 | This article needs additional citations for verification. (September 2012) |
A metropolitan-area Ethernet, Ethernet MAN, carrier Ethernet[1] or metro Ethernet network is a metropolitan area network (MAN) that is based on Ethernet standards. It is commonly used to connect subscribers to a larger service network or for internet access. Businesses can also use metropolitan-area Ethernet to connect their own offices to each other.[2]
An Ethernet interface is typically more economical than a synchronous digital hierarchy (SONET/SDH) or plesiochronous digital hierarchy (PDH) interface of the same bandwidth. Another distinct advantage of an Ethernet-based access network is that it can be easily connected to the customer network, due to the prevalent use of Ethernet in corporate and residential networks.
A typical service provider's network is a collection of switches and routers connected through optical fiber. The topology could be a ring, hub-and-spoke (star), or full or partial mesh. The network will also have a hierarchy: core, distribution (aggregation), and access. The core in most cases is an existing IP/MPLS backbone but may migrate to newer forms of Ethernet transport in the form of 10 Gbit/s, 40 Gbit/s, or 100 Gbit/s speeds or even possibly 400 Gbit/s to Terabit Ethernet network in the future.
Ethernet on the MAN can be used as pure Ethernet, Ethernet over SDH, Ethernet over Multiprotocol Label Switching (MPLS), or Ethernet over DWDM. Ethernet-based deployments with no other underlying transport are cheaper but are harder to implement in a resilient and scalable manner, which has limited its use to small-scale or experimental deployments. SDH-based deployments are useful when there is an existing SDH infrastructure already in place; its main shortcoming is the loss of flexibility in bandwidth management due to the rigid hierarchy imposed by the SDH network. MPLS-based deployments are costly but highly reliable and scalable and are typically used by large service providers.
- ^ Beasley, Jeffrey S.; Nilkaew, Piyasat (March 2012). Networking Essentials. Pearson Education. ISBN 978-0-13-338170-2.
- ^ Ralph Santitoro (2003). "Metro Ethernet Services – A Technical Overview" (PDF). mef.net. Archived from the original (PDF) on 2018-12-22. Retrieved 2016-01-09.