10BASE5 (also known as thick
Ethernet or thicknet) was the first
commercially available variant of Ethernet.
10BASE5 uses a thick and
stiff coaxial cable up to 500 metres (1,600 ft) in length. Up to
100 stations can be connected to the cable using vampire taps and
share a single collision domain with 10 Mbit/s of bandwidth
shared among them. The system is difficult to install and maintain.
10BASE5 was superseded by much cheaper and more convenient
alternatives: first by
10BASE2 based on a thinner coaxial cable, and
Ethernet over twisted pair was developed, by
100BASE-TX and 1000BASE-T. As of 2003,
IEEE 802.3 has
deprecated this standard for new installations.
1 Name origination
2 Network design and installation
4 See also
10BASE5 is derived from several characteristics of the
physical medium. The 10 refers to its transmission speed of
10 Mbit/s. The BASE is short for baseband signalling (as opposed
to broadband), and the 5 stands for the maximum segment length of 500
metres (1,600 ft).
Network design and installation
For its physical layer
10BASE5 uses cable similar to RG-8/U coaxial
cable but with extra braided shielding. This is a stiff, 0.375-inch
(9.5 mm) diameter cable with an impedance of 50 ohms, a
solid center conductor, a foam insulating filler, a shielding braid,
and an outer jacket. The outer jacket is often yellow-to-orange
fluorinated ethylene propylene (for fire resistance) so it often is
called "yellow cable", "orange hose", or sometimes humorously "frozen
yellow garden hose".
10BASE5 coaxial cables had a maximum length of
500 metres (1,600 ft). Up to 100 nodes could be connected to a
Transceiver nodes can be connected to cable segments with N
connectors, or via a vampire tap, which allows new nodes to be added
while existing connections are live. A vampire tap clamps onto the
cable, a hole is drilled through the outer shielding, and a spike is
forced to pierce and contact the inner conductor while other spikes
bite into the outer braided shield. Care is required to keep the outer
shield from touching the spike; installation kits include a "coring
tool" to drill through the outer layers and a "braid pick" to clear
stray pieces of the outer shield.
Transceivers should be installed only at precise 2.5-metre intervals.
This distance was chosen to not correspond to the wavelength of the
signal; this ensures that the reflections from multiple taps are not
in phase. These suitable points are marked on the cable with black
bands. The cable is required to be one continuous run; T-connections
are not allowed.
As is the case with most other high-speed buses, segments must be
terminated at each end. For coaxial-cable-based Ethernet, each end of
the cable has a 50 ohm resistor attached. Typically this resistor
is built into a male
N connector and attached to the end of the cable
just past the last device. With termination missing, or if there is a
break in the cable, the signal on the bus will be reflected, rather
than dissipated when it reached the end. This reflected signal is
indistinguishable from a collision, and prevents communication.
Adding new stations to network is complicated by the need to
accurately pierce the cable. The cable is stiff and difficult to bend
around corners. One improper connection could take down the whole
network and finding the source of the trouble is difficult.
Wikimedia Commons has media related to 10BASE5.
Attachment Unit Interface
IEEE 802.3-2005 8. Medium attachment unit and baseband medium
specifications, type 10BASE5
^ Stallings, William (1993). Local and Metropolitan Area Networks.
Macmillan Publishing Company. p. 107.
^ All-in-One Networking+ Certification Exam Guide, Mike Meyers, 3rd
Ed., McGraw-Hill, 2004, p. 79.
^ "5-4-3 rule". Retrieved 2010-06-30.
^ sponsor Technical Committee on Computer Communications of the IEEE
Computer Society. (1985).
IEEE Standard 802.3-1985. IEEE. p. 121.
^ Urd Von Burg; Martin Kenny (December 2003). "Sponsors, Communities,
Ethernet vs. Token Ring in the Local Area Networking
Business" (PDF). Archived (PDF) from the original on 2012-03-22.
This article is based on material taken from the Free On-line
Dictionary of Computing prior to 1 November 2008 and incorporated
under the "relicensing" terms of the GFDL, version 1.3 or later.
Ethernet family of local area network technologies
2.5 and 5 Gbit/s
25 and 50 Gbit/s
40 and 100 Gbit/s
200 and 400 Gbit/s
Power over Ethernet