Title: TCP/IP and Subnets
Course: 2016FA-MCO-110-401 > Section: Module 9: Networking

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The TCP/IP Model

TCP/IP is the suite of communication protocols that are used as the standard for transmitting data over networks. It is the protocol on which the Internet is based. The Transmission Control Protocol is responsible for the creation of multiple packets from a single file for transfer across a network as well as reassembling the file at the destination. It is also the Internet Protocol which handles the addressing of the generated packets. These two protocols work together to ensure the proper transfer and receipt of the millions of terabytes of data transferred across the Internet daily.

IP Addresses

IP Addresses are unique numerical labels assigned to individual devices that are a part of a computer network. It is through use of this address that data can be transmitted and received over a network. The addresses of both the transmitting and receiving devices are contained within data packets. This ensures that the data reaches the correct destination as well as allows for confirmation to the transmitting device of receipt. IP addresses can be public or private which determines if the device is accessible through the larger public network. The majority of IP addresses currently adhere to the IPv4 standard with future plans for the widespread deployment of the updated IPv6 standard. The primary driving factor for the adoption of the IPv6 standard is the continued proliferation of connected devices will eventually cause an adoption of all available addresses, preventing the assignment of any new devices. IPv6, being a much more robust protocol, will provide the needed address range to accommodate all devices for the foreseeable future.

IP Address Classes

To prevent IP conflicts, certain ranges of IPs are reserved for private use. This means that these ranges of IPs are not routed publicly and are specifically for private internal network use only. Networks using these IPs are not visible to the Internet without use of a gateway device (modem). These networks are also governed by a class structure and are as follows:

- Class A: IP Address 10.0.0.0 through 10.255.255.255.
- Class B: IP address 172.16.0.0 through 172.31.255.255
- Class C: IP address 192.168.0.0 through 192.168.255.255.

The Private Address space is arguably the most often reused range of IP addresses as it is possible for two different organizations to use the exact same range of addresses since their networks are not connected. This also helps to prevent the depletion of publicly available addresses.

Subnets

A Subnet, or Subnetwork, is a portion of a network that shares a common address component. Subnets allow the creation of multiple logical networks within a Class of IP addresses. This becomes a necessary means of managing a larger network containing many devices (nodes), as it allows the efficient allocation of addresses. This has the effect of improving network performance as devices within a specific subnet will only have access to the portions of the network allocated, keeping unnecessary traffic to a minimum.

Subnet Masks

Once a network reaches a level of complexity requiring subnets, Subnet Masks are used as the method by which an IP address is assigned to a specific subnet. The subnet mask divides the IP address into a network address and a host address. A portion of the host address is utilized to identify to which subnet it belongs. Checking your extended network information will provide your current subnet.

Example below:
192.168.1.1 (IP Address)
255.255.255.0 (Subnet Mask)

Subnet calculation is one of the more complicated parts of complex network configuration. So much so, that there are many programs and websites dedicated specifically to the calculation of subnet addresses.

Objectives met:
- C9
- 9.4
- 9.5
- 9.6