Network Router
Computer NetworkingComputer networking is the scientific and engineering discipline concerned with communication between computer systems. Such networks involve at least two devices capable of being networked with at least one usually being a computer. The devices can be separated by a few meters (e.g. via Bluetooth) or thousands of kilometers (e.g. via the Internet). Computer networking is sometimes considered a sub-discipline of telecommunications. Excerpt of "Computer networking." Wikipedia, The Free Encyclopedia. 25 Oct 2006, 23:26 UTC. Wikimedia Foundation, Inc. 26 Oct 2006 http://en.wikipedia.org/w/index.php?title=Computer_networking&oldid=83737145
Types of routers
In the original era of routing (from the mid-1970s through the 1980s),
general-purpose mini-computers served as routers. Although
general-purpose computers can perform routing, modern high-speed
routers are highly specialised computers, generally with extra hardware
added to accelerate both common routing functions such as packet
forwarding and specialised functions such as IPsec encryption.
Other changes also improve reliability, such as using DC power rather
than line power (which can be provided from batteries in data centers),
and using solid-state rather than magnetic storage for program loading.
Large modern routers have thus come to resemble telephone switches,
with whose technology they are currently converging and may eventually
replace, whilst small routers have become a common household item.
A router that connects clients to the Internet is called an edge
router. A router that serves solely to transmit data between other
routers, e.g. inside the network of an Internet service provider, is
called a core router.
A router is normally used to connect at least two networks, but a
special variety of router is the one-armed router, used to route
packets in a virtual LAN environment. In the case of a one-armed router
the multiple attachments to different networks are all over the same
physical link.
In mobile ad-hoc networks every host performs routing and forwarding by
itself, while in wired networks there is usually just one router for a
whole broadcast domain.
In recent times many routing functions have been added to LAN switches
(a marketing term for high-speed bridges), creating "Layer 2/3
Switches" which route traffic at near wire speed.
Routers are also now being implemented as Internet gateways, primarily
for small networks like those used in homes and small offices. This
application is mainly where the Internet connection is an always-on
broadband connection like cable modem or DSL. These are routers in the
true sense because they join two networks together - the WAN and the
LAN – and have a routing table. Often these small routers support the
RIP protocol, although in a home application the routing function does
not serve much purpose since there are only two ways to go - the WAN
and the LAN. In addition, these routers typically provide DHCP, NAT,
DMZ and Firewall services. Sometimes these routers can provide content
filtering and VPN. Typically they are used in conjunction with either a
cable modem or DSL modem, but that function can also be built-in.
Manufacturers of routers
There are a number manufacturers of routers including:
- 3Com
- Alcatel
- Belkin
- Buffalo Technology
- Cisco Systems, Inc.
- Cyclades Corporation
- D-Link Systems
- Enterasys Networks
- Hawking Technologies
- Hewlett-Packard
- Huawei Technologies
- Juniper Networks
- Linksys
- Mikrotik
- Motorola
- NETGEAR
- Nortel
- Pivotal Networking
- Redback Networks
- Siemens AG
- SMC Networks
- Tellabs
- MRV Communications
- U.S. Robotics
- Zoom Telephonics (www.zoom.com)
- Trendware (www.trendware.com)
- ZyXEL (www.us.zyxel.com)
Excerpt of 'Router.' Wikipedia, The Free Encyclopedia.
26 Feb 2006, 02:56 UTC. 3 Mar 2006, 23:23
http://en.wikipedia.org/w/index.php?title=Router&oldid=41258236
Image from 'Cisco 7600 Series Routers: Large Photo.'
Cisco Systems, Inc. 03 Mar 2006, 11:24 UTC
http://www.cisco.com/en/US/products/hw/routers/ps368/prod_view_selector.html
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