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Visitor
Visitor
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Registered: ‎06-06-2019

1G/10G/25G Ethernet Subsystem Ultrascale+ Implementation & Licensing

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I am exploring options for implementing the '1G/10G/25G Ethernet Subsystem' in a design using the Avnet Ultrascale+ EV System On Module (SOM). The solution requires > 1Gbe performance but can be less than 10Gbe. A notional block diagram is included below. BlockDiagram.PNG

  1. Can the ‘1G/10G/25G Switching Ethernet Subsystem’ support 2.5Gbe?
  2. Will an additional 2.5Gbe PHY be required from the ‘Switch’ to the RJ45?
  3. How is the link rate negotiated for each port? Can some be fixed while others are auto-negotiated?
  4. The solution requires Forward Error Correction to maintain acceptable Bit Error Rates. At a minimum it appears that the following licenses will be required:
    - xxv_eth_mac_pcs [EF-DI-25GEMAC-PROJ] 
    - xxv_eth_basekr ieee802d3_25g_rs_fec_full [EF-DI-25GBASE-KR-PROJ] 
    Are these the correct licenses and are any additional licenses required for this type of solution? Can you explain the 1 year duration for the license?
  5. Are there any ITAR restrictions imposed on Xilinx Ethernet based IP solutions?
  6. Are there any 'demo' applications of the Ethernet Subsystem for the Ultrascale+ that could be leveraged as a starting point? 

I have no experience implementing Ethernet IP based solutions so any input/feedback would be appreciated. 

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Xilinx Employee
Xilinx Employee
597 Views
Registered: ‎05-01-2013

I'm afraid that the switching IP core doesn't support 2.5Gbps.

Also RSFEC is for 10G/25G, not for 1G/2.5G.

https://www.xilinx.com/support/documentation/ip_documentation/ethernet_1_10_25g/v2_5/pg292-ethernet-1-10-25g.pdf

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Xilinx Employee
Xilinx Employee
619 Views
Registered: ‎05-01-2013

I don't see any 10G or 25G link in the diagram.

Why don't you just use 1G/2.5G SGMII IP core?

https://www.xilinx.com/support/documentation/ip_documentation/gig_ethernet_pcs_pma/v16_1/pg047-gig-eth-pcs-pma.pdf

Or AXI 1G/2.5G Ethernet Subsystem which includes MAC?

https://www.xilinx.com/support/documentation/ip_documentation/axi_ethernet/v7_1/pg138-axi-ethernet.pdf

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Visitor
Visitor
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Registered: ‎06-06-2019

You are correct, as stated, there is no 10G/25G requirement. However, the switching capability of the 1G/10G/25G Switching Ethernet Subsystem seemed appealing for this application since I require four network ports. I'm not aware that either of the solutions mentioned would provide this capability but I clearly could be missing something. In addition, the 'Switching Ethernet Subsystem' can incorporate RS-FEC, hence the questions regarding licensing. Ultimately my question is that can a single IP block be configured to meet the requirements or am I forced to stitch together multiple blocks. If the IP block in question can be configured to support 2.5Gbe then it seems like a tightly integrated solution. 

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Xilinx Employee
Xilinx Employee
598 Views
Registered: ‎05-01-2013

I'm afraid that the switching IP core doesn't support 2.5Gbps.

Also RSFEC is for 10G/25G, not for 1G/2.5G.

https://www.xilinx.com/support/documentation/ip_documentation/ethernet_1_10_25g/v2_5/pg292-ethernet-1-10-25g.pdf

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Visitor
Visitor
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Registered: ‎06-06-2019

Thank you. That's what I needed to know. I had looked at the User Guide but it was not clear to me whether or not it would support a 2.5Gb rate. 

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Xilinx Employee
Xilinx Employee
587 Views
Registered: ‎05-01-2013

In PG292, customer can use the input "ctl_core_speed_sel" to select the IP core speed while the output "stat_core_speed_*" indicates the IP core current speed.

There're only 3 speed choices of the IP core, 1G, 10G or 25G.

 

ctl_core_speed_sel

This signal is used to set the operating speed of the core.
• 2'b00 = 25G
• 2'b01= 1G
• 2'b01= 10G
• 2'b11 = Reserved

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Visitor
Visitor
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Registered: ‎06-06-2019

It is still a bit confusing that the User Guide, PG292, Table 31 Note 3. states that "The values provided by these two register bits are ignored when Auto-Negotiation is enabled. Auto-switching is performed according to the resolved speed between the local device and the link partner."

So, does this still imply that auto-negotiation will only allow 1G, 10G or 25G connections even if the 'link partner' will support 2.5G or 5G?

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Xilinx Employee
Xilinx Employee
569 Views
Registered: ‎05-01-2013

Yes, even though you enable Auto-negotiation, the IP can only switch the speed to 1G, 10G or 25G automatically, as Figure 38 suggests.

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