Network Address Planning

The Internet Protocol especially IPv4 is now being used for almost all business and personal digital communications, from data centers to telephones to industrial control systems. Now, the Internet protocols have been adopted for 3G, 4G, and 4G LTE mobile systems and are a serious enabler for the Internet of Things. This time billions of IP addresses are being used in the world.

The network address planning is a documentation usually developed by the network administrator and network engineers to show how the IP addresses will be distributed among the network devices based on the network architecture or topology in a way that supports the required services.  There are multiple levels of network address planning are required.

Setting up network subnets requires a check of both the needs of an organization’s network usage and how the subnets will be organized. Performing a network address planning, a study is the starting point.

Before you effectively implement an IP network infrastructure, you have to identify your IP addressing requirements. The address plan includes determining the needs of each subnet.Some of the things that you need to consider include:

• Will you need a public or private IP address range on the internal network?


• Does the network require multiple subnets?


• How many hosts per subnet?


• How will host addresses be assigned, static or automatic?


• Which hosts will require static IP addresses?


• Which hosts can use DHCP for obtaining their addressing information?

The subnet size involves planning the number of hosts that will require IP host addresses in each subnet of the subdivided private network.

For example, in an organization network design, you may consider how many hosts are needed in the 

 

Management LAN, Finance LAN, Sales LAN, HR LAN and Engineer department LAN. In a home network, a consideration may be done by the number of hosts.

We already discussed the private IP address range in previous lessons. The use of private addresses on a LAN is the selection of the network administrator and desires careful to be sure that sufficient host addresses will be available for the currently known hosts and for future expansion. The ranges of private IP address for different classes are following:

Class-A

10.0.0.0 - 10.255.255.255 with a subnet mask of 255.0.0.0 or /8

Class-B

172.16.0.0 - 172.31.255.255 with a subnet mask of 255.240.0.0 or /12

Class-C

192.168.0.0 - 192.168.255.255 with a subnet mask of 255.255.0.0 or /16

You should know the IP address requirements will determine the range or ranges of host addresses you implement.

Knowing IP address requirement is necessary for network administrator for determine the host addresses. Subnetting the chosen private IP address space will give the host addresses to cover your network needs. Public addresses are typically allocated from a service provider. For subnetting of public IP address the same principles would apply, this is the responsibility of the service provider.

Planning to Address the Network

The four primary segments for planning address allocation are Management LAN, Finance LAN, Sales LAN, HR LAN and Engineer department LAN in our example.

To Preventing the IP address conflict required each host in an internetwork must have a unique address. An IP address conflict resulting in access issues for both hosts. Without the proper network address planning and documentation, an address could be assigned to more than one host.

Some hosts like servers provide and share resource to other hosts. The IP address assigned to a server can be used to control access to that server. If the address is randomly assigned and not static, controlling access is more difficult.

Monitoring performance and security of hosts means network traffic is examined for source IP addresses that are generating or receiving too many packets. The proper network address planning of network addressing, problematic network devices can easily be found.

Assigning Addresses to Network Devices

There are different types of devices can be found in the network that requires IP addresses including:

• End-user clients– Many network administrators allocate addresses automatically using DHCP to their end-user clients. The automatic IP address assignment reduces the load on network support staff and also eliminates the IP address assignment errors. The DHCP has only leased the IP addresses for a period of time. Changing the subnetting scheme is easy and the administrator just needs to reconfigure the DHCP server, and the clients must renew their IP addresses.


• Servers and peripherals– The servers provide service and share resource to other hosts inside the network and also outside the network. The IP address assigned to a server can be used to control access to that server. So the must be static to provide service and share the resources. Use a consistent numbering system for these devices.


• Servers that are accessible from the Internet–Some servers must be made available to the remote users from the internet. In the major cases, these servers are assigned private IP addresses internally, and the router at the edge of the network must be configured to translate the internal address into a public IP address.


• Intermediary network devices– These network devices are assigned addresses for network management, monitoring, and security. These devices should have statically assigned IP addresses.


• Gateway- Routers have an IP address assigned to every interface which serves as the gateway for the hosts in that network. Typically, the router interface uses both the lowest or highest address in the network.