WAN connectivity comes into the play when your organization has to connect to the Internet or the branch offices. It plays an important role in today’s era because without WAN connection there is almost no business, we have to have use Internet to do the taks.
This is the simple diagram illustrating the WAN connectivity where you control the LAN and then Service Provider and Internet comes that you do not control. The router that gets us connected to the WAN is called Edge router. It could be a firewall or standard router whatever it is, it is called Edge router if it connects us to the WAN connection.
This is a DUAL WAN connection where you do not completely rely on one ISP and you have a back-up plan if one ISP goes down. In some case we use BGP in this scenario.
Hub & Spoke Topology
The Internet connection is not always considered WAN connection. There could be organization who only wants to connect its headquarter to branches. In this network only one central device is used for control and the device is called Hub, the other connected devices to the central device are called Spokes.
There you see the headquarter is in control and if any branch want to make communication to other branch it has to go through headquarter. This topology is used where security is more concerned than performance. With the central network traffic movement we can completely control the traffic flow and detect the threat as well.
Now if we want to connect to the Internet as well then we can connect the Internet router to the Headquarter router and then if Branch-1 wants to serve the Internet it has to go through the Headquarter.
Full Mesh Topology
This is the network infrastructure that is used for high availability. This topology requires more and more cables and the formula for this is N – 1 where N is the number of nodes.
We can also use the same topology using virtual cables via ISP.
This is how we create virtual links using ISP, we use frame relay or MPLS technology to make connection among our network using tunnels. The tunnel that is being used in this scenario is GRE which is not secure.
The above diagram is showing another tunnel which is more secure and it covers security triad CIA to ensure you have security when connected to the Internet.
Prerequisites for 200-301
200-301 is a single exam, consisting of about 120 questions. It covers a wide range of topics, such as routing and switching, security, wireless networking, and even some programming concepts. As with other Cisco certifications, you can take it at any of the Pearson VUE certification centers.
The recommended training program that can be taken at a Cisco academy is called Implementing and Administering Cisco Solutions (CCNA). The successful completion of a training course will get you a training badge.
Full Version 200-301 Dumps