in platform-level entries should be reviewed carefully.

Field	Required	Description
name	yes	Identifier, unique within the surrounding list.
description	no	Free-form explanation of the setting.
condition	yes	The test to evaluate against the variant configuration. Its keys are listed in the table below.
apply	no	Inline settings applied when the condition is satisfied, keyed by target output table name.
apply_from	no	Reference to a data block elsewhere in the ASIC file; the named source block is copied into the named target_table when the condition is satisfied.
skip_from_sai_common	no	Keys to omit from the vendor SAI common layer while the condition is satisfied. Honored only on ASIC-level entries.

The condition object contains exactly the following three keys, all of which are required:

Key	Description
source	The variant-config section holding the parameter to evaluate: either asic_config_params or features.
param	The name of the parameter to compare.
equals	The value the parameter must equal for the condition to be satisfied.

Vendor Common Configuration

Vendor common configuration, defined by vendor_common.schema.json. This schema validates the family-wide common files, such as vendors/broadcom/xgs/sdk_common.json and vendors/broadcom/xgs/sai_common.json.

Field	Required	Description
global	yes	SDK or SAI settings copied into the global output table according to the layering order described in the Overview.