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In this article I describe the Wide Area Network WAN concepts for CCNA 200-301 exam. WAN is combination of multiple LAN’s. Multiple devices used to create the inter-network between different LAN‘s. So i think it is better to discuss about Local Area Network before going to Wide Area Network WAN.
The basics of Wide Area Network WAN are very similar to internetworking basics. There are end point devices, networking devices, some common protocols used by devices. In this article I describe some common terms related to a Wide Area Network WAN.
Wide Area Network WAN connects the different networks each other via routers. A Wide Area Network WAN created to share the resources and information between different networks. Wide Area Network WAN created to share the resources and information of different network. Wide Area Network WAN creates by connectivity of different networks globally.
Devices in a Wide Area Network WAN
Layer 3 devices used to connect the different networks. A lots of protocols followed to flow the data between different LAN. The below diagram shows three LAN connected with a Router which creates a Wide Area Network WAN. All the three LANs are different. Internet can be access in all LANs. WAP can also use in all LAN to connect nodes on Wi-Fi.
Basic concept of Wide Area Network (WAN)
The Best example of Wide Area Network (WAN) is internet. In a company the branches may be connected via Wide Area Network (WAN). In Banking all branches connected with each other via Wide Area Network (WAN). Many networking devices are used to connect the LAN to a WAN. In today life WAN is the most important thing which resolves our problems. Railway, Airways, Banks, Schools all provides their services to the customer via Wide Area Network (WAN). It is very easy to purchase anything from home online. It became possible because of world wide web WAN. In the below diagram you can see how a ISP connects two different LAN.
Wide Area Network WAN explained in detail
Networking is the base of Wide Area Network WAN. Before going to deep for Wide Area Network WAN, the concept of networking should be well known. In networking different devices are connected with some switches only. The data flows within the network nodes in a LAN. The concept of Wide Area Network WAN comes when we need to transfer the data from outside of LAN. For example, internet when we need to access internet from our local network the traffic come from outside the LAN. This function is possible because of connectivity or different networks via routers. Wide Area Network WAN means access to https://ccnatutorials.in/internetworking/local-area-network/different networks from different networks.
Multiple protocols work between different networks to provide connectivity. Some of important protocols are Transfer Control Protocol TCP and Internet Protocol IP. Some routing protocols like RIP, OSPF etc works in router for IP routing in router. IP routing provides the data flow between different networks in WAN. Three terms are related to Wide Area Network WAN are Internet, Intranet and Extranet. So lets discuss about these three terms in detail below.
Internet – We all works on internet. Internet is the best example to understand the internetworking basics in CCNA. Billions of networks are connected on internet and we all access the multiple websites and services from our LAN. Many big company like google, Microsoft maintains their LAN and provide a gateway to enter and exit the data packets from there. There are many services provided by the data centre of these companies like email, drive etc to keep and share the data. There are multiple routers works on different protocols to connect the internet world wide.
Intranet – Intranet is very similar to the internet. The only difference is that the access of intranet network is allowed to some limited persons only. The physical layout of intranet is same as internet locations. By using some special protocols and private IP addresses the access of intranet computers is not allowed to any public computer like internet. The example of intranet is any private organization which have main office at a fix place and the branches are located at various different locations. The client of the organisation can access the data centre services. A common computer of internet cannot access the services of private organization from internet. Example of intranet is the army network of any country.
Extranet– extranet is the advance version of intranet. In intranet only single organization can access the private network. Extranet provide multiple intranet to communicate with each other over the internet. I mean the user of one organization can access the data of other organization. The data of extranet is not allowed access to public on the internet. Multiple intranet creates an extranet on the internet.
Address system of Wide Area Network WAN
Different types of address systems available for Wide Area Network WAN. Addressing system provide the identity to the networks and computers in WAN. When data transfers from one network to another network three different address works. The three address systems are Data Link Layer address, MAC address and network layer address. I give some basic Idea about these three address types.
Data Link Layer address for Wide Area Network WAN
Data link address identifies all the networks connected with the router. Suppose there are three networks connected with a router on different interface. The network address of each network connected with the router is known as Data link address. Router knows what network addresses are connected with it and forward the packets according to data link address associated with each interface. End point devices connected with single network address, so all End point devices maintain a single data link address associates with them. Routers usually have multiple physical network connections so eventually have multiple data-link addresses.
MAC address for data transfer in Wide Area Network WAN
MAC address is known as the physical address of a device. Every device which can connected with network have it’s own MAC address. MAC address is a 48 bit long hexadecimal combination. In a LAN the MAC address identified by the switch. The data forwarded on the basis of MAC address of connected devices. Some digits of the MAC address present the organization by OUI. OUI stands for Organizational Unique Identifier. Some digits of the MAC address present the merchant or vendor of the hardware. In a LAN the switch forward the data packets according to the MAC address of devices.
Network Layer Address for Wide Area Network WAN
Network layer address referred as virtual or logical addresses. Generally, the network layer address known as the network address or IP address. The network and internetworking works on IP address system of networking devices. The IP addresses are of two types IPv4 and IPv6. IP routing is depending on IP addresses of network. A router may be connected with multiple networks with its interfaces. The IP packets routed according to the network ID attached with it.
Local Area Network LAN basic
LAN connects the nodes with each other in a small area like office or building. A LAN allow to share the hardware and software resources with each other. LAN connects different devices with the help of switch. There is no concern of routing in a LAN. VLAN works to for security and break the broadcast domains.
Layer 2 devices connects different devices with each other. Wi-Fi switches also used to connect different devices with each other. Layer 2 protocols works in a LAN. CSMA/CD used for transmit and receive the data in a LAN. IP address can be allotted automatically by using a DHCP server in the LAN.
Different topology can be used to create a LAN. For example BUS, Star and Mesh etc. Bus topology created by using a common back bone for all devices. Bus topology is not in picture in today technology scenario. Ring topology connects the devices like hand to hand in a circle. In star topology the computers or devices are connected with a common switch. In mesh topology all devices connected with each other as shown in above diagram. After a small revision of LAN let’s go ahead on the WAN.
Wide Area Network WAN
Wide Area Network come into the picture when we need to transfer the data from one LAN to another LAN. In this case the LAN’s can be very far away from each other. Router works on layer 3 network layer and provides the IP routing. Multiple devices used for establish communication between two different LAN. Security concern is also important when we works with an open network. The different LAN may be geographical located.
The best example of WAN is internet which is used world wide. At home multiple devices connected with each other via WAP or Switch. All devices can also access the internet. Internet is open source for everyone in the world but there is another term come in mind which is Intranet. Intranet also works on internet but the access of LAN is limited for specific user. For example a big business company may be located at different locations. The main office of the company require to be access from its other branches located far away. This can be done by using some special protocols on internet like IPsec. Railways, Airways, Banks and Schools works on intranet and internet both.
Function of different devices in WAN
In the below diagram you can see how a ISP connects two different LAN. Modem connects the LAN with the ISP. Modem works like gateway to the whole devices of the LANs. The digital signal can not be send far away on a carrier. So we convert the digital signal into analog signal by using the modem. The converted analog signal can be transmit for a location far away. The ISP is responsible to carry the analog signal via different routers and gateways.
Firewall in wide area network WAN
The main task of firewall is to filter the incoming and outgoing data. Firewall uses for security concern. The filtering of data done according to the rules set by the network administrator in firewall. Firewall drop the data packets if it goes against the rule. The rules are generally port numbers allowed and not allowed. For example web service works on port 80 for HTTP. In this case only traffic with port 80 allowed to enter in the LAN else the packet drop by the firewall. Firewall is the main device uses to keep protected the network. Firewall is optional and come in both form hardware or software. Windows have its own firewall with the OS but less of us know how to use that. In a network that firewall can not be considered for protection of network.
Function of Routers in internetworking for Wide Area Network WAN
Consider a Network as shown in below figure. Router breaks up the broadcast domain. This network have two broadcast domains for each port of router. Computer A can communicate with computer B as both in same broadcast domain. Computer A send data for all nodes of its network. switch transmit the data from all ports. when router received the data. It will deny it. So computer C and D did not receive the data of computer A. If computer A want to send data for computer C or D then router will pass the data through it. I hope you understood the Importance of breaking up a broadcast domain.
Router can filter layer 3 (Network layer) information such as an IP address. Routers can do packet filtering via access lists. Router connects two or more networks by using logical addressing. Routers use routing table for logical addressing. Routing table also used for selection of best path for packets.
Layer 2 switches can not used for internetworking because all switch ports belongs to same broadcast domain. Switches used to overcome the problem of HUB. Switch forward only frames from one port to another port. Switching done in a router. Virtually switch also break the broadcast domain. this process called VLAN.
In case of internet the modem have built in routing facility. So no need to keep any router at home network. When we are going for Intranet router is must required for routing data and provide connectivity to private IP via public IP addresses. The configuration of routing in router done such as only our own data can be enter into own network. This is also another wall for security when someone send the fake data to our network.
Connection technique of Wide Area Network WAN
Many technologies used for Wide Area Network WAN. Technology depend on requirement basis. Many company needs only data sharing. These company needs low band width. Many company wants to share a lot of data among the peoples. These company need more bandwidth. Financial company needs security over the WAN. Some commercial companies like you-tube needs more bandwidth.
Connection technology may be telephone lines, radio wave, and optical fiber. Different data speed used as per requirement. 64 kbps is minimum requirement for a video transmission. LAN connected with Internet via Dial-up, ADSL, Wimax technology. WAN uses multi protocol label switching. Wireless WAN may uses cellular data networks, public Wi-Fi or satellite networks.
There are multiple technologies used for connectivity for wide area network. Each LAN required different bandwidth as per requirement. For example if only data required the bandwidth required less. For video conferencing or video streaming bandwidth required more than only for data. Generally the ISP provides telephone lines, fiber optic connectivity upto the modem in any LAN. The connection techniques are Dial up, ADSL, OFC, cellular data networks, Wimax and satellite networks etc.
In this article I describe the Wide Area Network WAN in details for CCNA 200-301 Exam. I assume you found this article helpful. For any query or suggestion you may drop a comment below or contact us. Your suggestions are always welcome.
