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SERVER

OCP NIC Community Update�April 2024

For Server Project�����Sub-group Project wiki: https://www.opencompute.org/wiki/Server/NIC�

Mailing List: https://ocp-all.groups.io/g/OCP-NIC

NIC3.0

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Agenda

  • OCP NIC specification version 1.44 update
  • Double-width SFF (DSFF) mechanical update
  • Double-width SFF (DSFF) SI update

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NIC Manageability

  • Introduce USB 2.0 for DSFF manageability
      • Routed on Primary Connector
      • Declared in 0xC0 OEM Record
        • USB CDC-EEM manageability type was introduced in version 1.3.0
      • Less signal integrity challenges compared to RBT
      • Not mandatory for DSFF

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  • SFF can continue to use RBT or new USB for NIC management
      • Also add USB CDC-EEM manageability to SFF

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Manageability, continued

  • RBT changes
      • DSFF RBT timing budget is 900 ps (align w/SFF)
      • Suggest minimum RBT route lengths as well
          • NIC (SFF): Min 350 ps (~2 in.) / max 900 ps
          • DC-SCM: Min 350 ps (~2 in.?) / max 680 ps
      • Add additional text to urge system vendors to minimize TSKEW; regain timing margin
        • OCP NIC assumes 1500 ps (max) skew, worst case per DSP0222
        • CLK/DATA paths on each individual card HPM/NIC/DC-SCM likely similar lengths
        • Easier for HPMs to minimize TSKEW.

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TDCSCI = 110 ps, max

TNIC_CONN = 110 ps, max

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Model doesn’t include buffers, or isolation logic propagation delays

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Mechanical Update: Help Needed

  • Request all hands on deck for next mechanical sync
    • 4/8, 9am PST
    • Need to close on direction for when there is interference in 1U chassis with half height PCIe card above OCP NIC
    • FLW and SDNO both have this problem

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SI Workstream Update

  • Aligned PCIe® Gen 5 SFF & DSFF to have -7dB insertion loss
  • OCP NIC 3.0 card channel budget defined from gold finger edge to end point silicon

Disclaimer: Current working material restricted by the OCP CLCA

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Latest Draft Spec

See wiki page:

https://www.opencompute.org/w/index.php?title=Server/NIC#Working_Draft_Docs

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Double-width SFF (D-SFF)

Spans over two 4C+ connectors

Aligned to spaced per M-FLW HPM specification

Regular and Tall options

Up to 160 Watt

Up to x32 PCIe lanes

Flexibility to configure between 2x SFF or 1x D-SFF

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Illustration

Arnon/Harvey

Double Width Small Form Factor

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Gather feedback throughout the year

Provide your feedback at:�https://tinyurl.com/feedback2ocpnic