computer networking A computer network is a set of computers sharing resources located on or provided by network nodes. The computers use common communication protocols over digital interconnections to communicate with each other. These interconnections are ma ...

and

telecommunications Telecommunication is the transmission of information by various types of technologies over wire, radio, optical, or other electromagnetic systems. It has its origin in the desire of humans for communication over a distance greater than that fe ...

, a pseudowire (or pseudo-wire) is an emulation of a

point-to-point connection In telecommunications, a point-to-point connection refers to a communications connection between two communication endpoints or nodes. An example is a telephone call, in which one telephone is connected with one other, and what is said by one c ...

over a

packet-switched network In telecommunications, packet switching is a method of grouping data into '' packets'' that are transmitted over a digital network. Packets are made of a header and a payload. Data in the header is used by networking hardware to direct the pack ...

(PSN). The pseudowire emulates the operation of a "transparent wire" carrying the service, but it is realized that this emulation will rarely be perfect. The service being carried over the "wire" may be

Asynchronous Transfer Mode Asynchronous Transfer Mode (ATM) is a telecommunications standard defined by American National Standards Institute (ANSI) and ITU-T (formerly CCITT) for digital transmission of multiple types of traffic. ATM was developed to meet the needs of ...

(ATM),

Frame Relay Frame Relay is a standardized wide area network (WAN) technology that specifies the physical and data link layers of digital telecommunications channels using a packet switching methodology. Originally designed for transport across Integrated Se ...

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 ...

time-division multiplexing Time-division multiplexing (TDM) is a method of transmitting and receiving independent signals over a common signal path by means of synchronized switches at each end of the transmission line so that each signal appears on the line only a fracti ...

(TDM) while the packet network may be

Multi-protocol Label Switching 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 ...

(MPLS),

Internet Protocol The Internet Protocol (IP) is the network layer communications protocol in the Internet protocol suite for relaying datagrams across network boundaries. Its routing function enables internetworking, and essentially establishes the Internet. IP h ...

(

IPv4 Internet Protocol version 4 (IPv4) is the fourth version of the Internet Protocol (IP). It is one of the core protocols of standards-based internetworking methods in the Internet and other packet-switched networks. IPv4 was the first version de ...

IPv6 Internet Protocol version 6 (IPv6) is the most recent version of the Internet Protocol (IP), the communication protocol, communications protocol that provides an identification and location system for computers on networks and routes traffic ...

), or Layer 2 Tunneling Protocol Version 3 (L2TPv3). The first pseudowire specifications were the

Martini draft Martini may refer to: * Martini (cocktail) * Martini (vermouth), a brand of vermouth * Martini (surname), an Italian surname * Martini (automobile company), a Swiss automobile company * Automobiles Martini, a French manufacturer of racing cars * M ...

for ATM pseudowires, and the

TDMoIP {{unsourced, date=October 2014 In computer networking and telecommunications, TDM over IP (TDMoIP) is the emulation of time-division multiplexing (TDM) over a packet-switched network (PSN). TDM refers to a Digital Signal 1, T1, E-carrier, E1, T-carr ...

draft for transport of E1/T1 over IP. In 2001, the

Internet Engineering Task Force The Internet Engineering Task Force (IETF) is a standards organization for the Internet and is responsible for the technical standards that make up the Internet protocol suite (TCP/IP). It has no formal membership roster or requirements and a ...

(IETF) set up the

PWE3 In 2001, the IETF set up the pseudowire emulation edge to edge working group, and this group was given the acronym PWE3 (the 3 standing for the third power of E, i.e. EEE). The working group was chartered to develop an architecture for service prov ...

working group, which was chartered to develop an architecture for service provider edge-to-edge pseudowires, and service-specific documents detailing the encapsulation techniques. Other standardization forums, including the

International Telecommunication Union The International Telecommunication Union is a specialized agency of the United Nations responsible for many matters related to information and communication technologies. It was established on 17 May 1865 as the International Telegraph Unio ...

(ITU) and the MFA Forum, are also active in producing standards and implementation agreements for pseudowires. Starting from 2006, telecom operators like

BellSouth BellSouth, LLC (stylized as ''BELLSOUTH'' and formerly known as BellSouth Corporation) was an American telecommunications holding company based in Atlanta, Georgia. BellSouth was one of the seven original Regional Bell Operating Companies after ...

, Supercomm,

AT&T AT&T Inc. is an American multinational telecommunications holding company headquartered at Whitacre Tower in Downtown Dallas, Texas. It is the world's largest telecommunications company by revenue and the third largest provider of mobile tel ...

, and

Verizon Verizon Communications Inc., commonly known as Verizon, is an American multinational telecommunications conglomerate and a corporate component of the Dow Jones Industrial Average. The company is headquartered at 1095 Avenue of the Americas in ...

began to invest more into pseudowire technology, pointing out its advantages to Ethernet in particular. Pseudowires tie services together across multiple transport technologies, including

Ethernet over SONET Ethernet Over SDH (EoS or EoSDH) or Ethernet over SONET refers to a set of protocols which allow Ethernet traffic to be carried over synchronous digital hierarchy networks in an efficient and flexible way. The same functions are available using SON ...

, WDM,

GPON G.984, commonly known as GPON (gigabit-capable passive optical network), is a standard for passive optical networks (PON) published by the ITU-T. It is commonly used to implement the outermost link to the customer (last kilometre or last mile) o ...

DSL 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 ...

, and

WiMax Worldwide Interoperability for Microwave Access (WiMAX) is a family of wireless broadband communication standards based on the IEEE 802.16 set of standards, which provide physical layer (PHY) and media access control (MAC) options. The WiMAX ...

. Over the next decade, the technology became mainstream. In 2017

Cisco Cisco Systems, Inc., commonly known as Cisco, is an American-based multinational digital communications technology conglomerate corporation headquartered in San Jose, California. Cisco develops, manufactures, and sells networking hardware, ...

published a comprehensive document explaining the concept, troubleshooting, and configuration details for all Cisco equipment pieces, which supported pseudowire. Today, the service is provided by a number of telecommunication companies like

Axerra Networks Axerra Networks is a leading provider of circuit emulation and service emulation solutions over packet access networks for mobile backhaul and business service delivery. Company overview Axerra's pseudowire (PW) solutions enable mobile operat ...

MCI Inc MCI, Inc. (subsequently Worldcom and MCI WorldCom) was a telecommunications company. For a time, it was the second largest long-distance telephone company in the United States, after AT&T. Worldcom grew largely by acquiring other telecommunic ...

, or by

Infrastructure as a service The first major provider of infrastructure as a service (IaaS) was Amazon in 2008. IaaS is a cloud computing service model by means of which computing resources are supplied by a cloud services provider. The IaaS vendor provides the storage, net ...

providers like Voxility. There are now many pseudowire standards, the most important of which are IETF RFCs as well as ITU-T Recommendations:

RFCs

* Pseudo Wire Emulation Edge-to-Edge (PWE3) Architecture. * Pseudowire Emulation Edge-to-Edge (PWE3) Control Word for Use over an MPLS PSN * Encapsulation Methods for Transport of Ethernet over MPLS Networks * Pseudowire Setup and Maintenance - Using the

Label Distribution Protocol Label Distribution Protocol (LDP) is a protocol in which routers capable of Multiprotocol Label Switching (MPLS) exchange label mapping information. Two routers with an established session are called LDP peers and the exchange of information is bi- ...

(LDP) * Structure-Agnostic Time Division Multiplexing (TDM) over Packet (SAToP) * Pseudowire Emulation Edge-to-Edge (PWE3) Fragmentation and Reassembly * Encapsulation Methods for Transport of PPP/High-Level Data Link Control (HDLC) over MPLS Networks * Encapsulation Methods for Transport of Frame Relay over Multiprotocol Label Switching (MPLS) Networks * Pseudowire Emulation Edge-to-Edge (PWE3) Frame Check Sequence Retention * Encapsulation Methods for Transport of Asynchronous Transfer Mode (ATM) over MPLS Networks * Pseudowire Emulation Edge-to-Edge (PWE3) Asynchronous Transfer Mode (ATM) Transparent Cell Transport Service * Synchronous Optical Network/Synchronous Digital Hierarchy (SONET/SDH) Circuit Emulation over Packet (CEP) * Time Division Multiplexing over IP (TDMoIP) * Structure-Aware Time Division Multiplexed (TDM) Circuit Emulation Service over Packet Switched Network (CESoPSN) * Pseudowire Virtual Circuit Connectivity Verification (VCCV): A Control Channel for Pseudowires * Control Protocol Extensions for the Setup of Time-Division Multiplexing (TDM) Pseudowires in MPLS Networks

ITU-T Recommendations

*Y.1411 ATM pseudowires *Y.1412 AAL5 pseudowires *Y.1413 TDM pseudowires *Y.1414 Voice Services pseudowires *Y.1415 Ethernet pseudowires *Y.1418 Pseudowire Layer Networks *Y.1452 Voice Services over IP *Y.1453 TDM over IP *X.84 Frame Relay pseudowires

References

{{Reflist

External links

Pseudowire Emulation Edge to Edge
Network architecture Tunneling protocols

RFCs

ITU-T Recommendations

See also

References

External links