A cross-connect is a physical cable, usually a fiber pair, that links your equipment to another party's equipment inside the same data center or carrier hotel, typically through the meet-me room. You order it from the facility operator using a letter of authorisation from the party you are connecting to, and you usually pay a one-time installation fee plus a monthly charge for as long as it is in place. It is simple in principle, and it is the step most likely to delay a turn-up if the paperwork or the optics are wrong.
Every service delivered inside a colocation facility, whether that is internet transit, a wavelength, a private cloud connection or an exchange port, reaches your cabinet over a cross-connect. Getting it right is mostly a matter of knowing the sequence and checking a few details before you order.
What it physically is
A typical cross-connect runs from a patch panel in your cabinet or cage, through the building's cable pathways, to the meet-me room, where it is patched to the other party's panel position. From there, the other party's own cabling runs back to its equipment. The facility operator installs and owns the cable in between and is responsible for it. Your side and their side each begin at the panel.
Because the cable is short and passive, a cross-connect adds almost nothing to latency and has no capacity limit of its own. Its speed is set entirely by the optics and equipment at each end. That is why one well-installed fiber pair can carry anything from a 1 Gbps hand-off today to a much faster service later, as long as the fiber type suits the new optics.
Types of cross-connect
| Type | Typical use | Notes |
|---|---|---|
| Single-mode fiber | Most carrier and network hand-offs | Works over long distances; the usual choice for carrier services |
| Multimode fiber | Short runs within one suite or floor | Cheaper optics at short range; distance-limited |
| Copper Ethernet | Low-speed hand-offs, management links | Short distances only |
| Coax | Some legacy telecom services | Increasingly rare |
Cross-connects can also run between buildings on the same campus, or between facilities in the same metro, but those are usually sold as short-haul circuits with their own pricing and lead times rather than simple in-building patches.
The LOA-CFA
Before the facility will connect you to anyone, it needs proof that the other party agrees and a precise location to connect to. That is the LOA-CFA: a letter of authorisation and connecting facility assignment. It is issued by the party you are connecting to, such as the carrier delivering your transit or wavelength, and it names the building, the room, the panel and the exact port positions to use.
Two practical points. An LOA-CFA usually has an expiry date, so order the cross-connect promptly after you receive it. And the details must match exactly: if the panel or port on the letter is wrong, the order stalls until a corrected one is issued.
How ordering works, step by step
- Order the service from the carrier or provider you are connecting to.
- Receive the LOA-CFA from that provider once it has assigned a port in the building.
- Place the cross-connect order with the facility or colocation operator, attaching the LOA-CFA and your own panel and port positions.
- The operator installs and tests the cable and confirms completion, often with a light-level reading.
- Both sides plug in and turn up the service, check light levels on their optics, and confirm the link comes up.
Lead times vary by facility and workload, commonly from a few days to a couple of weeks. The cross-connect usually follows the service order, so it sits on the critical path. Ask for the LOA-CFA as early as the provider can issue it.
What goes wrong on turn-up day
- Fiber type mismatch. Single-mode optics on one end and a multimode cross-connect, or the other way round, will not work reliably.
- Optic mismatch. Both ends must use compatible optics for the speed and distance, for example matching long-reach single-mode optics at 10 Gbps. Confirm what the other party's port expects.
- Connector type. LC connectors are the most common; SC and others still appear. Patch cords can adapt, but only if someone brings the right ones.
- Polarity. Fiber pairs have a transmit and a receive strand. If they are crossed the wrong way, the link stays down until someone swaps them.
- Dirty connectors. A speck of dust on a fiber end-face can cause loss or no light at all. Cleaning and inspecting connectors solves more turn-up problems than anything else.
- Wrong port. A typo on the LOA-CFA or the order puts the cable on the wrong position.
Redundancy: two is not always two
If a service matters, order two cross-connects, and make them genuinely separate. Two cables that run through the same tray to the same panel in the same meet-me room share every physical risk. Where the building allows it, use different rooms, different pathways or different panels, and make sure the other party is terminating them on separate equipment. The same principle applies to your own site; see route diversity and redundancy.
Virtual cross-connects
Some facilities and interconnection providers offer a platform where you take one physical port and then create logical connections to many parties over it, often including cloud providers, through a software portal. These are sometimes called virtual cross-connects. They can be much faster to set up and easier to change, at the cost of sharing one physical port. Our cloud connectivity page covers private cloud on-ramps.
Who is responsible for what
A cross-connect has three owners, and knowing the boundaries saves time when something breaks.
- The facility operator owns the cable between the two panels, and fixes it if it is damaged or patched to the wrong position.
- You own everything from your panel to your equipment: patch cords, optics and the port on your router or switch.
- The other party owns everything from its panel back to its equipment, and the service it delivers over the link.
When a link goes down, the quickest route to a fix is to read the light levels at each end. If your optic sees no light from the other side, the fault sits somewhere between their optic and yours, and the operator can test the cross-connect itself. If light levels look normal but the service is still down, the problem is almost certainly configuration, not cable.
Moving, upgrading and renewing
Cross-connects are tied to specific panel positions, so changes in your own space ripple through them. Moving to a larger cage usually means new cross-connects to the new location, each with its own install fee and lead time, and a period where you pay for old and new together. Upgrading a service to a higher speed may reuse the same fiber pair if it is single-mode and the new optics suit it, but confirm that before assuming. At colocation renewal, cross-connect pricing belongs in the negotiation, because monthly charges can rise over time. Whatever the change, plan an overlap long enough to test the new path, then disconnect the old one promptly.
A worked example
All figures are invented for illustration. Real cross-connect prices vary widely by facility and are not quoted here.
A SaaS company puts two cabinets in a colocation facility. Its design needs internet transit from two carriers, a private connection to one cloud provider and an Ethernet transport link to its office, each doubled for redundancy.
| Service | Cross-connects |
|---|---|
| Transit, carrier A | 1 |
| Transit, carrier B | 1 |
| Cloud on-ramp, two diverse ports | 2 |
| Ethernet transport to the office, two paths | 2 |
| Link between its own two cabinets | 1 |
| Total | 7 |
If each cross-connect cost a hypothetical $250 a month, the design carries $1,750 a month, or $21,000 a year, in cross-connects alone, before space and power. That is not a reason to skimp on redundancy. It is a reason to count cross-connects when comparing designs, and to disconnect any that are no longer used, because billing continues until a disconnect order is placed.
Checklist before you order
- LOA-CFA in hand, in date, with panel and port positions checked.
- Fiber type agreed with the other party: single-mode or multimode.
- Optics matched on both ends for speed and reach.
- Connector type known, and the right patch cords on site.
- Your own panel and port positions confirmed.
- For redundant pairs, separate rooms or pathways requested in writing.
- A named contact on each side for turn-up day.
- A record of every cross-connect you pay for, so unused ones get disconnected.
Questions to ask your provider
- What does a cross-connect cost to install and per month here, and can the monthly price rise at renewal?
- What is the typical lead time right now?
- Do you test and report light levels at completion?
- Can redundant cross-connects be routed through separate rooms or pathways?
- Who issues the LOA-CFA for this service, and how long is it valid?
- How do I disconnect a cross-connect, and when does billing stop?
Count the cables before you compare the quotes
When we price IP transit, wavelengths or colocation, we include the cross-connects and building charges in the comparison, so a low service price with expensive interconnection does not win by accident. Tier 1 carriers bid, the carrier pays us so there is no markup, and the quote is free. Tell us what you need to connect and where, call 478-758-8091 or text (347) 870-0965. For the building side, read what is a carrier hotel.
