VPN Router
VPN (Virtual Private Network)
A virtual private network (VPN) is a private communications
network often used within a company, or by several companies or organizations,
to communicate confidentially over a publicly accessible network. VPN message
traffic can be carried over a public networking infrastructure (e.g. the
Internet) on top of standard protocols, or over a service provider's private
network with a defined Service Level Agreement (SLA) between the VPN customer
and the VPN service provider.
...
Types of VPN
Secure VPNs use cryptographic tunneling protocols to provide the intended
confidentiality (blocking snooping and thus Packet sniffing), sender authentication
(blocking identity spoofing), and message integrity (blocking message alteration)
to achieve privacy. When properly chosen, implemented, and used, such techniques
can provide secure communications over unsecured networks. This has been the
usually intended purpose for VPN for some years.
Because such choice,
implementation, and use are not trivial, there are many insecure VPN schemes
available on the market.
Secure VPN technologies may also be used to enhance security as a "security
overlay" within dedicated networking infrastructures.
Secure VPN protocols
include the following:
- IPsec (IP security) - commonly used over IPv4, and an obligatory part of
IPv6.
- SSL used either for tunneling the entire network stack, as in the OpenVPN
project, or for securing what is, essentially, a web proxy. SSL is framework
more often associated with e-commerce, but it has been built-upon by vendors
like Aventail and Juniper to provide remote access VPN capabilities.
- PPTP (point-to-point tunneling protocol), developed jointly by a number
of companies, including Microsoft.
- L2TP (Layer 2 Tunnelling Protocol), which includes work by both Microsoft
and Cisco.
- L2TPv3 (Layer 2 Tunnelling Protocol version 3), a new release.
- VPN-Q The machine at the other end of a VPN could be a threat and a source
of attack; this has no necessary connection with VPN designs and has been
usually left to system adminstration efforts. There has been at least one
attempt to address this issue in the context of VPNs. On Microsoft ISA Server,
an applications called QSS (Quarantine Security Suite) is available.
Some large ISPs now offer "managed" VPN service for business
customers who want the security and convenience of a VPN but prefer not to
undertake administering a VPN server themselves. In addition to providing
remote workers with secure access to their employer's internal network, other
security and management services are sometimes included as part of the package.
Examples include keeping anti-virus and anti-spyware programs updated on each
client's computer.
Trusted VPNs do not use cryptographic tunneling, and
instead rely on the security of a single provider's network to protect the
traffic. In a sense, these are an elaboration of traditional network and system
administration work.
- Multi-protocol label switching (MPLS) is often used to build trusted VPN.
- L2F (Layer 2 Forwarding), developed by Cisco, can also be used.
Excerpt of "Virtual private network." Wikipedia, The Free Encyclopedia.
26 Oct 2006, 12:49 UTC. Wikimedia Foundation, Inc. 26 Oct 2006
http://en.wikipedia.org/w/index.php?title=Virtual_private_network&oldid=83833157 Router
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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