UK Leased Lines Explained: DIA vs Ethernet, Business Benefits & Shared Offices
How UK leased lines differ from broadband, Ethernet and point-to-point — product comparison, business benefits, and why Fast2Host supports managed and shared office spaces.
“Leased line” gets used as a catch-all for any business fibre. In practice UK buyers are choosing between Dedicated Internet Access (DIA), Carrier Ethernet, point-to-point private wires, and sometimes a private cloud on-ramp — each solves a different job.
This guide compares those products, spells out the business case versus contended broadband, and explains how we support managed workspaces, serviced offices and shared business centres on a single bearer with clean tenant separation.
Start with the product page if you already know you need internet breakout: UK leased lines / DIA. For the wider menu, see Internet connectivity.
What a leased line actually is
A leased line (also called Dedicated Internet Access / DIA) is a symmetric, uncontended fibre circuit between your premises and the provider’s network. You get the committed rate 24/7, identical upload and download, static IP space, a hard uptime SLA, and proactive monitoring — not a “best effort” cabinet share.
At Fast2Host that means:
- Committed rates from 100Mbps to 10Gbps on 1Gbps or 10Gbps Ethernet bearers
- 1:1 uncontended — the bandwidth is reserved for you
- 99.99% SLA, carrier-diverse delivery (Openreach, Virgin Media O2 Business, CityFibre, Colt and others)
- Always-on 600Gbps Corero DDoS included — see DDoS protection
- Optional BGP, PI space, and IPv4 / IPv6 services
- Optional extended LAN into your rack at our Cambridge colocation facility
Product detail and quote tool: Leased lines.
Product differences: what to buy for which job
| Product | What it is | Public internet? | Typical use |
|---|---|---|---|
| Leased line / DIA | Routed, symmetric internet access to one site | Yes — that’s the point | Offices, shared workspaces, cloud apps, VoIP, primary breakout |
| Carrier Ethernet | MEF layer-2 WAN (EPL / EVPL / E-LAN) | No (private wire) | Site-to-site LAN extension, multi-site WAN, DC handoff |
| Point-to-point | Simple two-building EPL | No | HQ ↔ DR, office ↔ Cambridge rack |
| Public cloud connect | Private on-ramp to AWS / Azure / GCP | No (private to cloud) | Hybrid cloud without riding the open internet |
| Business broadband | Contended FTTP/FTTC | Yes | Home office / light use — not a DIA substitute |
DIA vs broadband (the decision most offices get wrong)
Broadband is contended — your speed varies with neighbours — and upload is often a fraction of download. Fine for browsing; fragile for:
- Cloud file sync and backup windows
- Teams / Zoom / Meet all day
- Hosted PBX and call centres
- Agencies pushing large assets
- Multi-tenant buildings where one noisy neighbour saturates the share
A leased line gives you the full committed rate both ways, static addressing, SLA credits, and a UK NOC watching the circuit. Cost is higher because fibre and bandwidth are reserved exclusively for you.
DIA vs Carrier Ethernet vs point-to-point
- Need internet at the desk / Wi‑Fi / firewall edge → DIA.
- Need a private wire between sites (no public hops) → Ethernet or a focused point-to-point.
- Need office VLANs presented in your colo cabinet → point-to-point / extended LAN into rackspace (our most common P2P pattern).
- Need private paths into AWS, Azure or GCP → Public cloud connect (often alongside DIA for breakout).
Many customers run both: DIA for internet, Ethernet or P2P for private replication and colo. Peering quality on the internet path still matters — we operate AS48825 with direct peering at LINX and LONAP.
Business benefits that show up on the invoice
- Predictable performance — cloud SaaS, VoIP and video stop fighting a contended uplink.
- Symmetric uploads — backup, DR replication and large file pushes complete in the window you planned.
- Hard SLA — 99.99% with proactive credits beats “we’ll look at it Monday”.
- Security posture — always-on edge DDoS on the circuit (Corero on AS48825) without emergency upgrade pricing.
- Addressing & routing — static IPs, reverse DNS, optional BGP / PI for ISPs and multi-homed designs (IP & BGP).
- Hybrid to colo — treat Cambridge as another floor of your LAN via extended Ethernet / P2P.
- One UK team — Cambridge NOC for the access circuit and the handover, not an offshore script.
Shared offices, serviced offices and co-working
We deliberately design leased lines for managed workspaces, serviced offices and shared business centres — not only single-tenant HQs.
How multi-tenant connectivity works
One fibre bearer into the building, then:
- Per-tenant VLANs with isolation
- Separate rate-limits so one tenant cannot starve another
- Optional per-tenant firewall / policy at the edge
- Single landlord bill or pass-through billing models
- One UK point of contact for break/fix and upgrades
That turns connectivity into a product feature of the tenancy — business-grade fibre without every SME ordering their own last mile.
Who this fits
- Serviced office operators and co-working hubs
- Business centres and multi-tenant campuses
- Landlords packaging “ready to work” suites
- Cambridge and wider UK managed workspace portfolios
If you are scoping a building, say so on the quote — we will design VLAN and contention policy up front. Start at leased lines or contact sales.
How it pairs with colo and cloud
| Goal | Typical stack |
|---|---|
| Office internet only | DIA |
| Office + private rack in Cambridge | DIA + point-to-point / extended LAN into colo |
| Multi-site private WAN | Carrier Ethernet (± DIA at each edge) |
| Hybrid public cloud | DIA + Public cloud connect |
| Lower latency UK paths | DIA on AS48825 with peering |
Remote hands and rack options sit under colocation and remote hands if you are extending into the facility.
Choosing a speed (rule of thumb)
| Footprint | Starting point (illustrative) |
|---|---|
| Small office / light SaaS | 100–200Mbps DIA |
| Busy office, VoIP + video, backups | 500Mbps–1Gbps DIA |
| Shared / serviced office (multi-tenant) | 1Gbps bearer with per-tenant caps |
| Media, wholesale, heavy cloud sync | 1–10Gbps DIA |
| Office ↔ colo private wire | Match to replication / backup window (often 1–10Gbps P2P) |
We size from concurrent users, backup windows and tenant count — not marketing tiers. Use the quote tool on the leased line page.
FAQ (short)
Is Ethernet the same as a leased line?
No. Ethernet is usually a private layer-2 service; a leased line / DIA is routed internet access. See Ethernet services.
Can you connect our office to a rack in Cambridge?
Yes — popular point-to-point delivery with VLAN transparency into your cabinet.
Do shared offices really get separate networks?
Yes — VLAN (and policy) separation on a shared bearer is the standard model we deploy for managed workspaces.
Is DDoS included?
Yes on Fast2Host DIA — 600Gbps Corero, no null-route culture.
Next step
Tell us your postcode, target commit rate, and whether the site is single-tenant or shared office. We will recommend DIA, Ethernet, P2P or a hybrid — and quote within one working day.