Metro Ethernet transport is a Carrier Ethernet service that connects locations within the same metropolitan area over a provider’s private Ethernet network. Each site gets an Ethernet port, and the carrier delivers a standardized Ethernet service between them with a committed amount of bandwidth, so offices, campuses and data centers across a city can behave much like one extended network. It is commonly bought to link a headquarters to a nearby data center or to tie several buildings together.
At a glance
- Metro Ethernet is Carrier Ethernet scoped to one metro area, delivered mostly over the carrier’s local fiber.
- It comes as point-to-point (E-Line: EPL or EVPL), multipoint (E-LAN) or hub-and-spoke (E-Tree) connections.
- Each connection has a bandwidth profile and, depending on the contract, service levels for availability, delay, jitter and frame loss.
- Distances are short, so latency is usually low, but performance still depends on the carrier’s network and your contract.
- Price and lead time are driven mostly by whether the carrier’s fiber already reaches each building.
What problem it solves
Organizations with several sites in one city often move large amounts of data between them: replication to a data center, shared applications, voice and video, backups. Sending that over the internet means variable performance and no single provider accountable for the path. Building your own fiber is rarely practical.
Metro Ethernet gives you private, high-capacity connections across the city that use the same Ethernet your internal network already runs. You can run your own routing, extend VLANs where appropriate and add capacity as needs grow, without managing the fiber yourself.
How it works
Handoffs. The carrier installs an Ethernet port at each site, commonly 1 or 10 Gbps, with faster ports available from some providers. That port is the demarcation point where the service is measured.
Ethernet service. The carrier provides an Ethernet virtual connection between your ports. Underneath, it may run over shared packet infrastructure, often fiber rings using MPLS or EVPN, or over transport dedicated to you; ask which. An Ethernet private line (EPL) uses the whole port for one connection; an Ethernet virtual private line (EVPL) lets several connections share a port by VLAN; an E-LAN joins many sites any-to-any.
Bandwidth profile. Each connection has a committed information rate, sometimes with an excess rate above it that is carried only when capacity allows, and burst sizes that determine how traffic spikes are handled. A committed rate is a contractual commitment, not a guarantee that traffic never drops; how the carrier engineers and oversubscribes its network matters too.
Class of service. Some providers offer several traffic classes and map your markings to their queues.
Testing and monitoring. Turn-up tests such as ITU-T Y.1564 or RFC 2544 check throughput, delay and loss before handover. Ethernet OAM tools then let the carrier, and sometimes you, keep measuring.
Protection. Some services are protected, with a second path around the ring; others are unprotected single paths. Protection inside the carrier’s network does not by itself make the building entrance or the lateral into it diverse.
When it matters for buyers
- Data center and colocation links, where steady replication and backup traffic need consistent capacity.
- Multi-building campuses and city offices that need to share systems as if on one network.
- Cloud adjacency, when a circuit runs to a facility that hosts cloud on-ramps.
- Resilience planning. Two circuits from different carriers can still share a conduit for much of the route. Ask for route maps and documented path diversity rather than relying on different logos.
- Project timelines. Construction to reach an off-net building can take months and drives non-recurring charges.
Questions to ask vendors
- Are both buildings on-net, and if not, what construction, cost and install interval apply?
- Which service type (EPL, EVPL, E-LAN) are you quoting, and which VLAN tags and control frames, such as Spanning Tree or LACP, will pass through?
- What committed rate, burst sizes and classes of service are included?
- What does the SLA cover, how is it measured, and what credits apply?
- Is the service protected, and will you provide route documentation showing where it is diverse from our other circuits?
- What end-to-end MTU do you support?
- Will you share turn-up test results and ongoing performance data?
Remember that a private circuit is not an encrypted one. If policy requires encryption, add MACsec or IPsec on your own equipment. Our private networking overview covers how Metro Ethernet compares with other private connectivity.
How it differs from Carrier Ethernet
Carrier Ethernet is the broader family of standardized Ethernet services that carriers sell at any distance, from across town to between countries. Metro Ethernet is Carrier Ethernet delivered within one metropolitan area, usually entirely on a single carrier’s local fiber, which tends to mean lower latency, simpler routes and, often, lower cost per megabit than long-haul services. For the highest-capacity links between two points, buyers also compare Metro Ethernet with a wavelength service or lit fiber, which dedicate optical capacity to one customer rather than sharing a packet network.
Problems this helps with
- Need fast private links between offices or campuses across a city
- Connecting an office to a nearby data center or colocation site
- Two circuits that were sold as diverse failed together
- Long, unpredictable lead times for new circuits
