{
  "status": "shipping",
  "advantages": [],
  "limitations": [],
  "supersedes": [],
  "supersededBy": [],
  "firstSeen": null,
  "lastSeen": null,
  "updated": "2026-10-21",
  "slug": "iser",
  "term": "iSCSI Extensions for RDMA (iSER)",
  "aliases": [
    "iSER",
    "iSCSI over RDMA"
  ],
  "definition": "iSER extends iSCSI to use an RDMA-capable transport for direct placement of SCSI data into registered I/O buffers.",
  "note": "Negotiation: RDMAExtensions is session-wide, defaults to No and requires both peers to offer Yes on the leading connection. Discovery sessions cannot negotiate it. Subsequent connections inherit the session's mode. [negotiation]\n\nTransfer direction: The target uses RDMA Write for SCSI-read data and RDMA Read to fetch solicited SCSI-write data. Immediate write data travels with the command in Send, while non-immediate unsolicited data uses Data-Out in Send. [transfer]\n\nProtection: In iSER-assisted mode, RDMAExtensions=Yes requires HeaderDigest=None and DataDigest=None for every connection in the session and delegates error detection to the RDMA-capable protocol. This does not establish peer authentication, encryption or persistence of a SCSI write. Buffer-access lifetime is a separate concern. [digest] [lifetime]",
  "related": [
    "iscsi",
    "rdma-storage",
    "nvme-rdma",
    "rdma-steering-tag",
    "iscsi-session",
    "iscsi-digest"
  ],
  "citations": [
    {
      "id": "negotiation",
      "title": "RFC 7145: iSER login and RDMAExtensions, sections 5.1 and 6.3",
      "url": "https://www.rfc-editor.org/rfc/rfc7145.html#section-6.3",
      "accessed": "2026-10-21"
    },
    {
      "id": "transfer",
      "title": "RFC 7145: transfer model and SCSI write operations, sections 1.4 and 9.5.1",
      "url": "https://www.rfc-editor.org/rfc/rfc7145.html#section-9.5.1",
      "accessed": "2026-10-21"
    },
    {
      "id": "digest",
      "title": "RFC 7145: HeaderDigest and DataDigest, section 6.1",
      "url": "https://www.rfc-editor.org/rfc/rfc7145.html#section-6.1",
      "accessed": "2026-10-21"
    },
    {
      "id": "lifetime",
      "title": "RFC 7145: STag invalidation and security considerations, sections 8.3.2 and 11",
      "url": "https://www.rfc-editor.org/rfc/rfc7145.html#section-11",
      "accessed": "2026-10-21"
    }
  ],
  "provenance": [
    "Protocol explanation based on RFC 7145, not an interoperability, performance or durability experiment."
  ]
}