Carrier Ethernet is a marketing term for extensions to

Ethernet Ethernet ( ) is a family of wired computer networking technologies commonly used in local area networks (LAN), metropolitan area networks (MAN) and wide area networks (WAN). It was commercially introduced in 1980 and first standardized in 198 ...

for

communications service provider A telecommunications company is a kind of electronic communications service provider, more precisely a telecommunications service provider (TSP), that provides telecommunications services such as telephony and data communications access. Many t ...

s that utilize Ethernet technology in their networks.

Background

has a long history. It has become dominant in enterprise networks. This dominance has led to high production-volume components, which in turn have allowed extremely low cost per bit. Likewise, Ethernet has a long history of re-inventing itself. From the original copper

coaxial cable Coaxial cable, or coax (pronounced ), is a type of electrical cable consisting of an inner Electrical conductor, conductor surrounded by a concentric conducting Electromagnetic shielding, shield, with the two separated by a dielectric (Insulat ...

format ("

thicknet 10BASE5 (also known as thick Ethernet or thicknet) was the first commercially available variant of Ethernet. The technology was standardized in 1982 as IEEE 802.3. 10BASE5 uses a thick and stiff coaxial cable up to in length. Up to 100 stati ...

") it has extended its scope to nearly all copper,

optical fiber An optical fiber, or optical fibre, is a flexible glass or plastic fiber that can transmit light from one end to the other. Such fibers find wide usage in fiber-optic communications, where they permit transmission over longer distances and at ...

and wireless physical media.

Bit rate In telecommunications and computing, bit rate (bitrate or as a variable ''R'') is the number of bits that are conveyed or processed per unit of time. The bit rate is expressed in the unit bit per second (symbol: bit/s), often in conjunction ...

s have continued to increase, traditionally growing tenfold each time a new rate is defined.

Gigabit Ethernet In computer networking, Gigabit Ethernet (GbE or 1 GigE) is the term applied to transmitting Ethernet frames at a rate of a gigabit per second. The most popular variant, 1000BASE-T, is defined by the IEEE 802.3ab standard. It came into use in ...

interfaces are widely deployed in PCs and servers, and 10 Gbit/s in

local area network A local area network (LAN) is a computer network that interconnects computers within a limited area such as a residence, campus, or building, and has its network equipment and interconnects locally managed. LANs facilitate the distribution of da ...

(LAN) backbones. Rates up to

100 Gigabit Ethernet 40 Gigabit Ethernet (40GbE) and 100 Gigabit Ethernet (100GbE) are groups of computer networking technologies for transmitting Ethernet frames at rates of 40 and 100 gigabits per second (Gbit/s), respectively. These technologies offer significantly ...

were standardized in 2010 and 2011. Ethernet's dominance is partly attributed to the simple advantages for the industry of adopting a single standard to drive up volumes and drive down prices. In part, it is also due to ease of deployment, using its ability to self-configure based on the key concepts of ''learning bridge'' (

flooding A flood is an overflow of water ( or rarely other fluids) that submerges land that is usually dry. In the sense of "flowing water", the word may also be applied to the inflow of the tide. Floods are of significant concern in agriculture, civi ...

, and associating learned destination

addresses An address is a collection of information, presented in a mostly fixed format, used to give the location of a building, apartment, or other structure or a plot of land, generally using border, political boundaries and street names as references, ...

with

bridge A bridge is a structure built to Span (engineering), span a physical obstacle (such as a body of water, valley, road, or railway) without blocking the path underneath. It is constructed for the purpose of providing passage over the obstacle, whi ...

ports) and

Spanning Tree Protocol The Spanning Tree Protocol (STP) is a network protocol that builds a loop-free logical topology for Ethernet networks. The basic function of STP is to prevent bridge loops and the broadcast radiation that results from them. Spanning tree al ...

(the protocol used for avoiding bridging loops). Historically, competing protocols and cabling have been created in order to access higher speed devices than contemporary Ethernet-connected devices handled at an affordable price. Examples include

FireWire IEEE 1394 is an interface standard for a serial bus for high-speed communications and isochronous real-time data transfer. It was developed in the late 1980s and early 1990s by Apple in cooperation with a number of companies, primarily Sony a ...

and

Light Peak Thunderbolt is the brand name of a Interface (computing)#Hardware interfaces, hardware interface for the connection of external peripherals to a computer. It was developed by Intel in collaboration with Apple Inc., Apple. It was initially marke ...

. One motive to create competing standards has been to drive down the price of comparable-speed Ethernet devices. Once this purpose is achieved, competing standards tend to disappear or be confined to very specialized niches. Ethernet is a fairly simple protocol which has scaled to hundreds of thousands of times faster speeds and consistently been able to adapt to meet the needs and demands of new markets. For example, time domain capabilities are being added to IEEE 802.3 Ethernet to support IEEE 802.1

Audio Video Bridging Audio Video Bridging (AVB) is a common name for a set of technical standards that provide improved synchronization, low latency, and reliability for switched Ethernet networks. AVB embodies the following technologies and standards: * IEEE 802 ...

(AVB),IEEE 802.1 Audio/Video Bridging
/ref> and these capabilities will be applicable to time sensitive carrier applications likewise

IEEE 1588 The Precision Time Protocol (PTP) is a protocol for clock synchronization throughout a computer network with relatively high precision and therefore ''potentially'' high accuracy. In a local area network (LAN), accuracy can be sub-microsecond ...

. Customer

LAN Lan or LAN may refer to: Science and technology * Local asymptotic normality, a fundamental property of regular models in statistics * Longitude of the ascending node, one of the orbital elements used to specify the orbit of an object in space * ...

networks are increasingly connected to wide-area telecommunications networks over Ethernet interfaces or to devices that bridge

digital subscriber line Digital subscriber line (DSL; originally digital subscriber loop) is a family of technologies that are used to transmit digital data over telephone lines. In telecommunications marketing, the term DSL is widely understood to mean asymmetric dig ...

(DSL) or

wireless Wireless communication (or just wireless, when the context allows) is the transfer of information (''telecommunication'') between two or more points without the use of an electrical conductor, optical fiber or other continuous guided transm ...

to these. Moreover, customers are familiar with the capabilities of Ethernet networks, and would like to extend these capabilities to multi-site networks. Meanwhile, the needs of such networks have expanded to include many services previously handled only on the LAN or by specialized connections, notably video and backup. It is not practical to expand most small networks beyond 1G or at most 2G ( dual teaming gigabit) capacity per segment, since the bottleneck remains in the wide area links to other offices and online services.

Carrier constraints

Thus

wide area network A wide area network (WAN) is a telecommunications network that extends over a large geographic area. Wide area networks are often established with leased telecommunication circuits. Businesses, as well as schools and government entities, use ...

(WAN) and

metropolitan area network A metropolitan area network (MAN) is a computer network that interconnects users with computer resources in a geographic region of the size of a metropolitan area. The term MAN is applied to the interconnection of local area networks (LANs) in ...

(MAN) providers find themselves with three needs: #To provide their customers with Ethernet services #To make use of the volume and cost advantages of Ethernet technologies in their networks #To replace non-Ethernet technologies with Ethernet competitors that have sufficient capacity for storage,

backup In information technology, a backup, or data backup is a copy of computer data taken and stored elsewhere so that it may be used to restore the original after a data loss event. The verb form, referring to the process of doing so, is "wikt:back ...

and

HD video High-definition video (HD video) is video of higher resolution and quality than standard-definition. While there is no standardized meaning for ''high-definition'', generally any video image with considerably more than 480 vertical scan lines (N ...

and guarantee features (transfer certainty, low latency) needed to support these services They are also constrained as services cannot be migrated from local to wide area services too fast lest they exceed the total provisioning available and result in unacceptable quality. Services that try to expand too fast lose money while those that wait too long lose customers. Accordingly, carriers must expand their services conservatively and pay close attention to

quality of service Quality of service (QoS) is the description or measurement of the overall performance of a service, such as a telephony or computer network, or a cloud computing service, particularly the performance seen by the users of the network. To quantitat ...

(QoS).

The Beginning: Metro Ethernet

The MEF was formed in 2001 in order to develop ubiquitous business services for Enterprise users principally accessed over optical metropolitan networks in order to connect their Enterprise LANs. The principal concept was to bring the simplicity and cost model of Ethernet to the wide area network.

Expansion to Carrier Ethernet

The success of Metro Ethernet Services caught the imagination of the world when the concept expanded to include worldwide services traversing national and global networks: * Access networks to provide availability to a much wider class of user over fiber, copper, cable,

passive optical network A passive optical network (PON) is a fiber-optic telecommunications network that uses only ''unpowered'' devices to carry signals, as opposed to electronic equipment. In practice, PONs are typically used for the '' last mile'' between Internet ...

(PON), and wireless * Economy of scale from the resulting converged business, residential and wireless networks sharing the same infrastructure and services * Scalability & rapid deployment of business applications * Adoption of the certification program * All while retaining the cost model and simplicity of Ethernet

Carrier Ethernet services

To create a market in Ethernet services, it is necessary to clarify and standardise the services to be provided. Recognising this, the industry created the MEF. This played a key role in defining: * Ethernet Virtual Private Line or E-Line: a service connecting two customer Ethernet ports over a WAN. * Ethernet Virtual Private LAN or E-LAN: a multipoint service connecting a set of customer endpoints, giving the appearance to the customer of a bridged Ethernet network connecting the sites. * Ethernet Virtual Private Tree or E-Tree: a multipoint service connecting one or more roots and a set of leaves, but preventing inter-leaf communication. All these services provide standard definitions of such characteristics as bandwidth, resilience and service multiplexing, allowing customers to compare service offerings and facilitating

service level agreement A service-level agreement (SLA) is an agreement between a service provider and a customer. Particular aspects of the service – quality, availability, responsibilities – are agreed between the service provider and the service user. T ...

s (SLAs). ''Analogous definitions for wireless networks are defined in IEEE 802.21 and IEEE 802.11u, though these are intended for much shorter time commitments and services appropriate for mobile users only.''

Ethernet Virtual Private Tree

Ethernet Virtual Private Tree or E-Tree is a

point-to-multipoint In telecommunications, point-to-multipoint communication (P2MP, PTMP or PMP) is communication which is accomplished via a distinct type of One-to-many (data model), one-to-many connection, providing multiple paths from a single location to mult ...

Ethernet Virtual Connection defined by the MEF — an Ethernet

VLAN A virtual local area network (VLAN) is any broadcast domain that is partitioned and isolated in a computer network at the data link layer ( OSI layer 2).IEEE 802.1Q-2011, ''1.4 VLAN aims and benefits'' In this context, virtual refers to a ...

configuration suitable for

multicast In computer networking, multicast is a type of group communication where data transmission is addressed to a group of destination computers simultaneously. Multicast can be one-to-many or many-to-many distribution. Multicast differs from ph ...

services.

Ethernet private line

Ethernet private line (EPL) and Ethernet virtual private line (EVPL) are data services defined by the MEF. EPL provides a point-to-point Ethernet virtual connection (EVC) between a pair of dedicated

user–network interface In telecommunications, a user–network interface (UNI) is a demarcation point between the responsibility of the service provider and the responsibility of the subscriber. This is distinct from a network-to-network interface (NNI) that defines a si ...

s (UNIs), with a high degree of transparency. EVPL provides a point-to-point or

connection between a pair of UNIs. The services are categorized as an E-line service type, with an expectation of low frame delay, frame delay variation and frame loss ratio. EPL is implemented using a point-to-point EVC with no service multiplexing at each UNI (physical interface), i.e., all service frames at the UNI are mapped to a single EVC (a.k.a. all-to-one bundling). Due to a high degree of transparency, EPL is often used to provide point-to-point transparent LAN service (TLS), where the service frame's header and payload are identical at both the source and destination UNI. Some implementations tunnel most Ethernet Layer 2 control protocols (L2CPs) except for some link-layer L2CPs such as IEEE 802.3x pause frames. Unlike EPL, EVPL allows for service multiplexing, i.e., multiple EVCs or Ethernet services per UNI. The other difference between the EVPL and EPL is the degree of transparency: while EPL is highly transparent, filtering only the pause frames, EVPL is required to either peer or drop most of the Layer 2 control protocols.

Ethernet Virtual Private LAN

Ethernet Virtual Private LAN (EVP-LAN) is a multipoint-to-multipoint Ethernet Virtual Connection defined by the MEF — a Carrier Ethernet equivalent of

Virtual Private LAN Service Virtual Private LAN Service (VPLS) is a way to provide Ethernet-based multipoint to multipoint communication over IP or MPLS networks. It allows geographically dispersed sites to share an Ethernet broadcast domain by connecting sites through p ...

(VPLS) or Transparent LAN Services. EVP-LAN enables any-to-any communication between all customer locations associated with the customer's Ethernet Virtual Connections (EVC). It is categorized as an E-LAN service type, with an expectation of low Frame Delay, Frame Delay Variation and Frame Loss Ratio. Service multiplexing is allowed at the UNI and EVPL and EVP-LAN service types may share the same port. CE-VLAN IDs are maintained across the network.

Transport of Ethernet services

The MEF does not specify how Ethernet services are to be provided in a carrier network. Despite the advantages described above, Ethernet has traditionally had a number of limitations in the WAN application. The "bridge" and "spanning tree" concepts described above do not scale to large international networks. Moreover, Ethernet has lacked some of the dependability features necessary in this application (in particular, mechanisms to isolate one customer's traffic from another, to measure performance of a customer service instance, and to rapidly detect and repair failures in large networks). Because of these limitations, and because of the need to make use of pre-existing equipment, Ethernet services have been carried across wide area networks using other technologies. Two types of technology have been widely used, while a third (Carrier-Ethernet transport) is rapidly emerging as a viable and logical option for Carrier-Ethernet services.

Ethernet over SDH/SONET

Point-to-point Ethernet links are carried over

SDH/SONET Synchronous Optical Networking (SONET) and Synchronous Digital Hierarchy (SDH) are standardized protocols that transfer multiple digital bit streams synchronously over optical fiber using lasers or highly coherent light from light-emitting diodes ...

networks, making use of virtual concatenation (ITU-T G.707) and LCAS (Link Capacity Adjustment Scheme - ITU-T G.7042) to create an appropriate size carrier bundle, of the

Generic Framing Procedure Generic Framing Procedure (GFP) is a multiplexing technique defined by ITU-T G.7041. This allows mapping of variable length, higher-layer client signals over a circuit switched transport network like OTN, SDH/SONET or PDH. The client signals can ...

of SDH equipment, and takes advantage of the management and recovery features of SDH to provide

high availability High availability (HA) is a characteristic of a system that aims to ensure an agreed level of operational performance, usually uptime, for a higher than normal period. There is now more dependence on these systems as a result of modernization ...

and resilience to failures.

Ethernet over MPLS

Ethernet services are carried over IP/

MPLS Multiprotocol Label Switching (MPLS) is a routing technique in telecommunications networks that directs data from one node to the next based on labels rather than network addresses. Whereas network addresses identify endpoints, the labels identi ...

networks making use of a wide range of IP-related protocols (see IETF pseudowire standards, e.g. RFC 3985, RFC 4448). Ethernet links are transported as "pseudowires" using

MPLS label-switched path Multiprotocol Label Switching (MPLS) is a routing technique in telecommunications networks that directs data from one node to the next based on labels rather than network addresses. Whereas network addresses identify endpoints, the labels identi ...

s (LSPs) inside an outer MPLS "tunnel". This strategy can support both point-to-point (Virtual Private Wire Service - VPWS) and multipoint (Virtual Private LAN service - VPLS) services, and has recently achieved significant deployment in routed networks. It makes use of a number of basic transport protocols, including SDH and (increasingly) Ethernet.

Ethernet over Carrier-Ethernet Transport (CET)

Proponents of Carrier-Class Ethernet argue Ethernet is the best for Metro Area Networks because all data traffic originates as Ethernet. Ethernet's ubiquitous presence in the LANs worldwide drives down the cost of Ethernet as a technology. Thus, the use of Ethernet in a metro network allows service providers to take advantage of volumes that a much larger enterprise segment commands. Carrier-Ethernet Transport (CET) usually involves an evolution of conventional Ethernet and comprises multiple technology components.

Provider Backbone Bridges IEEE 802.1ah is an amendment to the IEEE 802.1Q networking standard which adds support for Provider Backbone Bridges. It includes an architecture and a set of protocols for routing over a provider's network, allowing interconnection of multiple p ...

(PBB) provides the scalability and a secure demarcation, while Provider Backbone Bridge Traffic Engineering (PBB-TE, commonly called PBT) provides for traffic-engineering and an effective transport for protected Ethernet services. Connectivity-Fault Management (CFM-OAM) provides the much-required OAM that makes Ethernet

carrier grade In telecommunications, a "carrier grade" or "carrier class" refers to a system, or a hardware or software component that is extremely reliable, well tested and proven in its capabilities. Carrier grade systems are tested and engineered to meet or ...

Carrier Ethernet demarcation

Carrier Ethernet demarcation is a key element in Carrier Ethernet services and transport networks for business, wholesale and mobile backhaul applications, as it enables service providers to extend their control over the entire service path, starting from the hand off points. This is achieved by connecting customer premises equipment (CPE) to the network with provider-owned demarcation devices that are deployed at customer locations, thereby enabling a clear separation between the user and provider networks. Carrier Ethernet demarcation devices (EDD) are required to support services, such as Ethernet Private Line (EPL), Ethernet Virtual Private Line (EVPL or E-LAN), and Ethernet Virtual Private Tree (E-Tree), as specified by the MEF. Such support needs to include

(SLA) management capabilities, with consistent performance over fiber, DSL, bonded PDH, and SDH/SONET access lines. As a result, must-have Carrier Ethernet demarcation features include sophisticated traffic management and hierarchical

(QoS) mechanisms, standard end-to-end operations, administration and maintenance (OAM) and performance monitoring, extensive fault management and diagnostics, and SDH/SONET-like resiliency to reduce service provider operating costs and capital expenses.

Carrier Ethernet technologies

The industry has made a concerted effort to resolve the limitations of Ethernet in the WAN described above, so as to allow the use of "native" Ethernet technologies by network providers. The key roles have been played by the

Institute of Electrical and Electronics Engineers The Institute of Electrical and Electronics Engineers (IEEE) is an American 501(c)(3) public charity professional organization for electrical engineering, electronics engineering, and other related disciplines. The IEEE has a corporate office ...

(IEEE) 802.1 and

802.3 IEEE 802.3 is a working group and a collection of standards defining the physical layer and data link layer's media access control (MAC) of wired Ethernet. The standards are produced by the working group of the Institute of Electrical and Electro ...

standards committees. IEEE 802.1 has addressed the scalability and management issues in the standards for Provider Bridges (802.1ad) and

(802.1ah). These standards allow for Ethernet networks of planetary scale. Associated standards ( IEEE 802.1ag, and related ITU-T standard Y.1731) provide Operations and Maintenance (OAM) capabilities allowing connectivity verification, rapid recovery, and performance measurement. Current work on PBB-TE (802.1Qay: Provider Backbone Bridging-Traffic Engineering) is allowing such an Ethernet to be controlled by an external control or management application (for example, a network management application or a transport control plane such as

GMPLS Generalized Multi-Protocol Label Switching (GMPLS) is a protocol suite extending MPLS Multiprotocol Label Switching (MPLS) is a routing technique in telecommunications networks that directs data from one node to the next based on labels rather th ...

(IETF RFC 3945)), so as to allow the full range of traffic engineering policies and strategies to a network provider. The IEEE

Working Group in close cooperation with the

ITU The International Telecommunication Union (ITU)In the other common languages of the ITU: * * is a specialized agency of the United Nations responsible for many matters related to information and communication technologies. It was established ...

have been working to simplify the transport of 40G and 100G technologies being developed by both bodies: 802.3 for LAN and ITU for the OTN. The OIF and the

Ethernet Alliance The Ethernet Alliance is an industry consortium founded in 2005 to promote and support Ethernet. Organization The Ethernet Alliance work groups are called subcommittees. These subcommittees are focused on efforts around specific standards-based ...

have also been working cooperatively with their members to enable future enhancements to Ethernet for the WAN while looking to the future speed of Ethernet technologies and services.

References

External links

Metro Ethernet Forum, Carrier Ethernet & CE 2.0
* * * - Metro Ethernet Services Definitions Phase 2) * - Metro Ethernet Services Definitions Phase I - superseded by MEF 6.1) * - Ethernet Services Attributes Phase 2 *
Metro Ethernet Forum
* https://www.mef.net/Assets/Technical_Specifications/PDF/MEF_6.1.pdf {{Ethernet Telecommunication services Ethernet