{
  "slug": "fc-sequence",
  "term": "Fibre Channel sequence",
  "aliases": [
    "FC sequence"
  ],
  "definition": "A Fibre Channel sequence is one or more related data frames sent in one direction within an exchange.",
  "note": "SEQ_ID distinguishes a sequence in the applicable exchange and port context; SEQ_CNT identifies frames within the sequence's counting rules. Sequence-ID reuse and uniqueness depend on negotiated conditions, so SEQ_ID alone is not a global trace key. [fcia]\n\nLinux v6.12 represents SEQ_ID with 8 bits and SEQ_CNT with 16 bits. A frame counter's width is not a count of outstanding storage commands. [linux-frame]",
  "related": [
    "fibre-channel",
    "fc-frame",
    "fc-exchange"
  ],
  "citations": [
    {
      "id": "fcia",
      "title": "FCIA: Inside a Modern Fibre Channel Architecture, Part 2 (2021), slides 7, 19, 23-31, 35 and 38",
      "url": "https://fibrechannel.org/wp-content/uploads/2021/11/Modern-FC-Architecture-Part-2.pdf",
      "accessed": "2026-10-19"
    },
    {
      "id": "linux-frame",
      "title": "Linux v6.12: fc_fs.h frame layout, identifiers and protocol types",
      "url": "https://github.com/torvalds/linux/blob/v6.12/include/uapi/scsi/fc/fc_fs.h",
      "accessed": "2026-10-19"
    }
  ],
  "status": "shipping",
  "advantages": [],
  "limitations": [],
  "supersedes": [],
  "supersededBy": [],
  "firstSeen": null,
  "lastSeen": null,
  "updated": "2026-10-19",
  "provenance": [
    "Source-backed protocol definition; no throughput, failure-rate or durability measurement is implied."
  ]
}