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| docs:guide-user:network:traffic-shaping:sqm-details [2022/11/17 19:58] – [SQM: Link Layer Adaptation Tab] moeller0 | docs:guide-user:network:traffic-shaping:sqm-details [2022/11/17 20:00] – [SQM: Link Layer Adaptation Tab] moeller0 | ||
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| * **ATM:** It is especially important to set the Link Layer Adaptation on links that use ATM framing (almost all DSL/ADSL links do), because ATM adds five additional bytes of overhead to a 48-byte frame. Unless the SQM algorithm knows to account for the ATM framing bytes, short packets will appear to take longer to send than expected, and will be penalized. For true ATM links, one often can measure the real per-packet overhead empirically, | * **ATM:** It is especially important to set the Link Layer Adaptation on links that use ATM framing (almost all DSL/ADSL links do), because ATM adds five additional bytes of overhead to a 48-byte frame. Unless the SQM algorithm knows to account for the ATM framing bytes, short packets will appear to take longer to send than expected, and will be penalized. For true ATM links, one often can measure the real per-packet overhead empirically, | ||
| - | * **Ethernet with Overhead:** SQM can also account for the overhead imposed by //VDSL2// links - add 22 bytes of overhead (mpu 68). Cable Modems (// | + | * **Ethernet with Overhead:** SQM can also account for the overhead imposed by //VDSL2// links - add 22 bytes of overhead (mpu 68). Cable Modems (// |
| * **None:** All shaping below the physical gross-rate of a link requires correct per-packet overhead accounting to be precise, so **None** is only useful if approximate shaping is sufficient, say if you want to clamp a guest network to at best ~50% of the available capacity or similar tasks, but even then configuring an approximate correct per-packet-overhead is recommended (overhead 44 (mpu 84) is a decent default to pick). | * **None:** All shaping below the physical gross-rate of a link requires correct per-packet overhead accounting to be precise, so **None** is only useful if approximate shaping is sufficient, say if you want to clamp a guest network to at best ~50% of the available capacity or similar tasks, but even then configuring an approximate correct per-packet-overhead is recommended (overhead 44 (mpu 84) is a decent default to pick). | ||