How to Read Fiber Chain Addresses (CLLI.OSX.tray.port)
A practical guide to decoding the address strings that appear in dark fiber assignment workbooks — EQIP format, numeric sequence format, and how TSmartLabel parses them.
Every fiber in a dark fiber build has a precise address that identifies exactly where it terminates. These addresses follow a structured format: SITE.SWITCH.sequence.OSX_A.OSX_B.OSX_C.tray.port. Understanding them is essential for generating accurate labels and catching mismatches before a truck rolls.
The Basic Structure
A full address looks like this:
AULTCOAT.OSPOCP.001.EQIP..002.007.8.C.B05
Breaking it down:
| Field | Value | Meaning |
|---|---|---|
| Site CLLI | AULTCOAT | 8-character Common Language Location Identifier for the site |
| Switch | OSPOCP | Optical switch or cross-connect identifier |
| Sequence | 001 | Span sequence within the Netbuild |
| Type | EQIP | Equipment-terminated (vs. numeric sequence) |
| OSX address | 002.007.8 | Optical switch module: shelf 002, slot 007, port group 8 |
| Tray | C | Physical tray letter within the panel |
| Port | B05 | Individual port designation |
The full address on the label will read: AULTCOAT.002.007.8.C.B05 — the OSPOCP and sequence fields are stripped because they’re routing artifacts, not physical identifiers.
EQIP vs. Numeric Sequence Format
You’ll encounter two address variants in the wild:
EQIP format (newer builds):
HDSNCOAJ.OSPOCP.001.EQIP..002.007.8.C.B05
The EQIP token signals that this fiber terminates at equipment rather than a cross-connect chassis. The double-dot (..) before the OSX address is characteristic of this format.
Numeric sequence format (older builds):
HDSNCOAJ.OSPOCP.0001..0100.002.007.8.C.B05
Here, 0001..0100 is a range marker indicating fiber 1 of 100. The OSX address follows the same pattern.
TSmartLabel’s parser handles both formats with the same regex engine, so you can mix workbook generations without manual cleanup.
Why This Matters for Labels
The label direction rule states: the label at site A shows the far-end address (site B) and vice versa. This means if you’re printing labels for fibers at Eaton, the label must show the Hudson termination address. Getting this wrong means the installer at Hudson can’t match the cable to the patch panel — the label is useless.
For a fiber chain:
AULTCOAT.002.007.8.C.B05 -- HDSNCOAJ.002.007.8.D.B12
The label installed at AULTCOAT reads the HDSNCOAJ address, and vice versa.
Common Parsing Issues
Trailing spaces: Many Excel exports include trailing spaces in address cells (AULTCOAT.OSPOCP with a trailing space). TSmartLabel strips these automatically.
Missing OSX segments: Some older worksheets only provide the tray and port without the full OSX address. TSmartLabel flags these as NEEDS_REVIEW rather than silently dropping the data.
Case inconsistencies: CLLI codes should be uppercase, but Excel exports sometimes produce mixed case. TSmartLabel normalizes to uppercase during ingestion.
Empty rows between fibers: Multi-sheet workbooks frequently have blank rows between fibers (especially around color groups). The parser skips these rather than treating them as parse errors.
Verifying Your Addresses
The fastest sanity check: open your fiber assignment worksheet, pick two adjacent fibers in the same tray, and verify that their OSX addresses share the same shelf and slot (002.007) with consecutive port groups. If they don’t, there may be a sort or format issue in the source data.
TSmartLabel’s conflict engine runs this check automatically and flags any port assignment gaps or duplicates as HIGH severity conflicts before you generate labels.