Additional Reference Material

Additional Information Regarding Redirection

Redirection was described in “GMP Redirection” on page 175. Here is some additional information regarding redirection:

  • It can be determined whether or not a MA within a device supports and uses redirection by performing a Get(ClassPortInfo) with the Management Class MAD field set to the GSA type in question. That GSA will return its ClassPortInfo attribute, and this attribute indicates whether or not the GSA supports redirection to a different destination port/QP and, if so, also identifies the redirect destination.

  • When a GSA is accessed via a QP other than QP1 (due to redirection), the GSA must validate arriving GMP MADs in the same manner that QP1 would have (see “GMP Validation by the GSI” on page 915).

  • The SA, as well as each GSA, may optionally support redirection.

  • If an attribute access request results in a response GMP MAD with the Redirect_Required status bit set, the access requester must be able to handle the redirection.

  • Different requesters issuing attribute access requests to the same GSA on a device may be redirected to different port/QP destinations.

  • A GRH is only included in a redirected class GMP if ClassPortInfo.RedirectGID is non zero.

GMP Validation by the GSI

Unless an attribute access request is a Get() or a Set(), a GMP failing one or more of the following checks is discarded and no further action is taken. The return of a GetResp() when validation has failed for a Get() or a Set() is optional.

  • The data payload length must be 256 bytes.

  • LRH:VL must not be 15. Only SMPs are transmitted using VL15.

  • BTH:DestQP must be set to 1.

  • The BTH:Opcode must be a Send Only UD.

  • The BaseVersion field in the base MAD header must be 1.

  • The Management Class in the base MAD header must specify a class handled by a GSA that is implemented on the CA, switch, or router.

PSNs in Packets Generated by QP1

There is no requirement for QP1's SQ Logic to increment the PSN inserted in each packet by one (from the PSN inserted in the previously generated packet).

Likewise, the QP1 RQ Logic does not verify the PSN in each GMP packet received.

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