Subnets

 Ip Subnetting is an extremely critical subjet for any IP network engineer to understand. But often times
it is difficult to grasp. Individuals often need time and practice to grasp the concepts. Students often struggle with the because it wasn't explained to them in a clear way.
 Ip Address is assigning  an address (Unique Identifier) to a single device on an IP network. This address
is a 32 bit number which is often too large for the need. This is when the network can be broken down.
 Ip Address are broken into Classes to keep this managable. You have Class A, B, and C. The difference

is the number of hosts that each network can have.
  Another concept is that there are Private and Public Internet addresses. The Private addresses are usually behind a firewall and router and that router typically preforms NAT (network Address Translation). NAT
is needed because private IP addresses are nonroutable across the public Internet.
 

Vlans

VLAN's exists when multiple devices are grouped together and function as a separate entity. This is
mainly for the purposes of maintaining security between groups of the network. On the whole, a VLAN is very similar to that of a physical LAN. Their main difference is VLANs capability to group end stations together without the requirement of being located on the same network switch. In VLAN, configuration of the network can be done via software extensively. Basically, VLANs are used at layer 2 to break up broadcast domains.
 Each VLAN is considered as a separate entity and it can only reach another VLAN through a router. You can use a single network with VLANs but when one network goes down for some reason, the entire logical network is concerned. VLANs are very useful when an IT professional (system or network admin) wants to group organization departments for better work performance, less traffic, and more efficiency.

A subnet is essentially a group of IP addresses. Any particular address can reach any address without using any routing device if they belong to the same subnet. Now, if the address you want to reach is outside of your subnet, then just like in VLANs, you will have to go through a router. Subnet is at layer 3 (IP), wherein IP addresses belong.

Subnet 2

WANs

  
  WANs often connect multiple smaller networks, such as local area networks (LANs) or metro area networks (MANs).  The most popular connection means is through the Internet. . Some segments of the Internet, like VPN-based extranet, are also WANs in themselves. Finally, many WANs for corporations or research networks utilize dedicated lines or other connection means to connect these entire WANs.
  WANs generally utilize different and much more expensive networking equipment than do LANs.

 While LAN and WAN are by far the most popular network types mentioned, you may also commonly see references to these others:

• Wireless Local Area Network - a LAN based on WiFi wireless network technology
• Metropolitan Area Network - a network spanning a physical area larger than a LAN but smaller than a WAN, such as a city. A MAN is typically owned an operated by a single entity such as a government body or large corporation.
• Campus Area Network - a network spanning multiple LANs but smaller than a MAN, such as on a university or local business campus.
• Storage Area Network - connects servers to data storage devices through a technology like Fibre Channel.
• System Area Network - links high-performance computers with high-speed connections in a cluster configuration. Also known as Cluster Area Network.