An LOA is a letter of authorization: written permission for one party to connect to, act on, or announce something that belongs to another. The LOA-CFA used for cross-connects adds a connecting facility assignment, the exact room, panel and ports where the connection should land. Most paperwork delays come from letters that have expired, are signed by the wrong person, or carry a company name or port number that does not match the order. All of those are preventable.
Network projects tend to be planned around equipment and construction. The letters get treated as admin, right up to the point where a finished circuit cannot be turned up because a data center will not run a cable without a valid one. This guide covers the documents you are most likely to meet, what goes in them, and how to stop them holding up a project.
The letters you are likely to meet
| Document | Issued by | Given to | Used for |
|---|---|---|---|
| LOA-CFA | The party whose port you are connecting to, such as a carrier or a cloud provider | The facility operator running the cable | Ordering a cross-connect in a data center or carrier hotel |
| LOA for IP announcement | The holder of the IP address space | The upstream carrier | Letting a carrier accept and announce your prefixes over BGP |
| Letter of agency | You, the customer | A carrier | Allowing an agent or consultant to request records, quotes or changes for your account |
| Porting authorization | You, the customer | The new phone provider | Moving phone numbers from one provider to another |
| Building access authorization | The building owner or manager | A carrier or contractor | Permission to install equipment or cable in the building |
The acronym is used loosely. "LOA" can mean letter of authorization or letter of agency depending on who is speaking, so when someone asks for "an LOA," ask which one and for what.
The LOA-CFA, field by field
A cross-connect is the physical cable between two parties inside a facility; our article on what a cross-connect is covers the cable itself. The LOA-CFA is the permission slip that lets the facility install it. A typical one contains:
- Issuing company and contact. The provider granting access to its port, with someone the facility can call to verify it.
- Authorized party. The company allowed to order the connection, which should match the name on your facility account exactly.
- Facility. The data center or carrier hotel, the building address, and often the facility's own site code.
- Location. Floor, room, cage or suite where the provider's equipment or panel sits.
- The CFA itself. The panel identifier and the specific port or position numbers to connect to.
- Media and connector. Single-mode or multimode fiber, or copper, and the connector type.
- Issue date and expiry. How long the letter is valid. The period varies by issuer and is stated on the letter.
- A reference. The provider's order or circuit number, so the connection can be tied to the service.
Outside data centers, "connecting facility assignment" also turns up in traditional carrier ordering, where it identifies the specific channel or port on a carrier's facility where a new circuit hands off, for example at another carrier's point of presence. The idea is the same: an exact address for the connection, not just a building.
LOAs for announcing IP addresses
If you run your own IP address space with BGP, any carrier you connect to will want proof that you are allowed to announce it before it accepts your routes. That proof usually combines a few things:
- An LOA from the registered holder of the address space, naming the prefixes and the autonomous system number that will announce them.
- Registry records. Many carriers check the regional internet registry and internet routing registries for matching route objects.
- RPKI. A growing number of networks validate route origin authorizations, so a missing or mismatched ROA can cause your announcement to be rejected.
Who signs the LOA matters. If the space is registered to your company, your company signs it. If the addresses were assigned to you by another provider, that provider has to authorize the announcement, and the permission typically ends when you stop buying from them. This is one of the reasons businesses that care about portability get their own space. Our guide to static IPs and BGP covers the background, and the IP transit page shows how we quote BGP services.
Letters of agency for agents and records
Carriers protect account information. They will not discuss your account, release your customer service record, or make changes for anyone who is not an authorized contact. A letter of agency is how a customer lets an agent or consultant do that work: request an inventory of services, pull the details needed to quote a replacement, open tickets or coordinate a disconnect.
A good one is specific. It names the customer, the account numbers, the agent, what the agent may do, and how long the authority lasts. It does not give the agent ownership of the account or the right to sign contracts for you unless you choose to grant that. Read it before signing, and keep a copy.
Porting phone numbers uses its own authorization, signed by the account holder and checked closely against the losing carrier's records. Our article on porting business phone numbers walks through that process and why names and addresses must match.
Why letters get rejected
| Problem | What happens | Fix |
|---|---|---|
| The letter has expired | The facility will not accept the order | Order the cross-connect promptly; ask for a reissue before expiry if you must wait |
| Company name does not match the facility account | The order is held while the facility checks who you are | Give the issuer your exact legal and account name when you request the letter |
| Wrong panel or port | The cable cannot be run, or is run to the wrong place | Ask the issuer to confirm the assignment against its records before sending |
| Connector or media mismatch | The cable arrives but cannot be patched | Confirm fiber type and connector on both sides before ordering |
| Unsigned or signed by someone without authority | The letter is not valid | Check who at the issuer is allowed to sign |
| IP LOA names the wrong prefix or ASN | The carrier filters your routes | Match the letter to registry records and your router configuration |
A worked example
Hypothetical dates and parties, for illustration only.
A company is connecting its office to a rack in a colocation facility using a wavelength service, and adding internet transit in the same facility. That means two cross-connects in the building, one to the wavelength carrier and one to the transit provider, plus an IP LOA because the company announces its own addresses.
- Week 1. Both services are ordered. The company asks each provider for its LOA-CFA as soon as a port is assigned, and sends its IP LOA and ASN details to the transit provider.
- Week 3. The transit provider's LOA-CFA arrives and the cross-connect is ordered the same day. The wavelength carrier's letter is promised for week 5.
- Week 5. The wavelength letter arrives listing the company's old trading name. The facility holds the order. A corrected letter takes four days.
- Week 6. Both cross-connects are complete. The transit provider has already accepted the routes, so turn-up happens the same week.
The four-day slip came from a name mismatch that one line in the original request would have prevented. Across a project with several letters, those slips add up, and they sit on the critical path because nothing can be patched until the paperwork clears.
Keeping paperwork off the critical path
- Make a list of every letter the project needs at the start: each cross-connect, each IP announcement, each agent authorization, each port.
- Send each issuer your exact company name as it appears on the facility account and your registry records.
- Ask for each LOA-CFA as soon as the provider assigns a port, not when the circuit is ready.
- Track issue and expiry dates in one place, with an owner for each letter.
- Check every field against the order before forwarding it: name, facility, room, panel, port, connector.
- Order the cross-connect the day the letter arrives.
- Keep the final letters with the circuit records, because you will need them again for moves, upgrades and disconnects.
Facilities and carrier hotels each have their own ordering portals and rules. Our guide to carrier hotels explains how those buildings are organized, and the colocation page covers what we can price inside them.
Questions to ask your provider
- When will you issue the LOA-CFA, and what do you need from me to issue it?
- How long is the letter valid, and how quickly can you reissue it if it lapses?
- What fiber type and connector is your side of the cross-connect?
- Do you need an IP LOA, registry objects or RPKI records before accepting my routes?
- Who at your company can sign or verify the letter if the facility calls?
- If I authorize an agent to act for me, what form of letter of agency do you accept?
Hand the paperwork to someone who tracks it
Paperwork is unglamorous, and it is where a lot of turn-up dates are lost. When we coordinate an interconnect, we ask for letters early, check every field against the order and chase reissues before they hold up the cable. Several Tier 1 carriers bid on the services themselves, the carrier pays FiberX, so there is no markup, and the quote is free with no obligation. Tell us what you are connecting, call 478-758-8091 or text (347) 870-0965, and you will usually hear back the same day.
