A router (including a wireless router) is a specializednetworking device connected to two or more networksrunning softwarethat allows the router to move data from one network to another. Router functions in an Internet protocol based network operate at the networklayer (OSIModel'slayer3). The primary function of a router is to connect networks together andkeep certain kinds of broadcast traffic under control. There areseveral companies that make routers: Cisco,Linksys, Juniper, Netgear, Nortel (Bay Networks), Redback, Lucent, 3Com, HP, Dlink and Belkin just to name a few.
Several networking exams (CCNA, CCNP, JNCIA, JNCIE) will test your ability to identify different typesof network equipment. This network certification tutorial on routers focuses on identifying network routers, and explaining the functions of routers provide. This tutorial is not specific to any vendor's technology.
- Update the device driver. In the search box on the taskbar, enter device manager, then select Device Manager. Select a category to see names of devices, then right-click (or press and hold) the one you’d like to update. Select Search automatically for updated driver software. Select Update Driver.
- Downloadable user guides for Linksys network adapters Setup & Installation Encountering problems when installing or updating the wireless adapter drivers on a Windows® XP computer.
How Do Routers Work?
Cisco linksys ae2500 driver wireless download upgrade to dual-band n to avoid disturbance and also enjoy the remarkable performance. Cisco linksys wrt120n is the wireless-n home router that has a wireless connection that's twice the speed of wireless-g. This interface is built according to cisco optical specifications.
Let's use a home wireless router connected to a cable provider's internet network in a very simplified example.
- The router powers on and loads it's OS from flash
- The router loads the configuration file last saved to NVRAM and sets up the network interfaces and routing protocols it will run.
- The router adds the network address and subnet for each interface to it's routing table along with the name of the interface itself.
- The router has a simple static default route to send all non-local data out the network port connected to the cable company.
- When the router receives a web page request from your computer, it checks the destination IP address against its routing table.
- The bits forming the destination IP address in the IP packet are used as a hash key to point to the correct route, which in turn points to the correct network interface that the packet should be forwarded out of.
- The router transmits the packet out the correct interface, to the next router, which repeats the process until the packet reaches the destination.
The process is mostly the same for any router.
CAVEAT: A small complication here. For home cable and wifi routers, the router is also acting as a 'proxy' so the router does one thing that is NOT normal for a router out on the Internet somwehere: it changes the source IP address in the IP packet to it's own address.
Why do I need a Router?
Routers are used to connect networks together and routers perform the following network functions, whish you should be able to identify and describe on the Network+, CCNA or JNCP exam:
FUNCTIONS OF A ROUTER (identify and describe)
- Restrict broadcasts to the LAN
- Act as the default gateway.
- Perform Protocol Translation (Wired Ethernet to Wireless/WiFi, or Ethernet to CATV)
- Learn and advertise loop free paths
- Calculate 'best paths' to reach network destinations.
Restrict Broadcasts to the LAN
Networks(especially Ethernetnetworks) use broadcastcommunication at the physical,datalinkand networklayer. Networklayerbroadcastsare transmissions sent to all hosts using the networklayer protocol (usually Internet Protocol[IP] or IPX). Networkbroadcastcommunication is used to communicate certain kinds of information thatmakes the networkfunction (ARP, RARP, DHCP, IPX-SAPbroadcasts etc.). Since several devices could attempt to transmitsimultaneously and cause collisions, it is preferable to separate largesets of hosts into different broadcast domains using a switch, orrouter.
As the number of hosts on the network increases,the amount of broadcasttraffic increases. If enough broadcast traffic is present on the network, thenordinary communication across the network becomesdifficult.
To reduce broadcasts, a network administrator can break up a network with a largenumber of hosts into two smaller networks. Broadcastsare then restricted to each network, and the router performs as the'default gateway' to reach the hosts on the other networks.
Act as the Default Gateway
Especially in today's networks, people want to use their computer to connect to the Internet. When your computer wants to talk to a computer on another network, it does soby sending your data to the defaultgateway. The default gateway is the local router connected to the same network your computer is connected to. The router serving as the default gateway receives your data, looksfor the remote address of that far-off computer and makes a routingdecision. Based on that routing decision, it forwards your data out a different interface that iscloser to that remote computer.There could be several routers between you and the remote computer, so several routerswill take part in handing off the packet,much like a fireman's bucket brigade.
Move (route) Data between Networks
Routers have the capability to move data from one network to another.This allows two networks managed by different organizations to exchangedata. They create a networkbetween them and exchange data between the routers on that network.Because a router can accept traffic from any kind of network it isattached to, and forward it to any other network, it can also allownetworks that could not normally communicate with each other toexchange data. In technical terms, a token ring network and anethernet networkcan communicate over a serial network. Routers make all this possible.
A router can take in an Ethernet frame,strip the ethernet data off, and then drop the IP data into aframe of another type such as SDH/SONET, PDH/T1, ATM, FDDI. In this waya router can also perform 'protocol conversion', provided it has theappropriate hardware and software to support such a function. The wholepoint, however, is to forward the data from the interface it receivesdata on, to another interface that retransmits the received data ontoanother interface serving another network.
Learn and Advertise Loop-Free Paths
Routers can only learn and advertise routes dynamically if they areusing a routing protocol such as RIP, OSPF, EIGRP, IS-IS orBGP. Otherwise, a human has to configure the routes byhand, which is called static routing.
Routing moves data on a hop-by-hop basis, what is often called 'hot potato' routing. If a set of routers ends up passing the data around in a circle, without reaching the destination, it's calleda a 'routing loop'. Packets get handed off around the loop until they die of old age: their 'Time To Live' expires. Time To Live is a counter that is part of the IP datagram header. The Time To Live value is decremented as it passes through each router and eventually it reaches zero and is discarded.
Drivers The Cisco-linksys Network & Wireless Cards Card
Router Components & Parts
Since routers are just specialized computers, the have the same 'parts' as other computers:
- Central Processing Unit (CPU)
- Flash Memory
- Non-Volitile RAM
- RAM
- Network Interfaces
- Console
Central Processing Unit: Runs special software called an 'operating system' such as JunOS on Juniper routers, or Cisco IOS (Nexus OS) for Cisco routers. The operating system manages the router's components and provies all the logical networking functions of the router.
Flash Memory is where the operating system is stored, and in this respect, is like the hard disk drive in your computer. If you use a Solid State Disk Drive (SSD), then your computer uses Flash RAM, just like the router does.
Non-Volitile RAM: This is additional memory for storing the backup or startup version of the operating system being used. The router will boot from this memory and load all it's programs from here.
RAM: When the router starts up, the operating system is loaded into RAM. Once the router finishes starting up, it begins to calculate its own routes and, if configured to do so, learns network routes from other routers via RIP (v1 and v2), OSPF, EIGRP, IS-IS or BGP. RAM is also used for caching ARP tables, routing tables, routing metrics and other data that can speed up the process of forwarding of packets.
Network Interfaces: Routers always have lots of network interfaces. The operating system contains 'drivers' that allow the operating sytem to access the network hardware in the interface modules. Routers will learn which networks are configured on which ports as they start up. After that, they will 'learn' routes from other routers they are connected to, and learn which interface to transmit packets on to reach a remote network destination.
Console: Last, but not least, is the console. In 'Ye Olden Days' managing and configuring a router was performed at the console of individual devices, as was most troubleshooting and diagnostics. Network certification exams will contain a large selection of questions on the configuration and troubleshooting commands you can issue from the console. However, manufacturers are rapidly doing away with a console on each device and building management systems for managing large numbers of network devices from a centralized location.
More IP Routing Tutorials
Routing | RoutingProtocols | Routing vs. RoutedProtocols | Default Route | Default Gateway | Routing Protocol Convergence | Interior vs. Exterior GatewayProtocols (IGP/EGP)| Dynamic vs.Static Routing | Distance Vector vs. LinkState Routing Protocols
You can find the guide on how to flash your router's firmware here.
What's New:
- Added controls to enable or disable WPS.
- WPS functionality will be locked down for a specified time after multiple repeated WPS connection failures.
- Added Danish language support.
- Fixed a bug that prevented the webUI from being accessed using HTTPS.
Superior wireless speed
The Linksys E2500 connects all your computers, tablets, Internet-ready TVs, game consoles and other devices at wireless transfer rates of up to 300 + 300 Mbps for an optimal home network experience.
Drivers The Cisco-linksys Network Storage System
Optimal wireless coverage
The enhanced MIMO antenna array offers increased signal strength to provide optimal coverage and reliability so you can enjoy wireless connectivity from anywhere in your home.
The power of Dual-Band
Double your network bandwidth with Dual-Band N (2.4 and 5 GHz) designed to avoid interference and maximize throughput ideal for HD media streaming, file transfers, and wireless gaming.
Advanced security
Advanced security features such as WPA2 wireless encryption and the integrated firewall help you keep your network protected.
Optimized for entertainment
Double your network bandwidth with Dual-Band N (2.4 and 5 GHz) designed to avoid interference and maximize throughput ideal for HD media streaming, file transfers, and wireless gaming.
IPv6 ready
Supports the latest Internet Protocol technology to help you future-proof your network.
Quick to install
Cisco Connect helps you set up your wireless network in a few easy steps on a Windows or Mac computer.
Easy to manage
Cisco Connect works with Mac and Windows computers and helps you customize settings or quickly add new devices to your network. Cisco Connect enables you to:
- Create a separate, password protected network for guests
- Limit access time and access to certain websites with parental controls
- Access advanced network settings easily
- Measure your connection speed with the Broadband Speed Meter
- Perform regular automated update checks for firmware and software with the option to install
Other Features:
- Simultaneous Dual-Band N (2.4 & 5 GHz)
- Fast Ethernet 4-port switch
- Fast speed up to 300 + 300 Mbps
- Additional antenna for extended coverage
- April 25, 2015
- Windows XP/Vista/7
- 6.7 MB
- November 27, 2015
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- April 16, 2009
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