Most radio station networks that I have seen are divided along several different lines based on functions. These functions are:<\/p>\n\n\n\n
\n
Office network; E-mail, document storage and retrieval, printing, applications like traffic and billing, promotions, music scheduling, and so on<\/li>\n\n\n\n
Automation network; automation servers, workstations, and audio editing machines used in production<\/li>\n\n\n\n
Audio over IP (AOIP) network; any AOIP consoles, devices, or STL equipment<\/li>\n\n\n\n
Voice over IP (VOIP); telephone system<\/li>\n\n\n\n
Wireless LAN; WLAN or WIFI<\/li>\n<\/ul>\n\n\n\n
It is helpful, then, to segment the network into different broadcast domains to reduce the congestion on any one network.\u00a0 That is where a good subnetting scheme can be beneficial.\u00a0 Subnets segment the network into smaller parts, reducing the amount of broadcast traffic and increasing network speeds by reducing MAC table sizes, and thus switching and lookup times.\u00a0 They also can secure certain areas of the network from the outside or other subnets, adding a level of security.\u00a0 For example, it may not be a good idea for automation computers or AOIP consoles to have access to the internet.\u00a0 Certain functions in routers and switches can be enabled for that added security.<\/p>\n\n\n\n
It is also important to efficiently use IP addresses in a large organization where WANs are used. The better the subnetting scheme, the easier it is to understand and the better it performs. Avoiding or reducing discontiguous networks is key to efficient and speedy routing. That is an important consideration where applications like AOIP and VOIP are concerned<\/p>\n\n\n\n
To really understand subnetting, it must be broken down into fundamental parts.\u00a0 This pertains to IPv4, which will likely remain in use for quite some time.\u00a0 The big chart, class B networks:<\/p>\n\n\n\n
The terms “Class B” and “Class C” networks are outdated. Basically, I broke the chart up along a classful boundary to make it easier to read.<\/p>\n\n\n\n
An IP v4 address consists of four octets of binary data. A common example is 192.168.1.154, which in binary numbers looks like this: 11000000.10101000.00000001.11111110. It is converted to base ten numbers (dotted decimal) so that we humans can deal with it. A typical subnet mask seen in many office networks is 255.255.255.0, which in binary looks like this: 11111111.11111111.11111111.00000000. When a router receives a packet, it does something called an “ANDing process.” When a router ANDs, it overlays the subnet mask on the network address and uses the following function: 1+1 = 1, 1+0 = 0 and 0+0 = 0. Thus, in the above example, a router AND would look like this:<\/p>\n\n\n\n
The subnet mask is telling the router to ignore the last octet, thus saving a bit of time and processing power. It may seem very small and insignificant. When considering that routers make sometimes hundreds or thousands of routing decisions in a second, even a small bit of work reduction adds up quickly. Subnet masks allow routers to look at only the layer three network address, ignoring the host portion. This takes advantage of IPs inherent hierarchical addressing system and speeds the process of routing to the proper destination.<\/p>\n\n\n\n
![\"IPv4](\"https:\/\/www.engineeringradio.us\/blog\/wp-content\/uploads\/2013\/01\/Subnet_Chart-479x600.jpg\")
<\/a>![\"Radio](\"https:\/\/www.engineeringradio.us\/blog\/wp-content\/uploads\/2013\/01\/broadcast-facility-converge-650x438.jpg\")