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In the RoCEv2 specification (Annex 17)

https://www.infinibandta.org/ibta-specifications-download/

the header BTH+ includes the Local Routing Header (LRH). The routing though is done with IP. Is there any use for the LRH ?

Are the source and destination local IDs used somewhere or are they set to 0 ?

Jim
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  • Did you even read the document? "_All references in the Base Specification to the LRH and its fields are Not Applicable to RoCEv2 ports._" – Ron Maupin Feb 03 '20 at 05:10
  • I saw that after, but does that mean there is no LRH in the header ? – Jim Feb 03 '20 at 05:33

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RoCEv2 packets do not include an LRH. They include an Ethernet MAC header instead, an IP header (which takes the role of the IB GRH header), a UDP header, and the BTH header: Annex 17: Figure 5 RoCEv2 Packet Format

haggai_e
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  • Are you certain ? In the above figure it doesn't say BTH (base transport header), it says BTH+. I know that the GRH does not appear, but I think the LRH is there ... – Jim Feb 02 '20 at 16:34
  • I'm not sure what the plus means, but I suspect it means the optional headers that come after BTH for certain operations, such as DETH or AtomicETH. – haggai_e Feb 03 '20 at 11:30
  • Thanks ! I'll try to look at some headers and verify. – Jim Feb 03 '20 at 18:46