LLR - Link Layer Retry HLD #2098
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/azp run |
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Signed-off-by: Ravi Minnikanti <[email protected]>
Signed-off-by: Ravi Minnikanti <[email protected]>
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/azp run |
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hzheng5
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Dec 8, 2025
| `llrmgrd` operates as a daemon within the swss Docker container and is initiated by supervisord, like other swss services. | ||
| - `llrmgrd` relies on a vendor-supplied ini file named `llr_buffer_lookup.ini` located in the HWSKU directory to generate LLR profile parameters based on port operating speed and cable length. | ||
| - A WARN log is generated if the `llr_buffer_lookup.ini` file is missing or inaccessible. | ||
| - Each generated profile is assigned a unique name in the format `llr_buffer_<speed>_<cable_len>_profile`. |
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It seems the profile is determined by the speed and cable_len. In the case where port speed is auto, and the speed changes, how can llrmgrd catch and handle such change?
| - If the LLR global configuration mode is set to Static, the configuration is driven by the configuration in CONFIG_DB. | ||
| - When set to Dynamic, the configuration is driven by the LLDP exchange (This mode is not supported in Phase I of development). | ||
| - It subscribes to CABLE_LENGTH table in CONFIG_DB for port cable length information. For operational speed updates, it subscribes to the PORT_TABLE in STATE_DB. | ||
| - When LLR is enabled both globally and on a port, `llrmgrd` generates an LLR profile for the port and writes the corresponding profile to CONFIG_DB. |
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Do we need a ref_count for each LLR profile so it can only be deleted if ref_count is 0?
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| PORT LLR Local State LLR Remote State LLR PROFILE | ||
| ---------- ----------------- ------------------ ------------------------------ | ||
| Ethernet1 enabled disabled llr_buffer_800000_40m_profile |
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Can you please help clarify the following questions?
- How can we get the LLR remote state, by lldp?
- Can LLR still work properly if the remote state is disabled?
- Will turn on/off LLR dynamically affect the outgoing traffic on this port?
thanks,
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This PR introduces HLD for the Link Layer Retry (LLR) feature