Request

• What does UR stand for?
− UR = Unsupported Request
− Watch out! This UR (Request) is NOT that UR (Completion)!
Always clarify the reference first!
• One reference of UR – Unsupported Request
− The TLP Type is a Posted or Non-Posted Request
− It means the completer receives a Posted or Non-Posted Request (for example, MWr/Rd,
IOWr/Rd and etc), however can’t handle it for some reason. Therefore, it treats this request as
Unsupported Request.
− The recipient of this Request TLP is the Completer!
− This TLP is NOT a Bad TLP. It may be a totally valid TLP without any error!
• The other reference of UR – Completion with UR completion status
− The TLP Type is Completion
− It means once the completer treats a Non-Posted Request as Unsupported Request, it will return
a Completion TLP with its status code marked as UR (001b).
− The recipient of this Completion TLP is the Original Requester!
− Some might simply call it UR Response, UR Completion or Completion w/UR status
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