What is router? How does it work?

Question

What is router? How does it work?

Answer 1

* Router is a networking device use mainly to interconnect more than one network at a time. So practically speaking, router will connect two different networks which is your home LAN and the Internet :)

* Router usually use primarily in office to interconnect their branches as well as to the Internet

* For home usage, router is use to connecting your LAN to the Internet

* Router can be both hardware (box) or software. It's not only hardware since this function (routing packet from one network to another network) can also be perform by software

* The latest home grade router available in market can also be use for simple firewalling (packet filtering, detecting Denial of Service), NAT (address translation), etc.

*If you need more sophisticated function of router, you should consider to purchase Mid to Enterprise grade routers



How does it work?

Simply by forwarding (routing) an IP packet from one network to another network by looking for the destination network address. It work like the Post Office Station which will redirect all incoming letters to the proper destination Postal Code :)



if you need more technical detail about how router work, you can go to http://en.wikipedia.org/wiki/router and start from there :)

Answer 2

A router in most cases is the device that people use to share internet from a high speed internet connection to more than one computer

This is perfectly legal . Your internet provider is more concerned about the flow of internet bandwidth through your account than how many computers are attached to that connection.

Think of it as a pipe with water flowing through the pipe.

It is the total amount of water you use that matters.

Basic internet browsing does not use much internet bandwidth .

Downloading and sharing movies does.

If you exceed the standard bandwidth allotment from your isp greatly you will get note from the "bandwidth department" or even be shut down.

by the way aggressive computer viruses remailing the world or tons of agressive spyware can do that to.

Technically the router is used to connect networks - in this case - the internet ( huge network of computers) to your home network attached to the router.

The part of the router that determines how things are moved between computers inside your network is called a "switch"

from computer a to computer b without going to the internet

The router and switch route traffic efficiently both inside your home network ( faster than going on the internet and back) and from the internet to the right computer on your home network.

On to the nirtty gritty.

Routers come in two basic forms

- wired ( 1 port in and 4 lan ports out) that you attach ethernet cables to

- wireless , which in most cases have wireless signals plus usually those 4 ports than an ethernet cable can be attached to.

- you need a wireless computer network adapter to receive the wireless signal

- the signal is the same frequency as standard home cordless phones

- the signal goes 1000 feet outdoors and 300 feet indoors.

although it is "high tech" " beam me up scotty" do not let anyone ever tell you that wireless is as fast as a standard cable. Wireless ( even the older b format ) is almost always faster than high speed internet connections but it can never be as fast and trouble free as standard cable ( which has to strung and run in houses and costs generally 50 cents to 1 $ a foot or so)

- the remote wireless computer needs a wireless network adapter. They come built in to newer laptops, network credit card style cards , pci ( toinstall in full size computers) and usb models.

The major brands of routers are Linksys and D Link. Linksys is the premium brand. DLink is a retail brand that somehow has a major following - cheap i guess and reasonable support.

All router brands are perfectly fine and ok. Big box stores frequently have routers on sale as it is a good draw to get customers in the store who have more than one computer and as the kids rule the newer computer ( leaving mom and dad with the now slower computer). A good chance once in they can be hit for another new computer.

If you are setting up a home wireless network it can be best to get the same brand router and adapter - i.e linksys / linksys or smc/smc. Better speed , easier setup and tech support cannot tell you to get lost and go to the other vendor.

All router brands are fine. The key thing with wireless internet is to make sure the router is high and not cluttered and most importantly Change the channel from the default channel 6. Channels 1 and 11 are next best bets. Your neighbour's wireless router signals will drift in long distances .

You will not be able to detect it in windows. You will have good signal strength but no internet. Change the channel.



a very useful program to set up and maintain home networks is network magic



www.networkmagic.com

Answer 3

A router is a device (usually a small box with lights and buttons and maybe an antenna if its wireless and connections for ethernet cables) that literally ROUTES the direction of internet traffic and local network traffic from computer to computer or from the internet to your computer. Everything will go through your router before it comes to you. A router also acts as a firewall by dropping any traffic that a computer didnt request. So if anyone was trying to connect to your computer to maliciously hack you, the router will prevent them from connecting to your computer by dropping the traffic from it.

Answer 4

Multipart answer required. Routers are devices mainly used to connect more than one computer to establish a network connection to a DSL line. It can also be used as the gateway device for multi-computers set up as a LAN without being connected to a DSL line. This allows all the connected computers to communicate with each other and exchange files. They come as wired or wireless devices for networking. When on a DSL connection, they are seen as one device and use what is called Network Address Translation. This issues a different internal address set to the computers and translates them to the one for the DSL. That is the best I can offer without using technical jargon.

Answer 5

its for you to surf the internet more faster..

Answer 6

A more precise definition of a router is a computer networking device that interconnects separate logical subnets. Routers connect to two or more logical subnets, which do not necessarily map one-to-one to the physical interfaces of the router. The term switch or layer 3 switch or network switch often is synonymous with router, but switch is really a marketing term without a rigorous technical definition.



Routers operate in two different planes



Control Plane, in which the router learns the outgoing interface that is most appropriate for forwarding specific packets to specific destinations,

Forwarding Plane, which is responsible for the actual process of sending a packet received on a logical interface to an outbound logical interface.

In simple terms, a routers acts like a waiter which takes the order from different tables, pass it over to the kitchen. Once processed, serves the result back to the table.



For the pure Internet Protocol (IP) forwarding function, router design tries to minimize the state information kept on individual packets. Routers do maintain state on routes, but not packets. Once a packet is forwarded, the router should retain no more than statistical information about it. It is the sending and receiving endpoint that keeps information on such things as errored or missing packets.



Forwarding decisions can involve decisions at layers other than the IP internetwork layer or OSI layer 3. Again, the marketing term switch can be applied to devices that have these capabilities. A function that forwards based on data link layer, or OSI layer 2, information, is properly called a bridge, or layer 2 switch. A physical device called a router may also have the capability to forward based on information at other layers.





Routers are like intersections whereas switches are like streets

Control Plane

Control Plane processing leads to the construction of what is variously called a routing table or routing information base (RIB). The RIB may be used by the Forwarding Plane to look up the outbound interface for a given packet, or, depending on the router implementation, the Control Plane may populate a separate Forwarding Information Base (FIB) with destination information. RIBs are optimized for efficient updating with control mechanisms such as routing protocols, while FIBs are optimized for the fastest possible lookup of the information needed to select the outbound interface.



The Control Plane constructs the routing table from knowledge of the up/down status of its local interfaces, from hard-coded static routes, and from exchanging routing protocol information with other routers. It is not compulsory for a router to use routing protocols to function, if for example it was configured solely with static routes. The routing table stores the best routes to certain network destinations, the "routing metrics" associated with those routes, and the path to the next hop router.



Routers do maintain state on the routes in the RIB/routing table, but this is quite distinct from not maintaining state on individual packets that have been forwarded.





Forwarding Plane

For the pure Internet Protocol (IP) forwarding function, router design tries to minimize the state information kept on individual packets. Once a packet is forwarded, the router should retain no more than statistical information about it. It is the sending and receiving endpoint that keeps information on such things as errored or missing packets.



Forwarding decisions can involve decisions at layers other than the IP internetwork layer or OSI layer 3. Again, the marketing term switch can be applied to devices that have these capabilities. A function that forwards based on data link layer, or OSI layer 2, information, is properly called a bridge, or layer 2 switch. A physical device called a router may also have the capability to forward based on information at other layers, if it has software that can make decisions at these other layers.





Types of routers



Cisco CRS-1 Backbone Core Router

Linksys befsr41 DSL RouterRouters may provide connectivity inside enterprises, between enterprises and the Internet, and inside Internet Service Providers (ISP). The largest routers (example: Cisco CRS-1, Juniper T1600) interconnect ISPs, are used inside ISPs , or may be used in very large enterprise networks (example: Cisco 7600 Series). The smallest routers provide connectivity for small and home offices (example: Linksys befsr41).





Routers for Internet connectivity and internal use

Routers intended for ISP and major enterprise connectivity will almost invariably exchange routing information with the Border Gateway Protocol. RFC 4098 [4] defines several types of BGP-speaking routers:



Provider Edge Router: Placed at the edge of an ISP network, it speaks external BGP (eBGP) to a BGP speaker in another provider or large enterprise Autonomous System (AS).

Subscriber Edge Router: Located at the edge of the subscriber's network, it speaks eBGP to its provider's AS(s). It belongs to an end user (enterprise) organization.

Inter-provider Border Router: Interconnecting ISPs, this is a BGP speaking router that maintains BGP sessions with other BGP speaking routers in other providers' ASes.

Core router: A router that resides within the middle or backbone of the network rather than at its periphery.

Within an ISP: Internal to the provider's AS, such a router speaks internal BGP (iBGP) to that provider's edge routers, other intra-provider core routers, or the provider's inter-provider border routers.

"Internet backbone:" The Internet does not have a clearly identifiable backbone, as did its predecessors. See default-free zone (DFZ). Nevertheless, it is the major ISPs' routers that make up what many would consider the core. These ISPs operate all four types of the BGP-speaking routers described here. In ISP usage, a "core" router is internal to an ISP, and used to interconnect its edge and border routers. Core routers may also have specialized functions in virtual private networks based on a combination of BGP and Multi-Protocol Label Switching (MPLS)[5].



Small and Home Office (SOHO) connectivity

Routers that are used in a homes usually connect to a broadband service such as IP over cable or DSL. A home router may allow connectivity to an enterprise via a secure Virtual Private Network.





Enterprise Routers

All sizes of routers may be found inside enterprises. While the most powerful routers tend to be found in ISPs, academic and research facilities, as well as large businesses, may need large routers.



A three-layer model is in common use, not all of which need be present in smaller networks [6].





Access

Access routers, including SOHO, are located at customer sites such as branch offices that do not need hierarchical routing of their own. Typically, they are optimized for low cost.





Distribution

Distribution routers aggregate traffic from multiple access routers, either at the same site, or to collect the data streams from multiple sites to a major enterprise location. Distribution routers often are responsible for enforcing quality of service across a WAN, so they may have considerable memory, multiple WAN interfaces, and substantial processing intelligence.



They may also provide connectivity to groups of servers. Either with a separate firewall or with an integrated firewall function, they may provide Internet or virtual private network VPN connectivity for an enterprise.



When an enterprise is primarily on one campus, there may not be a distinct distribution tier, other than perhaps off-campus access. In such cases, the access routers, connected to LANs, interconnect via core routers.





Core

In enterprises, core routers may provide a "collapsed backbone" interconnecting the distribution tier routers from multiple buildings of a campus, or large enterprise locations. They tend to be optimized for high bandwidth.



When an enterprise is widely distributed with no central location(s), the function of core routing may be subsumed by the WAN service to which the enterprise subscribes, and the distribution routers become the highest tier