Ethernet extender
Encyclopedia
An Ethernet extender is any device used to extend an Ethernet
or network segment beyond its inherent distance limitation which is approximately 100 metres (328.1 ft) for most common forms of twisted pair Ethernet. These devices employ a variety of transmission technologies and physical media (wireless, copper wire, fiber-optic cable, coaxial cable).
The extender forwards traffic between LAN
s transparent to higher network-layer protocols
over distances that far exceed the limitations of standard Ethernet.
s. Network extenders use various methods (line encodings), such as TC-PAM
, 2B1Q
or DMT, to transmit information. While transmitting over copper wire does not allow for the speeds that fiber-optic transmission does, it allows the use of existing voice-grade copper or CCTV coaxial cable wiring. Copper-based Ethernet extenders must be used on unconditioned wire (without load coils), such as unused twisted pairs and alarm circuit
s.
Connecting a private LAN
between buildings or more distant locations is a challenge. Wi-Fi
requires a clear line-of-sight, special antennas, and is subject to weather. If the buildings are within 100m, a normal Ethernet cable segment can be used, with due consideration of potential grounding problems between the locations. Up to 200m, it may be possible to set up an ordinary Ethernet bridge or router in the middle, if power and weather protection can be arranged.
Fiber optic connection is ideal, allowing connections of over a km and high speeds with no electrical shock or surge issues, but is technically specialized and expensive for both the end equipment interfaces and the cable. Damage to the cable requires special skills to repair or total replacement.
Specialized equipment can inter-connect two LANs over a single twisted pair of wires, such as Cisco LRE (Long Reach Ethernet
), Patton CopperLink or EtherWAN Ethernet Extenders using VDSL technology. Distances of 300 m (1000 feet) at 50 Mbit/s up to 8 km (5 mi) at 128 kbit/s is possible. Coaxial cable
are often permitting higher speeds and larger distances than twisted pair wires. The equipment is mostly simple to operate, and the connection wire is common, cheap and maintainable.
Ordinary ADSL modems cannot be connected back-to-back, because the ATU-R (ADSL Termination Unit - Remote) units that are used by customers require specialized ATU-C (Central Office) support provided by phone company equipment, usually by a complex and expensive DSLAM (DSL access multiplexer). However some symmetric digital subscriber line
(SDSL) modems such as the SpeedStream 5851 can be connected back-to-back, allowing upload and download speeds of about 2Mbps over substantial distances, using a simple twisted pair of wires.
Back-to-back operation may also be possible with single-pair high-speed digital subscriber line (G.SHDSL) modems.
Similar technologies were standardized as Ethernet in the first mile
:
Ethernet
Ethernet is a family of computer networking technologies for local area networks commercially introduced in 1980. Standardized in IEEE 802.3, Ethernet has largely replaced competing wired LAN technologies....
or network segment beyond its inherent distance limitation which is approximately 100 metres (328.1 ft) for most common forms of twisted pair Ethernet. These devices employ a variety of transmission technologies and physical media (wireless, copper wire, fiber-optic cable, coaxial cable).
The extender forwards traffic between LAN
Län
Län and lääni refer to the administrative divisions used in Sweden and previously in Finland. The provinces of Finland were abolished on January 1, 2010....
s transparent to higher network-layer protocols
Communications protocol
A communications protocol is a system of digital message formats and rules for exchanging those messages in or between computing systems and in telecommunications...
over distances that far exceed the limitations of standard Ethernet.
Options
Extenders that use copper wire include 2- and 4-wire variants using unconditioned copper wiring to extend a LANLän
Län and lääni refer to the administrative divisions used in Sweden and previously in Finland. The provinces of Finland were abolished on January 1, 2010....
s. Network extenders use various methods (line encodings), such as TC-PAM
TC-PAM
TC-PAM is an acronym for Trellis Coded Pulse Amplitude Modulation. It is the modulation format that is used in both HDSL2 and SHDSL, and provides vigorous presentation over an assortment of loop circumstances...
, 2B1Q
2B1Q
Two-binary, one-quaternary is a physical layer encoding used for Integrated Services Digital Network Basic Rate Interface implementations...
or DMT, to transmit information. While transmitting over copper wire does not allow for the speeds that fiber-optic transmission does, it allows the use of existing voice-grade copper or CCTV coaxial cable wiring. Copper-based Ethernet extenders must be used on unconditioned wire (without load coils), such as unused twisted pairs and alarm circuit
Alarm circuit
A dry loop is an unconditioned leased pair of telephone wire from a Telco. The pair does not have a dial-tone or "battery" , as opposed to a "wet pair" .A dry pair was originally used with a security system, but more recently may also be used with DSL equipment or an...
s.
Connecting a private LAN
Län
Län and lääni refer to the administrative divisions used in Sweden and previously in Finland. The provinces of Finland were abolished on January 1, 2010....
between buildings or more distant locations is a challenge. Wi-Fi
Wi-Fi
Wi-Fi or Wifi, is a mechanism for wirelessly connecting electronic devices. A device enabled with Wi-Fi, such as a personal computer, video game console, smartphone, or digital audio player, can connect to the Internet via a wireless network access point. An access point has a range of about 20...
requires a clear line-of-sight, special antennas, and is subject to weather. If the buildings are within 100m, a normal Ethernet cable segment can be used, with due consideration of potential grounding problems between the locations. Up to 200m, it may be possible to set up an ordinary Ethernet bridge or router in the middle, if power and weather protection can be arranged.
Fiber optic connection is ideal, allowing connections of over a km and high speeds with no electrical shock or surge issues, but is technically specialized and expensive for both the end equipment interfaces and the cable. Damage to the cable requires special skills to repair or total replacement.
Specialized equipment can inter-connect two LANs over a single twisted pair of wires, such as Cisco LRE (Long Reach Ethernet
Long Reach Ethernet
Long Reach Ethernet was a proprietary networking protocol marketed by Cisco Systems, intended to support multi-megabit performance over telephone-grade unshielded twisted pair wiring over distances up to 5,000 feet ....
), Patton CopperLink or EtherWAN Ethernet Extenders using VDSL technology. Distances of 300 m (1000 feet) at 50 Mbit/s up to 8 km (5 mi) at 128 kbit/s is possible. Coaxial cable
Coaxial cable
Coaxial cable, or coax, has an inner conductor surrounded by a flexible, tubular insulating layer, surrounded by a tubular conducting shield. The term coaxial comes from the inner conductor and the outer shield sharing the same geometric axis...
are often permitting higher speeds and larger distances than twisted pair wires. The equipment is mostly simple to operate, and the connection wire is common, cheap and maintainable.
Ordinary ADSL modems cannot be connected back-to-back, because the ATU-R (ADSL Termination Unit - Remote) units that are used by customers require specialized ATU-C (Central Office) support provided by phone company equipment, usually by a complex and expensive DSLAM (DSL access multiplexer). However some symmetric digital subscriber line
Symmetric Digital Subscriber Line
Symmetric digital subscriber line can have two meanings:* In the wider sense it is a collection of Internet access technologies based on DSL that offer symmetric bandwidth upstream and downstream...
(SDSL) modems such as the SpeedStream 5851 can be connected back-to-back, allowing upload and download speeds of about 2Mbps over substantial distances, using a simple twisted pair of wires.
Back-to-back operation may also be possible with single-pair high-speed digital subscriber line (G.SHDSL) modems.
Similar technologies were standardized as Ethernet in the first mile
Ethernet in the first mile
Ethernet in the first mile refers to using one of the Ethernet family of computer network protocols between a telecommunications company and a customer's premise. From the customer's point of view it is their "first" mile, although from the access networks' point of view it is known as the "last...
:
- 2BASE-TL2BASE-TL2BASE-TL is an IEEE 802.3-2008 Physical Layer specification for a full-duplex long reach point-to-point Ethernet link over voice-grade copper wiring...
— Full-duplex long reach Point-to-Point link over voice-grade copper wiring. 2BASE-TL PHY can deliver a minimum of 2 Mbit/s and a maximum of 5.69 Mbit/s over distances of up to 2700 m (9,000 ft), using ITU-TITU-TThe ITU Telecommunication Standardization Sector is one of the three sectors of the International Telecommunication Union ; it coordinates standards for telecommunications....
G.991.2 (G.SHDSL.bis) technology over a single copper pair. - 10PASS-TS10PASS-TS10PASS-TS is an IEEE 802.3-2008 Physical Layer specification for a full-duplex short reach point-to-point Ethernet link over voice-grade copper wiring, used in Ethernet in the first mile applications....
— Full-duplex short reach Point-to-Point link over voice-grade copper wiring. 10PASS-TS PHY can deliver a minimum of 10 Mbit/s over distances of up to 750 m (2460 ft), using ITU-T G.993.1 (VDSL) technology over a single copper pair.