Editing DOCSIS (section)

== Throughput ==
Tables assume 256-QAM modulation for downstream and 64-QAM for upstream on DOCSIS 3.0, and 4096-QAM modulation for OFDM/OFDMA (first downstream/upstream methods) on DOCSIS 3.1, although real-world data rates may be lower due to variable modulation depending on SNR. Higher data rates are possible but require higher order QAM schemes which require higher downstream [[modulation error ratio]] (MER). DOCSIS 3.1 was designed to support up to 8192-QAM/16,384-QAM, but only support of up through 4096-QAM is mandatory to meet the minimum DOCSIS 3.1 standards.

{| class="wikitable" style="text-align:center" border="1"
|+ Maximum raw throughput including overhead
|-
! rowspan="3" | Version !! colspan="6" | Downstream !! colspan="5" | Upstream
|-
! colspan="4" | Channel configuration !! rowspan="2" | DOCSIS throughput in Mbit/s !! rowspan="2" | EuroDOCSIS throughput in Mbit/s !! colspan="4" | Channel configuration !! rowspan="2" | Throughput in Mbit/s
|-
! Minimum selectable number of channels !! Minimum number of channels that hardware must support !! Selected number of channels !! Maximum number of channels !! Minimum selectable number of channels !! Minimum number of channels that hardware must support !! Selected number of channels !! Maximum number of channels
|-
| 1.x || 1 || 1 || 1 || 1 || 42.88 || 55.62 || 1 || 1 || 1 || 1 || 10.24
|-
| 2.0 || 1 || 1 || 1 || 1 || 42.88 || 55.62 || 1 || 1 || 1 || 1 || 30.72
|-
| 3.0 || 1 || 4 || ''m'' || Not defined || ''m''&nbsp;×&nbsp;42.88 || ''m''&nbsp;×&nbsp;55.62 || 1 || 4 || ''n'' || Not defined || ''n''&nbsp;×&nbsp;30.72
|-
| 3.1 || 1 OFDM channel <br />or<br />1 SC-QAM channel || 2 OFDM channels<br/>and<br/>32 SC-QAM channels || ''m<sub>1</sub>''<br/>''m<sub>2</sub>'' || Not defined || Dependent on OFDM channel bandwidth in MHz<br />plus<br />''m<sub>2</sub>''&nbsp;×&nbsp;42.88 || Dependent on OFDM channel bandwidth in MHz<br />plus<br />''m<sub>2</sub>''&nbsp;×&nbsp;55.62 || 1 OFDMA channel<br/>or<br/>1 SC-QAM channel || 2 OFDMA channels<br/>and<br/>8 SC-QAM channels || ''n<sub>1</sub>''<br/>''n<sub>2</sub>'' || Not defined || Dependent on OFDMA channel bandwidth in MHz<br />plus<br />''n<sub>2</sub>''&nbsp;×&nbsp;30.72
|}

For DOCSIS 3.0, the theoretical maximum throughput for the number of bonded channels are listed in the table below.<ref>Data-Over-Cable Service Interface Specifications
DOCSIS® 3.0
MAC and Upper Layer Protocols Interface 
Specification
CM-SP-MULPIv3.0-C01-171207</ref>

{| class="wikitable" style="text-align:center" border="1"
|-
! colspan="2" | Number of channels !! colspan="2" | Downstream throughput !! rowspan="2" | Upstream throughput
|-
! Downstream !! Upstream !! DOCSIS !! EuroDOCSIS
|-
| 4 || 4 || 171.52 Mbit/s || 222.48 Mbit/s || rowspan="3" | 122.88 Mbit/s
|-
| 8 || 4 || 343.04 Mbit/s || 444.96 Mbit/s
|-
| 16 || 4 || 686.08 Mbit/s || 889.92 Mbit/s
|-
| 24 || 8 || 1029.12 Mbit/s || 1334.784 Mbit/s || rowspan="2" | 245.76 Mbit/s
|-
| 32 || 8 || 1372.16 Mbit/s || 1779.712 Mbit/s
|}

Note that the number of channels a cable system can support is dependent on how the cable system is set up. For example, the amount of available bandwidth in each direction, the width of the channels selected in the upstream direction, and hardware constraints limit the maximum amount of channels in each direction.{{Citation needed|date=October 2022}}

Note that the maximum downstream bandwidth on all versions of DOCSIS depends on the version of DOCSIS used and the number of upstream channels used if DOCSIS 3.0 is used, but the upstream channel widths are independent of whether DOCSIS or EuroDOCSIS is used.{{Citation needed|date=October 2022}}

=== Upstream ===
Traditional DOCSIS upstream in North America uses the 5–42&nbsp;MHz frequency range. The 5–65&nbsp;MHz range is used by EuroDOCSIS. This is known as a "low-split" or "sub-split" design, capable of a total shared capacity of ~108&nbsp;Mbit/s upstream (assuming 4 SC-QAM upstream channels) for the service group.<ref>{{Cite web |title=StackPath |url=https://www.broadbandtechreport.com/docsis/headend-hub/article/16437269/the-significant-differences-between-docsis-and-eurodocsis |website=BroadbandTechReport.com |access-date=June 25, 2022 }}</ref>

In recent years,{{When|date=June 2022}} cable operators{{Which|date=October 2022}} have begun to increase the amount of bandwidth dedicated to the upstream. The two most popular options for this include a "mid-split" or "high-split".<ref>{{Cite web |date=December 9, 2021 |title=Band Splits 101: Splitting Our Way to 10G |url=https://www.cablelabs.com/blog/band-splits-splitting-our-way-to-10g |publisher=CableLabs |access-date=June 25, 2022 }}</ref>

A mid-split increases the upstream frequency range to 5–85&nbsp;MHz, supporting a total shared upstream capacity of ~450&nbsp;Mbit/s (assuming 4 SC-QAM + OFDMA channels) for the service group.<ref name="Howald 2021">{{Cite conference |last1=Howald |first1=Robert |last2=Wolcott |first2=Larry |last3=Ellis |first3=Leslie |date=October 11, 2021 |title=Execute the Upstream Makeover without Leaving Scars |url=https://www.scte.org/documents/4614/2104_Howald_3441_paper.pdf |conference=Cable-Tec Expo |publisher=SCTE |access-date=June 26, 2022 }}</ref>

A high-split increases the upstream frequency range to 5–204&nbsp;MHz, supporting a total shared upstream capacity of ~1.5&nbsp;Gbit/s (assuming 4 SC-QAM + OFDMA channels) for the service group.<ref name="Howald 2021" />

DOCSIS&nbsp;4.0 in both full-duplex (FDX) and extended spectrum DOCSIS (ESD) configurations will support upstream speeds surpassing 5&nbsp;Gbit/s.<ref>{{Cite web |last=Baumgartner |first=Jeff |date=April 29, 2022 |title=Comcast, Charter Take DOCSIS 4.0 and '10G' a Step Toward Commercial Reality |url=https://www.lightreading.com/cable-tech/comcast-charter-take-docsis-40-and-10g-step-toward-commercial-reality-/d/d-id/777103 |website=Light Reading |location=Louisville, Colorado |access-date=June 26, 2022 }}</ref>